Perhaps you should try some spelling variations:
sach tien » sach tren, sach thieu
tien chai » tieng thai, tien khi, trien chi
noi khoa » hoc khoa, tai khoa
chai hoa » chai khoa, chat hoa, cai hoa
cau xin » cau kien, cau vinh, cau hien
te sach » toc sach
tu cau » tu cac, cu cau, tu can

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu cau xin ((noi khoa) or (ngoai khoa)) hoc ) or ( te sach tien chai hoa hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu cau xin ((noi khoa) OR (ngoai khoa)) hoc ) OR ( te sach tien chai hoa hoc )).
• Adding a wildcard symbol may retrieve word variants: (( tu cau xin ((noi khoa) or (ngoai khoa)) hoc ) or ( te sach tien chai hoa hoc ))*.