Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
thuc dan » thuc hanh, hoc dan, thuc vat
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
thuc va » thuc vat, thuc day
dan tai » van tai, dan thi, han tai
buu tre » cuu tre

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 lang xa hoi. hieu van nam ((thuc va) or (thuc dan)) dan tai buu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky lang xa hoi. hieu van nam ((thuc va) OR (thuc dan)) dan tai buu tre.
• Adding a wildcard symbol may retrieve word variants: doc sach ky lang xa hoi. hieu van nam ((thuc va) or (thuc dan)) dan tai buu tre*.