全文获取类型
收费全文 | 2987篇 |
免费 | 221篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 35篇 |
儿科学 | 163篇 |
妇产科学 | 62篇 |
基础医学 | 408篇 |
口腔科学 | 25篇 |
临床医学 | 245篇 |
内科学 | 622篇 |
皮肤病学 | 50篇 |
神经病学 | 156篇 |
特种医学 | 60篇 |
外国民族医学 | 1篇 |
外科学 | 431篇 |
综合类 | 163篇 |
一般理论 | 1篇 |
预防医学 | 202篇 |
眼科学 | 63篇 |
药学 | 275篇 |
中国医学 | 12篇 |
肿瘤学 | 259篇 |
出版年
2023年 | 21篇 |
2022年 | 37篇 |
2021年 | 71篇 |
2020年 | 34篇 |
2019年 | 59篇 |
2018年 | 56篇 |
2017年 | 49篇 |
2016年 | 66篇 |
2015年 | 69篇 |
2014年 | 87篇 |
2013年 | 122篇 |
2012年 | 160篇 |
2011年 | 183篇 |
2010年 | 105篇 |
2009年 | 100篇 |
2008年 | 148篇 |
2007年 | 170篇 |
2006年 | 173篇 |
2005年 | 156篇 |
2004年 | 148篇 |
2003年 | 111篇 |
2002年 | 101篇 |
2001年 | 78篇 |
2000年 | 78篇 |
1999年 | 78篇 |
1998年 | 29篇 |
1997年 | 29篇 |
1996年 | 17篇 |
1992年 | 35篇 |
1991年 | 46篇 |
1990年 | 45篇 |
1989年 | 28篇 |
1988年 | 28篇 |
1987年 | 30篇 |
1986年 | 28篇 |
1985年 | 30篇 |
1984年 | 18篇 |
1981年 | 19篇 |
1980年 | 16篇 |
1979年 | 30篇 |
1978年 | 24篇 |
1977年 | 22篇 |
1976年 | 15篇 |
1975年 | 22篇 |
1974年 | 22篇 |
1973年 | 27篇 |
1972年 | 23篇 |
1971年 | 25篇 |
1970年 | 16篇 |
1969年 | 19篇 |
排序方式: 共有3233条查询结果,搜索用时 15 毫秒
1.
Metabolic abnormalities of gastrointestinal mucosa in celiac disease: An in vitro proton nuclear magnetic resonance spectroscopy study
下载免费PDF全文
![点击此处可从《Journal of gastroenterology and hepatology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
2.
I. Fishtik C.A. Callaghan J.D. Fehribach R. Datta 《Journal of electroanalytical chemistry (Lausanne, Switzerland)》2005,576(1):57-63
The reaction route (RR) graph approach recently developed by us for complex, non-linear kinetic mechanisms is applied to the hydrogen oxidation and evolution reactions. A corresponding RR graph is constructed and translated into an equivalent electrical circuit network by associating each elementary step with a characteristic resistance for the steady-state case and considering the overall reaction as a power source. It is further shown that the steady-state kinetics of the reaction can be investigated employing the conventional methods of the electrical network theory. Using a set of rate constants for the hydrogen evolution reaction (her) in alkaline solutions from the literature, the dominant RRs are identified and simplified mechanisms and kinetics derived. 相似文献
3.
4.
5.
6.
A. Datta R. David S. Glennie D. Scott E. Cernuda-Morollon R. I. Lechler A. J. Ridley F. M. Marelli-Berg 《American journal of transplantation》2006,6(12):2871-2883
The best-characterized mechanism of the action of immunosuppressive drugs is to prevent T-cell clonal expansion, thus containing the magnitude of the ensuing immune response. As T-cell recruitment to the inflammatory site is another key step in the development of T-cell-mediated inflammation, we analyzed and compared the effects of two commonly used immunosuppressants, cyclosporin A (CsA) and the rapamycin-related compound SDZ-RAD, on the motility of human CD4+ T cells. We show that CsA, but not SDZ-RAD, inhibits T-cell transendothelial migration in vitro. CsA selectively impaired chemokine-induced T-cell chemotaxis while integrin-mediated migration was unaffected. The inhibition of T-cell chemotaxis correlated with reduced AKT/PKB but not ERK activation following exposure to the chemokine CXCL-12/SDF-1. In addition, CsA, but not SDZ-RAD, prevents some T-cell receptor-mediated effects on T-cell motility. Finally, we show that CsA, but not SDZ-RAD inhibits tissue infiltration by T cells in vivo. Our data suggest a prominent antiinflammatory role for CsA in T-cell-mediated tissue damage, by inhibiting T-cell trafficking into tissues in addition to containing clonal expansion. 相似文献
7.
8.
9.
Osteoclastic inhibition: an action of nitric oxide not mediated by cyclic GMP. 总被引:18,自引:3,他引:15
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
I MacIntyre M Zaidi A S Alam H K Datta B S Moonga P S Lidbury M Hecker J R Vane 《Proceedings of the National Academy of Sciences of the United States of America》1991,88(7):2936-2940
The osteoclast is unique in its ability to resorb bone, and excessive osteoclastic activity has been implicated in osteoporosis, Paget disease of bone, rheumatoid arthritis, and the growth of metastases in bone. The activity of this cell is controlled by the main circulating inhibitor, calcitonin, in association with locally produced modulators. We show that nitric oxide (NO) may be an important member of the latter group. NO is produced by the vascular endothelium and nervous system and is involved in both neurotransmission and the regulation of blood pressure. However, our results show that the autocoid is also a potent inhibitor of osteoclast function. NO (30 microM) produced a decrease to approximately 50% of the original osteoclast spread area. Similar effects were also produced by 3-morpholinosydnonimine or sodium nitroprusside, reagents that spontaneously release NO. These shape changes were associated with a reduction of bone resorption after a 24-hr incubation of isolated osteoclasts on devitalized bone slices. NO is thought to act by stimulating guanylate cyclase, with a consequent increase in cyclic GMP, but a different mode of action is likely in the osteoclast since dibutyryl or 8-bromo cyclic GMP have no effect. It should be noted that calcitonin can produce similar changes in shape and activity but is associated with an increase in osteoclast intracellular calcium and cessation of membrane movement; neither of these is produced by NO, suggesting that its mode of action is different. The abundance of NO-producing endothelial cells in bone marrow and their proximity to osteoclasts suggests that marrow endothelial cells may play a physiological role in the regulation of osteoclastic activity. 相似文献
10.
Vinay Puri Andrew McQuillin Khalid Choudhury Susmita Datta Jonathan Pimm Srinivasa Thirumalai Robert Krasucki Jacob Lawrence Digby Quested Nicholas Bass Helen Moorey Jenny Morgan Bhaskar Punukollu Gomathinayagam Kandasami David Curtis Hugh Gurling 《Neuropsychopharmacology》2007,61(7):873-879
BACKGROUND: Linkage studies by us and others have confirmed that chromosome 1q23.3 is a susceptibility locus for schizophrenia. Based on this information, several research groups have published evidence that markers within both the RGS4 and CAPON genes, which are 700 kb apart, independently showed allelic association with schizophrenia. Tests of allelic association with both of these genes in our case control sample were negative. Therefore, we carried out further fine mapping between the RGS4 and CAPON genes. METHODS: Twenty-nine SNP and microsatellite markers in the 1q23.3 region were genotyped in the United Kingdom based sample of 450 cases and 450 supernormal control subjects. RESULTS: We detected positive allelic association after the eighth marker was genotyped and found that three microsatellite markers (p = .011, p = .014, p = .049) and two SNPs (p = .004, p = .043) localized in the 700 kb region between the RGS4 and CAPON genes, within the UHMK1 gene, were associated with schizophrenia. Tests of significance for marker rs10494370 remained significant following Bonferroni correction (alpha = .006) for multiple tests. Tests of haplotypic association were also significant for UHMK1 (p = .009) using empirical permutation tests, which make it unnecessary to further correct for both multiple alleles and multiple markers. CONCLUSIONS: These results provide preliminary evidence that the UHMK1 gene increases susceptibility to schizophrenia. Further confirmation in adequately powered samples is needed. UHMK1 is a serine threonine kinase nuclear protein and is highly expressed in regions of the brain implicated in schizophrenia. 相似文献