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   5045篇
  免费   256篇
  国内免费   42篇
耳鼻咽喉   154篇
儿科学   253篇
妇产科学   148篇
基础医学   373篇
口腔科学   199篇
临床医学   392篇
内科学   1197篇
皮肤病学   81篇
神经病学   358篇
特种医学   193篇
外科学   1076篇
综合类   99篇
一般理论   1篇
预防医学   269篇
眼科学   136篇
药学   197篇
中国医学   14篇
肿瘤学   203篇
  2023年   47篇
  2022年   65篇
  2021年   136篇
  2020年   76篇
  2019年   111篇
  2018年   144篇
  2017年   91篇
  2016年   162篇
  2015年   160篇
  2014年   175篇
  2013年   277篇
  2012年   381篇
  2011年   372篇
  2010年   201篇
  2009年   176篇
  2008年   369篇
  2007年   392篇
  2006年   411篇
  2005年   364篇
  2004年   317篇
  2003年   243篇
  2002年   213篇
  2001年   29篇
  2000年   40篇
  1999年   34篇
  1998年   10篇
  1997年   12篇
  1996年   12篇
  1995年   9篇
  1994年   7篇
  1992年   21篇
  1991年   8篇
  1990年   15篇
  1989年   9篇
  1988年   17篇
  1987年   14篇
  1986年   16篇
  1985年   27篇
  1984年   12篇
  1983年   9篇
  1982年   9篇
  1981年   7篇
  1979年   17篇
  1978年   8篇
  1976年   7篇
  1975年   6篇
  1974年   9篇
  1972年   11篇
  1969年   8篇
  1968年   9篇
排序方式: 共有5343条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
95.
Background:Polycystic ovary syndrome (PCOS) is the most common endocrine-metabolic disease in women in reproductive age, and occurs in one of 10 women. The disease includes menstrual irregularity and excess of male hormones and is the most common cause of female infertility. Dyspnea is a frequent symptom and is often thought to be due to obesity, and whether it is due to cardiac dysfunction is unknown.Objective:To evaluate right ventricle-pulmonary artery (RV-PA) coupling and pulmonary arterial stiffness in patients with PCOS.Methods:44 PCOS patients and 60 controls were included; venous blood samples were taken for laboratory tests and 2-D, m-mode and tissue doppler transthoracic echocardiography were performed for all the participants. P<0,05 was considered as statistically significant.Results:When compared to the control group, PCOS patients had higher pulmonary artery stiffness values (p=0,001), which were positively correlated with HOMA-IR (r=0,545 and p<0,001). RV-PA coupling was also impaired in 34% of the study patients.Conclusion:Pulmonary artery stiffness is increased and RV-PA coupling is impaired in patients with PCOS. (Arq Bras Cardiol. 2021; 116(4):806-811)Palavras-chave: Diseases of the Endocrine System, Arterial Stiffness, Female infertility, Obesity, Dyspnea, Pulmonary hypertension  相似文献   
96.
呼吸前反馈调节、情景想象和过度通气   总被引:1,自引:0,他引:1  
通过大量的科学证据 ,我们论述了代谢的负反馈调节不是呼吸调节的唯一机制。醒觉时呼吸的前反馈调节起了主导作用 ,前反馈调节可以在血气异常引起的负反馈调节之前 ,对将要发生的异常进行纠正 ,预见性地改变通气 ,而代谢的变化随后发生 ,避免了负反馈调节所具有的波动和滞后的缺点 ,使呼吸调节系统具有更大的灵活性和适应能力。在前反馈调节的形成过程中 ,经典的巴甫洛夫条件反射学说可能起了重要作用 .尤其重要的是表象作为条件刺激形成的条件反射 ,研究表象作为条件刺激如何形成呼吸的前反馈调节对揭示高通气综合征的发病机制具有重要意义…  相似文献   
97.
98.
99.
ObjectiveThe aim was to compare coronary high-definition CT (HDCT) with standard-definition CT (SDCT) angiography as to radiation dose, image quality and accuracy.ResultsThe intraclass correlation coefficient (ICC) of measured vessel attenuation values in SDCT between the two radiologists was exceedingly good. The ICC was higher in HDCT. The radiation dose of HDCT was higher than that of SDCT. The mean tube current was 180 (mA) in HDCT and 147(mA) in SDCT with the same tube voltage (kVp). There was no significant difference between image quality.ConclusionHDCT has a higher radiation dose but has much more atenuation and the spatial resolution which improve measurement accuracy for imaging coronary arteries.  相似文献   
100.
Intra-abdominal hypertension and abdominal compartment syndrome (IAH/ACS) are life-threatening conditions and caused by several clinical status. Although there is insufficient data regarding its effects on adrenal glands. This study aimed to identify whether elevated intra-abdominal pressure (IAP) caused any alteration on the morphology and function of adrenal glands in a rat model. Twenty four Sprague-Dawley male rats were included in the study. Animals were allocated into 4 groups. IAP was elevated to 15 mmHg for one hour and four hours in group 2 and 4. Group 1 and 3 were sham groups. Blood samples were taken for the assessment of plasma adrenaline, noradrenaline, and corticosterone levels and adrenalectomies were performed to evaluate apoptosis. Blood adrenaline, noradrenaline and corticosterone levels were significantly higher in the study groups compared with the sham groups. However, there were no significant changes in apoptotic index scores in the study groups as compared to sham groups. These results support that increased IAH leads to discharge of catecholamine and corticosterone from the adrenal glands. Failure to demonstrate similar changes in apoptotic index score may be concluded as apoptosis is not a leading pathway for impairment of adrenal glands during IAH period.  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