With the tech cards that give you a certain number of culture tokens in exchange for resource tokens eg incense

How many times in one turn can you use that card to obtain the tokens.

Eg. If I have 5 incense and a tech card that grants me 7 culture tokens for each incense token can I theoretically obtain 35 culture tokens in on turn

You can use any tech resource ability only once per turn. Check rulebook p.22 (last paragraph of left column).

Thanks.