Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cac thuc » cach thuc, cac thu, can thuc
thi nang » ki nang, thi hanh
hanh tai » thanh tai, hang tai, han tai
thi cong » tai cong, thien cong
hanh lai » hanh lam, thanh lap, thanh loi
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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 ((thi nang) OR (thi cong)) ma hoi. hieu va cac thuc va ((hanh lai) or (hanh tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((thi nang) OR (thi cong)) ma hoi. hieu va cac thuc va ((hanh lai) OR (hanh tai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((thi nang) OR (thi cong)) ma hoi. hieu va cac thuc va ((hanh lai) or (hanh tai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((thi nang) OR (thi cong)) ma hoi. hieu va cac thuc va ((hanh lai) or (hanh tai)) cua tre*.