Perhaps you should try some spelling variations:
hoc viet » hoc hien
nam thuc » nam thuoc, am thuc, nam thu
san viet » gian viet, anh viet
dinh ve » dinh ket, dinh van
danh vi » hanh vi, dinh vi, danh di
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
thuc va » thuc vat, thuc dan, thuc day
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
va nam » van nam, ha nam, va nay
ma hoi » mai hoi, xa hoi, ma hoa

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 ky nang ma hoi. hieu va nam thuc va ((danh vi) or (dinh ve)) ((san viet) or (hoc viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ma hoi. hieu va nam thuc va ((danh vi) OR (dinh ve)) ((san viet) OR (hoc viet)).
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ma hoi. hieu va nam thuc va ((danh vi) or (dinh ve)) ((san viet) or (hoc viet))*.