首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1824篇
  免费   104篇
  国内免费   12篇
耳鼻咽喉   1篇
儿科学   42篇
妇产科学   46篇
基础医学   228篇
口腔科学   55篇
临床医学   158篇
内科学   536篇
皮肤病学   61篇
神经病学   147篇
特种医学   30篇
外科学   175篇
综合类   4篇
一般理论   3篇
预防医学   204篇
眼科学   22篇
药学   97篇
中国医学   9篇
肿瘤学   122篇
  2023年   22篇
  2022年   29篇
  2021年   89篇
  2020年   46篇
  2019年   74篇
  2018年   71篇
  2017年   51篇
  2016年   36篇
  2015年   73篇
  2014年   69篇
  2013年   108篇
  2012年   165篇
  2011年   173篇
  2010年   92篇
  2009年   94篇
  2008年   137篇
  2007年   106篇
  2006年   111篇
  2005年   89篇
  2004年   87篇
  2003年   66篇
  2002年   59篇
  2001年   11篇
  2000年   11篇
  1999年   11篇
  1998年   14篇
  1997年   10篇
  1996年   8篇
  1995年   8篇
  1994年   6篇
  1993年   3篇
  1992年   3篇
  1991年   1篇
  1990年   2篇
  1989年   2篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
排序方式: 共有1940条查询结果,搜索用时 10 毫秒
91.
92.
93.
OBJECTIVE: To evaluate the relationship among appropriateness of the use of cholecystectomy and outcomes. SUMMARY BACKGROUND DATA: The use of cholecystectomy varies widely across regions and countries. Explicit appropriateness criteria may help identify suitable candidates for this commonly performed procedure. This study evaluates the relationship among appropriateness of the use of cholecystectomy and outcomes. METHODS: Prospective observational study in 6 public hospitals in Spain of all consecutive patients on waiting lists to undergo cholecystectomy for nonmalignant disease. Explicit appropriateness criteria for the use of cholecystectomy were developed by a panel of experts using the RAND appropriateness methodology and applied to recruited patients. Patients were asked to complete 2 questionnaires that measure health-related quality of life-the Short Form 36 (SF-36) and the Gastrointestinal Quality of Life Index (GIQLI)-before the intervention and 3 months after it. RESULTS: Patients judged as being appropriate candidates for cholecystectomy, using the panel's explicit appropriateness criteria, had greater improvements in the bodily pain, vitality, and social function domains of the SF-36 than those judged to be inappropriate candidates. They also demonstrated improvements in the GIQLI's physical impairment domain. Interventions judged as inappropriate were performed primarily among patients without symptoms of cholelithiasis. Those asymptomatic had a lower improvement in the bodily pain, social functioning, and physical summary scale of the SF-36 and in the symptomatology, physical impairment, and total score domains of the GIQLI. CONCLUSIONS: These results suggest a direct relationship between the application of explicit appropriateness criteria and better outcomes, as measured by health-related quality of life. They also indicate that patients without symptoms are not good candidates for cholecystectomy.  相似文献   
94.
We describe a new videolaryngoscopic device designed for use in cases of difficult airway. The device consists of a plastic blade with a video camera located halfway along its length. A mounted light source assembly means that bleeding ocurring in the airway will not obstruct the view. A 7-inch liquid crystal display monitor that can be transported quickly is useful in situations away from an operating room. Because the GlideScope can be introduced without moving the neck, it has been used in patients with cervical instability. We report the case of a 56-year-old man who underwent surgery for severe cervical spondylolisthesis. We describe a modified approach to managing the videolaryngoscope that facilitated maneuvering and intubation and that offers an effective alternative to techniques with other devices. The advantages and disadvantages reported in the literature are reviewed.  相似文献   
95.
96.
BACKGROUND: Despite high cardiovascular mortality in rheumatoid arthritis (RA), few studies of body mass index (BMI) and obesity as risk factors for death in RA have been published. METHODS: We estimated the effect of BMI on survival in a cohort of 779 patients with RA adjusting for comorbidity, RA disease severity, erythrocyte sedimentation rate (ESR), and other potential confounders. RESULTS: The cohort accrued 123 deaths in 3460 person-years (3.6 deaths per 100 person-years; 95% confidence interval [CI], 3.0-4.2). The BMI was inversely associated with mortality. Patients with BMIs of 30 or higher had the lowest mortality, 1.7 deaths per 100 person-years (95% CI, 1.1-2.5). Mortality was higher in each lower BMI category, reaching its highest rate among patients with BMIs lower than 20 with 15.0 deaths per 100 person-years (95% CI, 9.9-23.0). The survival advantage of high BMI was independent of RA onset age, RA duration, sex, ethnic group, socioeconomic status, smoking status, and use of methotrexate but was lost on adjusting for comorbidity and RA severity. We observed an interaction between BMI and ESR, where the BMI protective influence occurred only if the ESR was low. The BMI x ESR interaction was independent of all covariates, including comorbidity and RA severity. CONCLUSIONS: Body mass has a paradoxical effect on mortality in RA. Patients with high BMI have lower mortality than thinner patients. This effect is mediated in part by comorbidity. The effect of body mass on survival seems to be modified by the level of systemic inflammation.  相似文献   
97.
OBJECTIVE: To estimate the contribution of cardiovascular (CV) risk factors and rheumatoid arthritis (RA) disease manifestations to atherosclerosis in RA. METHODS: We used high-resolution carotid ultrasound to measure the carotid intima-media thickness (IMT) and plaque in 631 RA patients. Using R(2) measures from multivariable models, we estimated the contribution of demographic characteristics (age, sex, and ethnic group), CV risk factors (diabetes mellitus, hypercholesterolemia, cigarette smoking, hypertension, and body mass index, and RA manifestations (joint tenderness, swelling, and deformity, nodules, erythrocyte sedimentation rate [ESR], C-reactive protein, rheumatoid factor, the HLA-DRB1 shared epitope, and cumulative glucocorticoid dose) to each of the outcomes. Estimates were obtained in the full sample, and within strata defined by age, sex, and ethnic group. We tested for interaction between CV risk factors and RA manifestations. RESULTS: The contribution of demographic factors, CV risk factors, and RA manifestations to IMT and plaque R(2) varied depending on the patients' age stratum. Demographic features explained 11-16% of IMT variance, CV risk factors explained 4%-12%, and RA manifestations explained 1-6%. The greatest contribution of RA manifestations occurred in the youngest age group, while that of CV risk factors occurred in the older age groups. Results for carotid plaque were similar. There was a significant interaction between the number of CV risk factors present and the ESR, suggesting that the ESR's effect on IMT varied according to the number of CV risk factors. CONCLUSION: Both established CV risk factors and manifestations of RA inflammation contribute significantly to carotid atherosclerosis in RA, and may modify one another's effects. These findings may have implications regarding the prevention of atherosclerosis in RA.  相似文献   
98.
Tumor necrosis factor-á (TNF-á) antagonists were unexpectedly found to have no beneficial effects in moderate-to-severe heart failure in two large randomized clinical trials. In certain doses, the agents were found to be harmful. These results have important implications for rheumatoid arthritis (RA). Patients with the disease have an increased risk for developing cardiovascular co-morbidity, including heart failure. Because of the beneficial effect of the TNF-á antagonists in the management of RA, these agents have gained widespread use. Rheumatologists and other physicians who provide care for RA are thus likely to encounter candidates for anti-TNF-á therapy who have overt or subclinical heart failure. Although data are currently not sufficient to support evidence-based recommendations, it is possible to make reasonable suggestions to guide clinical practice.  相似文献   
99.
100.
Amino acid transporter SNAT5 localizes to glial cells in the rat brain   总被引:1,自引:0,他引:1  
The SNAT5 transporter is a neutral amino acid carrier whose function remains unclear. Structural and mechanistically, SNAT5 is closely related to the SNAT3 transporter that mediates the efflux of glutamine from glial cells and that participates in the glutamate-glutamine cycle in the brain. In this study, we have analyzed the distribution of SNAT5 in the rat central nervous system using specific antibodies. Through immunoblotting we observed that SNAT5 is ubiquitously but unevenly distributed in the CNS. It accumulates most intensely in the neocortex, the hippocampus, the striatum, and the spinal cord, whereas moderate levels were found in the thalamus, hypothalamus, and brainstem. Light microscopy revealed that the distribution of SNAT5 paralleled that of the vesicular glutamate transporter vGLUT1 in the forebrain regions, whereas in the diencephalon and brainstem, SNAT5 staining was better correlated with that of vGLUT1 and vGLUT2. However, the cellular localization differed from that of the glutamatergic markers, since SNAT5 was expressed exclusively in astrocyte cell bodies and their processes, ensheathing glutamatergic GABAergic and glycinergic terminals. The presence of SNAT5 in astrocyte processes was confirmed by electron microscopy. They were seen not only to surround different neuronal structures, but they were also found in astrocyte endfeet. Taking into consideration the higher levels of SNAT5 in the neighborhood of glutamatergic terminals and the ability of this transporter family to promote the efflux of amino acids from intracellular stores (including glutamine and perhaps glycine), this transporter is likely to be involved in glutamatergic pathways in the brain.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号