Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu va » hieu qua
nha hoc » nha thuoc, khoa hoc, nha nuoc
cuu tre » cua tre, cau tren, cau treo
nang o » nang co, nang ho, nang ro
vi cuu » vi luu, vinh cuu
o hai » co hai, so hai, o lai

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