aclm/((("polymer electrolyte membrane" or pem) and ("fuel cells" or "fuel cell")) or pemfc) AND aclm/(reform$ and catalyst$) AND aclm/("carbon monoxide" or co)
14
10
140%
aclm/((("polymer electrolyte membrane" or pem) and ("fuel cells" or "fuel cell")) or pemfc) AND aclm/(reform$ and catalyst$) NOT aclm/("carbon monoxide" or co) AND spec/("carbon monoxide" or co)
1
2
50%
aclm/((("polymer electrolyte membrane" or pem) and ("fuel cells" or "fuel cell")) or pemfc) NOT aclm/(reform$ and catalyst$) AND aclm/("carbon monoxide" or co) AND spec/(reform$ and catalyst$)
19
18
105.5%
NOT aclm/((("polymer electrolyte membrane" or pem) and ("fuel cells" or "fuel cell")) or pemfc) AND aclm/(reform$ and catalyst$) AND aclm/("carbon monoxide" or co) AND spec/((("polymer electrolyte membrane" or pem) and ("fuel cells" or "fuel cell")) or pemfc)