Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, mang xa
cac duc » cac du, cao duc, cac dac
va danh » va dinh, va dan, va hanh
danh di » danh du, xanh di, danh dien
nang ma » tang ma, sang ma, nang cao
sach v » sach va, sach 2, sach vay
di cau » da cau, diem cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc ((sach v) or (sach y)) ((nang xa) or (nang ma)) hoi. hieu va cac duc va danh di cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach v) OR (sach y)) ((nang xa) OR (nang ma)) hoi. hieu va cac duc va danh di cau tren.
• Adding a wildcard symbol may retrieve word variants: toc ((sach v) or (sach y)) ((nang xa) or (nang ma)) hoi. hieu va cac duc va danh di cau tren*.