Perhaps you should try some spelling variations:
hanh vai » hanh vi, hanh va, hanh tai
hieu van » hieu va, thien van, lieu va
truc va » thuc va, thuc vat, trung va
cua tre » cua te, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
van cau » van dau, van hau, van chat
sach ky » sac ky, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
cuu tre » cau tren, cau treo

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) or (sach y)) nang xa hoi. hieu van cau truc va hanh vai ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang xa hoi. hieu van cau truc va hanh vai ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach y)) nang xa hoi. hieu van cau truc va hanh vai ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach y)) nang xa hoi. hieu van cau truc va hanh vai ((cua tre) OR (cuu tre))*.