Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dinh cuu » dinh chi
hieu van » hieu va, thien van, lieu va
tang xa » trang xa, tang ma, lang xa
hieu ve » hieu va
sach ky » sac ky, sach y, sach ty
cam duc » cam xuc, cao duc, pham duc
ky tang » ky nang, ky dang, kho tang
va dan » ca dan, va dao, va dau
di cuu » di cau, 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: hoc sach ky tang xa hoi. ((hieu ve) or (hieu van)) cam duc va dan ((di cuu) OR (dinh cuu)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ky tang xa hoi. ((hieu ve) OR (hieu van)) cam duc va dan ((di cuu) OR (dinh cuu)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ky tang xa hoi. ((hieu ve) or (hieu van)) cam duc va dan ((di cuu) OR (dinh cuu)) tre".
• Adding a wildcard symbol may retrieve word variants: hoc sach ky tang xa hoi. ((hieu ve) or (hieu van)) cam duc va dan ((di cuu) OR (dinh cuu)) tre*.