全文获取类型
收费全文 | 11397篇 |
免费 | 1149篇 |
国内免费 | 16篇 |
出版年
2022年 | 98篇 |
2021年 | 228篇 |
2020年 | 152篇 |
2019年 | 147篇 |
2018年 | 187篇 |
2017年 | 160篇 |
2016年 | 274篇 |
2015年 | 425篇 |
2014年 | 481篇 |
2013年 | 551篇 |
2012年 | 705篇 |
2011年 | 738篇 |
2010年 | 505篇 |
2009年 | 397篇 |
2008年 | 640篇 |
2007年 | 639篇 |
2006年 | 621篇 |
2005年 | 589篇 |
2004年 | 502篇 |
2003年 | 480篇 |
2002年 | 493篇 |
2001年 | 158篇 |
2000年 | 150篇 |
1999年 | 162篇 |
1998年 | 135篇 |
1997年 | 95篇 |
1996年 | 93篇 |
1995年 | 103篇 |
1994年 | 87篇 |
1993年 | 76篇 |
1992年 | 94篇 |
1991年 | 100篇 |
1990年 | 100篇 |
1989年 | 91篇 |
1988年 | 86篇 |
1987年 | 62篇 |
1986年 | 69篇 |
1985年 | 76篇 |
1984年 | 72篇 |
1983年 | 64篇 |
1982年 | 81篇 |
1981年 | 100篇 |
1980年 | 100篇 |
1979年 | 61篇 |
1978年 | 63篇 |
1977年 | 62篇 |
1976年 | 73篇 |
1975年 | 64篇 |
1973年 | 57篇 |
1972年 | 59篇 |
排序方式: 共有10000条查询结果,搜索用时 687 毫秒
11.
Enzymes are remarkable molecules which make metabolism possible. Their processing powers are considerable for not only are they catalysts they also contribute to information processing, integration, coherence and memory in the cell. This complex of attributes suggests that a complementary perspective to enzyme nature and activity is needed related to what enzymes and verbs have in common. The value of this kind of thinking is that it shifts the focus from objects and mechanisms to processes and information. In order to support this idea a number of features which enzymes and verbs share are discussed including, context-dependence, occurrence, cases, voice, mood and glue/integrative capacities. The paper concludes with some reflections on the utility of a view of enzymes as verbs. 相似文献
12.
13.
R T Francis R R Becker 《Comparative biochemistry and physiology. A, Comparative physiology》1984,79(1):109-113
The capability of Taricha granulosa to conserve hemoglobin upon in vivo hemolysis has been investigated. 59Fe incorporation into Taricha hemoglobin was similar in rate to mammals and birds. Phenylhydrazine-induced hemolysis resulted in comparatively low levels of 59Fe and no discernible amounts of hemoglobin excreted after 10 days. The addition of 59Fe Hb to Taricha circulation resulted in relatively low levels of 59Fe excretion and significant amounts of 59Fe incorporation into new hemoglobin within 10 days. 相似文献
14.
15.
Willoughby de Broke Rudyard Kipling Hugh Elliot E. Ray Lankester Leonard Hill Laurence R. Philipps Wm. Arbuthnot Lane James Crichton-Browne H. Bryan Donkin Francis Lloyd R. A. Lyster John MacAlister F. W. Mott William Osler C. W. Saleeby J. H. Sequeira Humphry Rolleston Hugh Wansey Bayly 《BMJ (Clinical research ed.)》1919,2(3074):725
16.
17.
18.
James E. Boggan Julian T. Hoff Edwin B. Boldrey William M. Wara 《The Western journal of medicine》1980,133(2):108-114
Thirty cases of intraspinal neoplasms occurring during the first two decades of life are reviewed. Histologic examination showed 13 of these to be astrocytomas, 6 neuroblastomas, 5 sarcomas, 3 ependymomas, 2 neurofibromas and 1 a schwannoma. Orthopedic deformities developed or worsened in 60 percent of patients surviving longer than a year after diagnosis. In five patients some form of endocrine deficiency developed after irradiation. For treatment of radiosensitive extradural malignant lesions, biopsy followed by irradiation is advocated. 相似文献
19.
20.
The cat hindlimb contains several long, biarticular strap muscles composed of parallel muscle fascicles that attach to short tendons. Three of these muscles--sartorius, tenuissimus, and semitendinosus--were studied by dissecting individual gold-stained fibers and determining the surface distribution of acetylcholinesterase-stained end-plate zones. In each muscle, fascicles were composed of muscle fibers that ran only part of the fascicle length and tapered to end as fine strands that interdigitated with other tapering fibers within the muscle mass. Most muscle fibers measured 2-3 cm in length. Fascicles of muscle fibers were crossed by short transverse bands of endplates (1 mm wide by 1-5 mm long) that were spaced at fairly regular intervals from the origin to the insertion of the muscle. The endplate pattern suggested that the fiber fascicles were organized into multiple longitudinal strips. In the sartorius, the temporospatial distribution of electromyographic (EMG) activity evoked by stimulating fine, longitudinal branches of the parent nerve confirmed that each strip was selectively innervated by a small subset of the motor axons. These axons appeared to distribute their endings throughout the entire length of the fascicles, providing for synchronous activation of their in-series fibers. 相似文献