Perhaps you should try some spelling variations:
thieu hach » thien hach, chieu sach, hieu cach
nhung cong » dung cong, thong cong, hang cong
hoc thieu » toc thieu, hoc hien
trung cua » truong cua, trung tuan, trung cap
tang cua » mang cua, hang cua, tang luan
dan than » dan chan, ban than, van than
van chat » cao chat

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu hach - hanh ((trung cua) OR (tang cua)) nhung cong ((dan than) OR (van chat)) cau~.
• Adding a wildcard symbol may retrieve word variants: hoc thieu hach - hanh ((trung cua) or (tang cua)) nhung cong ((dan than) or (van chat)) cau*.