Perhaps you should try some spelling variations:
cau treo » cau theo, cau tren, cau triet
hieu van » hieu va, thien van, lieu va
dan thai » dang thai, dan thi, dan than
sach ty » sach y, sach tu, sach thu
cuu tre » cua tre, cau tren
cac tac » cac toc, cac bac, cac dac
tu sach » thu sach, su sach, te sach
cac tuc » cac toc, cac tu, cac nuoc
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
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 ty nang xa hoi. hieu van ((cac tuc) or (cac tac)) va dan thai ((cuu tre) OR (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang xa hoi. hieu van ((cac tuc) OR (cac tac)) va dan thai ((cuu tre) OR (cau treo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang xa hoi. hieu van ((cac tuc) or (cac tac)) va dan thai ((cuu tre) OR (cau treo))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang xa hoi. hieu van ((cac tuc) or (cac tac)) va dan thai ((cuu tre) OR (cau treo))*.