Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cau tren » cu tren, dau tren, ca tren
tang xa » trang xa, tang ma, lang xa
hieu ca » hieu cac, hieu cua, hieu va
ky tang » ky nang, ky dang, kho tang
thuc va » thuc dan, thuc day
sach ky » sac ky, sach y, sach ty
dan vai » dan va, dan tai, dan vat
cuu tre » cua tre, cau treo
ca nam » cua nam, cai nam, ha nam

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 tang xa hoi. hieu ca nam ((thuc va) OR (thuc vat)) dan vai ((cuu tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky tang xa hoi. hieu ca nam ((thuc va) OR (thuc vat)) dan vai ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky tang xa hoi. hieu ca nam ((thuc va) OR (thuc vat)) dan vai ((cuu tre) or (cau tren))".
• Adding a wildcard symbol may retrieve word variants: toc sach ky tang xa hoi. hieu ca nam ((thuc va) OR (thuc vat)) dan vai ((cuu tre) or (cau tren))*.