Perhaps you should try some spelling variations:
trinh cao » trinh chao, trinh co, trinh cau
trinh sau » trinh san, trinh cau, trinh su
sau luan » su luan, dau luan, sau lan
thi viet » thi lien
cau giay » cuu giai, cac giai
soi viet » hoi viet, oi viet, doi viet
cao cay » cao cap, cho cay, tao cay
luan va » luan van, luat va
so viet » hoc viet
cao van » cac van, dao van, cao dang
van va » van vat, van van, ban va
co soi » cot soi, co hoi, co loi
va cao » va cac, va co, va dao
cay co » cac co, tay co, cay cong
cay o » cay mo, cay ot, cay so

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( cong trinh cao van va ((cau xay) or (cau giay)) co soi viet nam ) or ((( chuong trinh sau luan va cao cay o ((mai viet) OR (thi viet)) nam ) or ( chuong trinh sau luan va cao cay co so viet nam ))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( cong trinh cao van va ((cau xay) OR (cau giay)) co soi viet nam ) OR ((( chuong trinh sau luan va cao cay o ((mai viet) OR (thi viet)) nam ) OR ( chuong trinh sau luan va cao cay co so viet nam )))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( cong trinh cao van va ((cau xay) or (cau giay)) co soi viet nam ) or ((( chuong trinh sau luan va cao cay o ((mai viet) OR (thi viet)) nam ) or ( chuong trinh sau luan va cao cay co so viet nam ))))".
• Adding a wildcard symbol may retrieve word variants: (( cong trinh cao van va ((cau xay) or (cau giay)) co soi viet nam ) or ((( chuong trinh sau luan va cao cay o ((mai viet) OR (thi viet)) nam ) or ( chuong trinh sau luan va cao cay co so viet nam ))))*.