Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
thuc dan » thuc hanh, hoc dan
hieu va » lieu va, hieu qua
lang ha » long ha
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
dan tai » van tai, dan thi, han tai
tai cuu » tai cuc, tai buu, tai cua
cuu tre » cua tre, cau tren, cau treo
ha hoi » hoa hoi, ha noi, xa hoi
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 lang ha hoi. hieu va nam ((thuc dan) or (((thuc day) OR (thuc vat)))) dan tai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky lang ha hoi. hieu va nam ((thuc dan) OR (((thuc day) OR (thuc vat)))) dan tai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ky lang ha hoi. hieu va nam ((thuc dan) or (((thuc day) OR (thuc vat)))) dan tai cuu tre".
• Adding a wildcard symbol may retrieve word variants: doc sach ky lang ha hoi. hieu va nam ((thuc dan) or (((thuc day) OR (thuc vat)))) dan tai cuu tre*.