Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
qua tham » qua cham, qua than, qua thanh
hanh tai » thanh tai, hang tai, han tai
hanh vai » hanh vi, hanh va, hanh van
thuc ban » thuoc ban, thuc dan, thu ban
cua viet » ca viet, hoa viet, cua vat
may hoi » may thoi, tay hoi, mai hoi
ky mang » ky nang, ke mang, ky dang
tu sach » thu sach, su sach, te sach
tu sac » tu cac, tu san, tu bac

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sac) or (tu sach)) ky mang may hoi. hieu qua tham thuc ban ((hanh vai) or (hanh tai)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sac) OR (tu sach)) ky mang may hoi. hieu qua tham thuc ban ((hanh vai) OR (hanh tai)) cua viet.
• Adding a wildcard symbol may retrieve word variants: ((tu sac) or (tu sach)) ky mang may hoi. hieu qua tham thuc ban ((hanh vai) or (hanh tai)) cua viet*.