Perhaps you should try some spelling variations:
thien thanh » tien thanh, thi thanh, hien hanh
hieu nganh » vien nganh, hiem ngan, hieu manh
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
tuong dan » huong dan, tung dan, truong dai
xuong dan » huong dan, xuong san, nguong dan
tinh cua » trinh cua, sinh cua, tinh chat
cua tong » cua cong, cua dong, cua nong
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu nganh) or (thien thanh)) - hanh tinh cua tong ((tuong dan) OR (xuong dan)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu nganh) OR (thien thanh)) - hanh tinh cua tong ((tuong dan) OR (xuong dan)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu nganh) or (thien thanh)) - hanh tinh cua tong ((tuong dan) OR (xuong dan)) toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu nganh) or (thien thanh)) - hanh tinh cua tong ((tuong dan) OR (xuong dan)) toan cau*.