Perhaps you should try some spelling variations:
hoc viet » hoc hien
sach ky » sac ky, sach y, sach ty
va dinh » van dinh, va kinh, va tinh
va danh » va dan, va hanh, dia danh
so sach » so sanh, bo sach, co sach
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
ve cac » vien cac
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: so sach ky tang xa hoi. hieu ((ve cac) or (va cac)) tuc ((va danh) or (va dinh)) vi hoc viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky tang xa hoi. hieu ((ve cac) OR (va cac)) tuc ((va danh) OR (va dinh)) vi hoc viet.
• Adding a wildcard symbol may retrieve word variants: so sach ky tang xa hoi. hieu ((ve cac) or (va cac)) tuc ((va danh) or (va dinh)) vi hoc viet*.