Perhaps you should try some spelling variations:
thien van » thi van
toc sach » hoc sach, doc sach, thuoc sach
lam duoc » nam duoc, luat duoc, lam thuoc
ty lang » tay lang, ty hang, tu lang
van lam » van nam
duoc va » nuoc va, duc va, duoc ma
va hang » van hang, va nang, va lang
va cua » va chua, via cua, ca cua
co cua » con cua, ca cua, cong cua

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 ((ty lang) or (ty xang)) xa hoi. thien van lam duoc va hang ((va cua) or (co cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty lang) OR (ty xang)) xa hoi. thien van lam duoc va hang ((va cua) OR (co cua)) tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ((ty lang) or (ty xang)) xa hoi. thien van lam duoc va hang ((va cua) or (co cua)) tre*.