Perhaps you should try some spelling variations:
thien van » thi van
sach nuoc » sach duoc, cac nuoc, bach tuoc
thu sach » tu sach, thuat sach, thuoc sach
van sach » ban sach, van hach, ngan sach
nang tri » nang tai, lang tri, quang tri
nang thi » dang thi, tang thi, nang tai
sach ky » sac ky, sach y, sach ty
cuu tre » cua tre, cau tren, cau treo
x hoi » o hoi, x ho, 5 hoi

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