Perhaps you should try some spelling variations:
hoc khien » hoc hien, hoc nghien, hoc thieu
hanh sinh » hanh tinh, hanh dinh, hinh sinh
dung cong » dung trong
cong van » cong vang, cong san, song van
van khan » van khanh, van khang, van phan
khan cap » khan ap, than cap, khoan cam
sinh va » sinh vat, tinh va, dinh van
va dung » van dung, va duong, vat dung

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((hoc khien) or (toc thieu)) tinh - hanh sinh va dung cong van khan cap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc khien) OR (toc thieu)) tinh - hanh sinh va dung cong van khan cap*.