Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh tai » thanh tai, hang tai, han tai
ve pham » vi pham, v pham, ve phat
tai cua » thai cua, tai cuc, tri cua
va hanh » van hanh, va thanh, va danh
ve phan » va phan, ke phan, ve phat
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
v nang » va nang, vu nang, van nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) v nang ma hoi. hieu ((ve pham) or (ve phan)) duc va hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) v nang ma hoi. hieu ((ve pham) OR (ve phan)) duc va hanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) v nang ma hoi. hieu ((ve pham) or (ve phan)) duc va hanh tai cua tre*.