Perhaps you should try some spelling variations:
thuyet lanh » thuyet anh, thuyet canh, thuyet kinh
hoc thuyet » hoc chuyen
tinh chuan » trinh chuan, tinh chua, tieu chuan
canh tinh » hanh tinh, manh tinh, canh tranh
dong cong » duong cong, dung cong, cong cong
dang cong » dung cong
thang ban » hang ban, tang ban, thanh ban
ban can » ban dan, ban hang, ban hanh

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc thuyet lanh - canh tinh chuan ((dong cong) or (dang cong)) thang ban can~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thuyet lanh - canh tinh chuan ((dong cong) OR (dang cong)) thang ban can.
• Adding a wildcard symbol may retrieve word variants: hoc thuyet lanh - canh tinh chuan ((dong cong) or (dang cong)) thang ban can*.