Perhaps you should try some spelling variations:
van thanhh » ban thanh, van hanh, van khanh
hieu tinh » chieu tinh, lieu tinh, kieu tinh
cach dung » sach dung, cach mang, tac dung
luan hang » luan nang, luan han, luan hung
hang cong » dang cong, hang nong, bang cong
van thanh » ban thanh, van tuan
doc hieu » toc thieu, hoc thieu, hoc hien

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 tinh - cach dung luan hang cong ((van thanh) or (van thanhh)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu tinh - cach dung luan hang cong ((van thanh) OR (van thanhh)) cau.
• Adding a wildcard symbol may retrieve word variants: doc hieu tinh - cach dung luan hang cong ((van thanh) or (van thanhh)) cau*.