Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu cach » hieu cac, chieu sach, hieu ca
hanh tang » hanh trang, hanh mang, hanh tung
cua nhung » va nhung
tuan phan » luan phan, toan phan, tuan pham
doc hieu » toc thieu, hoc thieu, hoc hien
anh tang » anh bang, anh dang, anh nang
cong van » cong vang, cong san, song van
van tuan » van quan, van ban, anh tuan

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu cach - ((hanh tang) or (anh tang)) cua nhung cong van tuan phan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu cach - ((hanh tang) OR (anh tang)) cua nhung cong van tuan phan.
• Adding a wildcard symbol may retrieve word variants: doc hieu cach - ((hanh tang) or (anh tang)) cua nhung cong van tuan phan*.