How to cover formatting problem while converting some pdf to word documents?

Hi to everyone. I have some files in PDF format and now convert into MS Word but whenever I try to convert some pdf to word format, appearance and text style disturb in Converted MS word file and it seems very hard to set all formats and layout again. I have tried many software available on the internet but none of them is covering this problem. Anyway some difference occurs at conversion. Please show some guidance.
