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   4694篇
  免费   372篇
  国内免费   34篇
耳鼻咽喉   32篇
儿科学   171篇
妇产科学   101篇
基础医学   588篇
口腔科学   115篇
临床医学   601篇
内科学   942篇
皮肤病学   49篇
神经病学   473篇
特种医学   364篇
外科学   566篇
综合类   96篇
一般理论   1篇
预防医学   364篇
眼科学   78篇
药学   333篇
中国医学   18篇
肿瘤学   208篇
  2023年   18篇
  2022年   27篇
  2021年   55篇
  2020年   34篇
  2019年   60篇
  2018年   77篇
  2017年   47篇
  2016年   67篇
  2015年   75篇
  2014年   127篇
  2013年   156篇
  2012年   226篇
  2011年   218篇
  2010年   150篇
  2009年   120篇
  2008年   221篇
  2007年   222篇
  2006年   216篇
  2005年   190篇
  2004年   184篇
  2003年   204篇
  2002年   188篇
  2001年   173篇
  2000年   165篇
  1999年   129篇
  1998年   98篇
  1997年   105篇
  1996年   111篇
  1995年   77篇
  1994年   58篇
  1993年   75篇
  1992年   89篇
  1991年   86篇
  1990年   105篇
  1989年   120篇
  1988年   109篇
  1987年   94篇
  1986年   95篇
  1985年   85篇
  1984年   44篇
  1983年   48篇
  1982年   23篇
  1981年   33篇
  1980年   27篇
  1979年   30篇
  1978年   27篇
  1977年   23篇
  1976年   32篇
  1975年   19篇
  1973年   23篇
排序方式: 共有5100条查询结果,搜索用时 16 毫秒
971.
Leishmania (Viannia) organisms are the most prevalent etiologic agents of human cutaneous leishmaniasis in the Americas. Nevertheless, our knowledge of the immunological mechanisms exploited by L. (Viannia) organisms remains limited and the mechanisms underlying disease are not well understood. Here, we report the development of a BALB/c mouse model of L. (V.) panamensis infection that is able to reproduce chronic disease, with persistent infection and clinically evident lesions for over 1 year. The immune response of the mouse resembles that found for L. (V.) panamensis‐infected patients with chronic and recurrent lesions, presenting a mixed Th1/Th2 response with the presence of TNF‐α, IFN‐γ, IL‐10 and IL‐13. Using immunodeficient mice, the critical role for IL‐13 and/or IL‐4Rα in determining susceptibility to chronic infection was evident. With the induction of healing in the immunodeficient mice, increases in IFN‐γ and IL‐17 were found, concomitant with parasite control and elimination. Specifically, increases in CD4+ (but not CD8+) T cells producing IFN‐γ were observed. These results suggest that IL‐13 represents an important target for disease control of L. (V.) panamensis infection. This murine model should be useful to further understand the pathology associated with chronic disease and to develop methods for the treatment and prevention of leishmaniasis caused by L. (Viannia) parasites.  相似文献   
972.
973.
The chlorinated englerins (3-9) were isolated from Phyllanthus engleri and shown to selectively inhibit the growth of renal cancer cells. The compounds were shown to be extraction artifacts produced by exposure to chloroform decomposition products during their isolation. The most active compound, 3, was synthesized from englerin A (1).  相似文献   
974.
975.
976.
977.
With the increasing number of Utah children identified with autism spectrum disorders (ASDs), information on the prevalence and characteristics of these children could help Maternal Child Health (MCH) programs develop population building activities focused on prevention, screening, and education. The purpose of this study is to describe Utah’s autism registry developed in collaboration with state MCH programs and assess the impact of different record-based surveillance methods on state ASD prevalence rates. The study was conducted using 212 ASD cases identified from a population of 26,217 eight year olds living in one of the three most populous counties in Utah (Davis, Salt Lake, and Utah) in 2002. ASD prevalence was determined using two records based approaches (administrative diagnoses versus abstraction and clinician review) by source of record ascertainment (education, health, and combined). ASD prevalence ranged from 7.5 per 1000 (95% CI 6.4–8.5) to 3.2 per 1000 (95% CI 2.5–3.9) varying significantly (P < .05) based on method and record source. The ratio of male-to-female ranged from 4.7:1 to 6.4:1. No significant differences were found between the two case ascertainment methods on 18 of the 23 case characteristics including median household income, parental education, and mean age of diagnosis. Broad support is needed from both education and health sources as well as collaboration with MCH programs to address the growing health concerns, monitoring, and treatment needs of children and their families impacted by autism spectrum disorders.  相似文献   
978.
Pediatric Radiology - Previous work at our institution demonstrated discrepancies between radiologists in interpretation of contrast-enhanced magnetic resonance imaging (MRI) in suspected hip...  相似文献   
979.
INTRODUCTION: This article describes findings from a causal comparative study of the characteristics of employers against whom allegations of hiring discrimination were filed with the U.S. Equal Employment Opportunity Commission (EEOC) under Title I of the Americans with Disabilities Act (ADA) between 1992 and 2005. METHODS: Employer characteristics derived from 19,527 closed Hiring allegations are compared and contrasted to 259,680 closed allegations aggregated from six other prevalent forms of discrimination including Discharge and Constructive Discharge, Reasonable Accommodation, Disability Harassment and Intimidation, and Terms and Conditions of Employment. Tests of Proportion distributed as chi-square are used to form comparisons along a variety of factors including industry classification, size of workforce, and location. RESULTS: As compared to non-hiring allegations, hiring allegations were more likely to be filed against employers with 15-100 employees, in the West U.S. Census track region, or in industries including educational services; public administration; transportation and warehousing; professional, scientific, and technical services; agriculture, forestry, fishing, and hunting; and construction. CONCLUSION: More outreach regarding ADA responsibilities appears indicated for those employers who share the aforementioned characteristics.  相似文献   
980.
INTRODUCTION: This article describes findings from a causal comparative study of the Merit Resolution rate for allegations of Hiring discrimination that were filed with the U.S. Equal Employment Opportunity Commission (EEOC) under Title I of the Americans with Disabilities Act (ADA) between 1992 and 2005. An allegation is the Charging Party's perception of discrimination, but a Merit Resolution is one in which the EEOC has determined that a discriminatory event did indeed occur. A Non-Merit Resolution is an allegation that is closed due to a technicality or lacks sufficient evidence to conclude that discrimination occurred. Merit favors the Charging Party; Non-Merit favors the Employer. METHODS: The Merit Resolution rate of 19,527 closed Hiring allegations is compared and contrasted to that of 259,680 allegations aggregated from six other prevalent forms of discrimination including Discharge and Constructive Discharge, Reasonable Accommodation, Disability Harassment and Intimidation, and Terms and Conditions of Employment. Tests of Proportion distributed as chi-square are used to form comparisons along a variety of subcategories of Merit and Non-Merit outcomes. RESULTS: The overall Merit Resolution rate for Hiring is 26% compared to Non-Hiring at 20.6%. Employers are less likely to settle claims of hiring discrimination without mediation, and less likely to accept the remedies recommended by the EEOC when hiring discrimination has been determined. CONCLUSION: Hiring is not an unusual discrimination issue in that the overwhelming majority of allegations are still closed in favor of the Employer. However, it is counterintuitive that Hiring has a higher merit resolution rate than other prevalent issues. This finding contradicts the assumption that hiring is an "invisible process." Considering that the EEOC makes merit determinations at a competitive rate, it is clear that hiring is sufficiently transparent.  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