Perhaps you should try some spelling variations:
pham chuc » pham duc, pham huu, kham chua
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, te sach, tu cach
su sach » so sach
vu sach » vu bach, vu khach
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
chuc va » thuc va, thuc vat
va dan » ca dan, va dao, va dau
ca cau » cua cau, cac cau, can cau

You may be able to get more results by adjusting your search query.

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