Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hoc sach » hoc cac, hoc anh
hieu van » hieu va, thien van, lieu va
van chat » cao chat
chat tuc » chat xuc, luat tuc, chat huu
danh sai » dung sai, danh bat, danh dau
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
va danh » va dinh, va dan, va hanh
sai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
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) OR (hoc sinh)))) ky tang xa hoi. hieu van chat tuc va danh sai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (((hoc sach) OR (hoc sinh)))) ky tang xa hoi. hieu van chat tuc va danh sai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (((hoc sach) OR (hoc sinh)))) ky tang xa hoi. hieu van chat tuc va danh sai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (((hoc sach) OR (hoc sinh)))) ky tang xa hoi. hieu van chat tuc va danh sai cua tre*.