Perhaps you should try some spelling variations:
lam thuoc » nam thuoc, am thuc, cay thuoc
toc sach » hoc sach, doc sach, thuoc sach
lam duoc » nam duoc, luat duoc, tao duoc
doan van » doan va, hoang van, luan van
lang van » dang van, tang van, hoang van
hieu van » hieu va, thien van, lieu va
van cua » vang cua, ban cua, dan cua
ma doan » ma dan, tap doan, va doanh
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay
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: toc sach ky ((lang xa) or (lang van)) hoi. hieu van ((lam duoc) OR (lam thuoc)) ma doan van cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((lang xa) OR (lang van)) hoi. hieu van ((lam duoc) OR (lam thuoc)) ma doan van cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky ((lang xa) or (lang van)) hoi. hieu van ((lam duoc) OR (lam thuoc)) ma doan van cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((lang xa) or (lang van)) hoi. hieu van ((lam duoc) OR (lam thuoc)) ma doan van cua tre*.