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   36971篇
  免费   3389篇
  国内免费   79篇
耳鼻咽喉   417篇
儿科学   965篇
妇产科学   690篇
基础医学   4958篇
口腔科学   1527篇
临床医学   4054篇
内科学   6854篇
皮肤病学   456篇
神经病学   3799篇
特种医学   1264篇
外科学   5708篇
综合类   700篇
一般理论   7篇
预防医学   3685篇
眼科学   741篇
药学   2337篇
中国医学   70篇
肿瘤学   2207篇
  2022年   246篇
  2021年   684篇
  2020年   417篇
  2019年   668篇
  2018年   849篇
  2017年   574篇
  2016年   597篇
  2015年   795篇
  2014年   1035篇
  2013年   1484篇
  2012年   2200篇
  2011年   2218篇
  2010年   1245篇
  2009年   1133篇
  2008年   1906篇
  2007年   1929篇
  2006年   1883篇
  2005年   1666篇
  2004年   1666篇
  2003年   1482篇
  2002年   1269篇
  2001年   981篇
  2000年   1028篇
  1999年   838篇
  1998年   373篇
  1997年   315篇
  1996年   332篇
  1995年   297篇
  1994年   272篇
  1993年   301篇
  1992年   666篇
  1991年   653篇
  1990年   622篇
  1989年   632篇
  1988年   576篇
  1987年   599篇
  1986年   539篇
  1985年   536篇
  1984年   415篇
  1983年   362篇
  1982年   245篇
  1981年   214篇
  1980年   210篇
  1979年   384篇
  1978年   205篇
  1977年   210篇
  1976年   229篇
  1974年   248篇
  1973年   239篇
  1972年   193篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Neorickettsia helminthoeca (NH), the agent of salmon poisoning disease or canine neorickettiosis (CN), is a bacterial endosymbiont of the nematode Nanophyetus salmincola, and infections are spreading among specific fish‐eating mammalians. This article describes the pathologic and immunohistochemical findings associated with spontaneous NH‐induced infections in dogs from Southern Brazil. The principal pathologic findings were hypertrophy of Peyer patches and lymphadenopathy with lymphocytic proliferation, chronic interstitial pneumonia, and chronic enteritis associated with positive intralesional immunoreactivity to antigens of NH within macrophages and histiocytes. Positive immunoreactivity against canine parvovirus‐2 (CPV‐2) or/and canine distemper virus was not detected in the evaluated intestinal segments or in the samples from the cerebellum and lungs, respectively, from the dogs evaluated. These findings demonstrated that NH was involved in the enteric, pulmonary, and lymphoid lesions herein described, and provide additional information to confirm the occurrence of this bacterial endosymbiont within this geographical location. It is proposed that chronic pneumonia should be considered as a pathologic manifestation of NH‐induced infections. Additionally, our results show that the occurrences of CN seem to be underdiagnosed in Southern Brazil due to the confusion with the incidence of CPV‐2.  相似文献   
3.
4.
5.
6.
Objective: Polyunsaturated fatty acids n-3 (PUFA n-3) have shown effects in reducing tumor growth, in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) abundantly present in fish oil (FO). When these fatty acids are provided in the diet, they alter the functions of the cells, particularly in tumor and immune cells. However, the effects of α-linolenic fatty acid (ALA), which is the precursor of EPA and DHA, are controversial. Thus, our objective was to test the effect of this parental fatty acid. Methods: Non-tumor-bearing and tumor-bearing Wistar rats (70 days) were supplemented with 1 g/kg body weight of FO or Oro Inca® (OI) oil (rich in ALA). Immune cells function, proliferation, cytokine production, and subpopulation profile were evaluated. Results: We have shown that innate immune cells enhanced phagocytosis capacity, and increased processing and elimination of antigens. Moreover, there was a decrease in production of pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6)) by macrophages. Lymphocytes showed decreased proliferation capacity, increased cluster of differentiation 8 (CD8+) subpopulation, and increased TNF-α production. Conclusions: Oil rich in ALA caused similar immune modulation in cancer when compared with FO.  相似文献   
7.
8.
9.
Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital condition. It responds well to early diagnosis and treatment, but otherwise the prognosis is poor. We present our case series of 12 patients (mean age, 2 ± 2.58 yr; age range, 2 mo–8 yr), emphasizing the diagnostic process and discussing our surgical results. The diagnosis of ALCAPA should be suspected in infants who have dilated cardiomyopathy with electrocardiographic changes that suggest ischemia, and in older children who have isolated mitral regurgitation. When clinical suspicion is high, the results of 2-dimensional echocardiography combined with color-flow Doppler studies in expert hands can establish the diagnosis, thus avoiding angiography in critically ill infants. The treatment of choice in our patients was transfer and reimplantation of the left coronary artery onto the ascending aorta. There were 2 deaths: both were infants in extremis who underwent emergency surgery. An older child with severe ventricular dysfunction was given mechanical ventricular assistance and then heart transplantation. As of this report, all 10 survivors remained well and asymptomatic.  相似文献   
10.
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