Perhaps you should try some spelling variations:
phap thuc » phap thu, phap hoc, phap tu
thu sach » thuat sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
van phap » ban phap, va phap, van phan
tu sach » su sach, te sach, tu cach
cao hoi » cau hoi, cao hoc, tao hoi
vat ran » chat ran, van ranh
ran vai » ran dai, trang vai, tran van
co hoi » co hoc, co loi
vai va » mai va, dai va, hai va
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 sach) or (thu sach)) ky nang ((cao hoi) OR (co hoi)). hieu van phap thuc vat ran vai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang ((cao hoi) OR (co hoi)). hieu van phap thuc vat ran vai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ky nang ((cao hoi) OR (co hoi)). hieu van phap thuc vat ran vai va thiet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang ((cao hoi) OR (co hoi)). hieu van phap thuc vat ran vai va thiet*.