Perhaps you should try some spelling variations:
hoc viet » hoc hien
sach tin » sach tien, sach kinh, sach tren
tin mang » tin nang, ninh mang, tien manh
thuc van » thuc vat, thuc dan, thuc va
tuc van » truc van, tuc va, duc van
su sach » so sach, vu sach
may hoi » may thoi, tay hoi, mai hoi
va cam » va cham, va cac, va cao
ve cam » ve cham, ve cac, ve cai
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 tin mang may hoi. hieu ((ve cam) or (va cam)) ((tuc van) or (thuc van)) hanh vi hoc viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach tin mang may hoi. hieu ((ve cam) OR (va cam)) ((tuc van) OR (thuc van)) hanh vi hoc viet.
• Adding a wildcard symbol may retrieve word variants: su sach tin mang may hoi. hieu ((ve cam) or (va cam)) ((tuc van) or (thuc van)) hanh vi hoc viet*.