Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hai cua » thai cua, hoi cua, lai cua
tuc van » thuc van, truc van, tuc va
hac tuc » thac toc, thai tuc
hieu va » lieu va, hieu qua
sach ky » sach y, sach ty, sach kem
nang ma » tang ma, sang ma, nang cao
va hac » van hac, va khac, va cac
ma hoi » mai hoi, xa hoi, ma hoa
sac ky » cac ky, sai ky

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

• If you are trying to use Boolean operators, they must be ALL CAPS: vu ((sach ky) OR (sac ky)) nang ma hoi. hieu va hac tuc van hanh ((hai cua) OR (dai cua)) tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu ((sach ky) or (sac ky)) nang ma hoi. hieu va hac tuc van hanh ((hai cua) OR (dai cua)) tre~".
• Adding a wildcard symbol may retrieve word variants: vu ((sach ky) or (sac ky)) nang ma hoi. hieu va hac tuc van hanh ((hai cua) OR (dai cua)) tre*.