Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
canh trinh » canh tranh, hanh trinh, canh tinh
hach trac » khach trai, hach toan, anh trac
thuc canh » thuc hanh, thu canh, thuc cach
nghien co » nghiep co, nghien o, nghien cuu
tu hach » tu hanh, tu cach, tu sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu hach trac nghiem _ hoc ) or ( thuc canh trinh nghien co hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu hach trac nghiem _ hoc ) OR ( thuc canh trinh nghien co hoc ))*.