Perhaps you should try some spelling variations:
sang thi » dang thi, sang tai, tang thi
hieu van » thien van, lieu va, hieu ve
su sach » so sach, vu sach
ky sang » ky nang, ky dang, ky tang
thi hai » thi mai, thi hanh
vai cua » dai cua, hai cua, lai cua
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
cam luc » cam xuc, cau luc
va dinh » van dinh, va kinh, va tinh
vi cua » di cua
luc va » duc va, tuc va, loc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky sang thi hai. ((hieu van) or (hieu va)) cam luc va dinh ((vi cua) OR (vai cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky sang thi hai. ((hieu van) OR (hieu va)) cam luc va dinh ((vi cua) OR (vai cua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky sang thi hai. ((hieu van) or (hieu va)) cam luc va dinh ((vi cua) OR (vai cua)) te".
• Adding a wildcard symbol may retrieve word variants: su sach ky sang thi hai. ((hieu van) or (hieu va)) cam luc va dinh ((vi cua) OR (vai cua)) te*.