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   3480篇
  免费   233篇
  国内免费   14篇
耳鼻咽喉   44篇
儿科学   87篇
妇产科学   89篇
基础医学   573篇
口腔科学   267篇
临床医学   380篇
内科学   708篇
皮肤病学   52篇
神经病学   335篇
特种医学   37篇
外科学   264篇
综合类   51篇
一般理论   2篇
预防医学   344篇
眼科学   51篇
药学   234篇
中国医学   14篇
肿瘤学   195篇
  2024年   8篇
  2023年   50篇
  2022年   74篇
  2021年   170篇
  2020年   112篇
  2019年   122篇
  2018年   123篇
  2017年   94篇
  2016年   117篇
  2015年   109篇
  2014年   136篇
  2013年   167篇
  2012年   273篇
  2011年   308篇
  2010年   174篇
  2009年   134篇
  2008年   223篇
  2007年   182篇
  2006年   185篇
  2005年   162篇
  2004年   109篇
  2003年   94篇
  2002年   76篇
  2001年   18篇
  2000年   8篇
  1999年   16篇
  1998年   11篇
  1997年   18篇
  1996年   23篇
  1995年   11篇
  1994年   11篇
  1993年   8篇
  1992年   9篇
  1991年   9篇
  1990年   10篇
  1989年   7篇
  1987年   10篇
  1986年   6篇
  1985年   6篇
  1982年   7篇
  1980年   6篇
  1959年   29篇
  1958年   40篇
  1957年   31篇
  1956年   32篇
  1955年   28篇
  1954年   44篇
  1949年   18篇
  1948年   34篇
  1946年   7篇
排序方式: 共有3727条查询结果,搜索用时 31 毫秒
121.

Background

Depression is associated with poor adherence to medications and worse prognosis in patients with acute coronary syndrome (ACS).

Purpose

To determine whether cognitive, behavioral, and/or psychosocial vulnerabilities for depression explain the association between depression and medication adherence among ACS patients.

Methods

One hundred sixty-nine ACS patients who agreed to have their aspirin adherence measured using an electronic pill bottle for 3 months were enrolled within 1 week of hospitalization. Linear regression was used to determine whether depression vulnerabilities predicted aspirin adherence after adjustment for depressive symptoms, demographics, and comorbidity.

Results

Of the depression vulnerabilities, only role transitions (beta?=??3.32; P?=?0.02) and interpersonal conflict (beta -3.78; P?=?0.03) predicted poor adherence. Depression vulnerabilities did not mediate the association between depressive symptoms and medication adherence.

Conclusions

Key elements of the psychosocial context preceding the ACS including major role transitions and conflict with close contacts place ACS patients at increased risk for poor medication adherence independent of depressive symptoms.  相似文献   
122.
123.
124.
Duplications of the alimentary tract are uncommon congenital malformations that can present diagnostic difficulties. We report a rare case of a cystic colonic duplication in a female adult. Preoperative investigations were suggestive of pancreatic tumor. The diagnosis was established based on the histopathological examination of the resected specimen. We concluded that, though uncommon, intestinal duplication should be considered in differential diagnosis of abdominal mass.  相似文献   
125.

Background

Many variants of the spatial QRS-T angle (QRS-Ta) are in use. We aimed to identify the best QRS-Ta for all-cause mortality prediction among different variants.

Methods

6667 individuals from the Inter99 General Population Study were followed for a median of 12.7?years. Vectorcardiograms were calculated using the Kors and Inverse Dower matrices. The QRS-Ta was calculated using both mean and peak vectors of the QRS- and T-loops. Hazard ratios (HR) for abnormal QRS-Tas were calculated using a Cox's Proportional Hazard Model.

Results

The highest HR and largest AUC for all-cause mortality was obtained with the Kors matrix and the mean vector (HR?=?2.2, 95% confidence interval: [1.38;3.43] p?<?0.001, in men). There was interaction with the orientation of the QRS-T plane.

Conclusion

For optimal prediction of all-cause mortality, the mean vectors in the QRS- and T-loops of the Kors-derived vectorcardiogram should be used. QRS-T plane orientation affects mortality prediction.  相似文献   
126.
The objective of this study was to evaluate a new technique of sizing atrial septal defects (ASDs) for transcatheter device closure. ASD closure using the Amplatzer septal occluder (ASO) device is commonly performed. Complications, including arrhythmias, pericardial effusions, and perforations, may be related to oversizing ASDs and choosing larger devices. Two methods were used to size ASDs using a compliant balloon. In some patients, the balloon was inflated until a waist was visible [(+)waist]; in others, only until no shunting was demonstrable by echocardiogram [echo; (-)waist]. The device was selected and implanted using standard procedure and echo guidance. One hundred seventeen patients underwent secundum ASD closure with an ASO device. There were 43 patients in the (-)waist group and 74 in the (+)waist group. All devices were implanted successfully. The initial echo ASD diameter was larger in the (-)waist group compared to the (+)waist group (P = 0.01). There was a smaller difference between the initial echo and balloon-sized ASD diameters in the (-)waist group (P < 0.02). ASO device size implanted (in mm greater than echo ASD diameter) was smaller in the (-)waist group (P < 0.01). There were 0/43 complications in the (-)waist group and 5/74 in the (+)waist group. The complete closure rate was the same in both groups. Sizing an ASD by inflating a compliant balloon just until shunting is eliminated, and not until a waist is visible, results in less overstretching of the ASD and selection of a smaller ASO device, achieving similar closure rates and potentially fewer complications.  相似文献   
127.
Transthoracic echocardiography (TTE) is frequently performed in patients with suspected acute pulmonary embolism (APE) to search for right ventricular (RV) pressure overload. We prospectively assessed the diagnostic value of a new Doppler echocardiographic sign of APE based on the disturbed RV ejection pattern ("60/60 sign") and compared its diagnostic performances with that of the presence of RV pressure overload, as well as with "McConnell sign" based on RV regional wall motion abnormalities. We assessed 100 consecutive patients with clinical suspicion of APE, including those with previous cardiorespiratory diseases. After TTE, all of the patients underwent reference diagnostic tests for APE. The 60/60 sign required RV acceleration time of 相似文献   
128.
Vascular endothelial (VE)-cadherin is the major adhesion molecule of endothelial adherens junctions. It plays an essential role in controlling endothelial permeability, vascular integrity, leukocyte transmigration, and angiogenesis. Elevated levels of soluble VE-cadherin are associated with diseases like coronary atherosclerosis. Previous data showed that the extracellular domain of VE-cadherin is released by an unknown metalloprotease activity during apoptosis. In this study, we used gain-of-function analyses, inhibitor studies, and RNA interference experiments to analyze the proteolytic release of VE-cadherin in human umbilical vein endothelial cells (HUVECs). We found that VE-cadherin is specifically cleaved by the disintegrin and metalloprotease ADAM10 in its ectodomain, releasing a soluble fragment and generating a carboxyl-terminal membrane-bound stub, which is a substrate for a subsequent gamma-secretase cleavage. This ADAM10-mediated proteolysis could be induced by Ca(2+) influx and staurosporine treatment, indicating that ADAM10-mediated VE-cadherin cleavage contributes to the dissolution of adherens junctions during endothelial cell activation and apoptosis, respectively. In contrast, protein kinase C activation or inhibition did not modulate VE-cadherin processing. Increased ADAM10 expression was functionally associated with an increase in endothelial permeability. Remarkably, our data indicate that ADAM10 activity also contributes to the thrombin-induced decrease of endothelial cell-cell adhesion. Moreover, knockdown of ADAM10 in HUVECs as well as in T cells by small interfering RNA impaired T-cell transmigration. Taken together, our data identify ADAM10 as a novel regulator of vascular permeability and demonstrate a hitherto unknown function of ADAM10 in the regulation of VE-cadherin-dependent endothelial cell functions and leukocyte transendothelial migration.  相似文献   
129.
130.
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