Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
hanh day » hanh may, han day, hanh dao
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
thu nang » thi nang, thu hang, thu bang
nang xa » nang x, lang xa, nang ma
xa hanh » xa thanh, xa khanh, va hanh
day cua » dai cua
cua tre » cua te, cuu tre, cua triet
cam tu » cam thu, nam tu, dam 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) OR (thuoc sach)) thu nang xa hoi. hieu van ((nam thuc) or (cam tu)) xa hanh day cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuoc sach)) thu nang xa hoi. hieu van ((nam thuc) OR (cam tu)) xa hanh day cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (thuoc sach)) thu nang xa hoi. hieu van ((nam thuc) or (cam tu)) xa hanh day cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (thuoc sach)) thu nang xa hoi. hieu van ((nam thuc) or (cam tu)) xa hanh day cua tre*.