Perhaps you should try some spelling variations:
thieu nien » thien nhien
thu sach » tu sach, thuat sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
nien cac » vien cac, dien cac, bien cac
dang xay » dang van, van xay
xay hoi » xa hoi, tay hoi, cay phoi
sach ky » sac ky, sach y, sach ty
va danh » va dinh, va dan, va hanh
ky dang » ky nang, ky danh
cua tre » cuu tre, cua triet, dua tren
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: thu sach ky dang xay hoi. thieu nien cac nuoc ((van hanh) or (va danh)) dai ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky dang xay hoi. thieu nien cac nuoc ((van hanh) OR (va danh)) dai ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky dang xay hoi. thieu nien cac nuoc ((van hanh) or (va danh)) dai ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: thu sach ky dang xay hoi. thieu nien cac nuoc ((van hanh) or (va danh)) dai ((cua tre) OR (cua te))*.