Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
hoc sach » hoc sinh, hoc cac, hoc anh
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
van cau » van dau, van hau, van chat
cau tuc » cau truc, cau tu, cau luc
tai cua » thai cua, tai cuc, dai cua
tuc va » thuc va, truc va, tuc xa

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

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