Perhaps you should try some spelling variations:
thien van » thi van
doc sach » hoc sach, toc sach, nuoc sach
tay lang » tai lang, tay tang, tay quang
ty lang » ty xang, ty hang, tu lang
duoc va » nuoc va, duc va, duong va
duoc ma » duoc lam
hang di » hang doi, hang vi, hang dien
di cua » dai cua, doi cua, de cua
cua te » cua tu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ((ty lang) or (tay lang)) xa hoi. thien van nam ((duoc va) OR (duoc ma)) hang di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ((ty lang) OR (tay lang)) xa hoi. thien van nam ((duoc va) OR (duoc ma)) hang di cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ((ty lang) or (tay lang)) xa hoi. thien van nam ((duoc va) OR (duoc ma)) hang di cua te*".