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   22465篇
  免费   1901篇
  国内免费   46篇
耳鼻咽喉   255篇
儿科学   757篇
妇产科学   577篇
基础医学   3175篇
口腔科学   378篇
临床医学   2632篇
内科学   4413篇
皮肤病学   378篇
神经病学   2174篇
特种医学   709篇
外国民族医学   5篇
外科学   2540篇
综合类   219篇
一般理论   15篇
预防医学   2690篇
眼科学   300篇
药学   1485篇
中国医学   15篇
肿瘤学   1695篇
  2023年   255篇
  2022年   471篇
  2021年   877篇
  2020年   479篇
  2019年   851篇
  2018年   934篇
  2017年   655篇
  2016年   703篇
  2015年   788篇
  2014年   1030篇
  2013年   1220篇
  2012年   1873篇
  2011年   1859篇
  2010年   943篇
  2009年   802篇
  2008年   1309篇
  2007年   1305篇
  2006年   1169篇
  2005年   1115篇
  2004年   1020篇
  2003年   815篇
  2002年   767篇
  2001年   212篇
  2000年   233篇
  1999年   186篇
  1998年   175篇
  1997年   129篇
  1996年   115篇
  1995年   98篇
  1994年   88篇
  1993年   78篇
  1992年   111篇
  1991年   128篇
  1990年   114篇
  1989年   116篇
  1988年   105篇
  1987年   81篇
  1986年   100篇
  1985年   98篇
  1984年   63篇
  1983年   97篇
  1981年   59篇
  1980年   47篇
  1979年   65篇
  1978年   52篇
  1977年   44篇
  1976年   52篇
  1975年   50篇
  1973年   55篇
  1972年   48篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
The yeast spectrum of the 'tea fungus Kombucha'   总被引:1,自引:0,他引:1  
  相似文献   
45.
We describe a case of giant cavernous haemangioma of the liver with disseminated intravascular coagulopathy (Kasabach-Merritt syndrome) which was cured by orthotopic liver transplant.A 47 year old man presented with bleeding and tender massive hepatomegaly after tooth extraction. Investigations showed disseminated intravascular coagulopathy and a giant hepatic haemangioma involving both lobes of the liver. Initial treatment failed to resolve the coagulopathy and liver resection was attempted. At laparotomy the turnout was unresectable and the only option for cure was to offer a liver transplantation. The orthotopic liver transplant was performed 20 days after initial laparotomy. Subsequently, all coagulation parameters returned to normal and the patient remains well after 12 months. Orthotopic liver transplant can be considered for giant hepatic haemangioma with Kasabach-Merritt syndrome when resection is necessary and a partial hepatectomy is not technically feasible.  相似文献   
46.
ABSTRACT: Managed care organizations (MCOs) joined local and state public health agencies in a pilot effort to improve hepatitis B immunization rates of adolescents in an urban and a suburban/rural school district. The pilot also explored issues inherent in public and private collaboration on population health improvement.
Local public health agencies provided links to schools in their communities, took the lead in implementing school-based immunization programs, and provided health education materials. MCOs contributed financial support necessary for the project. The final cost per fully vaccinated student, not taking into account the work group's planning and coordination time, was little more than the catalog price of the vaccine alone.
Managed care organizations face challenges that complicate their participation and funding of school-based vaccinations: 1) Limited data on health plans of participating students complicate allocation of costs to each MCO; 2) Double-paying occurs for MCOs paying clinics a monthly, per-member rate that already includes adolescent immunizations; 3) When schools provide adolescent immunizations, MCOs lose the "hook" that draws adolescents to clinics for comprehensive health services.
When self-consenting is permitted, schools can achieve a high consent and completion rates for multi-dose adolescent immunizations such as hepatitis B. At the same time, MCOs have the responsibility to provide members with comprehensive care and should continue to examine both internal modifications and external partnerships as opportunities to improve their services to adolescents.  相似文献   
47.
BACKGROUND: Alveolar macrophages are thought to play an important part in regulating lung immune responses. While it is clear that human alveolar macrophages suppress T cell proliferation in vitro, the mechanisms by which this is achieved are not clear, nor is it known whether alveolar macrophages also inhibit other aspects of T cell function. METHODS: Peripheral blood mononuclear cells were stimulated with phytohaemagglutinin or house dust mite allergen, and cultured with variable numbers of autologous alveolar macrophages obtained by bronchoalveolar lavage from 20 normal subjects. RESULTS: Alveolar macrophages induced a reversible inhibition of T cell proliferation in response to both mitogen and allergen stimulation, with the latter being considerably more susceptible to inhibition. This was achieved via heterogenous mechanisms, involving both soluble factors derived from alveolar macrophages and cell-cell contact. Despite inhibiting proliferation, alveolar macrophages had little or no effect on T cell calcium flux, the characteristic changes in CD3, CD2, CD28 and interleukin-2 (IL-2) receptor expression which accompany normal T cell activation, and IL-2 and interferon gamma secretion. In contrast, alveolar macrophages inhibited the tyrosine phosphorylation of proteins which may be involved in IL-2 receptor-associated signal transduction. CONCLUSIONS: The immunoregulatory properties of alveolar macrophages are relatively selective, allowing T cell activation and cytokine secretion while inhibiting T cell proliferation within the lung.


  相似文献   
48.
49.
The value of positron emission tomography using [18F]-fluoro-deoxy-glucose (FDG-PET) for pretherapeutic evaluation of patients with non-small cell lung cancer (NSCLC) is beyond doubt. Due to the increasing availability of PET and PET-CT scanners the method is now widely available, and its technical integration has become possible for radiotherapy planning systems. Due to the depiction of malignant tissue with high diagnostic accuracy, the use of FDG-PET in radiotherapy planning of NSCLC is very promising. However, by uncritical application, PET could impair rather than improve the prognosis of patients. Therefore, in the present paper we give an overview of technical factors influencing PET and PET-CT data, and their consequences for radiotherapy planning. We further review the relevant literature concerning the diagnostic value of FDG-PET and on the integration of FDG-PET data in RT planning for NSCLC. We point out the possible impact in gross tumor volume (GTV) definition and describe methods of target volume contouring of the primary tumor, as well as concepts for the integration of diagnostic information on lymph node involvement into the clinical target volume (CTV), and the possible implications of PET data on the definition of the planning target volume (PTV). Finally, we give an idea of the possible future use of tracers other than [18F]-FDG in lung cancer.  相似文献   
50.
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