Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thuc dan » thuc hanh, hoc dan
tu sach » thu sach, te sach, tu cach
hanh le » thanh le, hanh ve, hanh de
van cuu » van cau, van chu, van cu
su sach » so sach, vu sach
le cua » ly cua
cua tu » cua tuc, cua su, cua cu
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: ((tu sach) or (su sach)) ky nang x hoi. hieu van cuu ((thuc dan) or (thuc vat)) hanh le cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang x hoi. hieu van cuu ((thuc dan) OR (thuc vat)) hanh le cua tu.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang x hoi. hieu van cuu ((thuc dan) or (thuc vat)) hanh le cua tu*.