Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
cuu thuc » cuu tac
hanh le » thanh le, hanh ve, hanh de
van cuu » van cau, van chu, van cu
tu sach » thu sach, su sach, tu cach
ky dang » ky nang, ky danh
ky tang » ky nang, kho tang, ky trong
te sach » toc sach
le cua » ly 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: ((tu sach) or (te sach)) ((ky tang) OR (ky dang)) xa hoi. hieu van cuu thuc dan hanh le cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ((ky tang) OR (ky dang)) xa hoi. hieu van cuu thuc dan hanh le cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (te sach)) ((ky tang) OR (ky dang)) xa hoi. hieu van cuu thuc dan hanh le cua te".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) ((ky tang) OR (ky dang)) xa hoi. hieu van cuu thuc dan hanh le cua te*.