Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
ban hanh » ban hang
va danh » va dinh, va dan, va hanh
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
dung ha » dung va, dung he, dung khoa
tang ha » lang ha, tang ma, trung ha
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ky ((tang ha) or (dung ha)) hoi. hieu va cam xuc ((ban hanh) or (va danh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky ((tang ha) OR (dung ha)) hoi. hieu va cam xuc ((ban hanh) OR (va danh)) vi cua tre.
• Adding a wildcard symbol may retrieve word variants: doc sach ky ((tang ha) or (dung ha)) hoi. hieu va cam xuc ((ban hanh) or (va danh)) vi cua tre*.