Perhaps you should try some spelling variations:
dung cong » dung trong
tran van » luan van
cong dan » cong san, cong tan, huong dan
dan than » dan chan, ban than, van than
than tap » toan tap, han tap, phan tap
hoc cuu » hoc huu, hoc cua, hoc chu
hoc cau » hoc cao, hoc cac, hoc can

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc cuu) or (hoc cau)) tinh - hanh ((hang va) or (tran van)) dung cong dan than tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc cuu) OR (hoc cau)) tinh - hanh ((hang va) OR (tran van)) dung cong dan than tap.
• Adding a wildcard symbol may retrieve word variants: ((hoc cuu) or (hoc cau)) tinh - hanh ((hang va) or (tran van)) dung cong dan than tap*.