Perhaps you should try some spelling variations:
khach trinh » hanh trinh, kha trinh, thanh trinh
khoan khoa » khuan khoa, khoa khoa, toan khoa
khoa thong » hoa thong, thoai thong, pho thong
kham thong » khap thong, khau thong, pham thuong
trinh thi » trinh tai, dinh thi, trinh tu
bach khoa » anh khoa
khoa kham » kho khan, khoa than
sach dai » sach dao, sach bai, sach dat
dai thuc » dan thuc, dai thu, dai thua
thuc cac » thuc cach, tuc cac, phuc cac
vu khach » vu khanh, vu khac, vay khach
thi bach » thi bich, thi hanh, thi anh
tu sach » thu sach, su sach, te 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 dai thuc cac khoan khoa thong ) or ( vu khach trinh thi bach khoa kham thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach dai thuc cac khoan khoa thong ) OR ( vu khach trinh thi bach khoa kham thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach dai thuc cac khoan khoa thong ) or ( vu khach trinh thi bach khoa kham thong ))*.