Perhaps you should try some spelling variations:
hoc phien » thuoc phien, hoc nghien, hoc phan
phien nam » hien nay, phien ban, mien nam
canh tac » canh tay, canh giac, cong tac
tac vang » tac dung, tac dong
vang hoc » nang hoc, vung hoc, bang hoc
hien nam » hien nay, mien nam, huyen nam
hanh cac » hang cac, hanh cat, nhanh cay
hoc vien » hoc viet, hoc tieng, hoc vi
vien nam » viet nam, vien dai, van nam
van hoc » van hoa
dan hoc » dan toc, dai hoc, toan hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((( canh tac vang hoc phien nam ) OR ( canh tac vang hoc hien nam ))) or ((( hanh cac van hoc vien nam ) or ( hanh cac dan hoc vien nam ))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((( canh tac vang hoc phien nam ) OR ( canh tac vang hoc hien nam ))) OR ((( hanh cac van hoc vien nam ) OR ( hanh cac dan hoc vien nam )))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( canh tac vang hoc phien nam ) OR ( canh tac vang hoc hien nam ))) or ((( hanh cac van hoc vien nam ) or ( hanh cac dan hoc vien nam ))))".
• Adding a wildcard symbol may retrieve word variants: (((( canh tac vang hoc phien nam ) OR ( canh tac vang hoc hien nam ))) or ((( hanh cac van hoc vien nam ) or ( hanh cac dan hoc vien nam ))))*.