Perhaps you should try some spelling variations:
trinh trong » trinh truong, tranh trong, trinh trung
hanh trong » hanh trang, anh trong, hinh trong
hieu cach » hieu cac, chieu sach, hieu ca
cong cong » cong dong, trong cong, dung cong
doc hieu » toc thieu, hoc thieu, hoc hien
cong san » cong tac
phan cau » phan dau, phan cac, phan lap

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 - ((trinh trong) or (hanh trong)) cua cong cong san ((phan cau) or (phan tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu cach - ((trinh trong) OR (hanh trong)) cua cong cong san ((phan cau) OR (phan tu)).
• Adding a wildcard symbol may retrieve word variants: doc hieu cach - ((trinh trong) or (hanh trong)) cua cong cong san ((phan cau) or (phan tu))*.