全文获取类型
收费全文 | 5736篇 |
免费 | 406篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 27篇 |
儿科学 | 180篇 |
妇产科学 | 203篇 |
基础医学 | 819篇 |
口腔科学 | 186篇 |
临床医学 | 446篇 |
内科学 | 1589篇 |
皮肤病学 | 74篇 |
神经病学 | 532篇 |
特种医学 | 276篇 |
外科学 | 657篇 |
综合类 | 54篇 |
一般理论 | 3篇 |
预防医学 | 397篇 |
眼科学 | 96篇 |
药学 | 279篇 |
中国医学 | 7篇 |
肿瘤学 | 351篇 |
出版年
2022年 | 45篇 |
2021年 | 92篇 |
2020年 | 62篇 |
2019年 | 89篇 |
2018年 | 127篇 |
2017年 | 83篇 |
2016年 | 96篇 |
2015年 | 90篇 |
2014年 | 158篇 |
2013年 | 202篇 |
2012年 | 306篇 |
2011年 | 280篇 |
2010年 | 175篇 |
2009年 | 118篇 |
2008年 | 267篇 |
2007年 | 333篇 |
2006年 | 301篇 |
2005年 | 289篇 |
2004年 | 271篇 |
2003年 | 240篇 |
2002年 | 223篇 |
2001年 | 179篇 |
2000年 | 128篇 |
1999年 | 116篇 |
1998年 | 65篇 |
1997年 | 56篇 |
1996年 | 61篇 |
1995年 | 43篇 |
1994年 | 36篇 |
1993年 | 39篇 |
1992年 | 105篇 |
1991年 | 90篇 |
1990年 | 99篇 |
1989年 | 99篇 |
1988年 | 85篇 |
1987年 | 71篇 |
1986年 | 79篇 |
1985年 | 63篇 |
1984年 | 55篇 |
1983年 | 38篇 |
1982年 | 35篇 |
1981年 | 39篇 |
1980年 | 34篇 |
1979年 | 43篇 |
1978年 | 35篇 |
1973年 | 45篇 |
1971年 | 27篇 |
1970年 | 31篇 |
1969年 | 28篇 |
1926年 | 27篇 |
排序方式: 共有6176条查询结果,搜索用时 31 毫秒
61.
Hananyah Glaubman Israel Orbach Ygal Gross Orit Aviram Irene Frieder Meira Frieman Odeda Pelled 《Psychophysiology》1979,16(5):467-470
The hypothesis that a load on focal attention prior to sleep results in subsequent changes in sleep patterns was investigated. Eight females and 2 males slept in the laboratory for 4 nights: 2 adaptation nights, 1 experimental night preceded by a focal attention load, and 1 control night preceded by relaxed activity. On the experimental night, time in bed, total sleep time, and stage REM sleep were significantly longer than on the control night. The results support the hypothesis and suggest that attention during REM sleep has a unique character. 相似文献
62.
Soluble egg antigen-stimulated T helper lymphocyte apoptosis and evidence for cell death mediated by FasL(+) T and B cells during murine Schistosoma mansoni infection 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Granuloma formation around schistosomal eggs is induced by soluble egg antigens (SEA) and mediated by the activity of CD4(+) Th lymphocytes and their cytokines. Regulation of the inflammatory Th cell response during infection is still insufficiently understood. The hypothesis of this study was that activation-induced cell death (AICD) of CD4(+) T cells is involved in the immune inflammatory response. This study investigated the dynamics of splenic and granuloma CD4(+) Th cell apoptosis and Fas ligand (FasL) expression during the acute and chronic stages of murine schistosomal infection. Enhanced apoptosis of freshly isolated CD4(+) Th lymphocytes commenced after egg deposition and persisted during the peak and modulated phases of granuloma formation. After oviposition, CD4(+), CD8(+), and CD19(+) splenocytes and granuloma cells expressed elevated levels of FasL but FasL expression declined during the downmodulated stage of infection. In culture, SEA induced splenic and granuloma CD4(+) T-cell apoptosis and stimulated expression of FasL on splenic but not granuloma CD4(+) T cells, CD8(+) T cells, and CD19(+) B cells. SEA-stimulated splenocytes and granuloma cells preferentially lysed a Fas-transfected target cell line. Depletion of B cells from SEA-stimulated splenic cultures decreased CD4(+) T cell apoptosis. Coculture of purified splenic B cells with CD4(+) T cells and adoptive transfer of purified B cells indicated that antigen-stimulated B cells can kill CD4(+) Th cells. However, CD4(+) T cells were the dominant mediators of apoptosis in the granuloma. This study indicates that AICD is involved in the apoptosis of CD4(+) T cells during schistosomal infection. 相似文献
63.
Epstein-Barr viral load as a marker of lymphoma in AIDS patients 总被引:5,自引:0,他引:5
Fan H Kim SC Chima CO Israel BF Lawless KM Eagan PA Elmore S Moore DT Schichman SA Swinnen LJ Gulley ML 《Journal of medical virology》2005,75(1):59-69
Epstein-Barr virus (EBV) is implicated in the pathogenesis of acquired immunodeficiency syndrome (AIDS) lymphoma, and viral DNA is present within the malignant cells in about half of affected patients. We examined the extent to which EBV viral load is elevated in the plasma of AIDS lymphoma patients compared to AIDS patients with opportunistic infections. Sixty-one AIDS patients were studied including 35 with lymphoma (24 non-Hodgkin, six Hodgkin, and five brain lymphoma) and 26 with various opportunistic infections. In situ hybridization revealed EBV encoded RNA (EBER) expression in the malignant cells of 17/28 AIDS lymphomas (61%). In 232 serial plasma samples from 35 lymphoma patients and in 128 samples from AIDS controls, EBV viral load was assayed by quantitative-polymerase chain reaction (Q-PCR) using a TaqMan probe targeting the BamH1W sequence. EBV was detected in plasma from all 17 EBER-positive AIDS lymphoma patients, with viral loads ranging from 34 to 1,500,000 copies per ml (median 3,210). Viral load usually fell rapidly upon initiation of lymphoma therapy and remained undetectable except in two patients with persistent tumor. In 11 AIDS patients, whose lymphoma lacked EBER expression, and in 26 control patients without lymphoma, levels of EBV in plasma were usually low or undetectable (range 0-1,995 and 0-2,409, median 0 and 0, respectively). There was no association between EBV viral load and human immunodeficiency virus (HIV) load or CD4 count. In conclusion, EBV viral load shows promise as a tool to assist in diagnosis and management of EBV-related lymphoma patients. 相似文献
64.
65.
M. Teresa Gómez Hernández Marta Fuentes Gago Nuria Novoa Valentín Israel Rodríguez Alvarado Marcelo F. Jiménez López 《Cirugía espa?ola》2021,99(6):421-427
IntroductionRobotic surgery has become a safe and effective approach for the treatment of pulmonary surgical pathology. However, the adoption of new surgical techniques requires the evaluation of the learning curve. The objective of this study is to analyze the learning curve of robotic anatomical lung resections.MethodsRetrospective analysis of all robotic anatomical lung resections performed by the same surgeon between June 2018 and March 2020. The learning curve was evaluated using CUSUM charts to estimate trend changes in surgical time, surgical failure and the occurrence of post-operative cardiorespiratory complications throughout the sequence of cases.ResultsThe study included a total of 73 cases. The median duration of all complications was 120 min (interquartile range: 90-150 min), the prevalence of surgical failure was 23.29%, while 4/73 patients had any postoperative cardiorespiratory complication. Based on the CUSUM analysis, the learning curve was divided into 3 different phases: phase i (from the first to the 14th intervention), phase ii (between the 15th and 30th intervention) and phase iii (from the 31st intervention).ConclusionsThe learning curve for robotic anatomical lung resections can be divided into 3 phases. The technical competence that guarantees satisfactory perioperative outcomes was achived in phase iii from the 31st intervention. 相似文献
66.
67.
Rabea Asleh Hilmi Alnsasra Amir Lerman Alexandros Briasoulis Naveen L. Pereira Brooks S. Edwards Takumi Toya John M. Stulak Alfredo L. Clavell Richard C. Daly Sudhir S. Kushwaha 《American journal of transplantation》2021,21(2):626-635
We have previously described the use of sirolimus (SRL) as primary immunosuppression following heart transplantation (HT). The advantages of this approach include attenuation of cardiac allograft vasculopathy (CAV), improvement in glomerular filtration rate (GFR), and reduced malignancy. However, in some patients SRL may cause significant proteinuria. We sought to investigate the prognostic value of proteinuria after conversion to SRL. CAV progression and adverse clinical events were studied. CAV progression was assessed by measuring the Δ change in plaque volume (PV) and plaque index (PI) per year using coronary intravascular ultrasound. Proteinuria was defined as Δ urine protein ≥300 mg/24 h at 1 year after conversion to SRL. Overall, 137 patients were analyzed (26% with proteinuria). Patients with proteinuria had significantly lower GFR (P = .005) but similar GFR during follow-up. Delta PV (P < .001) and Δ PI (P = .001) were significantly higher among patients with proteinuria after adjustment for baseline characteristics. Multivariate Cox regression analysis showed higher all-cause mortality (hazard ratio 3.8; P = .01) with proteinuria but similar risk of CAV-related events (P = .61). Our results indicate that proteinuria is a marker of baseline renal dysfunction, and that HT recipients who develop proteinuria after conversion to SRL have less attenuation of CAV progression and higher mortality risk. 相似文献
68.
69.
Work stress,nonwork stress,and health 总被引:1,自引:0,他引:1
Susan Klitzman James S. House Barbara A. Israel Richard P. Mero 《Journal of behavioral medicine》1990,13(3):221-243
This paper examines the interface between work stress and nonwork stress and how it relates to health. Results indicate that the way people feel at work is largely a function of conditions at work. Similarly, the way people feel outside of work is largely a function of things that occur outside the job. Both work and nonwork stress are independently associated with physical and mental health, although the relationship between nonwork stress and health is slightly stronger. Excessive demands or stresses in one domain can interfere with life in the other. Such conflict operates equally in both directions. When present it can be an added source of stress and adversely affect health. Taken together these findings suggest that the stress people experience at work is not simply a reflection of their "personal problems." This has implications for the design of health promotion and stress prevention programs in the workplace. 相似文献
70.