Perhaps you should try some spelling variations:
trinh han » trinh quan
trinh cho » trinh chao, trinh chat, trinh cham
trinh co » trinh do, trinh cong, trinh hoa
lang van » dang van, tang van, hoang van
han yang » hai yang, phan dang, nhan dang
loi viet » loai viet, hoi viet, doi viet
cho lang » cho hang, chi lang, cho mang
yang va » hang va, dang va, sang va
co bang » cao bang, con bang, co ban
van cac » van hac, van cau, van bac
bang va » hang va, ban va, trang va
cac cac » cac cach, ca cac, cac bac
oi viet » hoi viet, o viet, cuoi viet
co dai » co dan, do dai
cay co » cac co, cay cong
tay co » ty co, tay o
co mai » co ma, co may, co gai

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 co bang va cac cac ((co mai) or (co dai)) viet nam ) or ((( cong trinh cho lang van cac ((cay co) OR (tay co)) loi viet nam ) or ( cong trinh han yang va cac ((cay co) OR (tay co)) oi viet nam ))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( cong trinh co bang va cac cac ((co mai) OR (co dai)) viet nam ) OR ((( cong trinh cho lang van cac ((cay co) OR (tay co)) loi viet nam ) OR ( cong trinh han yang va cac ((cay co) OR (tay co)) oi viet nam )))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( cong trinh co bang va cac cac ((co mai) or (co dai)) viet nam ) or ((( cong trinh cho lang van cac ((cay co) OR (tay co)) loi viet nam ) or ( cong trinh han yang va cac ((cay co) OR (tay co)) oi viet nam ))))".
• Adding a wildcard symbol may retrieve word variants: (( cong trinh co bang va cac cac ((co mai) or (co dai)) viet nam ) or ((( cong trinh cho lang van cac ((cay co) OR (tay co)) loi viet nam ) or ( cong trinh han yang va cac ((cay co) OR (tay co)) oi viet nam ))))*.