Perhaps you should try some spelling variations:
thiet hach » thien hach, thuyet hach, thiet hai
hoc thiet » hoc thieu, hoc thuyet, hoc hien
huong cao » luong cao, duong cao, huong cau
cao trong » cao truong, cay trong, tao trong
cong tac » cong ty
tac hang » tac vang, bac thang, tac chong
hang cau » hang dau, hang ca, nhung cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc thiet hach - anh huong cao trong cong tac hang cau~.
• Adding a wildcard symbol may retrieve word variants: hoc thiet hach - anh huong cao trong cong tac hang cau*.