Perhaps you should try some spelling variations:
sach tham » sach nha
sach thu » sach thue, sach thieu, cach thuc
cac tac » cac toc, cac bac, cac dac
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
tac va » tac da, tac xa, tuc va
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu ((sach thu) or (sach tham)) lang xa hoi. hieu va cac tac va dan vi ((cua te) or (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu ((sach thu) OR (sach tham)) lang xa hoi. hieu va cac tac va dan vi ((cua te) OR (cua tu)).
• Adding a wildcard symbol may retrieve word variants: vu ((sach thu) or (sach tham)) lang xa hoi. hieu va cac tac va dan vi ((cua te) or (cua tu))*.