Problems on searching references

I have found that some problems when searching references.

For example, when i searched "circulation" in Jounal, references in Circulation will not be displayed, and when i search "vessels" in Jounal, but references in Heart And Vessels can not be found. I found that search in abstract can be the most efficient.

I performed search in the "Advanced Search" option.

Advance Seach is case

Advance Seach is case sensitive. Fast Search is case insensitive.