Perhaps you should try some spelling variations:
su sach » so sach, vu sach
tang ma » mang may, tang van
qua cam » qua cham, qua cac, qua ca
truc va » thuc vat, trung va
thuc va » thuc vat, thuc dan, thuc day
danh vu » danh tu, anh vu, danh du
y tang » ky tang, 6 tang, 7 tang
ma hoi » mai hoi, xa hoi, ma hoa
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: su sach y tang ma hoi. hieu qua cam ((truc va) or (thuc va)) danh vu va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y tang ma hoi. hieu qua cam ((truc va) OR (thuc va)) danh vu va thiet.
• Adding a wildcard symbol may retrieve word variants: su sach y tang ma hoi. hieu qua cam ((truc va) or (thuc va)) danh vu va thiet*.