Perhaps you should try some spelling variations:
kham thong » khap thong, khau thong, pham thuong
sach truc » cach thuc, sach tren, sach thu
khoa kham » kho khan, khoa than
bach hoa » bach khoa, bach ha, cach hoan
sach gai » sach bai, sach tai, sach giao
gai tren » gi tren, tai tren, loai tren
tren may » tiet may
may khoa » da khoa, ly khoa, y khoa
tu sach » thu sach, su sach, te sach
du bach » vu bach, du bac, huu bach
so sach » so sanh, bo sach, co sach

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 truc du bach hoa he thong ) or ( so sach gai tren may khoa kham thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach truc du bach hoa he thong ) OR ( so sach gai tren may khoa kham thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach truc du bach hoa he thong ) or ( so sach gai tren may khoa kham thong ))*.