Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
thu nang » thi nang, thu hang, thu bang
hieu cua » hieu qua, dieu cua, bieu cua
cua nhan » ca nhan, cua ngan, cua nha
nhan tuc » nhan thuc, nhan luc, nhanh thuc
te sach » toc sach
han tai » hang tai, nhan tai, van tai
cua tuc » cua duc, cua thuoc, luat tuc
tuc va » thuc va, truc va, tuc xa
va han » va phan, van han, va hanh
cua tu » cua su, cua cu, cua te

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach thu nang ((xa hoi) or (x ho)). hieu cua nhan tuc va han tai ((cua tu) OR (cua tuc))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach thu nang ((xa hoi) OR (x ho)). hieu cua nhan tuc va han tai ((cua tu) OR (cua tuc)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach thu nang ((xa hoi) or (x ho)). hieu cua nhan tuc va han tai ((cua tu) OR (cua tuc))".
• Adding a wildcard symbol may retrieve word variants: te sach thu nang ((xa hoi) or (x ho)). hieu cua nhan tuc va han tai ((cua tu) OR (cua tuc))*.