Difference between seek and seek for?

English as a Second Language English Vocabulary, Grammar and Idioms
1

And what is the difference between seek and seek for?

2

Seek means look for both in the literal sense: The police are seeking information … and in the figurative sense: Religions are always seeking the truth about life and death. Seek for is not used very often - in fact I would never use it and would prefer search for.

3

How to explain this sentence “Yet a great many processes depending on such research are sought for with complete secrecy until the stage at which patents can be taken out.”

4

Does it help to replace ‘are sought for’ with one of these, Xupeng?

are looked for
are searched out

5

Again, do ‘search for’ and ‘search out’ mean the same in this context?

6

‘Search out’ suggests a more determined approach than ‘search for’.

7

Thanks, Alan.