Perhaps you should try some spelling variations:
thien van » thi van
thu sach » thuat sach, thuoc sach, thu hoach
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
van dang » van dong, van dung, van nang
tran cua » tranh cua, than cua, tan cua
tu sach » su sach, te sach, tu cach
van cac » van hac, van cau, van bac
va dang » va nang, va lang, da dang
cua tre » cua te, cuu tre, cua triet
x hoi » xa hoi, o hoi, x ho

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