Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
te sach » toc sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
tu truc » tu thuoc, tu trung
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua

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