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   1300篇
  免费   67篇
  国内免费   9篇
耳鼻咽喉   4篇
儿科学   38篇
妇产科学   15篇
基础医学   133篇
口腔科学   38篇
临床医学   138篇
内科学   366篇
皮肤病学   13篇
神经病学   44篇
特种医学   230篇
外科学   141篇
综合类   19篇
预防医学   62篇
眼科学   15篇
药学   41篇
中国医学   4篇
肿瘤学   75篇
  2021年   24篇
  2020年   12篇
  2019年   11篇
  2018年   20篇
  2017年   18篇
  2016年   12篇
  2015年   21篇
  2014年   26篇
  2013年   26篇
  2012年   40篇
  2011年   51篇
  2010年   58篇
  2009年   39篇
  2008年   43篇
  2007年   47篇
  2006年   31篇
  2005年   46篇
  2004年   27篇
  2003年   20篇
  2002年   28篇
  2001年   26篇
  2000年   24篇
  1999年   21篇
  1998年   50篇
  1997年   58篇
  1996年   53篇
  1995年   50篇
  1994年   46篇
  1993年   31篇
  1992年   23篇
  1991年   13篇
  1990年   15篇
  1989年   24篇
  1988年   45篇
  1987年   24篇
  1986年   42篇
  1985年   37篇
  1984年   19篇
  1983年   26篇
  1982年   22篇
  1981年   14篇
  1980年   15篇
  1979年   8篇
  1978年   11篇
  1977年   13篇
  1976年   18篇
  1975年   9篇
  1969年   4篇
  1966年   8篇
  1965年   8篇
排序方式: 共有1376条查询结果,搜索用时 15 毫秒
21.
An influenza A virus antigenically similar to A/FPV/Dutch/27 (Hav1Neq1) [H7N7] was isolated from harbor seals (Phoca vitulina) that had died of acute hemorrhagic pneumonia on Cape Cod Peninsula, beginning in the winter of 1979–1980. High titers of virus were obtained from the lungs and lower titers from the brains of the seals. Although antigenic analyses and characterization of the RNAs show that all of the genes and gene products are closely related to different avian influenza viruses, biologically the virus behaves more like a mammalian strain. The seal virus replicated and produced pneumonia in experimentally infected harbor seals, but the clinical course and pathology were less severe than in the natural infection; the virus also replicated in ferrets, cats, and pigs but produced no disease. In avian species, the seal influenza virus replicated poorly, produced no disease signs, and was not shed in the feces. Although the seal influenza virus can cause conjunctivitis in humans who have known contamination of the eyes from infected animals, serological studies detected no evidence of seroconversion among persons working with infected seals or with the virus. Preliminary studies detected antibodies to this virus in harbor seals on the New England coast but not in harbor seals, gray seals, or fur seals from other areas, suggesting that this virus may be a new introduction to this species. An Hav1Neq1 [H7N7] virus was also isolated from feral ducks in Iceland in 1980, but the two viruses could be distinguished by analysis of their RNAs and host range. The A/Seal/Mass/1/80 influenza virus provides the first evidence suggesting that a strain deriving all of its genes from one or more avian influenza viruses can be associated with severe disease in a mammalian population in nature. Whether this breach of species specificity represents a unique event in influenza evolution remains to be determined, but raises the possibility that human or animal influenza viruses may be derived directly from avian strains.  相似文献   
22.
23.
In order to retrospectively evaluate the prevalence of immigrant patients affected by active tuberculosis, we analysed the clinical data of 2255 immigrant patients hospitalised during 2002 in ordinary admission or in Day Hospital in 48 Clinics of Infectious Diseases. In all, 303 patients were affected by active tuberculosis (13.4% of the total immigrant hospitalised patients); 30 patients (9.9%) were also HIV-positive. There was a considerable male gender bias (62.5%); the mean age was 29.7 years; 144 patients were from Africa (47.5%), 72 (23.7%) from Asia, 47 (15.5%) from eastern Europe and 40 (13.2%) from South America. The clinical variants were: pulmonary (57.7%), lymph node (15.8%), meningitis (13.8%), intestinal (4.2%), bone (3.3%), pleurical (2.3%), peritoneal (2.3%) and renal (0.6%). We conclude that tuberculosis is a very frequent disease among immigrants, especially of African origin. The high percentage is due to several factors, such as no vaccine prophylaxis and poor, overcrowded living conditions. It is fundamental to focus on the need to provide better health support for all subjects by setting up screening plans to estimate the real incidence of this pathology and ensure medical treatment to prevent the spread of this infection among immigrants and the local host population.  相似文献   
24.
25.

Background  

The purpose of the present investigation was to determine if the salivary counts of 40 common oral bacteria in subjects with an oral squamous cell carcinoma (OSCC) lesion would differ from those found in cancer-free (OSCC-free) controls.  相似文献   
26.
27.
Given the abrupt and time-limited nature of daytime-awake and nocturnal-sleep panic attacks, several chemical and neuroendocrine challenge tests have been employed to investigate the neurobiology of "spontaneous" panic attacks. Previously we demonstrated that panic disorder patients have blunted growth hormone (GH) responses to clonidine, an alpha 2-adrenergic agonist. However, the mechanism of this blunted response and the role of hypothalamic-GH dysfunction, if any, remains unclear. To further delineate the status of hypothalamic-GH function in panic disorder, we review the literature and present original data on the GH responses to a number of different chemical and neuroendocrine challenge paradigms. Although stress-mediated increases in GH are thought to be a common correlate of stress in humans, our findings indicate that panic disorder patients have significantly blunted GH responses to clonidine, yohimbine, growth-hormone releasing factor, and caffeine compared to normal control subjects. A similar trend was noted in the delayed rise in GH after glucose challenge. There was no difference in the rate of abnormal GH responses to thyrotropin-releasing hormone in panic disorder compared to normal control subjects. No drug or neuroendocrine challenge, even if associated with marked increases in anxiety, produced a significantly enhanced GH response compared to normal control subjects. These findings provide support for a hyporesponsive hypothalamic-GH system in panic disorder. These observations, combined with preliminary observations from our clinic of short stature in several cases of prepubescent children with anxiety disorders, also underscore the need for assessing early growth patterns in individuals with panic disorder. Strategies for investigating the site(s) of possible neurotransmitter or hypothalamic-GH-somatomedin dysfunction are discussed.  相似文献   
28.
29.
BACKGROUND: Personal experience in the treatment of inguinal hernia in "One day Surgery" is reported. METHODS: Design: retrospective evaluation of cases treated in a twelve months period. The follow-up has been programmed at 1, 3, 6 and 12 months after the treatment. Setting: general, thoracic and oncological surgery, Department of Surgical and Anatomical Disciplines. Polyclinic, University of Palermo. Subjects: 54 patients aged between 17 and 86 years (middle age 51.9), 48 male have been treated; in 3 cases recurrent hernias were found. Interventions: in every case Trabucco's procedure with local anaesthesia has been performed. Premedication with Midazolam 10 mg i.v. has been associated. Main outcome measures: postoperative course and morbidity have been valued. RESULTS: Twice general anaesthesia has been necessary. No case of allergic reactions has been found. All the patients but three have been discharged before the sixth hour. Wound infections, seromas, deep hematomas, neuralgias and short-time recurrences have not been observed. CONCLUSIONS: Tension-free procedures and local anaesthesia, in personal experience, are mandatory to perform the treatment of inguinal hernia in "One Day Surgery".  相似文献   
30.
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