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   10235篇
  免费   724篇
  国内免费   26篇
耳鼻咽喉   80篇
儿科学   275篇
妇产科学   269篇
基础医学   972篇
口腔科学   175篇
临床医学   1356篇
内科学   2240篇
皮肤病学   90篇
神经病学   777篇
特种医学   179篇
外科学   1605篇
综合类   103篇
一般理论   10篇
预防医学   1151篇
眼科学   135篇
药学   689篇
中国医学   10篇
肿瘤学   869篇
  2023年   47篇
  2022年   63篇
  2021年   244篇
  2020年   134篇
  2019年   196篇
  2018年   279篇
  2017年   191篇
  2016年   203篇
  2015年   213篇
  2014年   300篇
  2013年   460篇
  2012年   693篇
  2011年   764篇
  2010年   432篇
  2009年   383篇
  2008年   676篇
  2007年   747篇
  2006年   731篇
  2005年   621篇
  2004年   603篇
  2003年   590篇
  2002年   547篇
  2001年   137篇
  2000年   128篇
  1999年   140篇
  1998年   111篇
  1997年   93篇
  1996年   70篇
  1995年   70篇
  1994年   65篇
  1993年   47篇
  1992年   60篇
  1991年   83篇
  1990年   73篇
  1989年   56篇
  1988年   52篇
  1987年   46篇
  1986年   42篇
  1985年   39篇
  1984年   39篇
  1983年   38篇
  1982年   33篇
  1981年   38篇
  1980年   42篇
  1979年   35篇
  1978年   34篇
  1977年   32篇
  1976年   27篇
  1973年   27篇
  1968年   22篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
First described in 1955 in New Jersey, epizootic haemorrhagic disease (EHD) causes a severe clinical disease in wild and domestic ruminants worldwide. Epizootic haemorrhagic disease outbreaks occur in deer populations each year from summer to late autumn. The etiological agent is EHD virus (EHDV) which is a double‐stranded segmented icosahedral RNA virus. EHD virus utilizes point mutations and reassortment strategies to maintain viral fitness during infection. In 2018, EHDV serotype 2 was predominantly detected in deer in Illinois. Whole genome sequencing was conducted for two 2018 EHDV2 isolates (IL41747 and IL42218) and the sequence analyses indicated that IL42218 was a reassortant between different serotypes whereas IL41747 was a genetically stable strain. Our data suggest that multiple strains contribute to outbreaks each year.  相似文献   
2.
3.
4.

Background  

In meningitis, the cerebrospinal fluid contains high levels of innate immune molecules (e.g. complement) which are essential to ward off the infectious challenge and to promote the infiltration of phagocytes (neutrophils, monocytes). However, epithelial cells of either the ependymal layer, one of the established niche for adult neural stem cells, or of the choroid plexus may be extremely vulnerable to bystander attack by cytotoxic and cytolytic complement components.  相似文献   
5.
6.
BACKGROUND: Changes in the hypothalamic-pituitary-adrenal (HPA) axis, as evidenced by patterns of cortisol secretion, have been of interest in understanding depression and anxiety disorders across the life span. Previous studies of pediatric depression have pointed to the period around sleep onset as a key time point for observing alterations in cortisol secretion associated with affective disorders. Evidence also indicates that pubertal development may influence the expression of HPA dysregulation. We hypothesized that adolescents with depression and youth with anxiety disorders exhibit elevated peri-sleep-onset cortisol. METHODS: Plasma cortisol was sampled every 20 min around sleep onset from children and adolescents with major depressive disorder (n = 116), anxiety disorders (n = 32), or no history of psychiatric disorder (control; n = 76). Sleep onset was determined by polysomnography. Classification of participants as children or adolescents was based on Tanner staging of pubertal maturation. RESULTS: Children with anxiety disorders had higher peri-sleep-onset cortisol than children with depression or control children. Adolescents with depression had marginally higher peri-sleep-onset cortisol than control adolescents and significantly higher peri-sleep-onset cortisol than children with depression. CONCLUSIONS: Depression and anxiety are associated with altered cortisol secretion around sleep onset, and these changes appear to be influenced by pubertal maturation.  相似文献   
7.
Some researchers speculate that as many as 10% of users worldwide suffer from “problematic” use of the internet, possibly stemming from an internet dependency. Research is in its early stages, making it an uncertain issue for mental health professionals. This paper provides: (1) a critical review of research on problematic internet use for the mental health and addictions professional; and (2) practical implications, including suggestions on treatment and prevention, given its uncertain clinical classification.  相似文献   
8.
9.
10.
Agenesis of the Gallbladder Revisited Laparoscopically   总被引:1,自引:0,他引:1  
Gallbladder agenesis is an extremely rare disease. Necropsy incidence has been reported to be 0.016%. Failure lo locate the gallbladder at the time of a planned cholecystectomy can be very challenging. We report such a case during a laparoscopic cholecystectomy. The indication for surgery in these patients are complaints of gallbladder symptoms along with a false-positive ultrasound study. During exploration, an abnormal location of the gallbladder has to be excluded. Ectopic gallbladder locations include intrahepatic, lesser omentum, retroperitoneal, retrohepatic, within the falciform ligament, retroduodenal, and retrohepatic areas. Thorough exploration and cholangiography are essential. Embryologically, the gallbladder and cystic duct arise from the caudal portion of the hepatic bud. All of the previously reported cases of gallbladder agenesis have shown an absence of both the gallbladder and cystic duct. We report an embryological oddity wherein a patent cystic duct was found along with an agenetic gallbladder. This is the first case report of this finding, along with this being the first absent gallbladder discovered laparoscopically.  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