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   3748篇
  免费   236篇
  国内免费   32篇
耳鼻咽喉   31篇
儿科学   167篇
妇产科学   136篇
基础医学   404篇
口腔科学   159篇
临床医学   332篇
内科学   797篇
皮肤病学   47篇
神经病学   123篇
特种医学   88篇
外国民族医学   2篇
外科学   857篇
综合类   78篇
一般理论   2篇
预防医学   193篇
眼科学   83篇
药学   270篇
中国医学   32篇
肿瘤学   215篇
  2023年   31篇
  2022年   72篇
  2021年   129篇
  2020年   93篇
  2019年   121篇
  2018年   141篇
  2017年   96篇
  2016年   118篇
  2015年   127篇
  2014年   164篇
  2013年   212篇
  2012年   301篇
  2011年   314篇
  2010年   155篇
  2009年   139篇
  2008年   231篇
  2007年   212篇
  2006年   197篇
  2005年   200篇
  2004年   182篇
  2003年   149篇
  2002年   134篇
  2001年   57篇
  2000年   47篇
  1999年   42篇
  1998年   25篇
  1997年   26篇
  1996年   23篇
  1995年   17篇
  1994年   17篇
  1993年   12篇
  1992年   13篇
  1991年   12篇
  1990年   19篇
  1989年   13篇
  1988年   13篇
  1987年   10篇
  1986年   16篇
  1985年   12篇
  1984年   9篇
  1983年   6篇
  1982年   8篇
  1981年   7篇
  1980年   8篇
  1979年   11篇
  1978年   11篇
  1975年   7篇
  1974年   6篇
  1967年   5篇
  1966年   5篇
排序方式: 共有4016条查询结果,搜索用时 484 毫秒
51.
52.
53.
54.
55.
56.
57.
ABSTRACT

In multilingual societies, where researchers and participants often do not speak the same language, research is a challenge as a mismatch of understanding between researchers, research instruments and participants often occurs. Reporting on the translation process is crucial because of the potential implications for the validity of the data that follow from it. We aimed to report on the complexities of such a translation process and many considerations that came to our attention. Methodologically, we used a detailed case study to demonstrate that the complexity of translation might be underestimated by researchers who may neglect to report on the challenges that they experience to benefit the wider research community. We emphasise that translating documents, particularly between languages that are not cognate, requires time and financial resources that researchers often do not anticipate or plan for. By discussing what happened to texts that were translated, and how we as researchers were challenged by considerations that were primarily linguistic but also straddled cultural and socio-political domains, we hope to encourage a deeper understanding of the translation task. We conclude that consideration of these complexities is necessary if the aim is the development of translated documents which complement the researchers’ goals.  相似文献   
58.

Background

Quantification of defect size and shunt flow is an important aspect of ventricular septal defect (VSD) evaluation. This study compared three‐dimensional echocardiography (3DE) with the current clinical standard two‐dimensional echocardiography (2DE) for quantifying defect area and tested the feasibility of real time 3D color Doppler echocardiography (RT3D‐CDE) for quantifying shunt volume of irregular shaped and multiple VSDs.

Methods

Latex balloons were sutured into the ventricles of 32 freshly harvested porcine hearts and were connected with tubing placed in septal perforations. Tubing was varied in area (0.13–5.22 cm²), number (1–3), and shape (circle, oval, crescent, triangle). A pulsatile pump was used to pump “blood” through the VSD (LV to RV) at stroke volumes of 30–70 mL with a stroke rate of 60 bpm. Two‐dimensional echocardiography (2DE), 3DE, and RT3D‐CDE images were acquired from the right side of the phantom.

Results

For circular VSDs, both 2DE and 3DE area measurements were consistent with the actual areas (R² = 0.98 vs 0.99). For noncircular/multiple VSDs, 3DE correlated with the actual area more closely than 2DE (R² = 0.99 vs 0.44). Shunt volumes obtained using RT3D‐CDE positively correlated with pumped stroke volumes (R² = 0.96).

Conclusions

Three‐dimensional echocardiography (3DE) is a feasible method for determining VSD area and is more accurate than 2DE for evaluating the area of multiple or noncircular VSDs. Real‐time 3D color Doppler echocardiography (RT3D‐CDE) is a feasible method for quantifying the shunt volume of multiple or noncircular VSDs.  相似文献   
59.
60.
The aim of this study was to evaluate the accuracy and feasibility of real-time 3-D echocardiography (3-DE) in assessing right ventricular (RV) systolic function. A latex balloon was inserted into the right ventricle of 20 freshly harvested pig hearts which were then passively driven by a pulsatile pump apparatus. The RV global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS) and RV ejection fraction (RVEF), derived from 3-DE, as well as the RVEF obtained from 2-D echocardiography (2-DE) were quantified at different stroke volumes (30–70 mL) and compared with sonomicrometry data. In all comparisons, 3-D GLS, GCS, GAS, 2-D RVEF and 3-D RVEF exhibited strong correlations with sonomicrometry data (r = 0.89, 0.79, 0.74, 0.80, and 0.93, respectively; all p values < 0.001). Bland–Altman analyses revealed slight overestimations of echo-derived GLS, GCS, 2-DE RVEF and 3-DE RVEF compared with sonomicrometry values (bias = 1.55, 2.72, 3.59 and 2.21, respectively). Furthermore, there is better agreement among GLS, 3-D RVEF and the sonomicrometry values than between GCS and 2-D RVEF. Real-time 3-DE is more feasible and accurate for assessing RV function than 2-DE. GLS is a potential alternative parameter for quantifying RV systolic function.  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