Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thuc dan » thuc hanh, hoc dan, thuc vat
cau theo » cau thi, cau tao
dan dan » dang dan, ban dan, dao dan
dan vai » dan va, dan tai, dan vat
vai cau » va cau, van cau, vai cac
y nang » ky nang, ly nang, v nang
va nam » van nam, va nay
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y nang x hoi. hieu ((va nam) or (ha nam)) thuc dan dan vai cau theo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang x hoi. hieu ((va nam) OR (ha nam)) thuc dan dan vai cau theo.
• Adding a wildcard symbol may retrieve word variants: toc sach y nang x hoi. hieu ((va nam) or (ha nam)) thuc dan dan vai cau theo*.