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   41701篇
  免费   1916篇
  国内免费   205篇
耳鼻咽喉   687篇
儿科学   684篇
妇产科学   742篇
基础医学   5406篇
口腔科学   1235篇
临床医学   2949篇
内科学   9943篇
皮肤病学   556篇
神经病学   3440篇
特种医学   1370篇
外科学   7162篇
综合类   189篇
一般理论   2篇
预防医学   1499篇
眼科学   642篇
药学   3543篇
中国医学   79篇
肿瘤学   3694篇
  2022年   416篇
  2021年   712篇
  2020年   355篇
  2019年   508篇
  2018年   610篇
  2017年   476篇
  2016年   582篇
  2015年   644篇
  2014年   816篇
  2013年   1076篇
  2012年   1749篇
  2011年   1861篇
  2010年   1083篇
  2009年   920篇
  2008年   1762篇
  2007年   1917篇
  2006年   1871篇
  2005年   1834篇
  2004年   1807篇
  2003年   1831篇
  2002年   1804篇
  2001年   1628篇
  2000年   1784篇
  1999年   1510篇
  1998年   489篇
  1997年   392篇
  1996年   361篇
  1995年   305篇
  1994年   288篇
  1993年   264篇
  1992年   1108篇
  1991年   925篇
  1990年   901篇
  1989年   940篇
  1988年   837篇
  1987年   831篇
  1986年   784篇
  1985年   769篇
  1984年   530篇
  1983年   422篇
  1982年   219篇
  1979年   484篇
  1978年   275篇
  1977年   252篇
  1975年   208篇
  1974年   223篇
  1972年   205篇
  1971年   230篇
  1969年   230篇
  1968年   216篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
A 38-year-old female presented with a lower abdominal mass. During the operation the mass was found to be retroperitoneal and was excised. Gross examination revealed a mucin-containing cystic lesion with a mural nodule. On microscopic examination, the cystic areas were lined by an invasive mucinous adenocarcinoma and the nodule was composed of an anaplastic sarcomatoid tumor that was immunoreactive for cytokeratin. This present case is the 21st example of a retroperitoneal primary mucinous cystadenocarcinoma and the fourth with a mural nodule. Three of four cases with a mural nodule, including our case, had a rapidly fatal outcome.  相似文献   
52.
Small bowel transplantation (SBT) is associated with a high incidence of infectious complications because of ischemia/reperfusion (I/R) mucosal injury concomitant with potent immunosuppression. In this study, we evaluated whether the cavitary two-layer method (cTLM) could reduce I/R injury and allow early mucosal restoration, particularly after prolonged preservation and transplantation. Canine heterotopic segmental SBT was performed immediately without preservation (group 1), after 24-h preservation in UW solution (group 2) or by the cTLM (group 3). The graft samples were taken 1 h after reperfusion and on days 1, 4 and 7. We assessed graft mucosa with detailed microscopic and electromicroscopic analyses. In Group 3, histological injury and cell apoptosis after transplantation were significantly alleviated and rapidly recovered to a similar level of group 1. The mucosal restoration was morphologically completed within 4 days. In contrast, in group 2, more pronounced mucosal injury and delayed recovery were noted. Crypt cell proliferation activity was well maintained in groups 1 and 3 throughout the experimental period. Our ultrastructural analysis suggested that mitochondrial integrity achieved by the cTLM was a basal mechanism under the prompt mucosal restoration. The cTLM could reduce I/R injury, facilitate mucosal regeneration and restore the nearly normal structure early after SBT.  相似文献   
53.
54.
A 65-year-old Japanese man was hospitalized because of acute hepatitis and severe cholestasis due to hepatitis E virus (HEV) infection combined with a drug reaction to a cold preparation. He died of disseminated intravascular coagulation and severe intestinal bleeding due to systemic cytomegalovirus reactivation following the development of severe eruptions with marked eosinophilia due to drug hypersensitivity to taurine and ursodeoxycholate preparations. The close interaction between viral infection or reactivation and drug hypersensitivity was considered as a pathophysiology in this case, which emphasizes the need for further study of the immunological mechanism of the interaction.  相似文献   
55.
OBJECTIVE: This study retrospectively explored the late-life functional status of Okinawan centenarians. METHODS: Activities of daily living were measured retrospectively at five time points (10, 5, 3, and 1 year prior and present) for 22 centenarians in relation to seven physical, two sensory, and two cognitive functions using the Inoue Index. RESULTS: In all, 82% of individuals were still functioning independently at a mean age of 92 years and almost two-thirds were still functioning independently at a mean age of 97 years. CONCLUSION: Preliminary analyses suggest high functional status in Okinawan centenarians throughout their 90 s. The genetic and environmental factors contributing to this successful aging phenomenon deserve further investigation.  相似文献   
56.
57.
Positron emission tomography was performed on six patients with Rett syndrome to investigate cerebral blood flow and oxygen metabolism, and the results were compared with the concurrent clinical status of the patients. The cerebral metabolic rate of oxygen (CMRO2) was low in five patients, and oxygen extraction fraction was low in four patients; both had a tendency to decline with advancing age. Although the cause is unknown, it is suggested that impaired oxidative metabolism exists in Rett syndrome. An analysis of the distribution among brain regions showed that the ratios of values for the frontal cortex to those for the temporal cortex for both cerebral blood flow and CMRO2 were lower than those for the controls, which may indicate the loss of hyperfrontality in Rett syndrome.  相似文献   
58.
59.
Reviewing the definition of "elderly"   总被引:1,自引:0,他引:1  
Conventionally, "elderly" has been defined as a chronological age of 65 years old or older, while those from 65 through 74 years old are referred to as "early elderly" and those over 75 years old as "late elderly." However, the evidence on which this definition is based is unknown. We have attempted to review the definition of elderly by analyzing data from long-term longitudinal epidemiological studies, and clinical and pathological studies that have been accumulated at the Tokyo Metropolitan Geriatric Hospital and the Tokyo Metropolitan Institute of Gerontology. Our recommendation might be a starting point in developing a strategy for a successful society by reviewing the definition of elderly based on comprehensive evidence in all aspects of social, cultural and medical sciences.  相似文献   
60.
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