Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
van pham » san pham, van phan, van phat
hieu van » hieu va, thien van, lieu va
thu sach » tu sach, thuat sach, thuoc sach
dan tai » van tai, dan thi, han tai
dan vai » dan va, dan vat, den vai
thuc va » thuc vat, thuc dan, thuc day
tu cach » tu cac
nang co » nang cao, nang doc, nang noi
co hoi » co hoc, co loi
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu cach) or (thu sach)) ky nang co hoi. hieu van pham thuc va ((dan vai) OR (dan tai)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (thu sach)) ky nang co hoi. hieu van pham thuc va ((dan vai) OR (dan tai)) va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cach) or (thu sach)) ky nang co hoi. hieu van pham thuc va ((dan vai) OR (dan tai)) va thiet".
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (thu sach)) ky nang co hoi. hieu van pham thuc va ((dan vai) OR (dan tai)) va thiet*.