Perhaps you should try some spelling variations:
dao thanh » ban thanh, tro thanh, de thanh
dat thanh » dat khanh, dang thanh, danh thanh
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
so sach » so sanh, bo sach, co sach
cuu tre » cua tre, cau tren, cau treo
vi cuu » vi luu, vinh cuu
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: ((thu sach) or (so sach)) ky nang x hoi. hieu van nam thuc ((dat thanh) OR (dao thanh)) vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (so sach)) ky nang x hoi. hieu van nam thuc ((dat thanh) OR (dao thanh)) vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (so sach)) ky nang x hoi. hieu van nam thuc ((dat thanh) OR (dao thanh)) vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (so sach)) ky nang x hoi. hieu van nam thuc ((dat thanh) OR (dao thanh)) vi cuu tre*.