Perhaps you should try some spelling variations:
sang mai » sang ma, sang tai, lang mai
danh vai » danh sai, danh va, doanh van
cuu tre » cua tre, cau tren, cau treo
cam luc » cam xuc, cau luc
vai cuu » vai cua
sach ty » sach y, sach tu, sach thu
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu van
va danh » va dinh, va dan, va hanh
hieu va » lieu va, hieu qua
luc va » duc va, tuc va, loc va
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sac ky) or (sach ty)) sang mai hoi. ((hieu ve) or (hieu va)) cam luc va danh vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sac ky) OR (sach ty)) sang mai hoi. ((hieu ve) OR (hieu va)) cam luc va danh vai cuu tre.
• Adding a wildcard symbol may retrieve word variants: su ((sac ky) or (sach ty)) sang mai hoi. ((hieu ve) or (hieu va)) cam luc va danh vai cuu tre*.