全文获取类型
收费全文 | 3370727篇 |
免费 | 272729篇 |
国内免费 | 13911篇 |
专业分类
耳鼻咽喉 | 45827篇 |
儿科学 | 100417篇 |
妇产科学 | 83775篇 |
基础医学 | 535214篇 |
口腔科学 | 91430篇 |
临床医学 | 302091篇 |
内科学 | 593177篇 |
皮肤病学 | 88894篇 |
神经病学 | 289964篇 |
特种医学 | 132556篇 |
外国民族医学 | 118篇 |
外科学 | 531926篇 |
综合类 | 97975篇 |
现状与发展 | 24篇 |
一般理论 | 2279篇 |
预防医学 | 274761篇 |
眼科学 | 77335篇 |
药学 | 233891篇 |
24篇 | |
中国医学 | 9775篇 |
肿瘤学 | 165914篇 |
出版年
2021年 | 56047篇 |
2020年 | 35683篇 |
2019年 | 58981篇 |
2018年 | 72278篇 |
2017年 | 55051篇 |
2016年 | 60824篇 |
2015年 | 74992篇 |
2014年 | 109611篇 |
2013年 | 175385篇 |
2012年 | 96244篇 |
2011年 | 96029篇 |
2010年 | 118261篇 |
2009年 | 122717篇 |
2008年 | 82846篇 |
2007年 | 85575篇 |
2006年 | 96384篇 |
2005年 | 91654篇 |
2004年 | 93036篇 |
2003年 | 83355篇 |
2002年 | 73080篇 |
2001年 | 103200篇 |
2000年 | 96006篇 |
1999年 | 96073篇 |
1998年 | 65107篇 |
1997年 | 62918篇 |
1996年 | 60536篇 |
1995年 | 55977篇 |
1994年 | 49970篇 |
1993年 | 46703篇 |
1992年 | 66566篇 |
1991年 | 62877篇 |
1990年 | 59346篇 |
1989年 | 58941篇 |
1988年 | 54343篇 |
1987年 | 53062篇 |
1986年 | 49974篇 |
1985年 | 50445篇 |
1984年 | 46106篇 |
1983年 | 42480篇 |
1982年 | 40694篇 |
1981年 | 38372篇 |
1980年 | 36072篇 |
1979年 | 37000篇 |
1978年 | 33155篇 |
1977年 | 30906篇 |
1976年 | 27716篇 |
1975年 | 26253篇 |
1974年 | 26630篇 |
1973年 | 25303篇 |
1972年 | 23775篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Dr. Robert L. Geggel David R. Fulton Harvey L. Chernoff Richard Cleveland Thomas J. Hougen 《Pediatric cardiology》1987,8(4):279-283
Summary An infant girl is described who had cor triatriatum and partial anomalous pulmonary venous connection of the left pulmonary
veins to the coronary sinus, the first report of this combination of lesions. The infant also had a Dandy-Walker malformation
and multiple facial and intrathoracic hemangiomas. The cardiac diagnosis was made by two-dimensional echocardiography. Cardiac
catheterization and angiography confirmed the findings and also demonstrated a persistent left superior vena cava draining
to the coronary sinus. The infant underwent successful surgical repair. Partial anomalous pulmonary venous connection and
left superior vena cava not infrequently are associated with cor triatriatum. Although two-dimensional echocardiography is
sensitive for the detection of cor triatriatum, preoperative cardiac catheterization is necessary to identify unequivocally
systemic and pulmonary venous connections. 相似文献
992.
Summary The left recurrent laryngeal nerves from five horses with sub-clinical neuropathy were examined by light and electron microscopy in a study designed to examine accumulation of axonal organelles at paranodal and internodal locations. Transverse sections of the nerve showed scattered fibres with split myelin sheaths and axonal accumulation of organelles. On longitudinal sections these collections were seen to result from an axonal outpouching in which dense lamellar bodies and mitochondria had accumulated. These paranodal collections, which could be found on both sides of the node, were often associated with infoldings of the terminal loops of myelin and with occasional paranodal demyelination. The fact that many of the organelles in the outpouches were lysosomal in nature was confirmed by their positive staining for cathepsin D activity. Longitudinal sections demonstrated a number of axons which were swollen over a long distance and which contained focal accumulations of similar organelles. In places, however, there was a clear separation between these organelles and the cytoskeletal proteins. In each case these swollen axons were surrounded by Schwann cell nuclei and their processes, forming well-ordered onion bulbs. The possibility that these two types of changes, i.e. the paranodal accumulations and the axonal swellings could result from a disturbance in axonal transport in this distal axonopathy is discussed. 相似文献
993.
994.
995.
996.
997.
Paul Wexberg MD BM Richard Pacher MD Suzanne Rdler MD Katharina Kiss MD Gilbert Beran MD Michael Grimm MD Gerald Maurer MD Dietmar Glogar MD FESC 《The Journal of heart and lung transplantation》2002,21(12):583-1263
BACKGROUND: Endothelin, a peptide with strong vasoconstrictive and mitogenic properties, has been found to increase after cardiac transplantation. We therefore assessed the association between its precursor peptide, big endothelin-1, and intimal hyperplasia and coronary flow reserve after heart transplantation. METHODS: Thirty-five patients without hemodynamically significant coronary artery disease after heart transplantation were investigated: Average peak flow velocity in the left anterior descending artery (LAD) was assessed by intracoronary Doppler at baseline as well as after injection of adenosine; coronary flow reserve was calculated as a ratio of both and was corrected for patient age and baseline average peak flow velocity. Lumen, intima + media and total vessel area were measured by intracoronary ultrasound. The plasma concentration of big endothelin-1 in venous blood was determined by radioimmunoassay. RESULTS: Patients with elevated big endothelin-1 levels (>2 fmol/ml) tended to have a decreased corrected coronary flow reserve (2.60 +/- 0.9 vs 3.21 +/- 1.0, p = 0.078). They also had a significantly larger intima + media area (5.82 +/- 2.9 vs 2.37 +/- 2.9 mm(2), p = 0.004) and total vessel area (18.36 +/- 5.8 vs 12.81 +/- 4.8 mm(2), p = 0.012) than those with normal plasma concentrations. CONCLUSIONS: Our study suggests an association between elevated big endothelin-1 plasma levels and the development of intimal hyperplasia and reduction of coronary flow reserve after cardiac transplantation. 相似文献
998.
999.
1000.