Perhaps you should try some spelling variations:
qua tham » qua cham, qua than, qua thanh
tham duc » pham duc, tham du, than duc
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, tu cach
te sach » toc sach
duc van » duc va, duc tan, duc manh
x hoi » xa hoi, o hoi, 5 hoi
vi va » vi van, vai va, vu 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 (te sach)) ky nang ((x hoi) or (x ho)). hieu qua tham duc van hanh vi va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ky nang ((x hoi) OR (x ho)). hieu qua tham duc van hanh vi va thiet.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) ky nang ((x hoi) or (x ho)). hieu qua tham duc van hanh vi va thiet*.