Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
sach thu » sach thue, sach thieu, sach tham
thuc xa » thuc xay, tuc xa, thuc va
hai cua » thai cua, dai cua, hoi cua
vai cua » dai cua, lai cua, bai cua
xa hanh » xa thanh, xa khanh, va hanh
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
van am » van nam, van lam, van dam

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 thu)) nang ma hoa. hieu van am thuc xa hanh ((vai cua) OR (hai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach thu)) nang ma hoa. hieu van am thuc xa hanh ((vai cua) OR (hai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach thu)) nang ma hoa. hieu van am thuc xa hanh ((vai cua) OR (hai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach thu)) nang ma hoa. hieu van am thuc xa hanh ((vai cua) OR (hai cua)) tre*.