Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
yen lang » den lang, ten lang, yen giang
thuc ban » thuoc ban, thuc dan, thu ban
tuc ban » truc ban, tu ban, tuc dan
va cham » va chat, va tham
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
_ lang » o lang, _ land
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 ((yen lang) or (_ lang)) van hoa. hieu va cham ((tuc ban) OR (thuc ban)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ((yen lang) OR (_ lang)) van hoa. hieu va cham ((tuc ban) OR (thuc ban)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ((yen lang) or (_ lang)) van hoa. hieu va cham ((tuc ban) OR (thuc ban)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: doc sach ((yen lang) or (_ lang)) van hoa. hieu va cham ((tuc ban) OR (thuc ban)) hanh vi cua tre*.