Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dang mai » dang hai, dang mau, dang bai
mai khoi » mai khoa, tai khoa, cac khoi
van hanh » van thanh, ban hanh, van anh
xuc van » duc van, luc van, vuc van
hai cua » thai cua, dai cua, hoi cua
vai cua » dai cua, lai cua, bai cua
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh
ve 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: toc sach ky dang mai khoi. hieu ((ve cac) OR (va cac)) xuc van hanh ((vai cua) or (hai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky dang mai khoi. hieu ((ve cac) OR (va cac)) xuc van hanh ((vai cua) OR (hai cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky dang mai khoi. hieu ((ve cac) OR (va cac)) xuc van hanh ((vai cua) or (hai cua)) tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky dang mai khoi. hieu ((ve cac) OR (va cac)) xuc van hanh ((vai cua) or (hai cua)) tre*.