Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va danh, ban hanh
cu tren » tu tren, dua tren
nam tu » nam thu, nam thuc
vi cu » vi su, vi xu, vi du

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 nang x ho. hieu van nam tu ((va hanh) OR (va thanh)) vi cu tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x ho. hieu van nam tu ((va hanh) OR (va thanh)) vi cu tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x ho. hieu van nam tu ((va hanh) OR (va thanh)) vi cu tren*.