全文获取类型
收费全文 | 678篇 |
免费 | 93篇 |
国内免费 | 1篇 |
出版年
2021年 | 9篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 20篇 |
2014年 | 21篇 |
2013年 | 25篇 |
2012年 | 27篇 |
2011年 | 24篇 |
2010年 | 25篇 |
2009年 | 20篇 |
2008年 | 31篇 |
2007年 | 41篇 |
2006年 | 19篇 |
2005年 | 43篇 |
2004年 | 28篇 |
2003年 | 33篇 |
2002年 | 21篇 |
2001年 | 28篇 |
2000年 | 20篇 |
1999年 | 25篇 |
1998年 | 13篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 20篇 |
1991年 | 18篇 |
1990年 | 14篇 |
1989年 | 15篇 |
1988年 | 16篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1983年 | 11篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 10篇 |
1974年 | 7篇 |
1973年 | 5篇 |
1972年 | 7篇 |
1971年 | 7篇 |
1970年 | 5篇 |
1969年 | 6篇 |
1968年 | 5篇 |
排序方式: 共有772条查询结果,搜索用时 31 毫秒
81.
Granja Nde M Ricardo SA Longatto Filho A Alves VA Bedrossian CW Wiley EL Schmitt FC 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》2005,27(2):61-66
OBJECTIVE: To evaluate the presence of allelic loss in 16q22.1, including the locus of E-cadherin, in pleural effusions in breast cancer patients. STUDY DESIGN: Molecular analysis of DNA was performed using a DNA extraction kit (NucleoSpin, Macherey-Nagel, Germany). Loss of heterozygosity (LOH) in primary tumors and pleural effusions was analyzed using a microsatellite marker of the CDH1 gene, D16S265, described in previous studies. LOH was evaluated by radioactive polymerase chain reaction assay in 17 samples of pleural effusions and breast tissues (primary tumors and nonneoplastic adjacent tissue) from breast cancer patients: 7 positive for neoplastic cells, 6 suspected and 4 cases without evidence of neoplastic cells in the effusions. RESULTS: Thirteen cases (76%) were informative. LOH was detected in 5 cases (38.5%). In 3 of them LOH was detected only in the cytologic sample, and in 2 of them LOH was detected in the primary tumor and cytologic sample. CONCLUSION: Results show that LOH in the CDH1 gene can identify tumor cells in pleural effusions when morphologic analysis is difficult. 相似文献
82.
The flow of information through the epidermal growth factor receptor (EGFR) is shaped by molecular interactions in the plasma membrane. The EGFR is associated with lipid rafts, but their role in modulating receptor mobility and subsequent interactions is unclear. To investigate the role of nanoscale rafts in EGFR dynamics, we used single-molecule fluorescence imaging to track individual receptors and their dimerization partner, human epidermal growth factor receptor 2 (HER2), in the membrane of human mammary epithelial cells. We found that the motion of both receptors was interrupted by dwellings within nanodomains. EGFR was significantly less mobile than HER2. This difference was likely due to F-actin because its depolymerization led to similar diffusion patterns between the EGFR and HER2. Manipulations of membrane cholesterol content dramatically altered the diffusion pattern of both receptors. Cholesterol depletion led to almost complete confinement of the receptors, whereas cholesterol enrichment extended the boundaries of the restricted areas. Interestingly, F-actin depolymerization partially restored receptor mobility in cholesterol-depleted membranes. Our observations suggest that membrane cholesterol provides a dynamic environment that facilitates the free motion of EGFR and HER2, possibly by modulating the dynamic state of F-actin. The association of the receptors with lipid rafts could therefore promote their rapid interactions only upon ligand stimulation. 相似文献
83.
Monine MI Berezhkovskii AM Joslin EJ Wiley HS Lauffenburger DA Shvartsman SY 《Biophysical journal》2005,88(4):2384-2390
Cell-culture assays are routinely used to analyze autocrine signaling systems, but quantitative experiments are rarely possible. To enable the quantitative design and analysis of experiments with autocrine cells, we develop a biophysical theory of ligand accumulation in cell-culture assays. Our theory predicts the ligand concentration as a function of time and measurable parameters of autocrine cells and cell-culture experiments. The key step of our analysis is the derivation of the survival probability of a single ligand released from the surface of an autocrine cell. An expression for this probability is derived using the boundary homogenization approach and tested by stochastic simulations. We use this expression in the integral balance equations, from which we find the Laplace transform of the ligand concentration. We demonstrate how the theory works by analyzing the autocrine epidermal growth factor receptor system and discuss the extension of our methods to other experiments with cultured autocrine cells. 相似文献
84.
Crosses between two species of deer mouse (Peromyscus) yield dramatic parent-of-origin effects. Female P. maniculatus (BW) crossed with male P. polionotus (PO) produce animals smaller than either parent. PO females crossed with BW males yield lethal overgrowth that has been associated with loss-of-imprinting (LOI). Previously, we mapped two loci influencing fetal growth. These two loci, however, do not account for the LOI, nor for the dysmorphic phenotypes. Here we report that maternal genetic background strongly influences the LOI. Analyses of crosses wherein maternal genetic background is varied suggest that this effect is likely due to the action of a small number of loci. We have termed these putative loci Meil. Estimation of Meil loci number was confounded by skewed allelic ratios in the intercross line employed. We show that the Meil loci are not identical to any of the DNA methyltransferases shown to be involved in regulation of genomic imprinting. 相似文献
85.
Bedell JA Budiman MA Nunberg A Citek RW Robbins D Jones J Flick E Rholfing T Fries J Bradford K McMenamy J Smith M Holeman H Roe BA Wiley G Korf IF Rabinowicz PD Lakey N McCombie WR Jeddeloh JA Martienssen RA 《PLoS biology》2005,3(1):e13
86.
87.
Hong S Morrow TJ Paulson PE Isom LL Wiley JW 《The Journal of biological chemistry》2004,279(28):29341-29350
Diabetic neuropathy is a common form of peripheral neuropathy, yet the mechanisms responsible for pain in this disease are poorly understood. Alterations in the expression and function of voltage-gated tetrodotoxin-resistant (TTX-R) sodium channels have been implicated in animal models of neuropathic pain, including models of diabetic neuropathy. We investigated the expression and function of TTX-sensitive (TTX-S) and TTX-R sodium channels in dorsal root ganglion (DRG) neurons and the responses to thermal hyperalgesia and mechanical allodynia in streptozotocin-treated rats between 4-8 weeks after onset of diabetes. Diabetic rats demonstrated a significant reduction in the threshold for escape from innocuous mechanical pressure (allodynia) and a reduction in the latency to withdrawal from a noxious thermal stimulus (hyperalgesia). Both TTX-S and TTX-R sodium currents increased significantly in small DRG neurons isolated from diabetic rats. The voltage-dependent activation and steady-state inactivation curves for these currents were shifted negatively. TTX-S currents induced by fast or slow voltage ramps increased markedly in neurons from diabetic rats. Immunoblots and immunofluorescence staining demonstrated significant increases in the expression of Na(v)1.3 (TTX-S) and Na(v) 1.7 (TTX-S) and decreases in the expression of Na(v) 1.6 (TTX-S) and Na(v)1.8 (TTX-R) in diabetic rats. The level of serine/threonine phosphorylation of Na(v) 1.6 and In Na(v)1.8 increased in response to diabetes. addition, increased tyrosine phosphorylation of Na(v)1.6 and Na(v)1.7 was observed in DRGs from diabetic rats. These results suggest that both TTX-S and TTX-R sodium channels play important roles and that differential phosphorylation of sodium channels involving both serine/threonine and tyrosine sites contributes to painful diabetic neuropathy. 相似文献
88.
Sluyter R Shemon AN Barden JA Wiley JS 《The Journal of biological chemistry》2004,279(43):44749-44755
Canine erythrocytes are known to undergo a reversible increase in cation permeability when incubated with extracellular ATP. We have examined the expression and function of P2X receptors on human erythrocytes using confocal microscopy and a panel of anti-P2X(1-7) antibodies and have measured monovalent cation fluxes in the presence of various nucleotide agonists. Human erythrocytes expressed P2X7 receptors on all cells examined from eight of eight subjects, as well as P2X2 at a far lower staining intensity in six of eight subjects. ATP stimulated the efflux of 86Rb+ (K+) from human erythrocytes in a dose-dependent fashion with an EC50 of approximately 95 microM. Other nucleotides also induced an efflux of 86Rb+ from erythrocytes with an order of agonist potency of 2'- and 3'-O(4-benzoylbenzoyl) ATP (BzATP) > ATP > 2-methylthio-ATP (2MeSATP) > adenosine 5'-O-(3-thiotriphosphate) (ATPgammaS), whereas ADP or UTP had no effect. ATP-induced efflux of 86Rb+ from erythrocytes was inhibited by extracellular Na+ and oxidized ATP, as well as by KN-62, an antagonist specific for the human P2X7 receptor. When erythrocytes were incubated in isotonic KCl medium, the addition of ATP stimulated an 86Rb+ influx approximately equal in magnitude to ATP-stimulated 86Rb+ efflux from the same cells. BzATP also stimulated the influx of 22Na+ into erythrocytes incubated in isotonic NaCl medium. Both ATP-induced efflux and influx of 86Rb+ and 22Na+ were impaired in erythrocytes from subjects who had inherited loss-of-function polymorphisms in the P2X7 receptor. These results suggest that the reversible permeabilization of erythrocytes by extracellular ATP is mediated by the P2X7 receptor. 相似文献
89.
Wiley RE Cwiartka M Alvarez D Mackenzie DC Johnson JR Goncharova S Lundblad L Jordana M 《Journal of immunology (Baltimore, Md. : 1950)》2004,172(8):4995-5005
Corticosteroids (CS) remain the most efficacious pharmacotherapeutic option for the management of asthma. Although the acute anti-inflammatory effects of CS treatment have been amply documented both clinically and experimentally, recent human data intimate that exposure to CS may be associated with retrograde immune phenomena, including enhanced synthesis of IgE in vivo and elevated Th2 cytokine production in vitro. We have investigated the long-term immunologic effects of CS treatment in a murine model of allergic airway inflammation. CS treatment during initial exposure to OVA or upon long-term Ag rechallenge remarkably attenuated eosinophilic airway inflammation and airway hyperresponsiveness. Interestingly, however, Th2 cytokine production by cultured splenocytes from CS-treated mice was significantly elevated, while IFN-gamma synthesis was depressed. Moreover, mice rechallenged with OVA several weeks after CS intervention during allergic sensitization not only developed airway inflammation, but also exhibited enhanced Th2 cytokine production in lymphoid tissues and OVA-specific IgE in serum. This amplification of the systemic immune response was associated with an intact APC compartment during CS-conditioned sensitization to OVA. These data indicate that immune processes underlying the allergic phenotype remain impervious to CS treatment and raise the possibility that treatment with CS during sensitization may amplify elements of the allergen-specific immune response. 相似文献
90.
A chimeric protein of simian immunodeficiency virus envelope glycoprotein gp140 and Escherichia coli aspartate transcarbamoylase
下载免费PDF全文
![点击此处可从《Journal of virology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Chen B Cheng Y Calder L Harrison SC Reinherz EL Skehel JJ Wiley DC 《Journal of virology》2004,78(9):4508-4516
The envelope glycoproteins of the human immunodeficiency virus and the related simian immunodeficiency virus (SIV) mediate viral entry into host cells by fusing viral and target cell membranes. We have reported expression, purification, and characterization of gp140 (also called gp160e), the soluble, trimeric ectodomain of the SIV envelope glycoprotein, gp160 (B. Chen et al., J. Biol. Chem. 275:34946-34953, 2000). We have now expressed and purified chimeric proteins of SIV gp140 and its variants with the catalytic subunit (C) of Escherichia coli aspartate transcarbamoylase (ATCase). The fusion proteins (SIV gp140-ATC) bind viral receptor CD4 and a number of monoclonal antibodies specific for SIV gp140. The chimeric molecule also has ATCase activity, which requires trimerization of the ATCase C chains. Thus, the fusion protein is trimeric. When ATCase regulatory subunit dimers (R(2)) are added, the fusion protein assembles into dimers of trimers as expected from the structure of C(6)R(6) ATCase. Negative-stain electron microscopy reveals spikey features of both SIV gp140 and SIV gp140-ATC. The production of the fusion proteins may enhance the possibilities for structure determination of the envelope glycoprotein either by electron cryomicroscopy or X-ray crystallography. 相似文献