Perhaps you should try some spelling variations:
thien van » thi van
nam thuc » nam thuoc, am thuc, nam thu
te sach » toc sach
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
vi cuu » vi luu, vinh cuu
x hoi » xa hoi, x ho, 5 hoi
o hoi » co hoi, o hoc, o hai

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ((x hoi) OR (o hoi)). ((lieu va) OR (thien van)) nam thuc va hanh vi cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang ((x hoi) OR (o hoi)). ((lieu va) or (thien van)) nam thuc va hanh vi cuu tre~".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang ((x hoi) OR (o hoi)). ((lieu va) or (thien van)) nam thuc va hanh vi cuu tre*.