Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
thuc day » thuc dan
sach ky » sac ky, sach y, sach ty
ky hang » ky nang, ly hang, ky dang
hieu va » lieu va, hieu qua
han tai » hang tai, nhan tai, van tai
buu tre » cuu tre
va hoe » van hoe, va hoc, va hoa
va nam » van nam, ha nam, va nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ky hang va hoe. hieu va nam ((thuc vat) or (thuc day)) han tai buu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky hang va hoe. hieu va nam ((thuc vat) OR (thuc day)) han tai buu tre.
• Adding a wildcard symbol may retrieve word variants: doc sach ky hang va hoe. hieu va nam ((thuc vat) or (thuc day)) han tai buu tre*.