Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hoc thuc » hoc huu
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
hoc tuc » hoc truc, hoc tu, hoc duc
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.

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