Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
hoc thien » hoc hien, hoc thieu, hoc thiet
canh sinh » canh tinh, canh binh, tinh sinh
dung cong » dung trong
vat dung » van dung, va dung, viet dung
dan chan » dan gian, dan ca, van chat
van tan » van tuan, van ban, van tai

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 thien hach - canh sinh vat dung cong ((van tan) OR (dan chan)) tap~.
• Adding a wildcard symbol may retrieve word variants: hoc thien hach - canh sinh vat dung cong ((van tan) or (dan chan)) tap*.