Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
dan thi » dang thi, tran thi, dinh thi
cua tre » cua te, cua triet, dua tren
cac tac » cac toc, cac bac, cac dac
hieu va » lieu va, hieu qua
cac tuc » cac toc, cac tu, cac nuoc
nang xa » nang x, lang xa, nang ma
cuu tre » cau tren, cau treo
y nang » ky nang, ly nang, v nang
va dan » ca dan, va dao, va dau

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 y nang xa hoi. hieu va ((cac tuc) or (cac tac)) va dan thi ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. hieu va ((cac tuc) OR (cac tac)) va dan thi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang xa hoi. hieu va ((cac tuc) or (cac tac)) va dan thi ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang xa hoi. hieu va ((cac tuc) or (cac tac)) va dan thi ((cua tre) OR (cuu tre))*.