全文获取类型
收费全文 | 1475篇 |
免费 | 152篇 |
出版年
2021年 | 16篇 |
2018年 | 18篇 |
2017年 | 15篇 |
2016年 | 19篇 |
2015年 | 41篇 |
2014年 | 45篇 |
2013年 | 42篇 |
2012年 | 54篇 |
2011年 | 50篇 |
2010年 | 24篇 |
2009年 | 31篇 |
2008年 | 30篇 |
2007年 | 41篇 |
2006年 | 45篇 |
2005年 | 32篇 |
2004年 | 48篇 |
2003年 | 50篇 |
2002年 | 45篇 |
2001年 | 40篇 |
2000年 | 42篇 |
1999年 | 40篇 |
1997年 | 18篇 |
1996年 | 21篇 |
1994年 | 27篇 |
1993年 | 17篇 |
1992年 | 45篇 |
1991年 | 33篇 |
1990年 | 36篇 |
1989年 | 45篇 |
1988年 | 36篇 |
1987年 | 36篇 |
1986年 | 32篇 |
1985年 | 24篇 |
1984年 | 26篇 |
1983年 | 25篇 |
1982年 | 21篇 |
1981年 | 15篇 |
1980年 | 17篇 |
1979年 | 21篇 |
1978年 | 30篇 |
1977年 | 29篇 |
1976年 | 24篇 |
1975年 | 23篇 |
1974年 | 24篇 |
1973年 | 33篇 |
1972年 | 16篇 |
1971年 | 21篇 |
1970年 | 14篇 |
1969年 | 14篇 |
1968年 | 20篇 |
排序方式: 共有1627条查询结果,搜索用时 187 毫秒
61.
Peter W. Marks Benjamin A. Kruskal Frederick R. Maxfield 《Journal of cellular physiology》1988,136(3):519-525
The calcium-sensitive fluorescent indicator fura-2 and a microscope equipped for rapidly changing excitation wavelengths were used to look at the effects of growth factors on cytosolic free calcium ([Ca2+]i,) in NRK-49F cells. In these cells bradykinin induced a rapid increase in [Ca2+]i, which generally decayed to near basal [Ca2+]i within 3 minutes. The initial rise in [Ca2+]i in response to bradykinin was relatively independent of extracellular calcium; however, the decay to basal [Ca2+]i was more rapid in the absence of extracellular calcium. Measurements made on individual cells showed a heterogeneity in the response to bradykinin. Epidermal growth factor (EGF) had no effect on [Ca2+]i in NRK-49F cells when added alone in the presence of extracellular calcium. Simultaneous addition of bradykinin and EGF produced a more prolonged increase in [Ca2+]i than bradykinin alone. The prolongation was dependent on the presence of extracellular calcium and did not occur in its absence. Transient increases in [Ca2+]i occurring after the initial peak were occasionally seen in these cells. Our results indicate that there is rapid interaction between the signaling mechanisms for bradykinin and EGF. When this occurs, one effect is the transport of calcium into the cell from the extracellular environment, causing a more prolonged rise in [Ca2+]i. This effect occurs within 1 minute after combined addition of bradykinin and EGF. 相似文献
62.
An acidic sequence within the cytoplasmic domain of furin functions as a determinant of trans-Golgi network localization and internalization from the cell surface. 总被引:29,自引:7,他引:22 下载免费PDF全文
P Voorhees E Deignan E van Donselaar J Humphrey M S Marks P J Peters J S Bonifacino 《The EMBO journal》1995,14(20):4961-4975
The mammalian endopeptidase, furin, is predominantly localized to the trans-Golgi network (TGN) at steady state. The localization of furin to this compartment seems to be the result of a dynamic process in which the protein undergoes cycling between the TGN and the plasma membrane. Both TGN localization and internalization from the plasma membrane are mediated by targeting information contained within the cytoplasmic domain of furin. Here, we report the results of a mutagenesis analysis aimed at identifying the source(s) of targeting information within the furin cytoplasmic domain. Our studies show that there are at least two cytoplasmic determinants that contribute to the steady-state localization and trafficking of furin. The first determinant corresponds to a canonical tyrosine-based motif, YKGL (residues 758-761), that functions mainly as an internalization signal. The second determinant consists of a strongly hydrophilic sequence (residues 766-783) that contains a large cluster of acidic residues (E and D) and is devoid of any tyrosine-based or di-leucine-based motifs. This second determinant is capable of conferring localization to the TGN as well as mediating internalization from the plasma membrane. Thus, these observations establish the existence of a novel, autonomous determinant distinct from sorting signals described previously. 相似文献
63.
64.
Neville Marks Martin J. Berg Abba J. Kastin David H. Coy 《Neurochemistry international》1984,6(3):347-353
N-Tyr-MIF-1 (Tyr-Pro-Leu-Gly·NH2), an immunoreactive neuropeptide exhibiting saturable high affinity binding in rat brain was found to be converted into MIF-1 (Pro-Leu-Gly·NH2) by a specific brain aminopeptidase present in rat brain homogenates or cytosol, but with low activity associated with synaptosomal plasma membranes and microsomes. Conversion occurred at a rate of 16 μmol per g w/wt per h and was unaffected by puromycin but inhibited by bestatin (I50, 5 × 10?5 M). Aminopeptidases purified from cytosolic fractions of rat brain (arylamidase), mouse brain (Mn2+-activated aminopeptidase) or porcine kidney (leucine aminopeptidase) were inactive towards N-Tyr-MIF-1 but degraded MIF-1 with release of Leu-Gly·NH2 as detected by RP-HPLC procedures. Morphiceptin (Tyr-Pro-Phe-Pro·NH2), a μ opioid agonist, also acted as a substrate for the N-Tyr-MIF-1 converting enzyme with cleavage of the Tyr-Pro bond. These tetrapeptides, but not MIF-1 or its N-blocked analogs, were degraded in vitro by a metalloendopeptidase purified from kidney membranes. Since dipeptide products were not detected for crude extracts, a significant role for brain metalloendopeptidase on turnover can be excluded. Thus the results point to the presence of a specific (X-Pro-degrading) aminopeptidase in brain cytosol as an enzyme responsible for converting N-Tyr-MIF-1 and inactivating morphiceptin. 相似文献
65.
66.
Vincent Marks 《BMJ (Clinical research ed.)》1984,289(6455):1379-1380
67.
68.
69.
G. E. Marks 《Chromosoma》1977,62(4):369-373
Derived telocentric chromosomes in Nigella doerfleri have pairs of Giemsa staining dots at their terminal centromeres which appear in size and behaviour to be identical with the centromeric dots of their submetacentric homologue. The telocentric chromosomes are stable and therefore their centromeres are functional and probably complete. That the centromeres also possess centromeric dots indicates that the dots represent essential components of the centromere, a conclusion which supports the contention that they are kinetochores. 相似文献
70.
Arrangement of lambda light chain genes in mutant clones of the MOPC 315 mouse myeloma cells 总被引:2,自引:0,他引:2
N Hozumi G Wu H Murialdo R Baumal T Mosmann L Winberry A Marks 《Journal of immunology (Baltimore, Md. : 1950)》1982,129(1):260-266
The synthesis of lambda light chains and the arrangement of the lambda-chain genes was examined in cells of the mouse myeloma MOPC 315, which is an alpha lambda 2 producer, and in several mutants derived from it. The mutants produce lambda 2 chains only (MOPC 315.26, MOPC 315.34, and MOPC 315.37) or fail to produce alpha and lambda 2 chains (MOPC 315.25 and MOPC 315.36). Messenger RNA from the lambda 2 chain-producing cells directed the synthesis of a lambda 2 chain precursor and a fragment of the lambda 1 chain (lambda 1 F) in a wheat embryo cellfree system, whereas mRNA from the cells that do not produce lambda 2 chains directed the synthesis of lambda 1 F only. DNA from the parental MOPC 315 cells and from the lambda 2 chain-producing cells contained discrete EcoRI restriction fragments coding for rearranged lambda 1 and lambda 23 chain genes and their respective germ-line V and J-C regions. DNA from the no-Ig-producing cells contained fragments coding for the rearranged lambda 1 chain gene and the germ-line V lambda 2 region, but it lacked the sequences coding for the rearranged lambda 2 chain gene and the germ-line V lambda 1 and J-C lambda 1 regions. These results suggest that rearrangements of the lambda 1 and lambda 2 chain genes occur on different chromosomes in MOPC 315 cells and imply that rearrangements of the lambda 1 and lambda 2 chain genes on the same chromosome may be mutually exclusive. 相似文献