全文获取类型
收费全文 | 189445篇 |
免费 | 1571篇 |
国内免费 | 71篇 |
专业分类
耳鼻咽喉 | 1211篇 |
儿科学 | 6848篇 |
妇产科学 | 3109篇 |
基础医学 | 18354篇 |
口腔科学 | 1848篇 |
临床医学 | 13376篇 |
内科学 | 34516篇 |
皮肤病学 | 936篇 |
神经病学 | 17568篇 |
特种医学 | 9688篇 |
外科学 | 31236篇 |
综合类 | 2384篇 |
一般理论 | 1篇 |
预防医学 | 18341篇 |
眼科学 | 3016篇 |
药学 | 10310篇 |
中国医学 | 647篇 |
肿瘤学 | 17698篇 |
出版年
2022年 | 139篇 |
2021年 | 246篇 |
2020年 | 138篇 |
2019年 | 176篇 |
2018年 | 22109篇 |
2017年 | 17513篇 |
2016年 | 19660篇 |
2015年 | 1132篇 |
2014年 | 1072篇 |
2013年 | 1102篇 |
2012年 | 7382篇 |
2011年 | 21535篇 |
2010年 | 19079篇 |
2009年 | 11744篇 |
2008年 | 19939篇 |
2007年 | 22199篇 |
2006年 | 1045篇 |
2005年 | 2682篇 |
2004年 | 3887篇 |
2003年 | 4895篇 |
2002年 | 3045篇 |
2001年 | 856篇 |
2000年 | 1018篇 |
1999年 | 726篇 |
1998年 | 403篇 |
1997年 | 375篇 |
1996年 | 227篇 |
1995年 | 232篇 |
1994年 | 240篇 |
1993年 | 159篇 |
1992年 | 517篇 |
1991年 | 446篇 |
1990年 | 524篇 |
1989年 | 473篇 |
1988年 | 430篇 |
1987年 | 382篇 |
1986年 | 348篇 |
1985年 | 388篇 |
1984年 | 228篇 |
1983年 | 218篇 |
1982年 | 114篇 |
1979年 | 172篇 |
1978年 | 108篇 |
1977年 | 111篇 |
1975年 | 96篇 |
1974年 | 96篇 |
1973年 | 100篇 |
1970年 | 102篇 |
1969年 | 117篇 |
1968年 | 122篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
Giampiero Beluffi 《La Radiologia medica》2012,117(1):162-163
994.
Edoardo Verna Sergio Ghiringhelli Simone Scotti Fabrizio Caravati 《Journal of nuclear cardiology》2012,19(1):53-62
Aim
To assess the predictive value of baseline ventricular dyssynchrony and myocardial contractile reserve (mCR) in identifying responders to cardiac resynchronization therapy (CRT). 相似文献995.
996.
Thomas S. Rector Brent C. Taylor Timothy J. Wilt 《Journal of general internal medicine》2012,27(1):94-101
A number of new biological markers are being studied as predictors of disease or adverse medical events among those who already have a disease. Systematic reviews of this growing literature can help determine whether the available evidence supports use of a new biomarker as a prognostic test that can more accurately place patients into different prognostic groups to improve treatment decisions and the accuracy of outcome predictions. Exemplary reviews of prognostic tests are not widely available, and the methods used to review diagnostic tests do not necessarily address the most important questions about prognostic tests that are used to predict the time-dependent likelihood of future patient outcomes. We provide suggestions for those interested in conducting systematic reviews of a prognostic test. The proposed use of the prognostic test should serve as the framework for a systematic review and to help define the key questions. The outcome probabilities or level of risk and other characteristics of prognostic groups are the most salient statistics for review and perhaps meta-analysis. Reclassification tables can help determine how a prognostic test affects the classification of patients into different prognostic groups, hence their treatment. Review of studies of the association between a potential prognostic test and patient outcomes would have little impact other than to determine whether further development as a prognostic test might be warranted. 相似文献
997.
Benign smooth muscle proliferations are relatively rare in the oral cavity. Most are classified as angioleiomyomas, some as hamartomatous growths and a few as cutaneous-type leiomyomas. We present two cases of benign smooth muscle proliferations in the tongue, provide a review, briefly discuss histogenesis and offer a clinico-pathological differential diagnosis. 相似文献
998.
Giovanni Merolla Arpit C. Dave Francesco Pegreffi Lorenza Belletti Giuseppe Porcellini 《Musculoskeletal surgery》2012,96(1):93-99
Alkaptonuria is a rare hereditary metabolic disease of autosomal recessive inheritance, resulting from deficiency of the enzyme homogentisic acid oxidase. The term “alkaptonuria” was first used in 1859 by Boedeker to describe a patient’s urinary reducing compound, and in 1866, Virchow coined the term “ochronosis” due to typical yellow pigmentation. Deposition of this pigment in articular cartilage leads to ochronotic arthropathy, the most incapacitating complication of alkaptonuria. We report a rare case of shoulder ochronotic arthritis, treated with total shoulder arthroplasty, achieving a successful long-term clinical and radiological outcomes. 相似文献
999.
Muhammad Arif 《Journal of medical systems》2012,36(3):1173-1181
In pattern classification problems, feature extraction is an important step. Quality of features in discriminating different classes plays an important role in pattern classification problems. In real life, pattern classification may require high dimensional feature space and it is impossible to visualize the feature space if the dimension of feature space is greater than four. In this paper, we have proposed a Similarity-Dissimilarity plot which can project high dimensional space to a two dimensional space while retaining important characteristics required to assess the discrimination quality of the features. Similarity-dissimilarity plot can reveal information about the amount of overlap of features of different classes. Separable data points of different classes will also be visible on the plot which can be classified correctly using appropriate classifier. Hence, approximate classification accuracy can be predicted. Moreover, it is possible to know about whom class the misclassified data points will be confused by the classifier. Outlier data points can also be located on the similarity-dissimilarity plot. Various examples of synthetic data are used to highlight important characteristics of the proposed plot. Some real life examples from biomedical data are also used for the analysis. The proposed plot is independent of number of dimensions of the feature space. 相似文献
1000.
Eystratios G. Keramidas Dimitris Maroulis Dimitris K. Iakovidis 《Journal of medical systems》2012,36(3):1271-1281
In this paper, we present a computer-aided-diagnosis (CAD) system prototype, named TND (Thyroid Nodule Detector), for the detection of nodular tissue in ultrasound (US) thyroid images and videos acquired during thyroid US examinations. The proposed system incorporates an original methodology that involves a novel algorithm for automatic definition of the boundaries of the thyroid gland, and a novel approach for the extraction of noise resilient image features effectively representing the textural and the echogenic properties of the thyroid tissue. Through extensive experimental evaluation on real thyroid US data, its accuracy in thyroid nodule detection has been estimated to exceed 95%. These results attest to the feasibility of the clinical application of TND, for the provision of a second more objective opinion to the radiologists by exploiting image evidences. 相似文献