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   2356篇
  免费   157篇
  国内免费   8篇
耳鼻咽喉   15篇
儿科学   88篇
妇产科学   120篇
基础医学   351篇
口腔科学   104篇
临床医学   249篇
内科学   451篇
皮肤病学   51篇
神经病学   327篇
特种医学   130篇
外科学   169篇
综合类   14篇
预防医学   118篇
眼科学   10篇
药学   216篇
中国医学   1篇
肿瘤学   107篇
  2023年   13篇
  2022年   28篇
  2021年   52篇
  2020年   22篇
  2019年   32篇
  2018年   55篇
  2017年   43篇
  2016年   38篇
  2015年   45篇
  2014年   68篇
  2013年   68篇
  2012年   143篇
  2011年   122篇
  2010年   65篇
  2009年   60篇
  2008年   100篇
  2007年   90篇
  2006年   92篇
  2005年   90篇
  2004年   86篇
  2003年   76篇
  2002年   94篇
  2001年   64篇
  2000年   78篇
  1999年   71篇
  1998年   30篇
  1997年   25篇
  1996年   34篇
  1995年   27篇
  1994年   22篇
  1993年   19篇
  1992年   71篇
  1991年   70篇
  1990年   56篇
  1989年   52篇
  1988年   43篇
  1987年   32篇
  1986年   29篇
  1985年   30篇
  1984年   17篇
  1983年   17篇
  1982年   23篇
  1981年   19篇
  1979年   15篇
  1978年   20篇
  1975年   15篇
  1974年   15篇
  1973年   15篇
  1967年   12篇
  1966年   11篇
排序方式: 共有2521条查询结果,搜索用时 15 毫秒
91.
92.
93.
So far, no suitable 5‐HT7R radioligand exists for clinical positron emission tomography (PET) imaging. [18F]2FP3 was first tested in vivo in cats, and the results were promising for further evaluations. Here, we evaluate the radioligand in pigs and non‐human primates (NHPs). Furthermore, we investigate species differences in 5‐HT7R binding with [3H]SB‐269970 autoradiography in post‐mortem pig, NHP, and human brain tissue. Specific binding of [18F]2FP3 was investigated by intravenous administration of the 5‐HT7R specific antagonist SB‐269970. [3H]SB‐269970 autoradiography was performed as previously described. [18F]2FP3 was synthesized in an overall yield of 35% to 45%. High brain uptake of the tracer was found in both pigs and NHPs; however, pretreatment with SB‐269970 only resulted in decreased binding of 20% in the thalamus, a 5‐HT7R–rich region. Autoradiography on post‐mortem pig, NHP, and human tissues revealed that specific binding of [3H]SB‐269970 was comparable in the thalamus of pig and NHP. Despite the high uptake of [18F]2FP3 in both species, the binding could only be blocked to a limited degree with the 5‐HT7R antagonists. We speculate that the affinity of the radioligand is too low for imaging the 5‐HT7Rs in vivo and that part of the PET signal arises from targets other than the 5‐HT7R.  相似文献   
94.
European Journal of Nuclear Medicine and Molecular Imaging - Meningiomas have an excellent survival prognosis, and radiotherapy (RT) is a central component of interdisciplinary treatment. During...  相似文献   
95.

OBJECTIVE:

to identify the relationship between different presentations of acute coronary syndrome and cardiovascular risk factors among hospitalized individuals.

METHOD:

cross-sectional study performed in a teaching hospital in São Paulo, in the State of São Paulo (SP). Socio-demographic, clinical and anthropometric data of 150 individuals hospitalized due to acute coronary syndrome were collected through interviews and review of clinical charts. Association between these data and the presentation of the syndrome were investigated.

RESULTS:

there was a predominance of ST segment elevation acute myocardial infarction. There was significant association of systemic hypertension with unstable angina and high values of low density lipoprotein with infarction, without influence from socio-demographic characteristics.

CONCLUSION:

arterial hypertension and high levels of low-density lipoprotein were associated with different presentations of coronary syndrome. The results can provide support for health professionals for secondary prevention programs aimed at behavioural changing.  相似文献   
96.
Using functional neuroimaging techniques two aspects of functional integration in the human brain have been investigated, functional connectivity and effective connectivity. In this study we examined both connectivity types in parallel within an executive attention network during rest and while performing an attention task. We analyzed the predictive value of resting‐state functional connectivity on task‐induced effective connectivity in patients with prodromal Alzheimer's disease (AD) and healthy elderly. We found that in healthy elderly, functional connectivity was a significant predictor for effective connectivity, however, it was frequency‐specific. Effective top‐down connectivity emerging from prefrontal areas was related with higher frequencies of functional connectivity (e.g., 0.08–0.15 Hz), in contrast to effective bottom‐up connectivity going to prefrontal areas, which was related to lower frequencies of functional connectivity (e.g., 0.001–0.03 Hz). In patients, the prediction of effective connectivity by functional connectivity was disturbed. We conclude that functional connectivity and effective connectivity are interrelated in healthy brains but this relationship is aberrant in very early AD. Hum Brain Mapp 35:954–963, 2014. © 2013 Wiley Periodicals, Inc.  相似文献   
97.
Advances in genome sequencing have led to a tremendous increase in the discovery of novel missense variants, but evidence for determining clinical significance can be limited or conflicting. Here, we present Learning from Evidence to Assess Pathogenicity (LEAP), a machine learning model that utilizes a variety of feature categories to classify variants, and achieves high performance in multiple genes and different health conditions. Feature categories include functional predictions, splice predictions, population frequencies, conservation scores, protein domain data, and clinical observation data such as personal and family history and covariant information. L2‐regularized logistic regression and random forest classification models were trained on missense variants detected and classified during the course of routine clinical testing at Color Genomics (14,226 variants from 24 cancer‐related genes and 5,398 variants from 30 cardiovascular‐related genes). Using 10‐fold cross‐validated predictions, the logistic regression model achieved an area under the receiver operating characteristic curve (AUROC) of 97.8% (cancer) and 98.8% (cardiovascular), while the random forest model achieved 98.3% (cancer) and 98.6% (cardiovascular). We demonstrate generalizability to different genes by validating predictions on genes withheld from training (96.8% AUROC). High accuracy and broad applicability make LEAP effective in the clinical setting as a high‐throughput quality control layer.  相似文献   
98.
CTLA‐4 and PD‐1 play a key role in tumor‐induced downregulation of lymphocytic immune responses. Immune checkpoint inhibitors have been shown to alter the immune response to various cancer types. Anti‐CTLA‐4 and anti‐PD‐1 antibodies affect the interaction between tumor, antigen‐presenting cells and T lymphocytes. Clinical studies of the anti‐CTLA‐4 antibody ipilimumab and the anti‐PD‐1 antibodies nivolumab and pembrolizumab have provided evidence of their positive effects on overall survival in melanoma patients. Combined treatment using ipilimumab and nivolumab has been shown to achieve five‐year survival rates of 52 %. Such enhancement of the immune response is inevitably associated with adverse events. Knowledge of the spectrum of side effects is essential, both in terms of prevention and management. Adverse events include colitis, dermatitis, hypophysitis, thyroiditis, hepatitis and other, less common autoimmune phenomena. In recent years, considerable progress has been made in the detection and treatment of the aforementioned immune‐related adverse events. However, early diagnosis of rare neurological or cardiac side effects, which may be associated with increased mortality, frequently pose a challenge. The present update highlights our current understanding as well as new insights into the spectrum of side effects associated with checkpoint inhibitors and their management.  相似文献   
99.
Monatsschrift Kinderheilkunde - Eine adäquate Energie- und Nährstoffversorgung ist Grundlage für ein gesundes Wachstum und Voraussetzung für die Erhaltung von Gesundheit und...  相似文献   
100.
There are 5 women over the age of 55 with an eating disorder described. In view of a possible increase in the eating disorders among the elderly, the correct diagnosis and treatment of these disorders were emphasized.  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