Perhaps you should try some spelling variations:
cong sinh » cong vinh, cong tinh, cong binh
trinh dan » trinh han, trinh san, trinh da
dan toan » van toan, dan than, manh toan
ly doan » ly doanh, le doan, ly don
cac tay » cac cay, cac tap, cam tay
cac tai » cao tai, cac dai, cac toi
so viet » hoc viet
cac mai » cac dai, cac mau, cac moi
toan va » tran van, toan ban, toan tap
cac tac » cac toc, cac bac, cac dac
cot so » cot soi, mot so, con so
bai co » bai con, bai ca, ban co
tac co » tuc co, cac co, toc co

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((( cong sinh ly doan va ((cac tay) or (cac tai)) cot so viet nam ) or ((( cong sinh ly doan va cac mai co so viet nam ) or ( cong sinh ly doan va cac bai co so viet nam ))))) or ( cong trinh dan toan va cac tac co so viet nam ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((( cong sinh ly doan va ((cac tay) OR (cac tai)) cot so viet nam ) OR ((( cong sinh ly doan va cac mai co so viet nam ) OR ( cong sinh ly doan va cac bai co so viet nam ))))) OR ( cong trinh dan toan va cac tac co so viet nam )).
• Adding a wildcard symbol may retrieve word variants: (((( cong sinh ly doan va ((cac tay) or (cac tai)) cot so viet nam ) or ((( cong sinh ly doan va cac mai co so viet nam ) or ( cong sinh ly doan va cac bai co so viet nam ))))) or ( cong trinh dan toan va cac tac co so viet nam ))*.