Perhaps you should try some spelling variations:
thuoc canh » thuoc thanh, thu canh, thuat canh
khoa thong » hoa thong, thoai thong, khoi khong
tranh duoc » tranh cuoc, trinh duoc, tran duc
sach hang » sach han, sach nang, khach hang
hang khoa » dung khoa
pho thong » he thong
cac bien » cach bien, cam bien, cac bieu
bien hoc » dien hoc, bien thuoc, khien hoc
hoc sach » hoc sinh, hoc cac, hoc anh
duoc cac » cuoc cach, duoc chat, duong cac
cac khoa » cac khoan, cac khoi, dac khoa
khoa pho » khoa phu, khoa khoa, khoa phau

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu cac bien hoc sach hang khoa thong ) or ( thuoc canh tranh duoc cac khoa pho thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu cac bien hoc sach hang khoa thong ) OR ( thuoc canh tranh duoc cac khoa pho thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu cac bien hoc sach hang khoa thong ) or ( thuoc canh tranh duoc cac khoa pho thong ))*.