Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
tang van » dang van, hoang van, trong van
hanh vu » hanh vi, hanh va, hanh tu
va hanh » van hanh, va thanh, va danh
van hoc » van hoa
ty tang » tay tang, ty xang, ty hang
so sanh » do sanh
cam lo » cam ly, cam o
nam lo » nam bo, nam so, nam co
vu va » vu van, tu va, su va
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc sach) or (so sanh)) ty tang van hoc. hieu qua ((cam lo) or (nam lo)) va hanh vu va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (so sanh)) ty tang van hoc. hieu qua ((cam lo) OR (nam lo)) va hanh vu va thiet.
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (so sanh)) ty tang van hoc. hieu qua ((cam lo) or (nam lo)) va hanh vu va thiet*.