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   9026篇
  免费   953篇
  国内免费   33篇
耳鼻咽喉   65篇
儿科学   200篇
妇产科学   240篇
基础医学   1556篇
口腔科学   179篇
临床医学   1205篇
内科学   1881篇
皮肤病学   79篇
神经病学   772篇
特种医学   288篇
外国民族医学   1篇
外科学   1164篇
综合类   145篇
一般理论   7篇
预防医学   943篇
眼科学   123篇
药学   462篇
中国医学   10篇
肿瘤学   692篇
  2022年   67篇
  2021年   148篇
  2020年   91篇
  2019年   145篇
  2018年   158篇
  2017年   136篇
  2016年   157篇
  2015年   171篇
  2014年   234篇
  2013年   358篇
  2012年   489篇
  2011年   503篇
  2010年   323篇
  2009年   281篇
  2008年   476篇
  2007年   489篇
  2006年   496篇
  2005年   420篇
  2004年   437篇
  2003年   464篇
  2002年   403篇
  2001年   186篇
  2000年   186篇
  1999年   172篇
  1998年   139篇
  1997年   110篇
  1996年   125篇
  1995年   83篇
  1994年   83篇
  1993年   82篇
  1992年   147篇
  1991年   154篇
  1990年   160篇
  1989年   136篇
  1988年   158篇
  1987年   120篇
  1986年   149篇
  1985年   130篇
  1984年   91篇
  1983年   100篇
  1982年   64篇
  1981年   64篇
  1979年   78篇
  1978年   59篇
  1977年   61篇
  1976年   58篇
  1975年   54篇
  1974年   61篇
  1973年   69篇
  1970年   55篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Purpose: Given the strong association of stroke and epilepsy in older persons, and the existence of a Stroke Belt in the United States, we hypothesized that geographic variation in epilepsy prevalence would follow geographic patterns similar to stroke. Methods: We used a 2005 5% random sample of Medicare beneficiaries 65 and older in 48 U.S. contiguous states. Epilepsy was identified from claims for physician visits, hospitalizations, and outpatient procedures. Prevalence was obtained by state and county. Logistic regressions determined the independent association of the likelihood of epilepsy (prevalent or new case) and residence in Stroke Belt states, controlling for residence in highest epilepsy prevalence states, demographics (race, age, gender), comorbid conditions, cerebrovascular disease, dementia, and county characteristics. Key Findings: Of 1,212,015 beneficiaries, 11.9 per 1,000 had prevalent and 2.9 new cases of epilepsy. Nine of 11 Stroke Belt states were among the 20 states with the highest epilepsy prevalence. Counties in the 10 highest epilepsy prevalence states were more likely to be large urban counties with a higher number of neurologists or neurosurgeons per capita. The higher likelihood of prevalent epilepsy cases associated with Stroke Belt residence was explained by beneficiaries’ race; that associated with residence in high epilepsy prevalence states was not. The likelihood of new epilepsy cases was negatively associated with Stroke Belt residence when controlling for covariates. Significance: The geographic variation in epilepsy prevalence is not explained by variations in known risk factors. Further research should investigate why eastern U.S. states have higher frequency of epilepsy.  相似文献   
993.
Objectives: This study compared fentanyl vs. sufentanil in intrathecal pain pumps. H1: both reduce patient subjective pain ratings. H2: sufentanil is more effective than fentanyl. H3: overall satisfaction with pain control is greater with sufentanil. Materials/Method: This is an archival study of patients in tertiary pain management (N= 97, mean age = 58.77, standard deviation = 14.88). Pain was measured using the subjective units of discomfort scale. Satisfaction with pain control/relief was measured by asking patients each visit if they are satisfied with pain management and is recorded in a “yes”/ “no” manner. Pain ratings were analyzed with repeated measures analysis of variance and satisfaction was analyzed with chi square. Results/Discussion: Sufentanil was found to be marginally more effective, but both medications controlled a significant degree of variance in pain reduction over time. A significantly greater number of patients maintained on sufentanil were satisfied with care than patients on fentanyl.  相似文献   
994.

Introduction  

Terminal myelocystocele is a rare form of spinal dysraphism characterised by cystic dilatation of the central canal of a low-lying terminal cord. Typical presentation is a skin-covered dorsal mass; early surgical repair has been recommended.  相似文献   
995.
Previous studies have replicated the four-factor structure of the WISC-III in children with traumatic brain injury (TBI) and demonstrated the sensitivity of WISC-III indexes to severity of injury. This archival study examined the growth curve characteristics of the indexes following traumatic brain injury. The primary hypothesis was that there is systematic variability in the components (e.g., slope) of the curves. Subjects included 40 children with documented loss of consciousness, age at injury 9.3 years (SD = 2.6), 68% severe TBI, evaluated with a full WISC-III a minimum of three times post-injury. Growth curve analyses with hierarchical linear modeling, conducted with factor scores recalculated as non-age-standardized z scores, indicated that although the intercept was reliable and could be predicted by injury characteristics, there was little systematic variation in index growth rates. Findings suggest that WISC-III indexes are of limited utility as repeated measures of recovery following TBI.  相似文献   
996.
Although laryngeal electromyography (LEMG) is commonly performed, there are no data confirming its efficacy. We evaluated 40 patients with a laryngoscopic diagnosis of unilateral vocal-fold immobility who underwent LEMG of the thyroarytenoid (TA) and cricothyroid (CT) muscle, with the immobile side of each muscle being compared to the normal side. The immobile side compared to the normal side showed more fibrillation potentials and positive sharp waves for the TA (p = 0.04), longer MUAP duration for the TA (p = 0.04) and CT (p = 0.01), more polyphasic potentials for the TA (p = 0.002), and more frequent decreased recruitment for the TA (p < 0.01) and CT (p = 0.008). Specificity and positive predictive value were around 90%. Sensitivity, negative predictive value and accuracy were around 50%. These results suggest that altered LEMG findings are reliable and they can be used to determine the innervation status of an immobile muscle. Conversely, when the LEMG is normal, the results should be reviewed.  相似文献   
997.
998.
999.
1000.
The survival of breast cancer patients is largely influenced by tumor characteristics, such as TNM stage, tumor grade and hormone receptor status. However, there is growing evidence that inherited genetic variation might affect the disease prognosis and response to treatment. Several lines of evidence suggest that alleles influencing breast cancer risk might also be associated with breast cancer survival. We examined the associations between 35 breast cancer susceptibility loci and the disease over‐all survival (OS) in 10,255 breast cancer patients from the National Cancer Institute Breast and Prostate Cancer Cohort Consortium (BPC3) of which 1,379 died, including 754 of breast cancer. We also conducted a meta‐analysis of almost 35,000 patients and 5,000 deaths, combining results from BPC3 and the Breast Cancer Association Consortium (BCAC) and performed in silico analyses of SNPs with significant associations. In BPC3, the C allele of LSP1‐rs3817198 was significantly associated with improved OS (HRper‐allele=0.70; 95% CI: 0.58–0.85; ptrend = 2.84 × 10?4; HRheterozygotes = 0.71; 95% CI: 0.55–0.92; HRhomozygotes = 0.48; 95% CI: 0.31–0.76; p2DF = 1.45 × 10?3). In silico, the C allele of LSP1‐rs3817198 was predicted to increase expression of the tumor suppressor cyclin‐dependent kinase inhibitor 1C (CDKN1C). In the meta‐analysis, TNRC9‐rs3803662 was significantly associated with increased death hazard (HRMETA =1.09; 95% CI: 1.04–1.15; ptrend = 6.6 × 10?4; HRheterozygotes = 0.96 95% CI: 0.90–1.03; HRhomozygotes = 1.21; 95% CI: 1.09–1.35; p2DF=1.25 × 10?4). In conclusion, we show that there is little overlap between the breast cancer risk single nucleotide polymorphisms (SNPs) identified so far and the SNPs associated with breast cancer prognosis, with the possible exceptions of LSP1‐rs3817198 and TNRC9‐rs3803662.  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