Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
cham duc » pham duc, cham soc, pham duy
dau tren » dau tien, dat tren, dau tieng
thanh va » thanh van, hanh va, thanh ha
sach ky » sac ky, sach y, sach ty
duc van » duc va, duc tan, duc manh
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
hieu ve » hieu van
cu tren » tu tren, dua tren
x hoi » xa hoi, o hoi, x ho

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 ky nang x hoi. ((hieu ve) or (hieu va)) cham duc van thanh va ((dau tren) or (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. ((hieu ve) OR (hieu va)) cham duc van thanh va ((dau tren) OR (cu tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. ((hieu ve) or (hieu va)) cham duc van thanh va ((dau tren) or (cu tren))*.