Perhaps you should try some spelling variations:
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
nuoc van » nuoc va, nuoc san, luoc van
hanh lai » hanh lam, hanh tai, thanh lap
van hanh » van thanh, ban hanh, van anh
cua tre » cua te, cua triet, dua tren
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
cuu tre » cau tren, cau treo

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 lang) OR (ky dang)) xa hoi. hieu va cac nuoc van hanh lai ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky lang) OR (ky dang)) xa hoi. hieu va cac nuoc van hanh lai ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky lang) OR (ky dang)) xa hoi. hieu va cac nuoc van hanh lai ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky lang) OR (ky dang)) xa hoi. hieu va cac nuoc van hanh lai ((cua tre) or (cuu tre))*.