Perhaps you should try some spelling variations:
manh thanh » danh thanh, minh thanh, manh thang
thanh lai » thanh hai, thanh lap, thanh loi
nam duoc » nam thuoc, da duoc, dat duoc
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
lai cua » dai cua, hai cua, lai chau
nam duc » pham duc, nam thuc, nam buoc
ty lang » tay lang, ty hang, tu lang
cua tre » cua te, cuu tre, cua triet

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 ((ty lang) or (ty xang)) xa hoi. hieu van ((nam duc) OR (nam duoc)) manh thanh lai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty lang) OR (ty xang)) xa hoi. hieu van ((nam duc) OR (nam duoc)) manh thanh lai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty lang) or (ty xang)) xa hoi. hieu van ((nam duc) OR (nam duoc)) manh thanh lai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty lang) or (ty xang)) xa hoi. hieu van ((nam duc) OR (nam duoc)) manh thanh lai cua tre*.