Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
cham hoi » cham voi, cham h'roi, pham hoai
sang mai » sang ma, sang tai, lang mai
hoi van » hoi va, hoi dan, hai van
va cham » va chat, va tham
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach kem
mai hoi » mai khoi, dai hoi, lai hoi
sach ty » sach y, sach tu, sach thu

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc ((sach ky) OR (sach ty)) sang mai hoi. hieu va cham hoi van hanh ((ly cua) or (le cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach ky) OR (sach ty)) sang mai hoi. hieu va cham hoi van hanh ((ly cua) OR (le cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((sach ky) OR (sach ty)) sang mai hoi. hieu va cham hoi van hanh ((ly cua) or (le cua)) tre".
• Adding a wildcard symbol may retrieve word variants: toc ((sach ky) OR (sach ty)) sang mai hoi. hieu va cham hoi van hanh ((ly cua) or (le cua)) tre*.