Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
thuc sach » thuoc sach, thu sach, thuc cach
trinh han » trinh quan
dung cong » dung trong
thang van » tang van, thanh van, thong van
hoc thuc » hoc huu
van hau » van ha, van hai, van 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 thuc sach - canh trinh han ((dung cong) or (dang cong)) thang van hau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thuc sach - canh trinh han ((dung cong) OR (dang cong)) thang van hau*.