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121.
Enzyme-linked immunosorbent assay for detection of staphylococcal enterotoxins in foods. 总被引:16,自引:13,他引:16 下载免费PDF全文
An enzyme-linked immunosorbent assay (ELISA) was developed for detection of staphylococcal enterotoxins in foods. The "double-antibody sandwich" protocol combines parts of several procedures reported previously. Horseradish peroxidase was conjugated to antibody specific for an enterotoxin, and the antibody-enzyme conjugate was assayed with a 2,2'-azino-di-(3-ethylbenzthiazoline sulfonic acid)-H2O2 substrate solution. Enterotoxins were added to a variety of foods that were representative of those implicated in staphylococcal food poisoning outbreaks. Extracts of the foods were assayed by the ELISA and radioimmunoassay. Enterotoxin levels below 1 ng/g of food were consistently detectable by the ELISA. These results compared favorably with those of the radioimmunoassay. Experiments confirmed the interference of protein A in double-antibody sandwich ELISAs. Although protein A interference has not been demonstrated to be a problem in food extracts, we suggest a screen for protein A interference in which immunoglobulin G from nonimmunized rabbits is used. All of the known staphylococcal enterotoxins could be detected by this method. Analysis of a food product for entertoxin by the ELISA can be completed in an 8-h working day. 相似文献
122.
123.
Afiniki B Zarafi AM Emechebe AD Akpa O Alabi 《Archives Of Phytopathology And Plant Protection》2013,46(1):11-17
The effect of various levels of nitrogen (0.0, 30.0, 60.0, 120.0) and phosphorus (0.0, 6.5, 13.0, 36.0) on the incidence and severity of downy mildew of pearl millet and yield of two pearl millet varieties (Zango and GB8375) were studied under field conditions in 2000 and 2001 respectively. Both nitrogen and phosphorus significantly increased incidence and severity of the disease in the two varieties. Grain yield and 1000 grain weight of the varieties also increased with nitrogen and phosphorus levels. 相似文献
124.
Dong Min Dando Emily E. Kotliar Ilana Su Xiaoyang Dzikovski Boris Freed Jack H. Lin Hening 《Journal of biological inorganic chemistry》2019,24(6):777-782
JBIC Journal of Biological Inorganic Chemistry - Diphthamide, the target of diphtheria toxin, is a post-translationally modified histidine residue found in archaeal and eukaryotic translation... 相似文献
125.
S Ghavami R H Cunnington S Gupta B Yeganeh K L Filomeno D H Freed S Chen T Klonisch A J Halayko E Ambrose R Singal I M C Dixon 《Cell death & disease》2015,6(3):e1696
Transforming growth factor-β1 (TGF-β1) is an important regulator of fibrogenesis in heart disease. In many other cellular systems, TGF-β1 may also induce autophagy, but a link between its fibrogenic and autophagic effects is unknown. Thus we tested whether or not TGF-β1-induced autophagy has a regulatory function on fibrosis in human atrial myofibroblasts (hATMyofbs). Primary hATMyofbs were treated with TGF-β1 to assess for fibrogenic and autophagic responses. Using immunoblotting, immunofluorescence and transmission electron microscopic analyses, we found that TGF-β1 promoted collagen type Iα2 and fibronectin synthesis in hATMyofbs and that this was paralleled by an increase in autophagic activation in these cells. Pharmacological inhibition of autophagy by bafilomycin-A1 and 3-methyladenine decreased the fibrotic response in hATMyofb cells. ATG7 knockdown in hATMyofbs and ATG5 knockout (mouse embryonic fibroblast) fibroblasts decreased the fibrotic effect of TGF-β1 in experimental versus control cells. Furthermore, using a coronary artery ligation model of myocardial infarction in rats, we observed increases in the levels of protein markers of fibrosis, autophagy and Smad2 phosphorylation in whole scar tissue lysates. Immunohistochemistry for LC3β indicated the localization of punctate LC3β with vimentin (a mesenchymal-derived cell marker), ED-A fibronectin and phosphorylated Smad2. These results support the hypothesis that TGF-β1-induced autophagy is required for the fibrogenic response in hATMyofbs.Interstitial fibrosis is common to many cardiovascular disease etiologies including myocardial infarction (MI),1 diabetic cardiomyopathy2 and hypertension.3 Fibrosis may arise due to maladaptive cardiac remodeling following injury and is a complex process resulting from activation of signaling pathways, such as TGF-β1.4 TGF-β1 signaling has broad-ranging effects that may affect cell growth, differentiation and the production of extracellular matrix (ECM) proteins.5, 6 Elevated TGF-β1 is observed in post-MI rat heart7 and is associated with fibroblast-to-myofibroblast phenoconversion and concomitant activation of canonical Smad signaling.8 The result is a proliferation of myofibroblasts, which then leads to inappropriate deposition of fibrillar collagens, impaired cardiac function and, ultimately, heart failure.9, 10Autophagy is necessary for cellular homeostasis and is involved in organelle and protein turnover.11, 12, 13, 14 Autophagy aids in cell survival by providing primary materials, for example, amino acids and fatty acids for anabolic pathways during starvation conditions.15, 16 Alternatively, autophagy may be associated with apoptosis through autodigestive cellular processes, cellular infection with pathogens or extracellular stimuli.17, 18, 19, 20 The overall control of cardiac fibrosis is likely due to the complex functioning of an array of regulatory factors, but to date, there is little evidence linking autophagy with fibrogenesis in cardiac tissue.11, 12, 13, 14, 15, 16, 17, 18, 21, 22Recent studies have demonstrated that TGF-β1 may not only promote autophagy in mouse fibroblasts and human tubular epithelial kidney cells15, 23, 24 but can also inhibit this process in fibroblasts extracted from human patients with idiopathic pulmonary fibrosis.25 Moreover, it has recently been reported that autophagy can negatively15 and positively25, 26, 27 regulate the fibrotic process in different model cell systems. In this study, we have explored the putative link between autophagy and TGF-β1-induced fibrogenesis in human atrial myofibroblasts (hATMyofbs) and in a model of MI rat heart. 相似文献
126.
127.
Yan Wu Anita Freed David Lavrich Ramesh Raghavachari Kim Huynh-Ba Ketan Shah Mark Alasandro 《AAPS PharmSciTech》2015,16(4):986-991
In the past decade, many guidance documents have been issued through collaboration of global organizations and regulatory authorities. Most of these are applicable to new products, but there is a risk that currently marketed products will not meet the new compliance standards during audits and inspections while companies continue to make changes through the product life cycle for continuous improvement or market demands. This discussion presents different strategies to bringing drug product marketing applications to meet current and emerging standards. It also discusses stability and method designs to meet process validation and global development efforts.At the 2014 American Association of Pharmaceutical Scientists (AAPS) annual meeting in San Diego, CA, Yan Wu (Merck) and Anita Freed (Pfizer) led a symposium entitled “Bringing Drug Product Marketing Applications to Current Regulatory Standards: Trials and Tribulations.” This symposium was very timely as this topic is a growing industry concern, evidenced by over 300 attendees, and considering the new guidances (1–8) that have been established over the past decade. While most of these quality standards are applicable to new drug products, there is a risk that currently marketed products, known as legacy products, will not meet the new compliance standards during audits and inspections. Companies also need to continuously make process or method changes for in-line products as part of product life cycle management efforts or to meet different market needs. If legacy (or in-line) products undergo a change, the question is how much extra effort is needed to have these products meet current standards to support the associated submission. This symposium addressed these issues and offered modeling tools using existing data or other approaches and case studies to effectively manage post-approval changes. Presentations included the following:
- Modeling historical data to support process and method stability changes
- Food and Drug Administration (FDA) perspectives on application of International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) Q8 to legacy products
- Assessment of impact on stability with manufacturing, packaging, and/or method changes
- Applying Association of Southeast Asian Nations (ASEAN) stability requirements to legacy products and managing specifications across climatic zones
128.
Adhikari AN Peng J Wilde M Xu J Freed KF Sosnick TR 《Protein science : a publication of the Protein Society》2012,21(1):107-121
Template-based methods for predicting protein structure provide models for a significant portion of the protein but often contain insertions or chain ends (InsEnds) of indeterminate conformation. The local structure prediction "problem" entails modeling the InsEnds onto the rest of the protein. A well-known limit involves predicting loops of ≤12 residues in crystal structures. However, InsEnds may contain as many as ~50 amino acids, and the template-based model of the protein itself may be imperfect. To address these challenges, we present a free modeling method for predicting the local structure of loops and large InsEnds in both crystal structures and template-based models. The approach uses single amino acid torsional angle "pivot" moves of the protein backbone with a C(β) level representation. Nevertheless, our accuracy for loops is comparable to existing methods. We also apply a more stringent test, the blind structure prediction and refinement categories of the CASP9 tournament, where we improve the quality of several homology based models by modeling InsEnds as long as 45 amino acids, sizes generally inaccessible to existing loop prediction methods. Our approach ranks as one of the best in the CASP9 refinement category that involves improving template-based models so that they can function as molecular replacement models to solve the phase problem for crystallographic structure determination. 相似文献
129.
M. Elizabeth Sublette Matthew S. Milak Joseph R. Hibbeln Peter J. Freed Maria A. Oquendo Kevin M. Malone Ramin V. Parsey J. John Mann 《Prostaglandins, leukotrienes, and essential fatty acids》2009,80(1):57-64
Deficiencies in polyunsaturated essential fatty acids (PUFA) are implicated in mood disorders, although mechanisms of action and regional specificity in the brain are unknown. We hypothesized that plasma phospholipid PUFA levels are correlated with regionally specific relative cerebral metabolic rates of glucose (rCMRglu). Medication-free depressed subjects (N=29) were studied using [18F]-fluoro-2-deoxyglucose positron emission tomography. Docosahexaenoic acid (22:6n-3), arachidonic acid (20:4n-6), and eicosapentaenoic acid (20:5n-3) were assessed as a percentage of total phospholipid PUFA (DHA%, AA%, and EPA%, respectively). DHA% and AA% correlated positively with rCMRglu in temporoparietal cortex. In addition, DHA% correlated negatively with rCMRglu in prefrontal cortex and anterior cingulate. No correlations were seen with EPA%. Thus, under conditions of low plasma DHA, rCMRglu was higher in temporoparietal cortex and lower in anterior cingulate/prefrontal cortex. Opposing effects of DHA on these regions is a hypothesis that could be addressed in future prospective studies with n-3 supplementation. This pilot study is the first to demonstrate fatty acid and regionally specific correlations in the brain between plasma PUFA and rCMRglu in humans. 相似文献
130.
Cheryl I. Champion Valerie A. Kickhoefer Guangchao Liu Raymond J. Moniz Amanda S. Freed Liisa L. Bergmann Dana Vaccari Sujna Raval-Fernandes Ann M. Chan Leonard H. Rome Kathleen A. Kelly 《PloS one》2009,4(4)