全文获取类型
收费全文 | 1320篇 |
免费 | 92篇 |
出版年
2022年 | 15篇 |
2021年 | 23篇 |
2020年 | 8篇 |
2019年 | 11篇 |
2018年 | 31篇 |
2017年 | 12篇 |
2016年 | 22篇 |
2015年 | 48篇 |
2014年 | 61篇 |
2013年 | 63篇 |
2012年 | 104篇 |
2011年 | 99篇 |
2010年 | 59篇 |
2009年 | 56篇 |
2008年 | 67篇 |
2007年 | 89篇 |
2006年 | 75篇 |
2005年 | 74篇 |
2004年 | 56篇 |
2003年 | 49篇 |
2002年 | 83篇 |
2001年 | 11篇 |
2000年 | 12篇 |
1999年 | 7篇 |
1998年 | 25篇 |
1997年 | 18篇 |
1996年 | 10篇 |
1995年 | 9篇 |
1994年 | 7篇 |
1993年 | 11篇 |
1992年 | 17篇 |
1991年 | 13篇 |
1990年 | 6篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 13篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1977年 | 5篇 |
1976年 | 11篇 |
1975年 | 5篇 |
1974年 | 7篇 |
1972年 | 5篇 |
1971年 | 9篇 |
1969年 | 5篇 |
排序方式: 共有1412条查询结果,搜索用时 15 毫秒
91.
Delivery of nucleic acid into mammalian cells by anthrax toxin 总被引:1,自引:0,他引:1
Gaur R Gupta PK Goyal A Wels W Singh Y 《Biochemical and biophysical research communications》2002,297(5):1121-1127
Gene delivery vehicles based on receptor-mediated endocytosis offer an attractive long-term solution as they might overcome the limitations of toxicity and cargo capacity inherent to many viral gene delivery systems. The protective antigen component of anthrax toxin bind to specific receptors and deliver lethal factor or edema factor into the cytosol of mammalian cells. The N-terminal 254 amino acids of LF (LF(1-254)) binds to PA and, when fused to heterologous proteins, delivers such proteins into the cytosol. However, so far no attempt has been made to use the anthrax toxin system for the intracellular delivery of DNA. In the present study, LF(1-254) of anthrax toxin was fused to the DNA-binding domain of GAL4 protein. The fusion protein (LF(254)-GAL4DBD) showed both PA binding as well as DNA-binding activity in solution. The complex of fusion protein with plasmid DNA containing a reporter gene (luciferase or green fluorescent protein) along with PA delivered plasmid DNA into the cytosol of COS-1 cells. These results suggest that anthrax toxin components can be used as a non-viral system for the efficient delivery of DNA into the cytosol of mammalian cells. 相似文献
92.
Schlomann U Wildeboer D Webster A Antropova O Zeuschner D Knight CG Docherty AJ Lambert M Skelton L Jockusch H Bartsch JW 《The Journal of biological chemistry》2002,277(50):48210-48219
ADAMs (a disintegrin and metalloprotease domains) are metalloprotease and disintegrin domain-containing transmembrane glycoproteins with proteolytic, cell adhesion, cell fusion, and cell signaling properties. ADAM8 was originally cloned from monocytic cells, and its distinct expression pattern indicates possible roles in both immunology and neuropathology. Here we describe our analysis of its biochemical properties. In transfected COS-7 cells, ADAM8 is localized to the plasma membrane and processed into two forms derived either by prodomain removal or as remnant protein comprising the extracellular region with the disintegrin domain at the N terminus. Proteolytic removal of the ADAM8 propeptide was completely blocked in mutant ADAM8 with a Glu(330) to Gln exchange (EQ-A8) in the Zn(2+) binding motif (HE(330)LGHNLGMSHD), arguing for autocatalytic prodomain removal. In co-transfection experiments, the ectodomain but not the entire MP domain of ADAM8 was able to remove the prodomain from EQ-ADAM8. With cells expressing ADAM8, cell adhesion to a substrate-bound recombinant ADAM8 disintegrin/Cys-rich domain was observed in the absence of serum, blocked by an antibody directed against the ADAM8 disintegrin domain. Soluble ADAM8 protease, consisting of either the metalloprotease domain or the complete ectodomain, cleaved myelin basic protein and a fluorogenic peptide substrate, and was inhibited by batimastat (BB-94, IC(50) approximately 50 nm) but not by recombinant tissue inhibitor of matrix metalloproteinases 1, 2, 3, and 4. Our findings demonstrate that ADAM8 processing by autocatalysis leads to a potential sheddase and to a form of ADAM8 with a function in cell adhesion. 相似文献
93.
94.
Astyanax scabripinnis specimens from four distinct populations in Brazil were studied with respect to their karyotype macrostructure, nucleolar
organizer regions, and 18S and 5S rRNA genes. The four populations showed a 2n = 50 chromosomes (3 M + 11 SM + 5 ST + 6 A pairs) and 1–2 B chromosomes. No chromosomal differentiations were observed between
sexes. Although a karyotypic diversity has been characterized in this fish group, the populations now analyzed presented the
same macrokaryotypic pattern. Chromosome mapping of 5S rDNA showed a total of eight sites located in four distinct chromosomal
pairs, with no apparent differences among populations. A comparative study on 18S rDNA locations and Ag-NORs showed some secondary
NOR sites that are not usually expressed in karyotypes and a probable differential NOR activity among populations. Correlations
between these data, environmental conditions and B chromosomes are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
95.
Dominant Negative Alleles of SEC10 Reveal Distinct
Domains Involved in Secretion and Morphogenesis in Yeast 总被引:2,自引:1,他引:1
下载免费PDF全文
![点击此处可从《Molecular biology of the cell》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The accurate targeting of secretory vesicles to distinct sites on the plasma membrane is necessary to achieve polarized growth and to establish specialized domains at the surface of eukaryotic cells. Members of a protein complex required for exocytosis, the exocyst, have been localized to regions of active secretion in the budding yeast Saccharomyces cerevisiae where they may function to specify sites on the plasma membrane for vesicle docking and fusion. In this study we have addressed the function of one member of the exocyst complex, Sec10p. We have identified two functional domains of Sec10p that act in a dominant-negative manner to inhibit cell growth upon overexpression. Phenotypic and biochemical analysis of the dominant-negative mutants points to a bifunctional role for Sec10p. One domain, consisting of the amino-terminal two-thirds of Sec10p directly interacts with Sec15p, another exocyst component. Overexpression of this domain displaces the full-length Sec10 from the exocyst complex, resulting in a block in exocytosis and an accumulation of secretory vesicles. The carboxy-terminal domain of Sec10p does not interact with other members of the exocyst complex and expression of this domain does not cause a secretory defect. Rather, this mutant results in the formation of elongated cells, suggesting that the second domain of Sec10p is required for morphogenesis, perhaps regulating the reorientation of the secretory pathway from the tip of the emerging daughter cell toward the mother–daughter connection during cell cycle progression. 相似文献
96.
Dagmar Weier Wilfried Lühs Josef Dettendorfer Margrit Frentzen 《Molecular breeding : new strategies in plant improvement》1998,4(1):39-46
The plsC gene of Escherichia coli encoding sn-1-acylglycerol-3-phosphate acyltransferase was modified by inserting an endoplasmic reticulum retrieval signal to its 3 end and introduced into rapeseed (Brassica napus L.) plants under the control of a napin promotor. In developing seeds from transgenic plants an sn-1-acylglycerol-3-phosphate acyltransferase activity was detectable which showed substrate specificities typical of the E. coli enzyme. Moreover, seed oil from the transformants unlike that from untransformed plants contained substantial amounts of triacylglycerol species esterified with very-long-chain fatty acids at each glycerol position. Analysis of fatty acids at the sn-2 position of triacylglycerol showed hardly any very-long-chain fatty acids in untransformed plants, but in certain transformants these fatty acids were present, namely about 4% erucic acid and 9% eicosenoic acid. These data demonstrate that the bacterial acyltransferase can function in developing rapeseed and alters the stereochemical composition of transgenic rape seed oil by directing very-long-chain fatty acids, especially cis-11 eicosenoic acid, to its sn-2 position. 相似文献
97.
Andrew Filer Philipp Antczak Greg N. Parsonage Holly M. Legault Margot O’Toole Mark J. Pearson Andrew M. Thomas Dagmar Scheel-Toellner Karim Raza Christopher D. Buckley Francesco Falciani 《PloS one》2015,10(3)
Synovial fibroblasts in persistent inflammatory arthritis have been suggested to have parallels with cancer growth and wound healing, both of which involve a stereotypical serum response programme. We tested the hypothesis that a serum response programme can be used to classify diseased tissues, and investigated the serum response programme in fibroblasts from multiple anatomical sites and two diseases. To test our hypothesis we utilized a bioinformatics approach to explore a publicly available microarray dataset including rheumatoid arthritis (RA), osteoarthritis (OA) and normal synovial tissue, then extended those findings in a new microarray dataset representing matched synovial, bone marrow and skin fibroblasts cultured from RA and OA patients undergoing arthroplasty. The classical fibroblast serum response programme discretely classified RA, OA and normal synovial tissues. Analysis of low and high serum treated fibroblast microarray data revealed a hierarchy of control, with anatomical site the most powerful classifier followed by response to serum and then disease. In contrast to skin and bone marrow fibroblasts, exposure of synovial fibroblasts to serum led to convergence of RA and OA expression profiles. Pathway analysis revealed three inter-linked gene networks characterising OA synovial fibroblasts: Cell remodelling through insulin-like growth factors, differentiation and angiogenesis through _3 integrin, and regulation of apoptosis through CD44. We have demonstrated that Fibroblast serum response signatures define disease at the tissue level, and that an OA specific, serum dependent repression of genes involved in cell adhesion, extracellular matrix remodelling and apoptosis is a critical discriminator between cultured OA and RA synovial fibroblasts. 相似文献
98.
Rocio Acuna-Hidalgo Denny Schanze Ariana Kariminejad Ann Nordgren Mohamad Hasan Kariminejad Peter Conner Giedre Grigelioniene Daniel Nilsson Magnus Nordenskjöld Anna Wedell Christoph Freyer Anna Wredenberg Dagmar Wieczorek Gabriele Gillessen-Kaesbach Hülya Kayserili Nursel Elcioglu Siavash Ghaderi-Sohi Payman Goodarzi Hamidreza Setayesh Maartje van de Vorst Marloes Steehouwer Rolph Pfundt Birgit Krabichler Cynthia Curry Malcolm G. MacKenzie Kym M. Boycott Christian Gilissen Andreas R. Janecke Alexander Hoischen Martin Zenker 《American journal of human genetics》2014
99.
100.
Dagmar Clough Michael Heistermann Peter M. Kappeler 《American journal of physical anthropology》2010,142(3):441-452
Parasites and infectious diseases represent ecological forces shaping animal social evolution. Although empirical studies supporting this link abound in various vertebrate orders, both the study of the dynamics and impact of parasite infections and infectious diseases in strepsirrhine primates have received little empirical attention. We conducted a longitudinal parasitological study on four groups of wild red‐fronted lemurs (Eulemur fulvus rufus) at Kirindy Forest, Madagascar, during two field seasons in consecutive years to investigate i) the degree of gastrointestinal parasite infection on population and individual levels and ii) factors potentially determining individual infection risk. Using a comprehensive dataset with multiple individually assignable parasite samples as well as information on age, sex, group size, social rank, and endocrine status (fecal androgen and glucocorticoid), we examined parasite infection patterns and host traits that may affect individual infection risk. In addition, we examined whether parasite infection affects mating and reproductive success. Our results indicated high variability in parasite infection on individual and population levels. Time of year and group size was important determinants of variability in parasite infection. Variation in hormone levels was also associated with parasite species richness and parasite infection intensity. Differences in parasite infection between years indicate a potential immune‐enhancing function of steroid hormones on nematode infections, which has not been reported before from other vertebrates studied under natural conditions. Male mating and reproductive success were not correlated to any measure of parasite infection, which suggests a nonfunctional role of the parasites we examined in primate sexual selection. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc. 相似文献