Perhaps you should try some spelling variations:
dinh cau » dinh chau, dinh cuu, dinh cu
hieu van » hieu va, thien van, lieu va
lang xa » lang ha, dang xay, lang van
sach ky » sach y, sach ty, sach kem
van cam » van nam, van lam, van cau
cam hoc » cao hoc, am hoc, cam hoa
va hanh » van hanh, va thanh, va danh
sac ky » cac ky, sai ky
va anh » van anh, va danh, va banh

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 (sac ky)) lang xa hoi. hieu van cam hoc ((va anh) or (va hanh)) dinh cau tao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) lang xa hoi. hieu van cam hoc ((va anh) OR (va hanh)) dinh cau tao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sac ky)) lang xa hoi. hieu van cam hoc ((va anh) or (va hanh)) dinh cau tao".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) OR (sac ky)) lang xa hoi. hieu van cam hoc ((va anh) or (va hanh)) dinh cau tao*.