Perhaps you should try some spelling variations:
hoc thuyet » hoc chuyen
hanh trang » thanh trung, canh tranh, hanh trinh
hoc thiet » hoc thieu, hoc hien, toc thieu
trang van » tran van, trang va, trong van
dung cong » dung trong
van dung » van dong, xay dung, tin dung
cong dan » cong san, cong tan, huong dan
than cau » toan cau, than cap, thanh chau
phan cau » phan dau, phan cac, phan tu

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 thiet) OR (hoc thuyet)) tach - hanh trang van dung cong dan ((than cau) OR (phan cau))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc thiet) OR (hoc thuyet)) tach - hanh trang van dung cong dan ((than cau) or (phan cau))~".
• Adding a wildcard symbol may retrieve word variants: ((hoc thiet) OR (hoc thuyet)) tach - hanh trang van dung cong dan ((than cau) or (phan cau))*.