全文获取类型
收费全文 | 629篇 |
免费 | 64篇 |
专业分类
693篇 |
出版年
2021年 | 6篇 |
2018年 | 5篇 |
2016年 | 8篇 |
2015年 | 18篇 |
2014年 | 22篇 |
2013年 | 20篇 |
2012年 | 36篇 |
2011年 | 37篇 |
2010年 | 13篇 |
2009年 | 14篇 |
2008年 | 29篇 |
2007年 | 21篇 |
2006年 | 24篇 |
2005年 | 26篇 |
2004年 | 25篇 |
2003年 | 17篇 |
2002年 | 21篇 |
2001年 | 20篇 |
2000年 | 20篇 |
1999年 | 15篇 |
1998年 | 5篇 |
1997年 | 8篇 |
1996年 | 14篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 13篇 |
1991年 | 16篇 |
1990年 | 13篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1981年 | 10篇 |
1980年 | 7篇 |
1979年 | 13篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 12篇 |
1975年 | 8篇 |
1974年 | 10篇 |
1973年 | 7篇 |
1972年 | 6篇 |
1971年 | 4篇 |
1969年 | 6篇 |
1966年 | 4篇 |
排序方式: 共有693条查询结果,搜索用时 0 毫秒
1.
2.
M R Walker A Solomon D T Weiss H F Deutsch R Jefferis 《Journal of immunology (Baltimore, Md. : 1950)》1988,140(5):1600-1604
The C region of human lambda L chains is specified by multiple C lambda genes of which three--C lambda 1, C lambda 2, and C lambda 3--encode for the isotypes designated Mcg+, Kern- Oz-, and Kern- Oz+, respectively. The Mcg, Kern, and Oz factors have been characterized by sequence differences involving specific C lambda amino acid residues. They have also been recognized serologically by polyclonal antisera but, with rare exception, these reagents are no longer available. We have obtained two murine anti-human lambda-chain mAb, 14G1 and 14D1, that recognize antigenic determinants specific for the C lambda isotypes Mcg and Oz, respectively. These antisera have been used to classify as Mcg+/Mcg- or Oz+/Oz- monoclonal lambda-chains (Bence Jones proteins) and intact Ig lambda proteins. There was complete concordance between the chemical and serologic assignment of lambda-chains as Mcg+/Mcg- or as Oz+/Oz-; no single protein expressed both isotypes. There was no evident association between the C region isotype Mcg or Oz and the V region subgroup of the protein tested. However, our finding that four of seven amyloid-associated lambda VI Bence Jones proteins were Oz+ suggests a predominant expression of the C lambda 3 gene product among proteins of this uncommon V lambda subgroup. 相似文献
3.
4.
Summary The pictures of isolated mitochondrial membranes, as seen on the electron-microscope, depend very much on the method of specimen preparation. Subunits of linear dimensions of about 25 m, (electron transport particles) are observed in carbon-replicas of the membranes and in specimens treated with trypsin or pepsin (0.02% for 30 mins) and shadowed with platinum. A three-layered structure of the unit membrane is seen in sections of specimens fixed with osmium tetroxide or formalin followed by post-fixation with osmium tetroxide. But fixation with potassium permanganate or with formalin, followed by post-fixation with potassium permanganate reveals an electron-dense globular structural element in the unit membrane. An electron-transparent ultrastructural element of the unit membrane is observed after treatment with trypsin (0.2% for 5 mins) and fixation with osmium tetroxide. Unsectioned specimens treated with 0.02% trypsin for 30 mins show a honeycomb-like structure of the membrane. Thus, part of the results appear to support the concept of a mosaic-like structure of the unit membrane, whereas other results are in agreement with the classical concept of a three-layered structure.The authors wish to express their gratitude to Dr. Sina Rosenthal, Department of Physiological Chemistry, Humboldt University, Berlin, who prepared the isolated membranes, to Mr. E. Fischer, Head Technician of the Department of Electron Microscopy, Greifswald University, who took most of the electron micrographs, to Mr. G. Bartsch, Department of Electron Microscopy, Greifswald University, and especially to Prof. W. Bargmann and to Doz. E. Lindner, Department of Anatomy, Kiel University, for many valuable suggestions. 相似文献
5.
The effects of enzymatic attack and of shear during the isolation and deproteinization of DNA have been investigated. Different methods of disaggregating DNA have been studied, and conditions under which reaggregation can occur are discussed. It was found that shaking with chloroform-octanol does not degrade DNA from the seven sources studied; that light scattering yields valid weight-average molecular weights for these samples; and that, when disaggregated, the molecular weights of these samples are in the range 1.2-2.4 million and the length-to-mass ratios are high. 相似文献
6.
Jan Hendrickx Paul Coucke Marie-Claude Hors-Cayla G. Peter A. Smit Yoon S. Shin Johann Deutsch Jan Smeitink Ruud Berger Philip Lee John Fernandes Patrick J. Willems 《Genomics》1994,21(3)
We describe here a new type of X-linked liver glycogen storage disease. The main symptoms include liver enlargement and growth retardation. The clinical and biochemical abnormalities of this glycogenosis are similar to those of classical X-linked liver glycogenosis due to phosphorylase kinase deficiency (XLG). However, in contrast to patients with XLG, the patients described here have no reduced phosphorylase kinase activity in erythrocytes and leukocytes, and no enzyme deficiency could be found. Linkage analysis of four families with this X-linked type of liver glycogenosis assigned the disease gene to Xp22. Lod scores obtained with the markers DXS987, DXS207, and DXS999 were 3.97, 2.71, and 2.40, respectively, all at 0% recombination. Multipoint linkage analysis localized the disease gene between DXS143 and DXS989 with a maximum lod score of 4.70 at θ = 0, relative to DXS987. As both the classical XLG gene and the liver α-subunit of PHK (PHKA2) are also located in Xp22, this variant type of XLG may be allelic to classical XLG, and both diseases may be caused by mutations in PHKA2. Therefore, we propose to classify XLG as XLG type I (the classical type of XLG) and XLG type II (the variant type of XLG). 相似文献
7.
8.
This ultrastructural study investigates the pathological changes in the penial, the sperm groove and the glandular cushion
epithelium in maleLittorina littorea (Mesogastropoda) related to TBT (tributyltin) contamination. The results are compared with those onOcinebrina aciculata (Neogastropoda), which shows a wide range of cell changes in the penis epithelia of male and imposex affected females. The
investigation of the different penis epithelia ofL. littorea revealed that the cells analysed show a low sensibility towards TBT. The cells display normal metabolism. Certain atypical
structures like swelling microvilli and cristae which tend to lie parallel to the long axis in the mitochondria, were detected
as pathological effects. 相似文献
9.
10.
Specific Activity of Brain Palmitoyl-CoA Pool Provides Rates of Incorporation of Palmitate in Brain Phospholipids in Awake Rats 总被引:4,自引:1,他引:3
Eric Grange Joseph Deutsch Quentin R. Smith Michael Chang Stanley I. Rapoport A. David Purdon 《Journal of neurochemistry》1995,65(5):2290-2298
Abstract: In vivo rates of palmitate incorporation into brain phospholipids were measured in awake rats following programmed intravenous infusion of unesterified [9,10-3 H]palmitate to maintain constant plasma specific activity. Animals were killed after 2–10 min of infusion by microwave irradiation and analyzed for tracer distribution in brain phospholipid and phospholipid precursor, i.e., brain unesterified palmitate and palmitoyl-CoA, pools. [9,10-3 H]Palmitate incorporation into brain phospholipids was linear with time and rapid, with >50% of brain tracer in choline-containing glycerophospholipids at 2 min of infusion. However, tracer specific activity in brain phospholipid precursor pools was low and averaged only 1.6–1.8% of plasma unesterified palmitate specific activity. Correction for brain palmitoyl-CoA specific activity increased the calculated rate of palmitate incorporation into brain phospholipids (0.52 nmol/s/g) by ∼60-fold. The results suggest that palmitate incorporation and turnover in brain phospholipids are far more rapid than generally assumed and that this rapid turnover dilutes tracer specific activity in brain palmitoyl-CoA pool owing to release and recycling of unlabeled fatty acid from phospholipid breakdown. 相似文献