Perhaps you should try some spelling variations:
thien van » thi van
ma hanh » va hanh, da hanh, na hanh
nha hoc » nha thuoc, khoa hoc, nha nuoc
hieu va » lieu va, hieu qua
sach ky » sac ky, sach ty, sach kem
nang co » nang cao, nang doc, nang noi
cuu tre » cua tre, cau tren, cau treo
co hoi » co hoc, co loi
vi cuu » vi luu, vinh cuu

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

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