Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, doc sach, nuoc sach
van tuan » van quan, van ban, anh tuan
nang mai » nang ma, nang tai, lang mai
cua tre » cuu tre, cua triet, dua tren
luc van » luoc van, luu van, duc van
cau luc » cau truc, cau phuc
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ve cau » ke cau, va cau, ve cac
v nang » va nang, vu nang, van nang
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) OR (thuoc sach)) v nang mai hoi. hieu ve cau luc van tuan le ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuoc sach)) v nang mai hoi. hieu ve cau luc van tuan le ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (thuoc sach)) v nang mai hoi. hieu ve cau luc van tuan le ((cua tre) or (cua te))".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (thuoc sach)) v nang mai hoi. hieu ve cau luc van tuan le ((cua tre) or (cua te))*.