Perhaps you should try some spelling variations:
sach tien » sach tren, sach thieu
tien thuc » trien thuc, kien thuc, bien thuc
pho thong » he thong
khach tri » khach trai, khac trai, khanh tra
thuc anh » thuc hanh, thuy anh, thu anh
anh khoa » doanh khoa, hang khoa
khoa pho » khoa phu, khoa khoa, khoa phau
vu khach » vu khanh, vu khac, vay khach
tri tham » thi tham, tri cham, tri tam
tham cac » thac cac, thoai cac, tham canh
cac khoi » cac thoi, cac khoan, cach thoi
khoi hoc » khoa hoc, hoi hoc, phoi hoc
hoc hong » hoc huong, hoc khong, hoc cong
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 tien thuc anh khoa pho thong ) or ( vu khach tri tham cac khoi hoc hong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach tien thuc anh khoa pho thong ) OR ( vu khach tri tham cac khoi hoc hong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach tien thuc anh khoa pho thong ) or ( vu khach tri tham cac khoi hoc hong ))*.