Perhaps you should try some spelling variations:
sach tranh » canh tranh
tranh thuc » trinh thuc, trang thuc, thanh thuy
cach thoat » cach thoi, cac hoat, cac thuat
thuc cach » thuoc sach, truoc cach, thuc hanh
sach tren » sach tien
tren thuc » trien thuc, tron thuc, trinh thuc
cach khoa » bach khoa, cac khoa, cac khoan
tu sach » thu sach, su sach, tu cach
te sach » toc sach
khoa he » hoa he, khoa hoc, khong he
khoi » hoi, thoi, khi
khong » phong
thong » trong

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu sach tranh thuc cach thoat khoi khong ) or ( te sach tren thuc cach khoa he thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach tranh thuc cach thoat khoi khong ) OR ( te sach tren thuc cach khoa he thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach tranh thuc cach thoat khoi khong ) or ( te sach tren thuc cach khoa he thong ))*.