The requested file:
https://pdf.datasheetcatalog.com/datasheets/120/236599_DS.pdf
is the data sheet for the following electronic components:

National Semiconductor

#	Part Name	Description
1	54157DMQB	Quad 2-Line to 1-Line Data Selectors/Multiplexers
2	54157FMQB	Quad 2-Line to 1-Line Data Selectors/Multiplexers
3	74157	Quad 2-Line to 1-Line Data Selectors/Multiplexers
4	DM54157J	Quad 2-Line to 1-Line Data Selectors/Multiplexers
5	DM54157W	Quad 2-Line to 1-Line Data Selectors/Multiplexers
6	DM74157N	Quad 2-Line to 1-Line Data Selectors/Multiplexers

Select the part name and then you can download the datasheet in PDF format.