Perhaps you should try some spelling variations:
thanh vai » thanh van, thanh tai, thanh oai
thanh hai » thanh phan, thanh hoa, thanh san
thu sach » tu sach, thuat sach, thuoc sach
dang mai » dang hai, dang mau, dang bai
luc van » luoc van, luu van, duc van
la tren » loai tren, dua tren, dat tren
sach ky » sac ky, sach y, sach ty
mai hoi » mai khoi, dai hoi, lai hoi
ky dang » ky nang, ky danh
ve cai » va cai, ve tai, ve cau
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: thu sach ky dang mai hoi. hieu ((ve cai) or (ve cac)) luc van ((thanh vai) OR (thanh hai)) la tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky dang mai hoi. hieu ((ve cai) OR (ve cac)) luc van ((thanh vai) OR (thanh hai)) la tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky dang mai hoi. hieu ((ve cai) or (ve cac)) luc van ((thanh vai) OR (thanh hai)) la tren".
• Adding a wildcard symbol may retrieve word variants: thu sach ky dang mai hoi. hieu ((ve cai) or (ve cac)) luc van ((thanh vai) OR (thanh hai)) la tren*.