Perhaps you should try some spelling variations:
cao hoi » cau hoi, co hoi, cao hoc
van cam » van lam, van cau, van dam
sach ly » sach y, sach lo, sach ty
truc va » thuc va, thuc vat, trung va
va danh » va dinh, va dan, va hanh
ly nang » ky nang, ly hang, ly vang
hai cau » hai chau, hai hau, hoi cau
hai chu » hai chau, hoi chu, hai chi
su sach » so sach, vu sach

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 ly nang cao hoi. hieu ((van cam) or (van nam)) truc va danh ((hai cau) OR (hai chu)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly nang cao hoi. hieu ((van cam) OR (van nam)) truc va danh ((hai cau) OR (hai chu)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ly nang cao hoi. hieu ((van cam) or (van nam)) truc va danh ((hai cau) OR (hai chu)) tren".
• Adding a wildcard symbol may retrieve word variants: su sach ly nang cao hoi. hieu ((van cam) or (van nam)) truc va danh ((hai cau) OR (hai chu)) tren*.