Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
tu sach » su sach, te sach, tu cach
thi cuc » tai cuc
dau thi » cau thi, dan thi, dao thi
cac bac » cac bai, cac ban, cac cach
cac dac » cac dan, cac dai, cac tac
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
cuc tre » duc tre, cua tre, cuu tre
va dau » va dao

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 nang xa hoi. lieu va ((cac dac) OR (cac bac)) va dau thi cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ty nang xa hoi. lieu va ((cac dac) OR (cac bac)) va dau thi cuc tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ty nang xa hoi. lieu va ((cac dac) OR (cac bac)) va dau thi cuc tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ty nang xa hoi. lieu va ((cac dac) OR (cac bac)) va dau thi cuc tre*.