Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam tu
cau tren » cu tren, dau tren, ca tren
dat tren » dat trong, dua tren
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
lieu ha » lieu nha, lieu va, liem ha
han tai » hang tai, nhan tai, van tai
va han » va phan, van han, va hanh
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: tu sach ky nang x hoi. lieu ha ((nam thuc) OR (nam thu)) va han tai ((cau tren) or (dat tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. lieu ha ((nam thuc) OR (nam thu)) va han tai ((cau tren) OR (dat tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. lieu ha ((nam thuc) OR (nam thu)) va han tai ((cau tren) or (dat tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. lieu ha ((nam thuc) OR (nam thu)) va han tai ((cau tren) or (dat tren))*.