Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
sach ky » sac ky, sach y, sach ty
dan thi » dang thi, tran thi, dinh thi
dan tai » van tai, han tai, ban tai
cuu tre » cua tre, cau tren, cau treo
thuc va » thuc dan, thuc day
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
va nam » van nam, ha nam, va nay

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

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