Perhaps you should try some spelling variations:
manh nhanh » danh nhan, anh nhan, danh thanh
thai cua » than cua, tai cuc, tri cua
duc manh » suc manh, duc anh, duc minh
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cau duc » cao duc, cau luc, chu duc
thi cua » thi cuc, tri cua, thi dua
van cau » van dau, van hau, van chat
ty nang » ky nang, ty xang, ty hang
sach ty » sach y, sach tu, sach thu
co hoi » co hoc, co loi
o hoi » o hoc, o hai, o hoa

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 ty nang ((o hoi) or (co hoi)). hieu van cau duc manh nhanh ((thi cua) OR (thai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((o hoi) OR (co hoi)). hieu van cau duc manh nhanh ((thi cua) OR (thai cua)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((o hoi) or (co hoi)). hieu van cau duc manh nhanh ((thi cua) OR (thai cua)) tre*".