Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
hanh tai » thanh tai, hang tai, han tai
luc van » luoc van, luu van, duc van
cau luc » cau truc, cau phuc
van cau » van dau, van hau, van chat
xu lang » cu lang, xu dang, xu quang
tu lang » cu lang, tu lanh, tu quang
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((tu lang) OR (xu lang)) xa hoi. hieu van cau luc van ((thanh san) or (hanh tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((tu lang) OR (xu lang)) xa hoi. hieu van cau luc van ((thanh san) OR (hanh tai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((tu lang) OR (xu lang)) xa hoi. hieu van cau luc van ((thanh san) or (hanh tai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ((tu lang) OR (xu lang)) xa hoi. hieu van cau luc van ((thanh san) or (hanh tai)) cua tre*.