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   4281篇
  免费   16篇
  国内免费   41篇
教育   2645篇
科学研究   601篇
各国文化   12篇
体育   769篇
综合类   171篇
文化理论   12篇
信息传播   128篇
  2024年   4篇
  2023年   31篇
  2022年   50篇
  2021年   35篇
  2020年   42篇
  2019年   37篇
  2018年   11篇
  2017年   35篇
  2016年   60篇
  2015年   106篇
  2014年   289篇
  2013年   305篇
  2012年   381篇
  2011年   415篇
  2010年   286篇
  2009年   282篇
  2008年   381篇
  2007年   260篇
  2006年   173篇
  2005年   205篇
  2004年   202篇
  2003年   201篇
  2002年   149篇
  2001年   118篇
  2000年   99篇
  1999年   38篇
  1998年   23篇
  1997年   22篇
  1996年   16篇
  1995年   20篇
  1994年   16篇
  1993年   14篇
  1992年   10篇
  1991年   14篇
  1990年   3篇
  1989年   4篇
  1988年   1篇
排序方式: 共有4338条查询结果,搜索用时 9 毫秒
71.
在中学语文教学中,常发现这样一种现象:当老师们准备时间不太充足时,常常从文言文单元讲起。在他们看来,文言文是死东西,有规律可循,较容易把握。可是,一旦讲开了,他们发现,学生的“意志力”有限,很快就患了文言文疲劳综合症。此时,老师们往往一筹莫展。或者硬着头皮讲下去,或者拿考试来吓唬学生,或者“画饼充饥”:坚持,坚持,下个星期,我们就转入现代文单元的学习了。有时候,为了迁就学生,我们将文言文的学习与现代文交叉进行,仿佛文言文是一个无味的馒头,需要蘸点果酱或辣椒酱什么的佐料才能勉强下咽似的。  相似文献   
72.
有这样一道化学、生物综合实验测试题,目的是考查学生的综合能力和实验的设计能力。试题提供了如下条件:一小撮小麦种子、一小块透气很好的纱布、一段15cm~20cm的小线绳、一个锥形瓶、一个橡皮塞、一瓶过了滤石灰水和一点点凡士林。试题的考查点放在试验的设计上,要求学生充分利用已经提供的条件设计一个实验装置,证明种子也是呼吸  相似文献   
73.
高原康胶囊预防、治疗急性高山反应200例分析   总被引:7,自引:0,他引:7  
  相似文献   
74.
笔者于1997~2000年间运用隔姜灸配合超短波,治疗急性细菌性痢疾31例,取得了较满意的疗效,现报告如下:  相似文献   
75.
由于高密度工厂化养鸡生产,使鸡的生存环境比较复杂,从而导致鸡的应激综合症及非传染病等症状出现,鸡啄癣即为该症状之一。究其发生原因是多种因素造成的,一般多为:不良环境因素影响、断喙、修喙不当、营养不平衡等所致。  相似文献   
76.
胃镜污染HBV、HCV和HIV的调查   总被引:1,自引:0,他引:1  
目的 检测胃镜常规清洗消毒后HBV、HCV、HIV污染残留状况.方法 随机取样.巢式聚合酶链反应法检测HBV DNA,逆转录巢式聚合酶链反应法检测HCV RNA、HIV RNA,放免法检测HBsAg.结果 对605例标本进行检测,未检出阳性标本.结论 胃镜经常规消毒后未检到HBV、HCV和HIV的污染,但进一步规范胃镜消毒操作方法,提高消毒质量,意义重大.  相似文献   
77.
脓疱疮俗称黄水疮,是一种常见的由化脓性球菌引起的急性炎症皮肤病,具有接触传染特征。脓疱疮90%以上见于儿童,以1-4岁为高发年龄,症见皮肤上发生小红疹子、水疱或脓汁沉于疱底、呈半月型积脓状的大疱、脓疱,疱易破溃,流黄水,结脓痂,患儿自觉瘙痒,一般无全身症状。由于接触传染  相似文献   
78.
Cell therapy in congestive heart failure   总被引:5,自引:0,他引:5  
Congestive heart failure (CHF) has emerged as a major worldwide epidemic and its main causes seem to be the aging of the population and the survival of patients with post-myocardial infarction. Cardiomyocyte dropout (necrosis and apoptosis) plays a critical role in the progress of CHF; thus treatment of CHF by exogenous cell implantation will be a promising medical approach. In the acute phase of cardiac damage cardiac stem cells (CSCs) within the heart divide symmetrically and/or asymmetrically in response to the change of heart homeostasis, and at the same time homing of bone marrow stem cells (BMCs) to injured area is thought to occur, which not only reconstitutes CSC population to normal levels but also repairs the heart by differentiation into cardiac tissue. So far, basic studies by using potential sources such as BMCs and CSCs to treat animat CHF have shown improved ventricular remodelling and heart function. Recently, however, a few of randomized, double-blind, placebo-controlled clinical trials demonstrated mixed results in heart failure with BMC therapy during acute myocardial infarction.  相似文献   
79.
Objective: The beneficial effect of percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) has been well established, but there is the problem of no-reflow phenomenon which is an adverse prognostic factor in primary PCI. In the present study the effect of a distal protection device (PercuSurge GuardWire; GW) on epicardial blood flow and myocardial perfusion was evaluated. Methods and Results: Patients with AMI were randomly divided into 2 groups, the GW and the control groups. The GW group included 52 patients with AMI who underwent primary PCI with GW protection and the control group included 60 patients who underwent primary PCI without GW protection. Epicardial blood flow in the infarct-related artery (IRA) and myocardial perfusion were evaluated according to the thrombolysis in myocardial infarction (TIMI) flow grade and the myocardial blush grade (MBG). We found TIMI score of 3 was obtained significantly more frequently in the GW group (96%) than in the control group (80%). The MBG score of 3 was obtained also significantly greater in the GW group (65%) than in the control group (33%). Conclusion: Primary PCI with GW protection can significantly improve epicardial blood flow and myocardial perfusion.  相似文献   
80.
Relationship between hyperuricemia and metabolic syndrome   总被引:6,自引:0,他引:6  
Objective: To investigate the relationship between metabolic syndrome and hyperuricemia. Methods: A total of 2 374 subjects who received health examination in our hospital from Jan. 2004 to Dec. 2006 were enrolled in our study. Hyperuricemia is defined as ≥7 mg/dl (in men) or ≥6.0 mg/dl (in women). Metabolic syndrome was defined using AHA/NHLBI (American Heart Association/National Heart, Lung, and Blood Institute) criteria. Results: (1) The overall prevalence of hyperuricemia was 13.10%. The condition was more common in men than in women (19.07% vs 3.42%). (2) Among men, uric acid concentration is statistically significantly positively correlated with waist circumference, blood pressure, and triglyceride. Uric acid is negatively correlated with serum high-density lipoprotein-cholesterol (HDL-C). Uric acid concentration is most strongly correlated with serum triglyceride (r=0.379) and waist circumference (r=0.297). Among women, statistically significant positive correlations were noted for the serum uric acid concentrations with waist circumference, triglyceride and fasting plasma glucose. Serum triglyceride (r=0.329) and waist circumference (r=0.234) are most strongly correlated with uric acid concentrations. (3) Men with hyperuricemia had a 1.634-fold increased risk of metabolic syndrome as compared with those without hyperuricemia odds ratio (OR)=1.634, P=0.000. Women with hyperuricemia had a 1.626-fold increased risk of metabolic syndrome (OR=1.626, P=0.000) as compared with those without hyperuricemia. Conclusion: Hyperuricemia is prevalent among Chinese population. Additionally, serum uric acid is positively associated with metabolic syndrome.  相似文献   
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