Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
dau tren » dau tien, dat tren, dau tieng
cua viet » ca viet, hoa viet, cua vat
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
hieu vi » hieu voi, hieu va, hieu ve
va hanh » va thanh, va danh, ban hanh
x hoi » xa hoi, o hoi, x ho
pham » phan

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 ty nang x hoi. hieu vi pham duc ((va hanh) OR (van hanh)) di ((dau tren) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang x hoi. hieu vi pham duc ((va hanh) OR (van hanh)) di ((dau tren) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty nang x hoi. hieu vi pham duc ((va hanh) OR (van hanh)) di ((dau tren) or (cua viet))".
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang x hoi. hieu vi pham duc ((va hanh) OR (van hanh)) di ((dau tren) or (cua viet))*.