Perhaps you should try some spelling variations:
hien sach » dien sach, kien sach, thien hach
lanh manh » lanh tranh, lan anh, van manh
cua trong » cua truong, cua trung, qua trong
manh cua » doanh cua, ban cua
cong sat » cong suat, cong hat, cong nhat
cong san » cong tac
phan lap » phan dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hien sach - lanh manh cua trong ((cong sat) or (cong san)) phan lap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien sach - lanh manh cua trong ((cong sat) OR (cong san)) phan lap*.