Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
trinh thuc » trinh tu, trinh thi
khoan cam » khoa cam, khoan va, phan cam
cam thong » nam thong, tam thuong, cam truong
hach toan » thanh toan, manh toan
toan thuc » toan hoc, dan thuc, nhan thuc
noi thong » noi khong, noi tong, hoi thong
thuc cac » thuc cach, tuc cac, phuc cac
thu hach » thu hoach, thu sach, tu hach
cac khoa » cac khoi, dac khoa, cao khoa
khoa noi » khoa doi, khoa hoi, khoan nhoi
tu canh » thu canh, tu chanh, tu can

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu canh trinh thuc cac khoan cam thong ) or ( thu hach toan thuc cac khoa noi thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu canh trinh thuc cac khoan cam thong ) OR ( thu hach toan thuc cac khoa noi thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu canh trinh thuc cac khoan cam thong ) or ( thu hach toan thuc cac khoa noi thong ))*.