Perhaps you should try some spelling variations:
trinh cho » trinh chao, trinh co, trinh chat
trinh han » trinh quan
han yang » hai yang, phan dang, nhan dang
loi viet » loai viet, hoi viet, oi viet
cho lang » cho hang, chi lang, cho mang
lang van » dang van, tang van, hoang van
cac cay » ca cay, cac cam, cac cap
cac cac » cac cach, ca cac, cac bac
co lang » so lang, co bang, cu lang
van hac » van hoc, van ha, van hai
hac cay » hoc cay, tac cay, chau cay
yang va » hang va, bang va, dang va
co doi » cho doi, co dot, co hoi
co mai » co ma, co may, co gai
o lang » hoa lang, hoi lang
cay co » cac co, tay co, cay cong
co dai » co dan, do dai
co loi » co hoi
co oi » co hoi, co toi, co gi
co o » co so, co _, so o

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