Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
day hang » dat hang, dai hang, day nang
thuc day » thuc dan, thuc vat
ve phan » va phan, ke phan, ve phat
hang di » hang doi, hang vi, hang dien
ve pham » vi pham, v pham, ve phat
cao hoc » co hoc, cho hoc, chat hoc
y nang » ky nang, ly nang, v nang
di cua » dai cua, doi cua, de cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y nang ((cau hoi) or (cao hoc)). hieu ((ve pham) OR (ve phan)) thuc day hang di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang ((cau hoi) OR (cao hoc)). hieu ((ve pham) OR (ve phan)) thuc day hang di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y nang ((cau hoi) or (cao hoc)). hieu ((ve pham) OR (ve phan)) thuc day hang di cua te".
• Adding a wildcard symbol may retrieve word variants: thu sach y nang ((cau hoi) or (cao hoc)). hieu ((ve pham) OR (ve phan)) thuc day hang di cua te*.