Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, cau treo
sach ky » sac ky, sach ty, sach kem
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
ca tren » cu tren, la tren, co tren
va cam » va cham, va cac, va cao
xuc va » duc va, tuc va, luc va
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 ky) or (sach y)) nang cao hoi. hieu va cam xuc va dan ca ((cau tren) OR (ca tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang cao hoi. hieu va cam xuc va dan ca ((cau tren) OR (ca tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach y)) nang cao hoi. hieu va cam xuc va dan ca ((cau tren) OR (ca tren))".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach y)) nang cao hoi. hieu va cam xuc va dan ca ((cau tren) OR (ca tren))*.