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   6414篇
  免费   351篇
  国内免费   48篇
耳鼻咽喉   32篇
儿科学   172篇
妇产科学   127篇
基础医学   921篇
口腔科学   32篇
临床医学   570篇
内科学   1635篇
皮肤病学   116篇
神经病学   879篇
特种医学   141篇
外科学   501篇
综合类   10篇
一般理论   1篇
预防医学   324篇
眼科学   66篇
药学   497篇
中国医学   14篇
肿瘤学   775篇
  2023年   40篇
  2022年   113篇
  2021年   170篇
  2020年   105篇
  2019年   150篇
  2018年   171篇
  2017年   141篇
  2016年   177篇
  2015年   174篇
  2014年   237篇
  2013年   303篇
  2012年   444篇
  2011年   461篇
  2010年   290篇
  2009年   272篇
  2008年   429篇
  2007年   414篇
  2006年   409篇
  2005年   422篇
  2004年   415篇
  2003年   332篇
  2002年   293篇
  2001年   63篇
  2000年   46篇
  1999年   66篇
  1998年   93篇
  1997年   70篇
  1996年   55篇
  1995年   55篇
  1994年   43篇
  1993年   40篇
  1992年   30篇
  1991年   36篇
  1990年   31篇
  1989年   29篇
  1988年   20篇
  1987年   20篇
  1986年   14篇
  1985年   23篇
  1984年   25篇
  1983年   15篇
  1982年   10篇
  1981年   8篇
  1980年   12篇
  1979年   5篇
  1978年   11篇
  1977年   13篇
  1976年   3篇
  1975年   3篇
  1966年   3篇
排序方式: 共有6813条查询结果,搜索用时 750 毫秒
91.
Apoptosis normally occurs in the human placenta. As a consequence, cell blebs, post-apoptotic debris (also referred to as syncytial knots) and membrane microparticles are released into the blood of pregnant women. These events become prominent during the best-characterized pregnancy complication, pre-eclampsia. An excessive or deregulated cell death, which results in the generation of an overwhelming burden of apoptotic material, alarms the immune system. This plays a role in the pathogenesis of systemic connective tissue diseases and possibly of small vessels vasculitis. Infiltration of leukocytes and activation of endothelial cells and platelets are hallmarks of normal pregnancy, indicating that physiologic pregnancy is a condition characterized by an activation of the innate immune system. Conversely, a failure in the physiologic termination of inflammatory events is probably a requirement for pre-eclampsia to develop. Here, we discuss recent findings suggesting a link between deregulated disposal of placental debris, the generation of endogenous pro-inflammatory signals (alarmins) and the widespread vascular inflammation that characterizes on one hand pre-eclampsia and on the other systemic autoimmune diseases.  相似文献   
92.
93.
Iron overload (IO) is poorly investigated in the congenital haemolytic anaemias (CHAs), a heterogeneous group of rare inherited diseases encompassing abnormalities of the erythrocyte membrane and metabolism, and defects of the erythropoiesis. In this study we systematically evaluated routine iron parameters and cardiac and hepatic magnetic resonance imaging, together with erythropoietin, hepcidin, non-transferrin bound iron (NTBI), and cytokine serum levels in patients with different CHAs. We found that 40% of patients had a liver iron concentration (LIC) >4 mg Fe/g dry weight. Hepatic IO was associated with ferritin levels (P = 0·0025), transferrin saturation (TfSat, P = 0·002) and NTBI (P = 0·003). Moreover, ferritin >500 μg/l plus TfSat >60% was demonstrated as the best combination able to identify increased LIC, and TfSat alteration as more important in cases with discordant values. Possible confounding factors, such as transfusions, hepatic disease, metabolic syndrome and hereditary haemochromatosis-associated mutations, had negligible effects on IO. Erythropoietin and hepcidin levels were increased in CHAs compared with controls, correlating with LIC and ferritin, respectively. Regarding cytokines, γ-interferon (IFN-γ) was increased, and both interleukin 6 and IFN-γ levels positively correlated with ferritin and hepcidin levels. Overall, these findings suggest the existence of a vicious cycle between chronic haemolysis, inflammatory response and IO in CHAs.  相似文献   
94.
95.
Objective: Metabolic disorders are a pandemic and increasing health problem. Women of childbearing age may also be affected, thus an abnormal metabolism may interfere with pregnancy short- and long-term outcomes, harming both mother and child. In the context of an abnormal maternal and intrauterine metabolic milieu the development of fetal organs, including pancreas, may be affected.

Aim: To investigate the effects of pregnancy metabolic disorders on the morphology of pancreatic Langerhans islets in human late-third trimester stillborn fetuses.

Methods: Samples from fetal pancreas underwent a quantitative histological evaluation to detect differences between pregnancy with (cases, n?=?9) or without (controls, n?=?6) abnormal metabolism.

Results: Results show that the islets size increases in fetuses from dysmetabolic pregnancies and that this increment is related to both beta-cell hyperplasia and hypertrophy. Moreover, according to pregnancy and fetal metabolic disorders, a threshold of abnormal size of the islets has been identified. Above this threshold the size of fetal pancreatic Langerhans islets should be considered excessively increased.

Conclusion: The study suggests that an accurate fetal pancreas analysis supplies an important tool in stillborn fetus, to discover metabolic disturbances that should be kept in mind and managed in future pregnancies.  相似文献   
96.
97.
98.
99.
100.
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