全文获取类型
收费全文 | 2375篇 |
免费 | 130篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 118篇 |
妇产科学 | 24篇 |
基础医学 | 323篇 |
口腔科学 | 17篇 |
临床医学 | 158篇 |
内科学 | 516篇 |
皮肤病学 | 45篇 |
神经病学 | 107篇 |
特种医学 | 65篇 |
外科学 | 347篇 |
综合类 | 87篇 |
预防医学 | 150篇 |
眼科学 | 98篇 |
药学 | 209篇 |
中国医学 | 7篇 |
肿瘤学 | 218篇 |
出版年
2023年 | 19篇 |
2022年 | 36篇 |
2021年 | 76篇 |
2020年 | 46篇 |
2019年 | 52篇 |
2018年 | 71篇 |
2017年 | 61篇 |
2016年 | 57篇 |
2015年 | 70篇 |
2014年 | 108篇 |
2013年 | 90篇 |
2012年 | 175篇 |
2011年 | 177篇 |
2010年 | 102篇 |
2009年 | 76篇 |
2008年 | 139篇 |
2007年 | 107篇 |
2006年 | 111篇 |
2005年 | 92篇 |
2004年 | 111篇 |
2003年 | 96篇 |
2002年 | 81篇 |
2001年 | 61篇 |
2000年 | 39篇 |
1999年 | 42篇 |
1998年 | 19篇 |
1997年 | 13篇 |
1996年 | 10篇 |
1995年 | 11篇 |
1994年 | 10篇 |
1993年 | 11篇 |
1992年 | 13篇 |
1991年 | 18篇 |
1990年 | 23篇 |
1989年 | 20篇 |
1988年 | 21篇 |
1987年 | 15篇 |
1985年 | 9篇 |
1984年 | 13篇 |
1983年 | 18篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1978年 | 9篇 |
1976年 | 9篇 |
1975年 | 13篇 |
1974年 | 11篇 |
1973年 | 14篇 |
1972年 | 9篇 |
1970年 | 14篇 |
1969年 | 10篇 |
排序方式: 共有2507条查询结果,搜索用时 15 毫秒
11.
N. K. Kaushik Parul Sharma Ashok Shah T. A. Venkitasubramanian 《Medical microbiology and immunology》1993,182(6):317-327
The phospholipid-associated protein (55–67 kDa) fraction of Mycobacterium tuberculosis H37Rv was purified as the DE-V protein fraction. This DE-V fraction was used for diagnosis of tuberculosis by enzyme-linked immunosorbent assay (ELISA), detecting IgG antibody in sera collected from different categories of tuberculosis patients, i.e. with acid fast bacilli (AFB) culture-positive pulmonary tuberculosis, with AFB culture-negative, but radiologically suspected, pulmonary tuberculosis, extrapulmonary tuberculosis, and control groups of patients suffering from diseases other than tuberculosis (asthma and/or rhinitis, lepromatous leprosy) as well as from healthy volunteers. Encouraging operational ELISA validity could be achieved with 93% sensitivity, 100% specificity, 97% efficiency, 100% positive predictivity and 95% negative predictability even among the extrapulmonary and suspected pulmonary tuberculosis patients. The above assay was insensitive but with 100% specificity among control group of patients suffering from diseases other than tuberculosis. The DE-V protein fraction was associated with phosphatidyl inositol and phosphatidyl inositol mannosides. The dissociation of phospholipid-protein complex decreased ELISA specificity. ELISA reactivity of the DE-V fraction appeared to be thermostable; thus, it may have serodiagnostic utility in developing countries. 相似文献
12.
N. B. Ruderman H. Park V. K. Kaushik D. Dean S. Constant M. Prentki A. K. Saha 《Acta physiologica (Oxford, England)》2003,178(4):435-442
An increasing body of evidence has revealed that activation of adenosine monophosphate (AMP)‐activated protein kinase (AMPK)‐activated protein kinase increases fatty acid oxidation by lowering the concentration of malonyl coenzyme A (CoA), an inhibitor of carnitine palmitoyl transferase 1. Studies carried out primarily in skeletal muscle suggest that AMPK modulates the concentration of malonyl CoA by concurrently phosphorylating and inhibiting acetyl CoA carboxylase (ACC), the rate limiting enzyme in malonyl CoA synthesis, and phosphorylating and activating malonyl CoA decarboxylase (MCD), an enzyme involved in its degradation. We have recently observed that AMPK and MCD activities are increased and ACC activity diminished in skeletal muscle, liver and, surprisingly, in adipose tissue 30 min following exercise (treadmill run) in normal rats. In liver and adipose tissue these changes were associated with a decrease in the activity of glycerol‐3‐phosphate acyltransferase (GPAT), which catalyses the first committed reaction in glycerolipid synthesis and, which like ACC, is phosphorylated and inhibited by AMPK. Similar changes in ACC, MCD and GPAT were observed following the administration of 5‐aminoimidazole 4‐carboxamide‐riboside (AICAR), further indicating that the exercise‐induced alterations in these enzymes were AMPK‐mediated. Conclusions: (1) AMPK plays a major role in regulating lipid metabolism in multiple tissues following exercise. (2) The net effect of its activation is to increase fatty acid oxidation and diminish glycerolipid synthesis. (3) The relevance of these findings to the regulation of muscle glycogen repletion in the post‐exercise state and to the demonstrated ability of AMPK activation to decrease adiposity and increase insulin sensitivity in rodents remains to be determined. 相似文献
13.
Pathological and molecular progression of astrocytomas in a GFAP:12 V-Ha-Ras mouse astrocytoma model 总被引:4,自引:0,他引:4
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Shannon P Sabha N Lau N Kamnasaran D Gutmann DH Guha A 《The American journal of pathology》2005,167(3):859-867
We previously characterized a genetically engineered mouse astrocytoma model with embryonic astrocyte-specific, activated 12V-Ha-RAS (GFAP-RAS) transgenesis. The GFAP-RAS line Ras-B8 appears normal at birth, but 50% of mice die by 4 months from low- and high-grade astrocytomas. We examined the development and progression of astrocytomas in the Ras-B8 genetically engineered mouse. At embryonic day 16.5 (E16.5), there were no pathological differences compared to control littermates, aside from transgene expression. Diffuse astroglial hyperplasia was the first distinguishing feature in the 1-week-old Ras-B8 mice; however, these astrocytes were not transformed in vitro or in vivo. From 3 to 8 weeks the incidence of low-grade astrocytomas progressively increased with 85% of 12-week-old mice harboring low- or high-grade astrocytomas, the latter characterized by increased proliferation, nuclear atypia, and angiogenesis. Tp53 mutations were detected in both astrocytoma grades, with high-grade astrocytomas expressing elevated levels of epidermal growth factor receptor and vascular endothelial growth factor, plus decreased levels of PTEN and p16, similar to human astrocytomas. We postulate that expression of 12V-Ha-RAS in astroglial precursors induces astroglial hyperplasia, but transformation and subsequent progression requires additional molecular alterations resulting from aberrant activated p21-RAS. Of interest, many of these acquired alterations occur in human astrocytomas, further validating GFAP-RAS as a useful model for studying astrocytoma development and progression. 相似文献
14.
15.
16.
Guha C Shah SJ Ghosh SS Lee SW Roy-Chowdhury N Roy-Chowdhury J 《BioDrugs : clinical immunotherapeutics, biopharmaceuticals and gene therapy》2003,17(2):81-91
Current treatment modalities available for hepatitis B virus (HBV) or hepatitis C virus (HCV) infections are not efficient. The enormous disease burden caused by these two infections makes the development of novel therapies critical. For HCV, the development of an effective vaccine is urgent in view of the escalating number of infected individuals. Molecular therapies for HBV and HCV infection can be directed at reducing viral load by interfering with the life cycle of the viruses or at generating immune response against viral epitopes. The antiviral approaches consist of the delivery or expression of antisense RNAs, ribozymes or dominant negative proteins. Viral biology can be interrupted by attacking various potential targets within the two viruses. DNA-based vaccination strategies are being explored for both prevention and treatment of these diseases. Both non-viral and recombinant viral vectors are being developed for safe, effective and long-term gene transfer to the liver. Although no "ideal" vector is available at this time, the ingenuity of numerous investigators is leading to the improvement of the vector systems, promising successful application of gene therapy to the prevention and treatment of viral hepatitis in the foreseeable future. 相似文献
17.
Adrian Bot Alpana Nangpal Luminita Pricop Bjarne Bogen Azad Kaushik Constantin A. Bona 《Molecular immunology》1996,33(17-18)
The contribution of the λ-light chain to the development of peripheral B cell repertoire and generation of specific antibodies to haptens and polysaccharide antigens was studied in genetically manipulated kappa-deficient and λ2-transgenic mice. The results clearly demonstrate a non-stoichiometric VH gene family expression in the absence of k-light chain and suggest a non-stochastic pairing between VH and Vλ genes, expressed in the peripheral B cell repertoire. A shift in VH gene utilization in the case of Vlλ+ antibodies was evident in response to β2–6 fructosan and TNP hapten. These observations demonstrate the availability of compensatory mechanisms in the absence of VK genes and are consistent with the hypothesis that VH gene family expression is controlled by genetic factors from inside the VH locus. Furthermore, genetic factors from outside the VH locus, namely restricted available light chain diversity, may lead to a shift in VH gene utilization in the peripheral B cell repertoire. 相似文献
18.
P?Mallick J?Chakrabarti Mallick B?Guha AR?Khuda-BukhshEmail author 《BMC complementary and alternative medicine》2003,3(1):7
Background
Arsenic in groundwater and its accumulation in plants and animals have assumed a menacing proportion in a large part of West Bengal, India and adjoining areas of Bangladesh. Because of the tremendous magnitude of the problem, there seems to be no way to tackle the problem overnight. Efforts to provide arsenic free water to the millions of people living in these dreaded zones are being made, but are awfully inadequate. In our quest for finding out an easy, safe and affordable means to combat this problem, a homeopathic drug, Arsenicum Album-30, appears to yield promising results in mice. The relative efficacies of two micro doses of this drug, namely, Arsenicum Album-30 and Arsenicum Album-200, in combating arsenic toxicity have been determined in the present study on the basis of some accepted biochemical protocols. 相似文献19.
High tidal volume ventilation induces proinflammatory signaling in rat lung endothelium 总被引:9,自引:0,他引:9
Bhattacharya S Sen N Yiming MT Patel R Parthasarathi K Quadri S Issekutz AC Bhattacharya J 《American journal of respiratory cell and molecular biology》2003,28(2):218-224
Alveolar overdistension during mechanical ventilation causes leukocyte sequestration, leading to lung injury. However, underlying endothelial cell (EC) mechanisms are undefined. In a new approach, we exposed isolated blood-perfused rat lungs to high tidal volume ventilation (HV) for 2 h, then obtained fresh lung endothelial cells (FLEC) by immunosorting at 4 degrees C. Immunoblotting experiments indicated that as compared with FLEC derived from lungs ventilated at low volume (LV), HV markedly enhanced tyrosine phosphorylation (TyrP). The tyrosine kinase blocker, genistein, inhibited this response. HV also induced focal adhesion (FA) formation in FLEC, as detected by immunofluorescent aggregates of the alpha(v)beta(3) integrin that co-localized with aggregations of focal adhesion kinase (FAK). Immunoprecipitation and blotting experiments revealed that HV increased TyrP of the FA protein, paxillin. In addition, HV induced a paxillin-associated P-selectin expression on FLEC that was also inhibited by genistein. However, HV did not increase lung water. These results indicate that in HV, EC signaling in situ causes FA formation and induces TyrP-dependent P-selectin expression. These signaling mechanisms may promote leukocyte-mediated responses in HV. 相似文献
20.