Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
danh vai » danh sai, danh va, doanh van
tu sach » su sach, te sach, tu cach
cac tac » cac toc, cac bac, cac dac
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, va hanh
cac tuc » cac toc, cac tu, cac nuoc
hieu va » lieu va, hieu qua
xang xa » lang xa, mang xa, ang xa
cua te » cua tu

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

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