Perhaps you should try some spelling variations:
nhan duc » nhan duoc, nhan luc, phan duc
dau tren » dau tien, dat tren, dau tieng
nang xa » lang xa, nang ma, mang xa
hieu va » lieu va, hieu qua
va nhan » van nhan, ca nhan, va phan
va danh » va dinh, va dan, va hanh
danh ve » dinh ve, hanh ve, anh ve
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
ve dau » va dau, ve du, ke dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky ((nang xa) or (nang x)) hoi. hieu va nhan duc va danh ve dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((nang xa) OR (nang x)) hoi. hieu va nhan duc va danh ve dau tren.
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((nang xa) or (nang x)) hoi. hieu va nhan duc va danh ve dau tren*.