Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
hieu ve » hieu va, hieu van
cuu tre » cua tre, cau tren, cau treo
y lang » o lang, tay lang, yen lang
_ lang » o lang, _ land
ve cam » ve cham, ve cac, va cam
cam tu » cam thu, nam tu, dam tu
tu van » tu va
vi cuu » vi luu, vinh cuu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ((y lang) OR (_ lang)) xa hoi. hieu ve cam tu van hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ((y lang) OR (_ lang)) xa hoi. hieu ve cam tu van hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ((y lang) OR (_ lang)) xa hoi. hieu ve cam tu van hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ((y lang) OR (_ lang)) xa hoi. hieu ve cam tu van hanh vi cuu tre*.