全文获取类型
收费全文 | 1003篇 |
免费 | 39篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 57篇 |
妇产科学 | 19篇 |
基础医学 | 93篇 |
口腔科学 | 57篇 |
临床医学 | 74篇 |
内科学 | 162篇 |
皮肤病学 | 13篇 |
神经病学 | 33篇 |
特种医学 | 213篇 |
外科学 | 134篇 |
综合类 | 26篇 |
预防医学 | 56篇 |
眼科学 | 49篇 |
药学 | 40篇 |
中国医学 | 1篇 |
肿瘤学 | 49篇 |
出版年
2022年 | 16篇 |
2021年 | 17篇 |
2020年 | 10篇 |
2019年 | 10篇 |
2018年 | 14篇 |
2017年 | 23篇 |
2016年 | 26篇 |
2015年 | 31篇 |
2014年 | 38篇 |
2013年 | 36篇 |
2012年 | 46篇 |
2011年 | 61篇 |
2010年 | 41篇 |
2009年 | 50篇 |
2008年 | 43篇 |
2007年 | 63篇 |
2006年 | 55篇 |
2005年 | 44篇 |
2004年 | 27篇 |
2003年 | 21篇 |
2002年 | 20篇 |
2001年 | 23篇 |
2000年 | 15篇 |
1999年 | 30篇 |
1998年 | 33篇 |
1997年 | 40篇 |
1996年 | 22篇 |
1995年 | 12篇 |
1994年 | 10篇 |
1993年 | 12篇 |
1992年 | 6篇 |
1991年 | 9篇 |
1990年 | 11篇 |
1989年 | 23篇 |
1988年 | 23篇 |
1987年 | 14篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 9篇 |
1981年 | 7篇 |
1977年 | 5篇 |
1975年 | 4篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1971年 | 4篇 |
1970年 | 4篇 |
1967年 | 4篇 |
1965年 | 3篇 |
1928年 | 3篇 |
排序方式: 共有1078条查询结果,搜索用时 421 毫秒
21.
Decreased expression of phospholipase C-beta 2 isozyme in human platelets with impaired function 总被引:4,自引:4,他引:4
Platelets from a patient with a mild inherited bleeding disorder and abnormal platelet aggregation and secretion show reduced generation of inositol 1,4,5-trisphosphate, mobilization of intracellular Ca2+, and phosphorylation of pleckstrin in response to several G protein mediated agonists, suggesting a possible defect at the level of phospholipase C (PLC) activation (see accompanying report). A procedure was developed that allows quantitation of platelet PLC isozymes. After fractionation of platelet extracts by high-performance liquid chromatography, 7 out of 10 known PLC isoforms were detected by immunoblot analysis. The amount of these isoforms in normal platelets decreased in the order PLC- gamma 2 > PLC-beta 2 > PLC-beta 3 > PLC-beta 1 > PLC-gamma 1 > PLC- delta 1 > PLC-beta 4. Compared with normal platelets, platelets from the patient contained approximately one-third the amount of PLC-beta 2, whereas PLC-beta 4 was increased threefold. These results suggest that the impaired platelet function in the patient in response to multiple G protein mediated agonists is attributable to a deficiency of PLC-beta 2. They document for the first time a specific PLC isozyme deficiency in human platelets and provide an unique opportunity to understand the role of different PLC isozymes in normal platelet function. 相似文献
22.
Digestive Diseases and Sciences - 相似文献
23.
Multilayer three-dimensional super resolution imaging of thick biological samples 总被引:1,自引:0,他引:1
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)
Alipasha Vaziri Jianyong Tang Hari Shroff Charles V. Shank 《Proceedings of the National Academy of Sciences of the United States of America》2008,105(51):20221-20226
Recent advances in optical microscopy have enabled biological imaging beyond the diffraction limit at nanometer resolution. A general feature of most of the techniques based on photoactivated localization microscopy (PALM) or stochastic optical reconstruction microscopy (STORM) has been the use of thin biological samples in combination with total internal reflection, thus limiting the imaging depth to a fraction of an optical wavelength. However, to study whole cells or organelles that are typically up to 15 μm deep into the cell, the extension of these methods to a three-dimensional (3D) super resolution technique is required. Here, we report an advance in optical microscopy that enables imaging of protein distributions in cells with a lateral localization precision better than 50 nm at multiple imaging planes deep in biological samples. The approach is based on combining the lateral super resolution provided by PALM with two-photon temporal focusing that provides optical sectioning. We have generated super-resolution images over an axial range of ≈10 μm in both mitochondrially labeled fixed cells, and in the membranes of living S2 Drosophila cells. 相似文献
24.
Javed Hussain Farooqui Archana Koul Ranjan Dutta Noshir Minoo Shroff 《Saudi Journal of Ophthalmology》2015,29(4):264-269
Purpose
Visual performance following toric intraocular lens implantation for cataract with moderate and severe astigmatism.Setting
Cataract services, Shroff Eye Centre, New Delhi, India.Design
Case series.Method
This prospective study included 64 eyes of 40 patients with more than 1.50 dioptre (D) of pre-existing corneal astigmatism undergoing phacoemulsification with implantation of the AcrySof® toric IntraOcular Lens (IOL). The unaided visual acuity (UCVA), best corrected visual acuity (BCVA), residual refractive sphere and refractive cylinders were evaluated. Toric IOL axis and alignment error was measured by slit lamp method and Adobe Photoshop (version 7) method. Patient satisfaction was evaluated using a satisfaction questionnaire at 3 months.Results
The mean residual refractive astigmatism was 0.57 D at the final follow-up of 3 months. Mean alignment error was 3.44 degrees (SD = 2.60) by slit lamp method and 3.88 degrees (SD = 2.86) by Photoshop method. Forty-six (71.9%) eyes showed misalignment of 5 degrees or less, and 60 (93.8%) eyes showed misalignment of 10 degrees or less. The mean log MAR UCVA at 1st post-op day was 0.172 (SD = 0.02), on 7th post-op day was 0.138 (SD = 0.11), and on 30th post-op day was 0.081 (SD = 0.11). The mean log MAR BCVA at three months was −0.04 (SD = 0.76).Conclusion
We believe that implantation of AcrySof® toric IOL is an effective, safe and predictable method to correct high amounts of corneal astigmatism during cataract surgery. 相似文献25.
Scott T. Chiesa Marietta Charakida Georgios Georgiopoulos Frida Dangardt Kaitlin H. Wade Alicja Rapala Devina J. Bhowruth Helen C. Nguyen Vivek Muthurangu Rukshana Shroff George Davey Smith Debbie A. Lawlor Naveed Sattar Nicholas J. Timpson Alun D. Hughes John E. Deanfield 《JACC: Cardiovascular Imaging》2021,14(2):468-478
ObjectivesThis study characterized the determinants of carotid intima-media thickness (cIMT) in a large (n > 4,000) longitudinal cohort of healthy young people age 9 to 21 years.BackgroundGreater cIMT is commonly used in the young as a marker of subclinical atherosclerosis, but its evolution at this age is still poorly understood.MethodsAssociations between cardiovascular risk factors and cIMT were investigated in both longitudinal (ages 9 to 17 years) and cross-sectional (ages 17 and 21 years) analyses, with the latter also related to other measures of carotid structure and stress. Additional use of ultra-high frequency ultrasound in the radial artery at age 21 years allowed investigation of the distinct layers (i.e., intima or media) that may underlie observed differences.ResultsFat-free mass (FFM) and systolic blood pressure were the only modifiable risk factors positively associated with cIMT (e.g., mean difference in cIMT per 1-SD increase in FFM at age 17: 0.007 mm: 95% confidence interval [CI]: 0.004 to 0.010; p < 0.001), whereas fat mass was negatively associated with cIMT (difference: ?0.0032; 95% CI: 0.004 to ?0.001; p = 0.001). Similar results were obtained when investigating cumulative exposure to these factors throughout adolescence. An increase in cIMT maintained circumferential wall stress in the face of increased mean arterial pressure when increases in body mass were attributable to increased FFM, but not fat mass. Risk factor?associated differences in the radial artery occurred in the media alone, and there was little evidence of a relationship between intimal thickness and any risk factor.ConclusionsSubtle changes in cIMT in the young may predominantly involve the media and represent physiological adaptations as opposed to subclinical atherosclerosis. Other vascular measures may be more appropriate for the identification of arterial disease before adulthood. 相似文献
26.
27.
SG Lindquist M Duno M Batbayli A Puschmann H Braendgaard S Mardosiene K Svenstrup LH Pinborg K Vestergaard LE Hjermind J Stokholm BB Andersen P Johannsen JE Nielsen 《Clinical genetics》2013,83(3):279-283
Recently, a hexanucleotide (GGGGCC) repeat expansion in the first intron of C9ORF72 was reported as the cause of chromosome 9p21‐linked frontotemporal dementia‐amyotrophic lateral sclerosis (FTD‐ALS). We here report the prevalence of the expansion in a hospital‐based cohort and associated clinical features indicating a wider clinical spectrum of C9ORF72 disease than previously described. We studied 280 patients previously screened for mutations in genes involved in early onset autosomal dominant inherited dementia disorders. A repeat‐primed polymerase chain reaction amplification assay was used to identify pathogenic GGGGCC expansions. As a potential modifier, confirmed cases were further investigated for abnormal CAG expansions in ATXN2. A pathogenic GGGGCC expansion was identified in a total of 14 probands. Three of these presented with atypical clinical features and were previously diagnosed with clinical olivopontocerebellar degeneration (OPCD), atypical Parkinsonian syndrome (APS) and a corticobasal syndrome (CBS). Further, the pathogenic expansion was identified in six FTD patients, four patients with FTD‐ALS and one ALS patient. All confirmed cases had normal ATXN2 repeat sizes. Our study widens the clinical spectrum of C9ORF72related disease and confirms the hexanucleotide expansion as a prevalent cause of FTD‐ALS disorders. There was no indication of a modifying effect of the ATXN2 gene. 相似文献
28.
Fabio Paglialonga Claus Peter Schmitt Rukshana Shroff Karel Vondrak Christoph Aufricht Alan Rees Watson Gema Ariceta Michael Fischbach Gunter Klaus Tuula Holtta Sevcan A. Bakkaloglu Alexandra Zurowska Augustina Jankauskiene Johan Vande Walle Betti Schaefer Elizabeth Wright Roy Connell Alberto Edefonti 《Pediatric nephrology (Berlin, Germany)》2015,30(1):103-111
29.
Stephanie Dufek Tuula Holtta Michel Fischbach Gema Ariceta Augustina Jankauskiene Rimante Cerkauskiene Claus Peter Schmitt Betti Schaefer Christoph Aufricht Elizabeth Wright Constantinos J. Stefanidis Mesiha Ekim Sevcan Bakkaloglu Günter Klaus Aleksandra Zurowska Karel Vondrak Johan Vande Walle Alberto Edefonti Rukshana Shroff 《Pediatric nephrology (Berlin, Germany)》2015,30(11):2021-2027
30.
Matthew J. Reilley Rachna Shroff Gauri R. Varadhachary 《The Indian journal of surgery》2015,77(5):403-408
The delivery of postoperative combined modality adjuvant therapy for completely resected pancreatic adenocarcinoma was initially shown to be beneficial based on a prospective, randomized trial published 30 years ago. Since then, oncologists have debated whether chemotherapy alone, chemoradiation, or both are optimal adjuvant therapies following pancreatectomy for pancreatic ductal adenocarcinomas (PDAC). No global consensus has emerged, and there is no one superior modality despite randomized trials in part, to poor trial design, poor patient selection, and poor therapy options itself. We need to have a disciplined approach to the selection of patients for pancreatectomy, pathologic assessment of surgical resection margins, and postoperative (pre-treatment) imaging. In the era of the multidetector CT optimized for pancreatic imaging, tumors of “borderline resectability” have emerged as a distinct subset of PDAC. The attempt to standardize the definition of borderline resectable is a work in progress and modified with time. This distinction (between resectable and borderline resectable) is essential to minimize potentially confounding results of clinical trials. Additionally, preoperative therapy is not only preferred but mandatory in a large population of borderline resectable patients. Ultimately, as we develop more effective systemic therapies for PDAC, proceeding with surgery after a period of induction therapy will be even more compelling especially if there is a clear positive impact on overall survival. 相似文献