Perhaps you should try some spelling variations:
tang van » dang van, hoang van, trong van
vu sach » vu bach, su sach, vu khach
doi cua » hoi cua
xa danh » va danh, dia danh, nam danh
cac toc » cac toi, cac nuoc, cac thoi
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
ve cac » va cac, vien cac
toc xa » tuc xa, toc ta, hoc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky ((nang ma) or (tang van)) hoi. hieu ve cac toc xa danh ((doi cua) OR (dai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky ((nang ma) OR (tang van)) hoi. hieu ve cac toc xa danh ((doi cua) OR (dai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky ((nang ma) or (tang van)) hoi. hieu ve cac toc xa danh ((doi cua) OR (dai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang ma) or (tang van)) hoi. hieu ve cac toc xa danh ((doi cua) OR (dai cua)) tre*.