Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
dat khanh » van khanh, duy khanh
dan hanh » dang hanh, dan khanh, dan thanh
cac tren » ca tren, cau tren, rac tren
bo sach » co sach, hoc sach
sach ky » sac ky, sach y, sach ty
thi van » thi lan, thi hanh, thi nang
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: bo sach ky nang x hoi. ((thien van) or (thi van)) nham thuc ((dan hanh) or (dat khanh)) va cac tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: bo sach ky nang x hoi. ((thien van) OR (thi van)) nham thuc ((dan hanh) OR (dat khanh)) va cac tren.
• Adding a wildcard symbol may retrieve word variants: bo sach ky nang x hoi. ((thien van) or (thi van)) nham thuc ((dan hanh) or (dat khanh)) va cac tren*.