Perhaps you should try some spelling variations:
day nhanh » day thanh, duy nhanh, dac nhan
cam thuc » am thuc, nam thuc, cam thu
day manh » van manh, duc manh, ha manh
hieu van » hieu va, thien van, lieu va
van cam » van nam, van lam, van cau
sach ky » sach y, sach ty, sach kem
sac ky » cac ky, sai ky
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

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) or (sac ky)) nang x hoi. hieu van cam thuc ((day manh) or (day nhanh)) dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu ((sach ky) OR (sac ky)) nang x hoi. hieu van cam thuc ((day manh) OR (day nhanh)) dai cua te.
• Adding a wildcard symbol may retrieve word variants: vu ((sach ky) or (sac ky)) nang x hoi. hieu van cam thuc ((day manh) or (day nhanh)) dai cua te*.