Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
cua tre » cua te, cua triet, dua tren
hanh de » hanh ve, hanh kem
sach ty » sach y, sach tu, sach thu
danh di » danh du, xanh di, danh dien
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
cuu tre » cau tren, cau treo
va am » va lam, va cam
thuc » thu

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 ty nang xa hoi. hieu va am thuc vat ((danh di) or (hanh de)) ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty nang xa hoi. hieu va am thuc vat ((danh di) OR (hanh de)) ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ty nang xa hoi. hieu va am thuc vat ((danh di) or (hanh de)) ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: doc sach ty nang xa hoi. hieu va am thuc vat ((danh di) or (hanh de)) ((cua tre) OR (cuu tre))*.