Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
ban hang » ngan hang
thuc ban » thuoc ban, thuc dan, thu ban
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
may hoi » may thoi, tay hoi, mai hoi
ke mang » ke nang, ke trang
ky mang » ky nang, ky dang, ky tang
vai cua » dai cua, hai cua, lai cua
vi cua » di cua
tu sai » tu bai, tu san, tu cai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sai ((ky mang) or (ke mang)) may hoi. hieu van tham thuc ban hang ((vi cua) OR (vai cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sai ((ky mang) OR (ke mang)) may hoi. hieu van tham thuc ban hang ((vi cua) OR (vai cua)) triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sai ((ky mang) or (ke mang)) may hoi. hieu van tham thuc ban hang ((vi cua) OR (vai cua)) triet*".