Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
doanh va » doan va, doanh tai, doanh cua
va doanh » van doanh, vay doanh, va danh
chat lua » chat cua, chat va, chat huu
chat luc » chat xuc, nhan luc, chat huu
hieu ve » hieu va, hieu van
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ((ky lang) or (ky dang)) xa hoi. hieu ve ((chat luc) OR (chat lua)) va doanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ((ky lang) OR (ky dang)) xa hoi. hieu ve ((chat luc) OR (chat lua)) va doanh va cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ((ky lang) or (ky dang)) xa hoi. hieu ve ((chat luc) OR (chat lua)) va doanh va cua tre*".