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51.
Ildikó Pándi Károly Penksza Zoltán Botta-Dukát György Kröel-Dulay 《Biodiversity and Conservation》2014,23(5):1289-1302
Agricultural land abandonment and rural depopulation are frequent phenomena in many parts of the developed world that often result in considerable conservation benefits. Although settlements are hotspots of alien species that may threaten ecosystem recovery, no study to date has systematically assessed the persistence and spread of cultivated alien plants following the abandonment of rural settlements. By examining 190 farmsteads abandoned between 1956 and 2005 in central Hungary, we show that cultivated species can remain for decades at abandoned settlements, with many species occurring in similar frequency in long-ago and recently abandoned farmsteads. Many species spread vegetatively, and persistence through time was not related to estimated longevity for woody species. Furthermore, by analysing vegetation samples from the surrounding landscape, we found that some of these cultivated species also occurred outside farmsteads in areas where they had not been planted, most often in tree plantations. In addition, the number of escaped cultivated species occurring in tree plantations was positively related to farmstead density, suggesting a prominent role of farmsteads as a source. Our results suggest that rural settlements and rural depopulation provide a special opportunity for cultivated alien plants. These special habitats serve as incubators, where many cultivated species can survive long-term, and even spread to the surrounding landscape. We conclude that farmsteads have a long-lasting local and landscape-scale legacy, and imprint a unique signature on the flora of their broader region. 相似文献
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53.
Sensitivity analysis, the study of how ecological variables of interest respond to changes in external conditions, is a theoretically well‐developed and widely applied approach in population ecology. Though the application of sensitivity analysis to predicting the response of species‐rich communities to disturbances also has a long history, derivation of a mathematical framework for understanding the factors leading to robust coexistence has only been a recent undertaking. Here we suggest that this development opens up a new perspective, providing advances ranging from the applied to the theoretical. First, it yields a framework to be applied in specific cases for assessing the extinction risk of community modules in the face of environmental change. Second, it can be used to determine trait combinations allowing for coexistence that is robust to environmental variation, and limits to diversity in the presence of environmental variation, for specific community types. Third, it offers general insights into the nature of communities that are robust to environmental variation. We apply recent community‐level extensions of mathematical sensitivity analysis to example models for illustration. We discuss the advantages and limitations of the method, and some of the empirical questions the theoretical framework could help answer. 相似文献
54.
The sympathetic nervous system plays a central role in establishing communication between the central nervous system and the immune system during inflammation. Inflammation activates the sympathetic nervous system, which causes release of the transmitters of the sympathetic nerv-ous system in the periphery. The transmitters of the sympathetic nervous system are the cate-cholamines noradrenaline and adrenaline and the purines ATP, adenosine, and inosine. Once these transmitters are released, they stimulate both presynaptic receptors on nerve terminals and post-synaptic receptors on immune cells. The receptors that are sensitive to catecholamines are termed adrenoceptors, whereas the receptors that bind purines are called purinoceptors. Stimulation of the presynaptic receptors exerts an autoregulatory effect on the release of transmitters. Ligation of the postsynaptic receptors on inflammatory cells modulates the inflammatory ac-tivities of these cells. The present review summarizes some of the most important aspects of the current state of knowledge about the interactions between the sympathetic nervous system and the immune system during inflammation with a special emphasis on the role of adreno and purinoceptors. 相似文献
55.
Dániel Szili Zsuzsanna Bankó Eszter Angéla Tóth Gy?rgy Nagy Bernadette Rojkovich Tamás Gáti Melinda Simon Zoltán Hérincs Gabriella Sármay 《PloS one》2014,9(5)
B cell development and activation are regulated by combined signals mediated by the B cell receptor (BCR), receptors for the B-cell activating factor of the tumor necrosis factor family (BAFF-R) and the innate receptor, Toll-like receptor 9 (TLR9). However, the underlying mechanisms by which these signals cooperate in human B cells remain unclear. Our aim was to elucidate the key signaling molecules at the crossroads of BCR, BAFF-R and TLR9 mediated pathways and to follow the functional consequences of costimulation.Therefore we stimulated purified human B cells by combinations of anti-Ig, B-cell activating factor of the tumor necrosis factor family (BAFF) and the TLR9 agonist, CpG oligodeoxynucleotide. Phosphorylation status of various signaling molecules, B cell proliferation, cytokine secretion, plasma blast generation and the frequency of IgG producing cells were investigated. We have found that BCR induced signals cooperate with BAFF-R- and TLR9-mediated signals at different levels of cell activation. BCR and BAFF- as well as TLR9 and BAFF-mediated signals cooperate at NFκB activation, while BCR and TLR9 synergistically costimulate mitogen activated protein kinases (MAPKs), ERK, JNK and p38. We show here for the first time that the MAP3K7 (TGF beta activated kinase, TAK1) is responsible for the synergistic costimulation of B cells by BCR and TLR9, resulting in an enhanced cell proliferation, plasma blast generation, cytokine and antibody production. Specific inhibitor of TAK1 as well as knocking down TAK1 by siRNA abrogates the synergistic signals. We conclude that TAK1 is a key regulator of receptor crosstalk between BCR and TLR9, thus plays a critical role in B cell development and activation. 相似文献
56.
Effect of High Sugar Intake on Glucose Transporter and Weight Regulating Hormones in Mice and Humans
Yvonne Ritze Gy?ngyi Bárdos Jan G. D’Haese Barbara Ernst Martin Thurnheer Bernd Schultes Stephan C. Bischoff 《PloS one》2014,9(7)
Objective
Sugar consumption has increased dramatically over the last decades in Western societies. Especially the intake of sugar-sweetened beverages seems to be a major risk for the development of obesity. Thus, we compared liquid versus solid high-sugar diets with regard to dietary intake, intestinal uptake and metabolic parameters in mice and partly in humans.Methods
Five iso-caloric diets, enriched with liquid (in water 30% vol/vol) or solid (in diet 65% g/g) fructose or sucrose or a control diet were fed for eight weeks to C57bl/6 mice. Sugar, liquid and caloric intake, small intestinal sugar transporters (GLUT2/5) and weight regulating hormone mRNA expression, as well as hepatic fat accumulation were measured. In obese versus lean humans that underwent either bariatric surgery or small bowel resection, we analyzed small intestinal GLUT2, GLUT5, and cholecystokinin expression.Results
In mice, the liquid high-sucrose diet caused an enhancement of total caloric intake compared to the solid high-sucrose diet and the control diet. In addition, the liquid high-sucrose diet increased expression of GLUT2, GLUT5, and cholecystokinin expression in the ileum (P<0.001). Enhanced liver triglyceride accumulation was observed in mice being fed the liquid high-sucrose or -fructose, and the solid high-sucrose diet compared to controls. In obese, GLUT2 and GLUT5 mRNA expression was enhanced in comparison to lean individuals.Conclusions
We show that the form of sugar intake (liquid versus solid) is presumably more important than the type of sugar, with regard to feeding behavior, intestinal sugar uptake and liver fat accumulation in mice. Interestingly, in obese individuals, an intestinal sugar transporter modulation also occurred when compared to lean individuals. 相似文献57.
Ingrid M. Bonilla Victor P. Long III Pedro Vargas-Pinto Patrick Wright Andriy Belevych Qing Lou Kent Mowrey Jae Yoo Philip F. Binkley Vadim V. Fedorov Sandor Gy?rke Paulus M. L. Janssen Ahmet Kilic Peter J. Mohler Cynthia A. Carnes 《PloS one》2014,9(10)
The role of IKCa in cardiac repolarization remains controversial and varies across species. The relevance of the current as a therapeutic target is therefore undefined. We examined the cellular electrophysiologic effects of IKCa blockade in controls, chronic heart failure (HF) and HF with sustained atrial fibrillation. We used perforated patch action potential recordings to maintain intrinsic calcium cycling. The IKCa blocker (apamin 100 nM) was used to examine the role of the current in atrial and ventricular myocytes. A canine tachypacing induced model of HF (1 and 4 months, n = 5 per group) was used, and compared to a group of 4 month HF with 6 weeks of superimposed atrial fibrillation (n = 7). A group of age-matched canine controls were used (n = 8). Human atrial and ventricular myocytes were isolated from explanted end-stage failing hearts which were obtained from transplant recipients, and studied in parallel. Atrial myocyte action potentials were unchanged by IKCa blockade in all of the groups studied. IKCa blockade did not affect ventricular myocyte repolarization in controls. HF caused prolongation of ventricular myocyte action potential repolarization. IKCa blockade caused further prolongation of ventricular repolarization in HF and also caused repolarization instability and early afterdepolarizations. SK2 and SK3 expression in the atria and SK3 in the ventricle were increased in canine heart failure. We conclude that during HF, IKCa blockade in ventricular myocytes results in cellular arrhythmias. Furthermore, our data suggest an important role for IKCa in the maintenance of ventricular repolarization stability during chronic heart failure. Our findings suggest that novel antiarrhythmic therapies should have safety and efficacy evaluated in both atria and ventricles. 相似文献
58.
Rebekah Baskin Sung O. Park Gy?rgy M. Keser? Kirpal S. Bisht Heather L. Wamsley Peter P. Sayeski 《PloS one》2014,9(8)
Glioblastoma multiforme (GBM) is the most common and the most aggressive form of primary brain tumor. Jak2 is a non-receptor tyrosine kinase that is involved in proliferative signaling through its association with various cell surface receptors. Hyperactive Jak2 signaling has been implicated in numerous hematological disorders as well as in various solid tumors including GBM. Our lab has developed a Jak2 small molecule inhibitor known as G6. It exhibits potent efficacy in vitro and in several in vivo models of Jak2-mediated hematological disease. Here, we hypothesized that G6 would inhibit the pathogenic growth of GBM cells expressing hyperactive Jak2. To test this, we screened several GBM cell lines and found that T98G cells express readily detectable levels of active Jak2. We found that G6 treatment of these cells reduced the phosphorylation of Jak2 and STAT3, in a dose-dependent manner. In addition, G6 treatment reduced the migratory potential, invasive potential, clonogenic growth potential, and overall viability of these cells. The effect of G6 was due to its direct suppression of Jak2 function and not via off-target kinases, as these effects were recapitulated in T98G cells that received Jak2 specific shRNA. G6 also significantly increased the levels of caspase-dependent apoptosis in T98G cells, when compared to cells that were treated with vehicle control. Lastly, when T98G cells were injected into nude mice, G6 treatment significantly reduced tumor volume and this was concomitant with significantly decreased levels of phospho-Jak2 and phospho-STAT3 within the tumors themselves. Furthermore, tumors harvested from mice that received G6 had significantly less vimentin protein levels when compared to tumors from mice that received vehicle control solution. Overall, these combined in vitro and in vivo results indicate that G6 may be a viable therapeutic option against GBM exhibiting hyperactivation of Jak2. 相似文献
59.
Charlotte Welinder G?ran B. J?nsson Christian Ingvar Lotta Lundgren Bo Baldetorp H?kan Olsson Thomas Breslin Melinda Rezeli Bo Jansson Thomas E. Fehniger Thomas Laurell Elisabet Wieslander Krzysztof Pawlowski Gy?rgy Marko-Varga 《PloS one》2014,9(10)
Globally, malignant melanoma shows a steady increase in the incidence among cancer diseases. Malignant melanoma represents a cancer type where currently no biomarker or diagnostics is available to identify disease stage, progression of disease or personalized medicine treatment. The aim of this study was to assess the tissue expression of alpha-synuclein, a protein implicated in several disease processes, in metastatic tissues from malignant melanoma patients. A targeted Selected Reaction Monitoring (SRM) assay was developed and utilized together with stable isotope labeling for the relative quantification of two target peptides of alpha-synuclein. Analysis of alpha-synuclein protein was then performed in ten metastatic tissue samples from the Lund Melanoma Biobank. The calibration curve using peak area ratio (heavy/light) versus concentration ratios showed linear regression over three orders of magnitude, for both of the selected target peptide sequences. In support of the measurements of specific protein expression levels, we also observed significant correlation between the protein and mRNA levels of alpha-synuclein in these tissues. Investigating levels of tissue alpha-synuclein may add novel aspect to biomarker development in melanoma, help to understand disease mechanisms and ultimately contribute to discriminate melanoma patients with different prognosis. 相似文献
60.