Perhaps you should try some spelling variations:
hoc phien » thuoc phien, hoc phan, hoc thieu
canh tac » canh tay, canh giac, cong tac
tac vang » tac dung, tac dong
vien nam » viet nam, vien dai, van nam
hoc vien » hoc viet, hoc tieng, hoc vi
hanh cac » hang cac, hanh cat, nhanh cay
hien nam » phien nam, hien nay, mien nam
vang hoc » nang hoc, vung hoc, bang hoc
cac van » cac dan
van hoc » van hoa
dan hoc » dan toc, toan hoc, dong 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) or (hoc nghien)) nam ) or ( canh tac vang hoc hien nam ))) or ((( hanh cac van hoc vien nam ) or ( hanh cac ((dan hoc) OR (dai hoc)) vien nam ))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((( canh tac vang ((hoc phien) OR (hoc nghien)) nam ) OR ( canh tac vang hoc hien nam ))) OR ((( hanh cac van hoc vien nam ) OR ( hanh cac ((dan hoc) OR (dai hoc)) vien nam )))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( canh tac vang ((hoc phien) or (hoc nghien)) nam ) or ( canh tac vang hoc hien nam ))) or ((( hanh cac van hoc vien nam ) or ( hanh cac ((dan hoc) OR (dai hoc)) vien nam ))))".
• Adding a wildcard symbol may retrieve word variants: (((( canh tac vang ((hoc phien) or (hoc nghien)) nam ) or ( canh tac vang hoc hien nam ))) or ((( hanh cac van hoc vien nam ) or ( hanh cac ((dan hoc) OR (dai hoc)) vien nam ))))*.