Perhaps you should try some spelling variations:
day nhanh » day thanh, duy nhanh, dac nhan
hieu van » hieu va, thien van, lieu va
cam thuc » am thuc, nam thuc, cam thu
duc manh » suc manh, duc anh, duc minh
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
van cam » van nam, van lam, van cau
di cua » dai cua, doi cua, de cua
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky nang x ho. hieu van cam thuc ((duc manh) or (day nhanh)) di cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang x ho. hieu van cam thuc ((duc manh) OR (day nhanh)) di cua tu.
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang x ho. hieu van cam thuc ((duc manh) or (day nhanh)) di cua tu*.