Perhaps you should try some spelling variations:
hoc thiet » hoc thuyet, hoc hien, toc thieu
hoc thieu » toc thieu, hoc hien
hanh tram » hanh tam, hanh trang, thanh tran
dung cong » dung trong
tram xay » tra xay, pham xay, thau xay
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 thieu)) tach - hanh tram xay 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 thieu)) tach - hanh tram xay dung cong dan ((than cau) or (phan cau))~".
• Adding a wildcard symbol may retrieve word variants: ((hoc thiet) OR (hoc thieu)) tach - hanh tram xay dung cong dan ((than cau) or (phan cau))*.