首页 | 官方网站   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   11361篇
  免费   667篇
  国内免费   75篇
医药卫生   12103篇
  2023年   58篇
  2022年   64篇
  2021年   241篇
  2020年   135篇
  2019年   199篇
  2018年   261篇
  2017年   203篇
  2016年   270篇
  2015年   273篇
  2014年   391篇
  2013年   496篇
  2012年   843篇
  2011年   857篇
  2010年   477篇
  2009年   428篇
  2008年   764篇
  2007年   803篇
  2006年   791篇
  2005年   757篇
  2004年   703篇
  2003年   707篇
  2002年   624篇
  2001年   153篇
  2000年   126篇
  1999年   146篇
  1998年   155篇
  1997年   103篇
  1996年   71篇
  1995年   86篇
  1994年   66篇
  1993年   49篇
  1992年   47篇
  1991年   66篇
  1990年   46篇
  1989年   45篇
  1988年   53篇
  1987年   32篇
  1986年   30篇
  1985年   36篇
  1984年   37篇
  1983年   30篇
  1982年   35篇
  1981年   33篇
  1980年   17篇
  1979年   15篇
  1978年   14篇
  1974年   19篇
  1973年   15篇
  1972年   14篇
  1971年   12篇
排序方式: 共有10000条查询结果,搜索用时 999 毫秒
1.
2.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
3.
Over the last decade, impressive technological advances have occurred in ultrasonography and small‐bowel endoscopy. Nowadays, endoscopic ultrasonography is an essential diagnostic tool and a therapeutic weapon for pancreatobiliary disorders. Capsule endoscopy and device‐assisted enteroscopy have quickly become the reference standard for the diagnosis of small‐bowel luminal diseases, thereby leading to radical changes in diagnostic and therapeutic pathways. We herein provide an up‐to‐date overview of the latest advances in endoscopic ultrasonography and small‐bowel endoscopy, focusing on the emerging paradigms and technological innovations that might improve clinical practice in the near future.  相似文献   
4.
5.
Stress related to parenting a child with autism spectrum disorder can differently affect caregiver's physiological reactivity to acute stress. Here, parental stress levels, psychological characteristics, and coping strategies were assessed alongside measures of heart rate, heart rate variability, and cortisol during a psychosocial stress test in mothers of children with ASD (M‐ASD, n = 15) and mothers of typically developing children (n = 15). M‐ASD reported significantly higher levels of parental stress, anxiety, negative affectivity, social inhibition, and a larger preference for avoidance strategies. M‐ASD showed larger heart rate and cortisol responses to the psychosocial stress test. A positive relationship was found between parental stress levels and the magnitude of the cortisol stress response in both groups. The present findings indicate exaggerated physiological reactivity to acute psychosocial stress in M‐ASD and prompt further research to explore the role of individual differences in mediating the effects of parental stress on physiological stress responses.  相似文献   
6.
7.
8.
9.
Accurate modeling of intratumor heterogeneity presents a bottleneck against drug testing. Flexibility in a preclinical platform is also desirable to support assessment of different endpoints. We established the model system, OHC-NB1, from a bone marrow metastasis from a patient diagnosed with MYCN-amplified neuroblastoma and performed whole-exome sequencing on the source metastasis and the different models and passages during model development (monolayer cell line, 3D spheroid culture and subcutaneous xenograft tumors propagated in mice). OHC-NB1 harbors a MYCN amplification in double minutes, 1p deletion, 17q gain and diploid karyotype, which persisted in all models. A total of 80–540 single-nucleotide variants (SNVs) was detected in each sample, and comparisons between the source metastasis and models identified 34 of 80 somatic SNVs to be propagated in the models. Clonal reconstruction using the combined copy number and SNV data revealed marked clonal heterogeneity in the originating metastasis, with four clones being reflected in the model systems. The set of OHC-NB1 models represents 43% of somatic SNVs and 23% of the cellularity in the originating metastasis with varying clonal compositions, indicating that heterogeneity is partially preserved in our model system.  相似文献   
10.
Coronary flow reserve (CFR) has been used toassess coronary microcirculation and epicardial coro-nary stenoses[1— 3 ] . CFR is defined as the ratio ofcoronary flow under maximal coronary vasodilatationto coronary flow under resting conditions[4 ] .Whenthe cross- sectional area of epicardial coronary arteriesis constant,coronary flow velocity (CFV) ratios areequal to volume flow ratios.The most common method used clinically formeasuring CFVR is intracoronary Doppler flow(ICD) analysis re…  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-23

京公网安备 11010802026262号