Perhaps you should try some spelling variations:
thien van » thi van
nam thuc » nam thuoc, am thuc, nam thu
cau treo » cau theo, cau tren, cau triet
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren
x hoi » xa hoi, o hoi, x ho

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 x hoi. ((lieu va) or (thien van)) nam thuc va hanh vi ((cuu tre) OR (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang x hoi. ((lieu va) OR (thien van)) nam thuc va hanh vi ((cuu tre) OR (cau treo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang x hoi. ((lieu va) or (thien van)) nam thuc va hanh vi ((cuu tre) OR (cau treo))".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang x hoi. ((lieu va) or (thien van)) nam thuc va hanh vi ((cuu tre) OR (cau treo))*.