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   1427100篇
  免费   109078篇
  国内免费   4600篇
耳鼻咽喉   17839篇
儿科学   45905篇
妇产科学   37822篇
基础医学   210814篇
口腔科学   38154篇
临床医学   139225篇
内科学   277341篇
皮肤病学   27996篇
神经病学   121830篇
特种医学   52051篇
外国民族医学   371篇
外科学   197897篇
综合类   29965篇
现状与发展   1篇
一般理论   528篇
预防医学   121763篇
眼科学   30616篇
药学   105259篇
  6篇
中国医学   3262篇
肿瘤学   82133篇
  2021年   12947篇
  2019年   13511篇
  2018年   18627篇
  2017年   14018篇
  2016年   15305篇
  2015年   17550篇
  2014年   23936篇
  2013年   36221篇
  2012年   50595篇
  2011年   53267篇
  2010年   30807篇
  2009年   28392篇
  2008年   48272篇
  2007年   51068篇
  2006年   50742篇
  2005年   49210篇
  2004年   46761篇
  2003年   44160篇
  2002年   42834篇
  2001年   62363篇
  2000年   63923篇
  1999年   53660篇
  1998年   15691篇
  1997年   14169篇
  1996年   13840篇
  1995年   13201篇
  1994年   12253篇
  1993年   11499篇
  1992年   42464篇
  1991年   41596篇
  1990年   40254篇
  1989年   38120篇
  1988年   35283篇
  1987年   34357篇
  1986年   32842篇
  1985年   31319篇
  1984年   23611篇
  1983年   20098篇
  1982年   12234篇
  1981年   10695篇
  1979年   21223篇
  1978年   15185篇
  1977年   12377篇
  1976年   12157篇
  1975年   12395篇
  1974年   15125篇
  1973年   14791篇
  1972年   13605篇
  1971年   12648篇
  1970年   11734篇
排序方式: 共有10000条查询结果,搜索用时 718 毫秒
101.
102.
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   
103.
104.
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   
105.
106.
107.
108.
109.
There is a large and growing population of long-term cancer survivors. Primary care physicians (PCPs) are playing an increasingly greater role in the care of these patients across the continuum of cancer survivorship. In this role, PCPs are faced with the responsibility of managing a range of medical and psychosocial late effects of cancer treatment. In particular, the sexual side effects of treatment which are common and have significant impact on quality of life for the cancer survivor, often go unaddressed. This is an area of clinical care and research that has received increasing attention, highlighted by the presentation of this special issue on Cancer and Sexual Health. The aims of this review are 3-fold. First, we seek to overview common presentations of sexual dysfunction related to major cancer diagnoses in order to give the PCP a sense of the medical issues that the survivor may present with. Barriers to communication about sexual health issues between patient/PCPs in order are also described in order to emphasize the importance of PCPs initiating this important conversation. Next, we provide strategies and resources to help guide the PCP in the management of sexual dysfunction in cancer survivors. Finally, we discuss case examples of survivorship sexual health issues and highlight the role that a PCP can play in each of these case examples.  相似文献   
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