Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh vai » hanh vi, hanh va, hanh tai
hau truc » hang truc, hoc truc, tu truc
te sach » toc sach
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
cua tre » cua te, cuu tre, cua triet

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

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