Perhaps you should try some spelling variations:
doanh cua » doanh luan
tu sach » thu sach, su sach, tu cach
cua cua » cua chua, ca cua, qua cua
hieu va » lieu va, hieu qua
va chao » va cao, va chat, va cham
nang ma » tang ma, sang ma, nang cao
te sach » toc sach
xu van » tu van, vu van, su van
y nang » ky nang, ly nang, v nang
cua te » cua tu
xu va » tu va, su va, vu va

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) or (te sach)) y nang ma hoa. hieu va chao ((xu va) OR (xu van)) doanh cua cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) y nang ma hoa. hieu va chao ((xu va) OR (xu van)) doanh cua cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (te sach)) y nang ma hoa. hieu va chao ((xu va) OR (xu van)) doanh cua cua te".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) y nang ma hoa. hieu va chao ((xu va) OR (xu van)) doanh cua cua te*.