Perhaps you should try some spelling variations:
thien van » thi van
lang than » lang thang, lang thanh, sang than
than cua » nhan cua, thai cua, ban cua
dat ngoc » dat nuoc, dau ngoc, dang ngoc
thu sach » thuat sach, thuoc sach, thu hoach
ky tang » ky nang, ky dang, kho tang
ky lang » ky nang, ky dang, tay lang
van dat » van dao, van dau, dan dat
ngoc va » nuoc va, ngoc ha, goc va
va lang » va nang, hoa lang
tu sach » su sach, te sach, tu cach
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: ((thu sach) or (tu sach)) ((ky lang) or (ky tang)) xa hoi. thien van dat ngoc va lang 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 ngoc va lang 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 ngoc va lang than cua tre*.