Perhaps you should try some spelling variations:
thai viet » tai viet, mai viet, tai vien
giao lan » gian lan, giao dan, giao la
trinh co » trinh do, trinh cong, trinh hoa
cau giay » cuu giai, cac giai
soi viet » so viet, oi viet, doi viet
hoi viet » hai viet, oi viet, cuoi viet
thi viet » thi lien
tay cac » tai cac, tay bac, tap cac
van cac » van hac, van cau, van bac
cac cay » ca cay, cac cam, cac cap
cay coc » cay co, cay cong
coc soi » cot soi, cong soi
cac tay » cac tac, cac tai, cac tap
cac hoi » cac thoi, cac khoi, cau hoi
dan van » dang van, doan van, dao van
co dan » co ban, ca dan, cao dang
ky lan » ky dan, ky la
lan va » luan va, lanh va, lan van

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 giao lan va cac tay cac hoi viet nam ) or ( cong trinh co dan van cac cay coc soi viet nam ))) or ( cong trinh ky lan va ((cau xay) or (cau giay)) co ((thai viet) OR (thi viet)) nam ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((( cong trinh giao lan va cac tay cac hoi viet nam ) OR ( cong trinh co dan van cac cay coc soi viet nam ))) OR ( cong trinh ky lan va ((cau xay) OR (cau giay)) co ((thai viet) OR (thi viet)) nam )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( cong trinh giao lan va cac tay cac hoi viet nam ) or ( cong trinh co dan van cac cay coc soi viet nam ))) or ( cong trinh ky lan va ((cau xay) or (cau giay)) co ((thai viet) OR (thi viet)) nam ))".
• Adding a wildcard symbol may retrieve word variants: (((( cong trinh giao lan va cac tay cac hoi viet nam ) or ( cong trinh co dan van cac cay coc soi viet nam ))) or ( cong trinh ky lan va ((cau xay) or (cau giay)) co ((thai viet) OR (thi viet)) nam ))*.