Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
thu sach » thuat sach, thuoc sach, thu hoach
tu sach » su sach, te sach, tu cach
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
thuc va » thuc vat, thuc dan, thuc day
dan dai » dat dai, can dai, dan dat
va dan » ca dan, va dao, va dau
dai va » mai va

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) or (thu sach)) ky nang cao hoi. hieu va pham thuc va dan dai va (thiet or thieu)~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang cao hoi. hieu va pham thuc va dan dai va (thiet OR thieu).
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang cao hoi. hieu va pham thuc va dan dai va (thiet or thieu)*.