全文获取类型
收费全文 | 7663篇 |
免费 | 389篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 118篇 |
儿科学 | 368篇 |
妇产科学 | 144篇 |
基础医学 | 850篇 |
口腔科学 | 141篇 |
临床医学 | 595篇 |
内科学 | 1734篇 |
皮肤病学 | 278篇 |
神经病学 | 611篇 |
特种医学 | 231篇 |
外科学 | 1280篇 |
综合类 | 158篇 |
预防医学 | 332篇 |
眼科学 | 215篇 |
药学 | 586篇 |
中国医学 | 34篇 |
肿瘤学 | 409篇 |
出版年
2023年 | 55篇 |
2022年 | 106篇 |
2021年 | 256篇 |
2020年 | 148篇 |
2019年 | 195篇 |
2018年 | 214篇 |
2017年 | 143篇 |
2016年 | 192篇 |
2015年 | 216篇 |
2014年 | 355篇 |
2013年 | 406篇 |
2012年 | 597篇 |
2011年 | 606篇 |
2010年 | 335篇 |
2009年 | 271篇 |
2008年 | 410篇 |
2007年 | 405篇 |
2006年 | 364篇 |
2005年 | 368篇 |
2004年 | 349篇 |
2003年 | 326篇 |
2002年 | 272篇 |
2001年 | 99篇 |
2000年 | 91篇 |
1999年 | 97篇 |
1998年 | 72篇 |
1997年 | 55篇 |
1996年 | 42篇 |
1995年 | 39篇 |
1994年 | 31篇 |
1993年 | 23篇 |
1992年 | 55篇 |
1991年 | 60篇 |
1990年 | 56篇 |
1989年 | 44篇 |
1988年 | 39篇 |
1987年 | 36篇 |
1986年 | 41篇 |
1985年 | 44篇 |
1984年 | 44篇 |
1983年 | 37篇 |
1982年 | 30篇 |
1981年 | 23篇 |
1980年 | 36篇 |
1979年 | 52篇 |
1978年 | 34篇 |
1977年 | 36篇 |
1974年 | 40篇 |
1973年 | 33篇 |
1970年 | 23篇 |
排序方式: 共有8084条查询结果,搜索用时 15 毫秒
1.
Background
The Association of Surgeons of Great Britain and Ireland (ASGBI) devised the electronic surgical logbook (version 2.4) for higher trainees in General Surgery enabling trainees to compile a uniform data set of their operative and training experience. This is in use by higher surgical trainees (HST) in the United Kingdom. This logbook permits trainees to submit data centrally into a Regional Analysis Database (RAD). With the implementation of the European Working Time Directive (EWTD) there is need for reliable data to assess the effects of the directive on training. In order to draw meaningful conclusions from the database the quality of data needs to be validated. We critically analysed the RAD in the Yorkshire region for a one-year period. 相似文献2.
Daniel D. Billadeau Subrha Chatterjee Patricia Bramati Raghavakaimal Sreekumar Vijay Shah Karen Hedin Raul Urrutia 《Journal of gastrointestinal cancer》2006,37(4):110-119
CXCL12 and its receptor, CXCR4, are emerging as promising targets for modulating growth, angiogenesis, and metastasis in several human cancers. Indeed, blocking the receptor is sufficient to prevent metastasis and angiogenesis in experimental breast cancer xenografts. Recently, the biological effect of the CXCR4 in pancreatic cancer, one of the most deadly neoplastic diseases, has been reported. However, the molecular mechanism by which CXCR4 contributes to these properties is not completely understood. In this paper, we characterize the signaling pathways activated by CXCR4 in pancreatic cancer. We show that after CXCR4 activation, EGFR becomes tyrosine phosphorylated, and the kinase activity of this receptor, together with the activation of MMPs, Src, and PI3-Kinase, is required for CXCR4-mediated ERK activation. Analysis of this cascade in pancreatic cancer cells revealed that the ERK-mediated pathway regulates genes involved in angiogenesis, such as VEGF, CD44, HIF1α, and IL-8. Furthermore, ERK blockage inhibits the migration and tube formation of endothelial cells induced by CXCL12. Considering that inhibitors for several components of this pathway, including CXCR4 itself, are at different stages of clinical trials, this study provides theoretical justification for the clinical testing of these drugs in pancreatic cancer, thus extending the list of potential targets for treating this dismal disease. 相似文献
3.
4.
Krishna K. Singh Yuxin Dong John T. Belisle Jeffrey Harder Vijay K. Arora Suman Laal 《Clinical and Vaccine Immunology : CVI》2005,12(2):354-358
Serum samples obtained from human immunodeficiency virus (HIV)-infected tuberculosis (TB) patients months prior to clinical TB were used to delineate the profile of Mycobacterium tuberculosis culture filtrate proteins recognized during subclinical TB. A subset of ~12 antigens was recognized by antibodies in these serum samples. Antibodies to two of these antigens (81 [88]-kDa malate synthase [GlcB] and MPT51) were present in serum samples obtained during incipient subclinical TB in 19 (~90%) of the 21 HIV-infected TB patients tested. These antigens will be useful for devising diagnostic tests that can identify HIV-positive individuals who are at a high risk for developing clinical TB. 相似文献
5.
Turf wars over medical imaging have become ubiquitous. At many centers, radiologists already have lost access to important technologies and their applications. A combination of decreasing revenues in other specialties and a growing attachment to imaging further threatens radiologists’ practices in the future. This is the first of an extended series of articles that will address the phenomenon of self-referral—its motivations, extent, and the threats it poses to radiologists. Each article will focus on a specific aspect and provide advice on how radiologists can deal with self-referral in their locales. 相似文献
6.
Prevalence of silent myocardial ischemia in asymptomatic individuals with subclinical atherosclerosis detected by electron beam tomography 总被引:3,自引:0,他引:3
Anand D. Vijay Lim Eric Raval Usha Lipkin David Lahiri Avijit 《Journal of nuclear cardiology》2004,11(4):450-457
BACKGROUND: Electron beam tomography coronary calcium imaging is an evolving technique for the early detection of coronary atherosclerosis, and recent studies have established its prognostic value in asymptomatic individuals. The relationship of coronary artery calcium scores (CAC) to obstructive coronary artery disease (CAD) has been poorly studied but is clinically relevant because it determines which individuals are likely to benefit from revascularization procedures. Hence, we prospectively evaluated the prevalence of myocardial ischemia in asymptomatic patients with cardiovascular risk factors and subclinical atherosclerosis. METHODS AND RESULTS: We studied 864 asymptomatic patients with no previous CAD but with cardiovascular risk factors, referred for electron beam tomography coronary calcium imaging to our institution over an 18-month period. From this group, 220 consecutive patients (85% men; mean age, 61 +/- 9 years; age range, 31-84 years) with moderate to severe atherosclerotic disease (coronary calcium score > or =100 Agatston units) were prospectively evaluated by technetium 99m sestamibi single photon emission computed tomography (SPECT). Patients were followed up (mean follow-up, 14 months) and data regarding their subsequent clinical management recorded. Of the 220 patients, 119 had moderate atherosclerosis (CAC score of 100-400 Agatston units) and 101 had severe atherosclerosis (CAC score > or =400 Agatston units). Abnormal SPECT findings were seen in 18% of patients with moderate atherosclerosis (n = 21) and 45% of patients with severe atherosclerosis (n = 45). Increasing severity of atherosclerosis was related to increasing ischemic burden (summed difference score = 1 +/- 0.2 for CAC score of 100-400 Agatston units and 3.2 +/- 0.5 for CAC score > or =400 Agatston units). In a multivariate linear regression model incorporating risk factors, CAC was the only predictor of silent ischemia. CONCLUSION: In comparison to previously published data, we detected a higher prevalence of silent ischemia even in patients with moderate coronary atherosclerosis (18%). This may reflect the differing risk factor profile of our patient population. When coronary calcium screening is used to preselect asymptomatic patients with cardiovascular risk factors for myocardial perfusion imaging, the optimum coronary calcium score threshold will depend on the population prevalence of risk factors and asymptomatic obstructive CAD. 相似文献
7.
8.
Alfred E Buxton Hugh Calkins David J Callans John P DiMarco John D Fisher H Leon Greene David E Haines David L Hayes Paul A Heidenreich John M Miller Athena Poppas Eric N Prystowsky Mark H Schoenfeld Peter J Zimetbaum Paul A Heidenreich David C Goff Frederick L Grover David J Malenka Eric D Peterson Martha J Radford Rita F Redberg 《Journal of the American College of Cardiology》2006,48(11):2360-2396
9.
Atul K. Sharma Moira S. Mills Vijay L. Grey Keith N. Drummond 《Pediatric nephrology (Berlin, Germany)》1997,11(6):711-713
Accurate, timed urine collections for the measurement of glomerular filtration rate (GFR) may be impractical in infants or
in patients with urological abnormalities. GFR may be measured without urine collection using a constant subcutaneous infusion
of iothalamate. We compare the infusion clearance with conventional renal clearance in 14 children and young adults. The mean
clearance ratio (infusion clearance/renal clearance ± 1 SD) was 0.99±0.1 and the mean discrepancy between the two methods
was 8.5%±4.7%. The 95% limits of agreement for the ratio of the two methods are 0.83–1.23. These data indicate that subcutaneous
infusion of iothalamate is a practical method for measuring GFR in children without a urine collection.
Received March 18, 1996; received in revised form February 12, 1997; accepted March 26, 1997 相似文献
10.
Sanjeev GULATI Sandeep GUPTA Vijay KHER Amit GUPTA Rajesh AHLAWAT Pradeep ARORA 《Nephrology (Carlton, Vic.)》1997,3(4):563-567
Summary: This study compares the outcomes of 229 renal transplants, of which 156 were live related renal transplants done at our centre and 73 unrelated transplants done at other centres but followed up at our centre. All the patients were on triple immunosuppression for periods varying between 9 months and 1 year. Patient characteristics, rejections, infections and 1 and 5 years patient and graft survival were analyzed in the two groups. the outcome of patients who continued on cyclosporine beyond 1 year was compared to those who discontinued cyclosporine at 1 year. Males predominated (191 vs 38) in both groups, while younger patients (<50 years) predominated in live related group (152 vs four). There was no difference in the incidence of infection, rejection, graft dysfunction, graft loss or death between the two groups. the 1 and 5 year patient survival in the related and unrelated group, (93.7% and 71.4% vs and 85% and 66%) and graft survival (90.4% and 69.4% vs 83.3% and 65.4%) were similar. However, in the unrelated group, patients who discontinued cyclosporine had a higher incidence of rejections (38% vs 14%) and graft loss (43% vs 11.8%), while in the related group no such difference was found. It is concluded that 1 and 5 year patient and graft survival is comparable between live related and live unrelated transplantation. However, in the unrelated group it is necessary to continue cyclosporine beyond 1 year in order to achieve comparable results. 相似文献