Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
nang mai » nang ma, nang tai, lang mai
mai khoi » mai khoa, tai khoa, cac khoi
sach ky » sac ky, sach y, sach ty
vai cau » va cau, van cau, vai cac
dan vai » dan va, dan tai, dan vat
su sach » so sach, vu sach
hieu ve » hieu van
hieu va » lieu va, hieu qua
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, tuc xa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang mai khoi. ((hieu ve) or (hieu va)) cam ((xuc va) OR (tuc va)) dan vai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang mai khoi. ((hieu ve) OR (hieu va)) cam ((xuc va) OR (tuc va)) dan vai cau tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang mai khoi. ((hieu ve) or (hieu va)) cam ((xuc va) OR (tuc va)) dan vai cau tren*".