Perhaps you should try some spelling variations:
trinh chao » trinh chat, trinh co, trinh giao
trinh cao » trinh co, trinh cau, tinh cao
trinh han » trinh quan
han yang » hai yang, phan dang, nhan dang
trang va » tran van, hang va
chao lan » cao lan, chao van, chao yang
cac cay » cac cam, cac cap, tac cay
yang va » hang va, bang va, dang va
cho doi » cho moi, cuoc doi, cho tuoi
oi viet » hoi viet, o viet, cuoi viet
cac cau » cac mau, bac cau, ca cau
do thai » do thi, toc thai
tang va » tang van, thang va, tang vat
ca cay » cua cay, ca cac, ca cao
cay co » cac co, tay co, cay cong
co doi » co dot, co dai, co hoi
do hai » doc hai, do dai, co hai
lan va » luan va, lanh va, lan van
va ca » va cao, va cai, va cau
co oi » co hoi, co loi, co toi

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 ((tang va) or (trang va)) cac cau ((do hai) or (do thai)) viet nam ) or ((( cong trinh chao lan va ca cay ((co doi) OR (cho doi)) viet nam ) or ( cong trinh han yang va cac cay co oi viet nam ))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( cong trinh cao ((tang va) OR (trang va)) cac cau ((do hai) OR (do thai)) viet nam ) OR ((( cong trinh chao lan va ca cay ((co doi) OR (cho doi)) viet nam ) OR ( cong trinh han yang va cac cay co oi viet nam )))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( cong trinh cao ((tang va) or (trang va)) cac cau ((do hai) or (do thai)) viet nam ) or ((( cong trinh chao lan va ca cay ((co doi) OR (cho doi)) viet nam ) or ( cong trinh han yang va cac cay co oi viet nam ))))".
• Adding a wildcard symbol may retrieve word variants: (( cong trinh cao ((tang va) or (trang va)) cac cau ((do hai) or (do thai)) viet nam ) or ((( cong trinh chao lan va ca cay ((co doi) OR (cho doi)) viet nam ) or ( cong trinh han yang va cac cay co oi viet nam ))))*.