Perhaps you should try some spelling variations:
nhanh hai » nhanh thai, thanh hai, nganh hai
toc sach » hoc sach, doc sach, thuoc sach
nang mai » nang ma, nang tai, lang mai
nhanh ha » thanh hoa, thanh hai, khanh hoa
cam duc » cam xuc, cao duc, pham duc
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
hieu ve » hieu van
mai hoi » mai khoi, dai hoi, lai hoi

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 nang mai hoi. ((hieu ve) OR (hieu va)) cam duc va ((nhanh hai) or (nhanh ha)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang mai hoi. ((hieu ve) OR (hieu va)) cam duc va ((nhanh hai) OR (nhanh ha)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang mai hoi. ((hieu ve) OR (hieu va)) cam duc va ((nhanh hai) or (nhanh ha)) cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang mai hoi. ((hieu ve) OR (hieu va)) cam duc va ((nhanh hai) or (nhanh ha)) cua tre*.