Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
thu xang » thu hang, thu dang, thu sang
viet cua » viec cua, viet ca, viet qua
thu bang » thu ban, thu hang, chu bang
van dinh » van minh, van dich, xuan dinh
va dinh » va kinh, va tinh, vu dinh
cua tre » cua te, cuu tre, cua triet
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac

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 ((thu xang) or (thu bang)) xa hoi. hieu ve cac duc ((van dinh) OR (va dinh)) viet cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ((thu xang) OR (thu bang)) xa hoi. hieu ve cac duc ((van dinh) OR (va dinh)) viet cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ((thu xang) or (thu bang)) xa hoi. hieu ve cac duc ((van dinh) OR (va dinh)) viet cua tre*".