Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
qua cam » qua cham, qua cac, qua ca
cam tuc » cam xuc, cam tu, nam thuc
va vanh » va van, va hanh, va anh
va danh » va dinh, va dan, va hanh
tai cau » tai cac
tai cao » thai cao, tao cao, tai sao

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 ky nang xa hoi. hieu qua cam tuc ((va vanh) OR (va danh)) ((tai cau) or (tai cao)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. hieu qua cam tuc ((va vanh) OR (va danh)) ((tai cau) OR (tai cao)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. hieu qua cam tuc ((va vanh) OR (va danh)) ((tai cau) or (tai cao)) triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. hieu qua cam tuc ((va vanh) OR (va danh)) ((tai cau) or (tai cao)) triet*.