The following are the published enactments of the U.S. Congress through 2007. The formats are PDF image-over-character, so are searchable. The following sources are available:

1. Library of Congress American Memory Project, Statutes at Large 1789-1875
2. Archive.org: All volumes of the Statutes at Large
3. GovInfo: United States States at Large, Volumes 65 (1951) through 127 (2013)
4. What is Taxed: Links are broken
5. SEDM Member Subscriptions: Requires Member Subscriber account to view

The volumes below are all statutes for the years indicated, although some years are divided. The omitted volumes 6-8 deal with treaties, post offices and roads, DC laws, etc. If you want to see those laws as they appeared in the mid 1870s, then look at the Revised Statutes.

Volume Number	Year(s)	Library Of Congress (LOC)	Archive.org	GovInfo
1	1789-1799
2	1799-1813
3	1813-1823
4	1835-1845
5	1835-1845
6	1789-1845
7	1778-1842
8	1778-1845
9	1845-1851
10	1851-1855
11	1855-1859
12	1859-1863
13	1863-1865
14	1865-1867
15	1867-1869
16	1869-1871
17	1871-1873
18	1873-1875
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65	1951
66	1952
67	1953
68	1954
69	1955
70	1956
71	1957
72	1958
73	1959
74	1960
75	1961
76	1962
77	1963
78	1964
79	1965
80	1966
81	1967
82	1968
83	1969
84	1970
85	1971
86	1972
87	1973
88	1974
89	1975
90	1976
91	1977
92	1978
93	1979
94	1980
95	1981
96	1982
97	1983
98	1984
99	1985
100	1986
101	1987
102	1988
103	1989
104	1990
105	1991
106	1992
107	1993
108	1994
109	1995
110	1996
111	1997
112	1998
113	1999
114	2000
115	2001
116	2002
117	2003
118	2004
119	2005
120	2006
121	2007
122	2008
123	2009
124	2010
125	2011
126	2012
127	2012

NOTES:

In addition to the above:

1. Various Revenue Acts may be found at Historial Federal Income Tax Acts, Family Guardian Fellowship.
2. State income tax acts may be found on State Legal Resources Page, Family Guardian Fellowship
3. Extensive legal research information is available on Legal Research Sources, Family Guardian Fellowship