全文获取类型
收费全文 | 210410篇 |
免费 | 15205篇 |
国内免费 | 749篇 |
学科分类
医药卫生 | 226364篇 |
出版年
2023年 | 843篇 |
2022年 | 1405篇 |
2021年 | 3440篇 |
2020年 | 2106篇 |
2019年 | 3391篇 |
2018年 | 3968篇 |
2017年 | 3212篇 |
2016年 | 3410篇 |
2015年 | 4066篇 |
2014年 | 6095篇 |
2013年 | 8823篇 |
2012年 | 13123篇 |
2011年 | 14321篇 |
2010年 | 8096篇 |
2009年 | 7304篇 |
2008年 | 13588篇 |
2007年 | 14424篇 |
2006年 | 13918篇 |
2005年 | 14396篇 |
2004年 | 13806篇 |
2003年 | 12900篇 |
2002年 | 12437篇 |
2001年 | 1878篇 |
2000年 | 1461篇 |
1999年 | 2054篇 |
1998年 | 2830篇 |
1997年 | 2439篇 |
1996年 | 2208篇 |
1995年 | 1954篇 |
1994年 | 1756篇 |
1993年 | 1657篇 |
1992年 | 1216篇 |
1991年 | 1150篇 |
1990年 | 1055篇 |
1989年 | 956篇 |
1988年 | 1017篇 |
1987年 | 1028篇 |
1986年 | 1004篇 |
1985年 | 1084篇 |
1984年 | 1484篇 |
1983年 | 1463篇 |
1982年 | 1815篇 |
1981年 | 1644篇 |
1980年 | 1556篇 |
1979年 | 814篇 |
1978年 | 959篇 |
1977年 | 936篇 |
1976年 | 831篇 |
1975年 | 683篇 |
1974年 | 669篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Outcomes at 3 years of a prospective pilot study of Campath-1H and sirolimus immunosuppression for renal transplantation 总被引:2,自引:0,他引:2
Rolf N. Barth Christina A. Janus Christine A. Lillesand Nancy A. Radke John D. Pirsch Bryan N. Becker Luis A. Fernandez L. Thomas Chin Yolanda T. Becker Jon S. Odorico Anthony M. D''Alessandro Hans W. Sollinger Stuart J. Knechtle 《Transplant international》2006,19(11):885-892
Campath-1H (alemtuzumab) induction was used for renal transplantation in combination with sirolimus as immunosuppression. We previously reported a high (28%) rate of early rejection with this regimen, and now report 3-year outcomes. Twenty-nine patients were recipients of either deceased donor or non-HLA (Human Leukocyte Antigen) identical living donor primary renal allografts. Clinical parameters including infection, malignancy, kidney function, and kidney histology were followed prospectively for 3 years. Three-year cumulative graft and patient survival were 96% and 100%, respectively. Twenty patients were maintained on steroid-free immunosuppressive regimens, and 15 patients were maintained on monotherapy for immunosuppression (12 on sirolimus). No serious infectious complications were observed and two patients developed basal cell skin cancer. The 3-year results of our initial pilot study demonstrate good graft (96%) and patient (100%) outcomes. Campath-1H induction has yielded a high proportion of patients maintained on immunosuppressive monotherapy (57%) without serious infectious- and no malignancy-related complications. The reported regimen yielded novel insights into both Campath-1H and sirolimus therapy in renal transplantation. Because of the higher incidence of early rejection, we recommend a modified strategy of immunosuppression including a brief course of a calcineurin inhibitor. 相似文献
32.
33.
34.
Adrenal disorders in pregnancy. 总被引:1,自引:0,他引:1
35.
Surendra Singh Susan John Thykkoothathil Pappy Joseph Thilak Soloman 《Journal of Medical Imaging and Radiation Oncology》2003,47(2):127-134
We report the MRI features in a series of four patients with primary angiitis of the central nervous system (PACNS). Based on MRI features, clinical presentation, paraclinical investigations and laboratory tests, including cerebrospinal fluid (CSF) analysis, various differentials were considered. In two patients with MRI findings of cortical, subcortical and deep white matter lesions, lack of mass effect, focal areas of bleed and heterogeneous parenchymal, leptomeningeal or pial enhancement and a normal magnetic resonance angiography, a differential diagnosis of primary angiitis of the CNS was also considered. In all patients, an open brain biopsy was advised to establish a definitive diagnosis of PACNS. Here, we briefly discuss the MRI features, correlation with clinical presentation and paraclinical parameters for the diagnosis of this entity. We also briefly review the literature. 相似文献
36.
Michael D Levitt Julie K Furne Michael Kuskowski John Ruddy 《Clinical gastroenterology and hepatology》2006,4(2):123-129
BACKGROUND & AIMS: Breath methane measurements reflect the in situ activity of the methanogenic colonic flora. Thirty-five years ago we found that 34% of healthy adult subjects were methane producers (breath methane level >1 ppm above atmospheric methane levels). The current study presents a new survey of breath methane levels designed to determine if the activity of the methanogenic flora has changed over the past 35 years. In addition, we review insights into the methanogenic flora that have resulted from breath methane measurements. METHODS: The end-alveolar breath methane concentrations of 212 healthy adults living in the Minneapolis area were determined via gas chromatography. The influence of sex, age, and bowel movement frequency on methane production was assessed. RESULTS: The findings that 36.4% of participants were methane producers, with a mean methane concentration in these producers of 16.6 ppm, are strikingly similar to the values of 33.6% and 15.2 ppm observed 35 years ago. Neither sex nor age showed a statistically significant relationship to methane production. There was a negative correlation between frequency of bowel movements and breath methane concentration in methane producers. CONCLUSIONS: The activity of the methanogenic flora of healthy adults remained remarkably stable over the past 35 years despite widespread antibiotic use and dietary changes. A literature review revealed that many associations have been shown between methane production and clinical states, but it remains to be determined if methanogens actively influence human physiology or are simply a marker of colonic function. 相似文献
37.
Prostatitis and male infertility are frequent disorders, and the role of prostatitis in male infertility has been under discussion for more than 30 years. Many researchers have shown relevant links between the two. Although a causal relationship has not been definitely demonstrated, increasing evidence shows that chronic prostatitis has a relevant negative impact on male fertility potential, at least in certain subgroups. In the following review, we focus on the present state of knowledge on the role of chronic prostatitis as an etiologic factor in male infertility. 相似文献
38.
PURPOSE: The aim of this study was to determine the reproducibility of measurements made using the Sonogage Corneo-Gage Plus 2 (Cleveland, Ohio) ultrasound pachymeter of total corneal and corneal epithelial thickness in 5 different regions of the cornea. METHODS: Twenty-seven subjects at the New England College of Optometry (NECO) and 20 subjects at the Southern College of Optometry (SCO) were enrolled in this study. Measurements were taken of the central cornea as well as the nasal and temporal regions of the midperipheral and peripheral regions of the right cornea of each subject. Identical measurements were again taken in these subjects 1 week later at approximately the same time of day. Within-subject variations were then assessed using paired t tests. RESULTS: The only significant measurement differences that were found between visits were for full corneal thickness at both the nasal and temporal midperipheral locations. The mean differences for these locations were 13.5 microm and 13.7 microm, respectively. CONCLUSIONS: Epithelial corneal thickness and central and peripheral total corneal thickness measurements using the Corneo-Gage Plus 2 pachymeter were reproducible; however, midperipheral total corneal thickness measurements showed poor reproducibility. 相似文献
39.
Jonathan Larkin Anne Bost John I Glass Seng-Lai Tan 《Journal of interferon & cytokine research》2006,26(12):854-865
Hepatitis C virus (HCV)-specific impairments in host immunity have been described at multiple levels of the innate and adaptive response, which may lead to viral persistence in the majority of infections. Understanding of HCV-associated immune defects could lead to novel therapeutic advances. Natural killer (NK) cells, the major effector cells of the innate immune system, are functionally impaired in chronic HCV infection. It has been suggested that this phenotype is a result of virus-specific defects in antigen-presenting cells (APCs) that regulate NK cell activity, as normal NK function is restored when they are stimulated ex vivo. In this study, we used human NK cell cytotoxicity assays to evaluate the activation-induced effects of NK cells on the HCV replicon-containing hepatic cells. We found that cytokine-activated NK cells were capable of inducing an HCV-associated, perforin/granzyme-dependent lysis of human hepatoma cells and that this required direct cellular contact and was independent of MHC class I expression levels. In contrast, on removal of cytokine stimulation, NK cells failed to exert any direct cytolytic effect on replicon targets. These findings suggest an important underlying mechanism by which NK cells control HCV infection and, with appropriate understanding of HCV-associated immune defects, could lead to novel therapeutic advances. 相似文献
40.