Perhaps you should try some spelling variations:
thien van » thi van
sang than » cang thang, dang thanh, sang tao
thu sach » thuat sach, thuoc sach, thu hoach
than cua » nhan cua, thai cua, ban cua
tu sach » su sach, te sach, tu cach
ky lang » ky nang, ky dang, tay lang
ky tang » ky nang, ky dang, kho tang
van dat » van dao, van dau, dan dat
va sang » van sang, vua sang, va nang
cua tre » cua te, cuu tre, cua triet
nuoc » quoc, duoc, ngoc

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 (tu sach)) ((ky lang) OR (ky tang)) xa hoi. thien van dat nuoc va sang than cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) ((ky lang) OR (ky tang)) xa hoi. thien van dat nuoc va sang than cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (tu sach)) ((ky lang) OR (ky tang)) xa hoi. thien van dat nuoc va sang than cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (tu sach)) ((ky lang) OR (ky tang)) xa hoi. thien van dat nuoc va sang than cua tre*.