Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
may duc » mai duc, my duc
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
cac tuc » cac toc, cac tu, cac tac
hieu ve » hieu va, hieu van
ky danh » ky anh
ky dang » ky nang
duc tre » duoc tren, duc tien
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: tu sach ((ky dang) or (ky danh)) ma hoa. hieu ve cac tuc ((va hanh) OR (va danh)) may duc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky dang) OR (ky danh)) ma hoa. hieu ve cac tuc ((va hanh) OR (va danh)) may duc tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky dang) or (ky danh)) ma hoa. hieu ve cac tuc ((va hanh) OR (va danh)) may duc tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky dang) or (ky danh)) ma hoa. hieu ve cac tuc ((va hanh) OR (va danh)) may duc tre*.