Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
canh trinh » canh tranh, hanh trinh, canh tinh
trinh vat » trinh van, trinh luat, sinh vat
thi hanh » thi thanh
phan cau » phan dau, phan cac, phan tu
hang dau » hang va, hang tai
doi thi » doi thoi, do thi, doi khi

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi thi hanh - canh trinh vat ((nhung cong) or (trong cong)) dan ((phan cau) or (hang dau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi thi hanh - canh trinh vat ((nhung cong) OR (trong cong)) dan ((phan cau) OR (hang dau)).
• Adding a wildcard symbol may retrieve word variants: doi thi hanh - canh trinh vat ((nhung cong) or (trong cong)) dan ((phan cau) or (hang dau))*.