Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
cham duc » pham duc, cham soc, pham duy
hanh lai » hanh lam, hanh tai, thanh lap
ty tang » tay tang, ty xang, ty hang
tang ma » mang may, tang van
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
va hanh » van hanh, va thanh, va danh
ma hoi » mai hoi, xa hoi, ma hoa
lai va » loai va, mai va, dai 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: ((thu hoach) or (thuat sach)) ty tang ma hoi. hieu ve cham duc va hanh lai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu hoach) OR (thuat sach)) ty tang ma hoi. hieu ve cham duc va hanh lai va thiet.
• Adding a wildcard symbol may retrieve word variants: ((thu hoach) or (thuat sach)) ty tang ma hoi. hieu ve cham duc va hanh lai va thiet*.