Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
doc sach » hoc sach, toc sach, nuoc sach
thanh vi » hanh vi, thanh va, thanh ve
cua tre » cua te, cua triet, dua tren
duc van » duc va, duc tan, duc manh
cam duc » cam xuc, cao duc, pham duc
hieu ve » hieu va, hieu van
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
cuu tre » cau tren, cau treo
ve cam » ve cham, ve cac, va cam

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

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