Perhaps you should try some spelling variations:
cap nuoc » dat nuoc
cau tren » cu tren, dau tren, ca tren
nang mai » nang ma, nang tai, lang mai
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu van
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
vi cau » va cau, ve cau, di 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 ky) or (cac ky)) nang mai hoi. ((hieu ve) or (hieu va)) cap nuoc va danh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach ky) OR (cac ky)) nang mai hoi. ((hieu ve) OR (hieu va)) cap nuoc va danh vi cau tren.
• Adding a wildcard symbol may retrieve word variants: toc ((sach ky) or (cac ky)) nang mai hoi. ((hieu ve) or (hieu va)) cap nuoc va danh vi cau tren*.