Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
dang hai » dang khai, hang hai, dung hai
hieu van » hieu va, thien van, lieu va
thac toc » cac toc, thac cac, thi toc
sach tu » sach thu, cach tu, sach ty
dan hai » doan hai, dan khai, van hai
tu sach » thu sach, su sach, te sach
hac tuc » thai tuc
nang xa » nang x, lang xa, nang ma
tu nang » tru nang, tu nong, tu nano

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach tu nang xa hoi. hieu van ((hac tuc) OR (thac toc)) va ((dan hai) or (dang hai)) cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu nang xa hoi. hieu van ((hac tuc) OR (thac toc)) va ((dan hai) OR (dang hai)) cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tu nang xa hoi. hieu van ((hac tuc) OR (thac toc)) va ((dan hai) or (dang hai)) cua triet".
• Adding a wildcard symbol may retrieve word variants: tu sach tu nang xa hoi. hieu van ((hac tuc) OR (thac toc)) va ((dan hai) or (dang hai)) cua triet*.