look for a needle in a haystack

Translations
искать иголку в стоге сена
He is trying to look for a needle in a haystack by finding the right document in this mess.
Он пытается искать иголку в стоге сена, находя нужный документ в этом беспорядке.
Definitions
To search for something that is extremely difficult or nearly impossible to find, often because it is hidden among many other things.
Words
look

verb
искать
for

preposition
для
a

article or possessive pronoun
неопределённый артикль
needle

noun
иголка
in

preposition
в
a

article or possessive pronoun
неопределённый артикль
haystack

noun
стог сена