The phrase "substantial support" is correct and usable in written English. You can use it when referring to a large amount of something, whether it be money, help, resources, or anything else that can be given in large amounts. Example sentence: The program received substantial support from local businesses.
The IPCC report provides substantial support for this argument.
Trump has already lost substantial support among the GOP.
There should be substantial support from the Stamford community.
Few mosques offer substantial support to new converts.
Still, Illumina appeared to have gained substantial support.
Let's hope the 'culture' secretary will confound expectations and provide substantial support.
Mr. bin Laden has substantial support in Yemen and Saudi Arabia.
When I feel like I can't trust my brain 100%, Ludwig really comes in handy. It makes me translate and proofread faster and my output more reliable.
Claudia Letizia
Head Translator and Proofreader @ organictranslations.eu