Perhaps you should try some spelling variations:
nuoc sach » nguoi sach, hoc sach, cuoc cach
van thanh » ban thanh, van tuan
thanh tai » thanh hai, thanh toan, doanh tai
dieu tra » dieu tri, kiem tra, dieu cua
sach ty » sach y, sach tu, sach thu
ty hang » ly hang, ty xang, thi hang
hang xa » hoang xa, hang va, hang ca
cac doi » cac dai, cac toi, cau doi
doi van » do van, doi va, doi ban
ca viet » va viet, co viet, hoa viet
tai ca » tai cac, tai cao, tai cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: nuoc sach ty hang xa hoi. ((dieu tra) or (hieu qua)) cac doi van thanh tai ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: nuoc sach ty hang xa hoi. ((dieu tra) OR (hieu qua)) cac doi van thanh tai ca viet.
• Adding a wildcard symbol may retrieve word variants: nuoc sach ty hang xa hoi. ((dieu tra) or (hieu qua)) cac doi van thanh tai ca viet*.