Perhaps you should try some spelling variations:
chat trung » chat trong, ha trung, cua trung
thu sach » tu sach, thuat sach, thuoc sach
hieu cac » hieu luc, hieu va, hieu van
cac chat » cao chat, cac thuat, cac nha
trung va » truong va, trang va, trung ha
vanh dai » vanh tai, lanh dao, van dao
cau treo » cau theo, cau tren, cau triet
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
van dai » van dao, van hai, can dai
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang xa hoi. hieu cac chat trung va ((vanh dai) OR (van dai)) ((cua tre) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang xa hoi. hieu cac chat trung va ((vanh dai) OR (van dai)) ((cua tre) OR (cau treo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang xa hoi. hieu cac chat trung va ((vanh dai) OR (van dai)) ((cua tre) or (cau treo))".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang xa hoi. hieu cac chat trung va ((vanh dai) OR (van dai)) ((cua tre) or (cau treo))*.