Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
lam thue » nam thue, luat thue, lam thuoc
hang doi » hang di, hang loi, huong doi
cam thue » cam thu, nam thue, cam thiet
hieu va » lieu va
sach tu » sach thu, cach tu, sach ty
nang xa » nang x, lang xa, nang ma
va hang » van hang, va nang, va lang
tu nang » tru nang, tu nong, tu nano
doi cuu » doi cua, doi cuoc
cuu tre » cua tre, cau tren, cau treo

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 tu nang xa hoi. ((hieu va) or (hieu qua)) ((cam thue) OR (lam thue)) va hang doi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach tu nang xa hoi. ((hieu va) OR (hieu qua)) ((cam thue) OR (lam thue)) va hang doi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach tu nang xa hoi. ((hieu va) or (hieu qua)) ((cam thue) OR (lam thue)) va hang doi cuu tre".
• Adding a wildcard symbol may retrieve word variants: toc sach tu nang xa hoi. ((hieu va) or (hieu qua)) ((cam thue) OR (lam thue)) va hang doi cuu tre*.