全文获取类型
收费全文 | 306170篇 |
免费 | 37511篇 |
国内免费 | 205篇 |
专业分类
343886篇 |
出版年
2016年 | 3099篇 |
2015年 | 4645篇 |
2014年 | 5380篇 |
2013年 | 7604篇 |
2012年 | 8648篇 |
2011年 | 8585篇 |
2010年 | 5910篇 |
2009年 | 5548篇 |
2008年 | 7862篇 |
2007年 | 8024篇 |
2006年 | 7605篇 |
2005年 | 7583篇 |
2004年 | 7412篇 |
2003年 | 7465篇 |
2002年 | 7164篇 |
2001年 | 11325篇 |
2000年 | 11425篇 |
1999年 | 9473篇 |
1998年 | 3791篇 |
1997年 | 3907篇 |
1996年 | 3894篇 |
1995年 | 3627篇 |
1994年 | 3631篇 |
1993年 | 3586篇 |
1992年 | 8368篇 |
1991年 | 8143篇 |
1990年 | 7958篇 |
1989年 | 7862篇 |
1988年 | 7429篇 |
1987年 | 7365篇 |
1986年 | 6829篇 |
1985年 | 7026篇 |
1984年 | 5921篇 |
1983年 | 5319篇 |
1982年 | 4288篇 |
1981年 | 4122篇 |
1980年 | 3773篇 |
1979年 | 6086篇 |
1978年 | 4794篇 |
1977年 | 4574篇 |
1976年 | 4358篇 |
1975年 | 4719篇 |
1974年 | 5185篇 |
1973年 | 5075篇 |
1972年 | 4683篇 |
1971年 | 4219篇 |
1970年 | 3748篇 |
1969年 | 3762篇 |
1968年 | 3343篇 |
1967年 | 2900篇 |
排序方式: 共有10000条查询结果,搜索用时 6 毫秒
151.
W P Hempfling 《Biochimica et biophysica acta》1970,205(2):169-182
152.
Summary The iliofibularis muscle ofXenopus laevis is reported to contain five types of fibres which have different force—velocity relationships. Ten fibres of each type were selected on the basis of succinate dehydrogenase activity, cross-sectional area and location in the muscle, in order to assess the validity of the fibre type classification.Maximum calcium-stimulated myofibrillar ATPase activity (V
max) and apparent Michaelis constant (K
m) for ATP were determined for these 50 fibres from serial sections. The values obtained varied according to the type of fibre. Type 1 had the highest and type 5 the lowest values forK
m andV
max.In a separate experiment, single freeze-dried fibres were used to determine the relationship between their ATP content and apparentK
m for ATP. There was a tendency for high ATP concentrations in fibres with highK
m values.When myofibrillar ATPase activity was related to the maximum velocity of shortening of the five fibre types, a significant correlation was found. It is concluded that calcium-stimulated myofibrillar ATPase histochemistry allows an estimate of the maximum shortening velocity of muscle fibres fromXenopus laevis. 相似文献
153.
Summary Pleiotropic mutants of Serratia marcescens have been isolated. They synthesize greater quantities of the bacteriocin marcescin A and exocellular lipase and exhibit higher rates of spontaneous induction of prophage than does the wild-type strain. These mutants were found to contain more marcescin A plasmid DNA than the parent strain and, furthermore, this increase in plasmid DNA was observed to be proportional to the increase in synthesis of marcescin A. From these results it is proposed that the mutation functions via a gene-dosage effect (at least in the case of bacteriocin synthesis) and causes an elevated synthesis of bacteriocin plasmid DNA.A preliminary report of this work was presented to the 1972 Summer Meeting of the Gesellschaft für Physiologische Chemie held in Bochum, Germany (Timmis and Winkler, 1972). 相似文献
154.
155.
AS it is not widely appreciated that diffusion within complex media can be strikingly and often qualitatively different from that in simple liquids such as water, there is confusion concerning transport processes across biological membranes1,2. We would like to draw attention to some fundamental differences between the diffusion process in simple liquids and that in more complex media-non-porous networks of hydrophobic polymers and biological membranes. 相似文献
156.
157.
R factors of compatibility group A 总被引:4,自引:0,他引:4
158.
159.
160.