Perhaps you should try some spelling variations:
hoc viet » hoc hien
truc van » truc va, thuc van, truc ban
tang van » dang van, hoang van, trong van
su sach » so sach, vu sach
tang ma » mang may
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
anh vi » hanh vi, anh va, anh ve
vi hoc » li hoc, va hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y ((tang ma) or (tang van)) hoi. hieu ve cam ((truc van) or (thuc vat)) anh vi hoc viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((tang ma) OR (tang van)) hoi. hieu ve cam ((truc van) OR (thuc vat)) anh vi hoc viet.
• Adding a wildcard symbol may retrieve word variants: su sach y ((tang ma) or (tang van)) hoi. hieu ve cam ((truc van) or (thuc vat)) anh vi hoc viet*.