Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
cau treo » cau theo, cau tren, cau triet
nang xa » nang x, lang xa, nang ma
qua nam » quan nam, cua nam, quang nam
ty nang » ky nang, ty xang, ty hang
thuc va » thuc vat, thuc dan, thuc day
sach ty » sach y, sach tu, sach thu
hanh de » hanh ve, hanh kem
cua tre » cua te, cuu tre, cua triet
danh di » danh du, xanh di, danh dien

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 ty nang xa hoi. hieu qua nam thuc va ((danh di) or (hanh de)) ((cua tre) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang xa hoi. hieu qua nam thuc va ((danh di) OR (hanh de)) ((cua tre) OR (cau treo)).
• Adding a wildcard symbol may retrieve word variants: toc sach ty nang xa hoi. hieu qua nam thuc va ((danh di) or (hanh de)) ((cua tre) or (cau treo))*.