Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
toc sach » hoc sach, doc sach, thuoc sach
va thuat » ky thuat, ki thuat, va thuc
thanh vi » hanh vi, thanh va, thanh ve
va triet » va thiet, va trien, ve triet
dang xay » dang van, van xay
sach ky » sac ky, sach y, sach ty
va tham » van tham, va cham, va thanh
xay hoi » xa hoi, tay hoi, cay phoi
duc van » duc va, duc tan, duc manh
ky dang » ky nang, ky danh
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky dang xay hoi. hieu ((va thuat) or (va tham)) duc van thanh vi ((cua tre) or (va triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky dang xay hoi. hieu ((va thuat) OR (va tham)) duc van thanh vi ((cua tre) OR (va triet)).
• Adding a wildcard symbol may retrieve word variants: toc sach ky dang xay hoi. hieu ((va thuat) or (va tham)) duc van thanh vi ((cua tre) or (va triet))*.