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   1446483篇
  免费   110605篇
  国内免费   4739篇
耳鼻咽喉   18200篇
儿科学   46431篇
妇产科学   38302篇
基础医学   212284篇
口腔科学   38745篇
临床医学   141333篇
内科学   281777篇
皮肤病学   28216篇
神经病学   122966篇
特种医学   52976篇
外国民族医学   370篇
外科学   202047篇
综合类   30040篇
现状与发展   1篇
一般理论   678篇
预防医学   123013篇
眼科学   31492篇
药学   105792篇
  8篇
中国医学   3324篇
肿瘤学   83832篇
  2021年   14045篇
  2019年   14365篇
  2018年   19546篇
  2017年   14663篇
  2016年   15741篇
  2015年   17982篇
  2014年   24739篇
  2013年   37273篇
  2012年   51849篇
  2011年   54681篇
  2010年   31484篇
  2009年   28815篇
  2008年   49344篇
  2007年   51674篇
  2006年   51547篇
  2005年   49759篇
  2004年   47221篇
  2003年   44727篇
  2002年   43204篇
  2001年   62342篇
  2000年   63932篇
  1999年   53739篇
  1998年   15704篇
  1997年   14245篇
  1996年   13964篇
  1995年   13281篇
  1994年   12324篇
  1993年   11575篇
  1992年   42657篇
  1991年   41844篇
  1990年   40410篇
  1989年   38300篇
  1988年   35453篇
  1987年   34616篇
  1986年   33077篇
  1985年   31585篇
  1984年   23882篇
  1983年   20298篇
  1982年   12350篇
  1981年   10841篇
  1979年   21458篇
  1978年   15356篇
  1977年   12552篇
  1976年   12332篇
  1975年   12535篇
  1974年   15325篇
  1973年   14916篇
  1972年   13739篇
  1971年   12775篇
  1970年   11772篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
101.
A 17‐year‐old boy presented with recurring severe dermatitis of the face of 5‐months duration that resembled impetigo. He had been treated with several courses of antibiotics without improvement. Biopsy showed changes consistent with allergic contact dermatitis and patch testing later revealed sensitization to benzoyl peroxide, which the patient had been using for the treatment of acne vulgaris.  相似文献   
102.
103.
In 1963, Goffman argued that forming a group based on shared stigma may provide benefits. However, there is no empirical research on whether perception that a separate, unique, coherent group exists (i.e., group entitativity) influences coping, such as educating others or secrecy, for the stigmatized individual or his or her spouse. Further, little is known about how spouses influence each other in terms of promoting the education of others about a stigmatizing condition, especially when it comes to the role of believing that stigma-based groups, to which they may both belong, exist. This study provides a step toward bridging this gap in the research by applying the label management model in efforts to understand coping for couples in which one spouse is diagnosed with genetic mutations leading to alpha-1 antitrypsin deficiency (AATD). This study included 50 married couples in which one spouse is diagnosed with genetic mutations leading to alpha-1 antitrypsin deficiency (AATD). We found that group entitativity related to those with AATD counterbalanced the influence of genetic stigma on spouses’ intentions to keep the diagnosis secret or to educate others about it. Intrapersonal and interpersonal influences appeared among spouses. Attention is needed on the power of creating groups for stigmatized persons and their relatives. Indeed, people live within a dynamic world of group entities, and multiple social identities including spousal and familial. While attention has been paid to the diffusion of stigmas to loved ones, less has been paid to the uplift of group entities for them.  相似文献   
104.
105.
Polyethylene (PE) has been used extensively in knee arthroplasty since the mid 20th century. Progress in material manufacturing and processing has led to newer polyethylenes over last few decades with different material properties. It has been established that PE wear in knee arthroplasty causes particle induced osteolysis which is the main reason for late failure and requires revision surgery. Although there are various causes of wear, the properties of PE have long been a matter of investigation as a contributory factor. The advent of newer highly cross linked PE has been shown to improve wear rates in hip arthroplasty but the benefits have not been shown to be of the same degree in knee arthroplasty. The laboratory and clinical studies so far are limited and slightly conflicting in their conclusions. The risks of using highly cross linked PE in knee arthroplasty include tibial post fracture, disruption of locking mechanism, liner fracture which can lead to increased wear and osteolysis. The current evidence suggests that highly cross linked polyethylenes should be used with caution and only considered in younger active patients. The results of a recently completed randomized trial to compare the conventional with high molecular weight PE in knee arthroplasty are awaited.  相似文献   
106.
Pancreatic ductal adenocarcinoma (PDAC) is predicted to become the second leading cause of cancer-related mortality within the next decade, with limited effective treatment options and a dismal long-term prognosis for patients. Genomic profiling has not yet manifested clinical benefits for diagnosis, treatment or prognosis in PDAC, due to the lack of available tissues for sequencing and the confounding effects of low tumour cellularity in many biopsy specimens. Increasing focus is now turning to the use of minimally invasive liquid biopsies to enhance the characterisation of actionable PDAC tumour genomes. Circulating tumour DNA (ctDNA) is the most comprehensively studied liquid biopsy analyte in blood and can provide insight into the molecular profile and biological characteristics of individual PDAC tumours, in real-time and in advance of traditional imaging modalities. This can pave the way for identification of new therapeutic targets, novel risk variants and markers of tumour response, to supplement diagnostic screening and provide enhanced scrutiny in treatment stratification. In the roadmap towards the application of precision medicine for clinical management in PDAC, ctDNA analyses may serve a leading role in streamlining candidate biomarkers for clinical integration. In this review, we highlight recent developments in the use of ctDNA-based liquid biopsies for PDAC and provide new insights into the technical, analytical and biological challenges that must be overcome for this potential to be realised.  相似文献   
107.
108.
ABSTRACT

Domestic chickens (Gallus gallus domesticus) were exposed to imidacloprid by gavage once daily for 7 consecutive days at 0, 0.03, 0.34, 3.42, 10.25, and 15.5 mg/kg/day (n = 20 per group; 5 6-week-old males, 5 6-week-old females, 5 9-week-old males, and 5 9-week-old females). The severity and duration of neurobehavioral abnormalities were recorded. Components of the innate and adaptive immune system were assessed with 7 standard functional assays. Temporary neurobehavioral abnormalities were observed in a dose-dependent manner, including muscle tremors, ataxia, and depressed mentation. Based upon mean clinical severity scores, the no observed adverse effect level (NOAEL) was 3.42 mg/kg/day, and the lowest observed adverse effect level (LOAEL) was 10.25 mg/kg/day. The effective dose value for the presence of any neurobehavioral abnormalities in 50% of the test group (ED50) was 4.62 ± 0.98 mg/kg/day. The ED50 for an adjusted score that included both severity and duration of neurobehavioral abnormalities was 11.24 ± 9.33 mg/kg/day. These ED50 values are equivalent to a 1 kg bird ingesting 29 or 70 imidacloprid treated soybean seeds respectively. Immunotoxicity was not documented, possible causes include the assays were insensitive, relevant immune functions were not examined, or imidacloprid is not immunotoxic at this dosing schedule in this species. Neurobehavioral abnormalities were a more sensitive indicator of the sublethal effects of imidacloprid than immunotoxicity.  相似文献   
109.
110.
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