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   1373640篇
  免费   105566篇
  国内免费   7150篇
耳鼻咽喉   17127篇
儿科学   44178篇
妇产科学   36912篇
基础医学   202699篇
口腔科学   36555篇
临床医学   135020篇
内科学   264394篇
皮肤病学   26759篇
神经病学   114334篇
特种医学   49474篇
外国民族医学   383篇
外科学   188406篇
综合类   35302篇
现状与发展   6篇
一般理论   466篇
预防医学   116742篇
眼科学   30119篇
药学   102892篇
  37篇
中国医学   5000篇
肿瘤学   79551篇
  2021年   12961篇
  2019年   13074篇
  2018年   17768篇
  2017年   13573篇
  2016年   14443篇
  2015年   16989篇
  2014年   23039篇
  2013年   34060篇
  2012年   47197篇
  2011年   50101篇
  2010年   29015篇
  2009年   26508篇
  2008年   44861篇
  2007年   47218篇
  2006年   47218篇
  2005年   45691篇
  2004年   42920篇
  2003年   40853篇
  2002年   39450篇
  2001年   61740篇
  2000年   63463篇
  1999年   53350篇
  1998年   15173篇
  1997年   13956篇
  1996年   13613篇
  1995年   12917篇
  1994年   12023篇
  1993年   11209篇
  1992年   41886篇
  1991年   41041篇
  1990年   39666篇
  1989年   37532篇
  1988年   34757篇
  1987年   33845篇
  1986年   32283篇
  1985年   30725篇
  1984年   23082篇
  1983年   19648篇
  1982年   11785篇
  1979年   20836篇
  1978年   14832篇
  1977年   12075篇
  1976年   11882篇
  1975年   12117篇
  1974年   14812篇
  1973年   14481篇
  1972年   13361篇
  1971年   12421篇
  1970年   11486篇
  1969年   10414篇
排序方式: 共有10000条查询结果,搜索用时 15 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.
104.
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   
105.
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