Use landsat   data and it is freely available.

https://earthexplorer.usgs.gov/

THIS CONTAIN HUGE DATA SET FROM 1975 TO 2017.

Thank you very much for your answer !

SEE THIS LINK ALSO

http://gisgeography.com/free-satellite-imagery-data-list/

As Firoz has said, try the landsat 8

Landsat  data is the best option and it is free

http://glovis.usgs.gov/

https://earthexplorer.usgs.gov/;

http://glcf.umd.edu/data/landsat/

Thi has Data from 1972 TO 2017 for all areas.

Methods to process data and analysis (applications) can be seen at 

https://www.researchgate.net/publication/230738894_Peri-Urban_to_Urban_Landscape_Patterns_Elucidation_through_Spatial_Metrics

https://www.researchgate.net/publication/260192602_Land_Surface_Temperature_Responses_to_Land_Use_Land_Cover_Dynamics

https://www.researchgate.net/publication/260908980_Spatio-temporal_dynamics_along_the_terrain_gradient_of_diverse_landscape

https://www.researchgate.net/publication/301609558_Geospatial_analysis_of_forest_fragmentation_in_Uttara_Kannada_District_India

Article Peri-Urban to Urban Landscape Patterns Elucidation through S...

Article Land Surface Temperature Responses to Land Use Land Cover Dynamics

Article Spatio-temporal dynamics along the terrain gradient of diver...

Article Geospatial analysis of forest fragmentation in Uttara Kannad...

The straight forward choice will be to use Landsat images.  But all remote sensing projects are objective driven.  Depending on the level of precision you require, it will determine the data you go in for.  So my advice will be that you have to be very clear in your mind what you want to achieve in the end. Landsat images have spatial resolution of 30m and so if your work is not for very detailed analysis then you can use it.

Thank you a lot for your answers ! 

Landsat 8 and Sentinel 2a are good for land use pattern in urban areas. They are free. I think Sentinel 2a is better than Landsat 8 because it has spectral and spatial resolution batter than landsat.

You can download Sentinel 2a with this link: https://scihub.copernicus.eu/ 

Hello!

Landsat and Sentinel

Source: Earthexplorer

Dear friend,i would like to inform you that choosing satellite image depends on the purpose of the study, if you're studying urban areas (areas - distance.....etc) so it should be used satellite images with high spatial resolution suh as Landsat 8 and Sentinel 2a they are good for land use pattern in urban areas and vice versa.

But if the purpose of your study, the study of climate elements in urban areas such as clouds or the Earth's temperature, in this case you must use satellite images with high spectral resolution (36 band) such as MODIS, and time can be overlooked spatial accuracy.

Regards

I agree with statement that Landsat is the best one due to its availability and time coverage! But the choice of image highly depends on the purpose or task! The Landsat images spatial resolution (pixel size 15-30 meter) sometimes is not enough, when you study small cities, or plan any other detailed research. Sentinel-2 has better spatial resolution (10-20 m), but it is "very young" - not much Earth area was covered by this satellite. There are many images with very high resolution (very detailed) which are represented at WWW-map services: eg. https://www.google.com/maps (Earth view), yandex.ru/maps (Satellite)... etc. I like to use Google Earth for my students-geographers (https://www.google.com/earth/ - need to be installed), as it contains new high resolution images for many places on the Earth, although they are mostly "pictures" - not suitable for computer analysis

LADSAT is the best because images are available beginning from the 1970s

Combination of optical data along with High incidence angle like polarized RADAR data acquired during summer season is probably the best data for Urban studies. Please go through one of my research publications using the link provided with the answer:

Comparative evaluation of potential of optical and SAR data for the detection of human settlements using digital classification (2006),

HS Srivastava, P Patel, Y Sharma, RR Navalgund - International Journal of Geoinformatics, Vol. 02, No. 03, pp. 21-28.

http://s3.amazonaws.com/academia.edu.documents/37092430/WMHuman_Settlements_2006_IJG_23_21-28.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&Expires=1486391252&Signature=KJpoJDr64fZ2RSDLyipM0lsparA%3D&response-content-disposition=inline%3B%20filename%3DComparative_evaluation_of_potential_of_o.pdf

Right with regards to the type image data you need is based on the region you are located is that Africa or any part of the world is depend on the acquisition period a good example of sub-Sahara Africa a dry season is best time for identifications and other image interpretations of land use and land cover change and the good data for that is QUICK BIRD  very high resolution image other 30 meter resolutions are land sat is free data from GLOVIS with ERDAS Imagine you can be able to classified land use and land cover in supervise classifications analysis of images of two different date data for change detection's with an accuracy assessments.   

Landsat and Sentinel for operational are the two free sources for a medium resolution (60 to 10 meters) approach.

Lower resolution (< 10m) come with a price

For urban studies you can use: Global Human Settlement Layer (derived  from Landsat multitemporal), European Settlement Map (derived from Spot 5/6) or Global Urban Footprint (TerraSAR-X) datasets.

http://ghsl.jrc.ec.europa.eu/

http://land.copernicus.eu/pan-european/GHSL/EU%20GHSL%202014

Dont know if the global urban footrpint is available online.

See its depends on your objective of study. If you want to study building level study then you need high resolution data but if you want to study on urban expatiation or regional level study then course resolutions data is needed.   If you mention more clearly about your study then I can help you more.

I've seen Landsat and Sentinel both mentioned, and both are good options, but it also depends on where you will be conducting the analysis.

In many higher-income countries, such as the US, there is freely available high-resolution aerial photography, which can often include a near-infrared band, which is useful for vegetation classification.

If you're interested in doing LCLUC research in US urban areas, check out :

https://www.fsa.usda.gov/programs-and-services/aerial-photography/imagery-programs/naip-imagery/

More generally:

http://gisgeography.com/free-satellite-imagery-data-list/

Thank you all for your answers.

Actually, I want to analyse the changes in land-use patterns in some urban areas from Romania between the years 1990 and 2015...

Earth explorer - you can find large naumeber of landsat and other satellite images