Perhaps you should try some spelling variations:
nha thuoc » nha nuoc, nhan thuc, nha hoc
thien van » thi van
cau treo » cau theo, cau tren, cau triet
thuoc ma » hoc ma, duoc ma
cuu tre » cua tre, cau tren
ma hanh » va hanh, da hanh, na hanh
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang o hoi. ((hieu va) or (thien van)) nha thuoc ma hanh vi ((cuu tre) OR (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang o hoi. ((hieu va) OR (thien van)) nha thuoc ma hanh vi ((cuu tre) OR (cau treo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang o hoi. ((hieu va) or (thien van)) nha thuoc ma hanh vi ((cuu tre) OR (cau treo))".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang o hoi. ((hieu va) or (thien van)) nha thuoc ma hanh vi ((cuu tre) OR (cau treo))*.