Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hac nuoc » cac nuoc, phap nuoc, nhat nuoc
hieu van » hieu va, thien van, lieu va
mai hoi » mai khoi, dai hoi, lai hoi
sach ky » sac ky, sach y, sach ty
ky sang » ky nang, ky dang, ky tang
va danh » va dinh, va dan, va hanh
danh di » danh du, xanh di, danh dien
cuu tre » cua tre, cau tren, cau treo
di cuu » di cau, di cua, dinh cuu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky sang ((xa hoi) or (mai hoi)). hieu van ((hac nuoc) or (hoc nuoc)) va danh di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky sang ((xa hoi) OR (mai hoi)). hieu van ((hac nuoc) OR (hoc nuoc)) va danh di cuu tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ky sang ((xa hoi) or (mai hoi)). hieu van ((hac nuoc) or (hoc nuoc)) va danh di cuu tre*.