Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
cau treo » cau theo, cau triet, cau trieu
cac truc » cau truc, cac trung, sach truc
sach ky » sac ky, sach y, sach ty
danh ca » dan ca, doanh cua, danh cho
va danh » va dinh, va dan, va hanh
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
cac tru » ca tru, cac tro, cac thu

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