Perhaps you should try some spelling variations:
cach thuc » anh thuc, cac thu
mai khoi » mai khoa, tai khoa, cac khoi
van hanh » van thanh, van anh, van ban
ban hanh » ban hang
su sach » so sach, vu sach
ky sang » ky dang, ky tang, duy sang
hieu va » lieu va, hieu qua
va cach » va cac
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua

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