Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
hanh vai » hanh vi, hanh va, hanh tai
cua viet » ca viet, hoa viet, cua dieu
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu vi » hieu voi, hieu va, hieu ve
thuc va » thuc dan, thuc day
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: doc sach ky nang ma hoi. hieu vi pham ((thuc va) OR (thuc vat)) hanh vai ((cua viet) or (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky nang ma hoi. hieu vi pham ((thuc va) OR (thuc vat)) hanh vai ((cua viet) OR (cua vat)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ky nang ma hoi. hieu vi pham ((thuc va) OR (thuc vat)) hanh vai ((cua viet) or (cua vat))".
• Adding a wildcard symbol may retrieve word variants: doc sach ky nang ma hoi. hieu vi pham ((thuc va) OR (thuc vat)) hanh vai ((cua viet) or (cua vat))*.