全文获取类型
收费全文 | 4706篇 |
免费 | 286篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 156篇 |
妇产科学 | 15篇 |
基础医学 | 371篇 |
口腔科学 | 2篇 |
临床医学 | 725篇 |
内科学 | 1662篇 |
皮肤病学 | 3篇 |
神经病学 | 450篇 |
特种医学 | 248篇 |
外科学 | 586篇 |
综合类 | 521篇 |
预防医学 | 57篇 |
眼科学 | 4篇 |
药学 | 184篇 |
1篇 | |
中国医学 | 32篇 |
肿瘤学 | 42篇 |
出版年
2023年 | 94篇 |
2022年 | 124篇 |
2021年 | 210篇 |
2020年 | 209篇 |
2019年 | 245篇 |
2018年 | 200篇 |
2017年 | 130篇 |
2016年 | 99篇 |
2015年 | 127篇 |
2014年 | 266篇 |
2013年 | 229篇 |
2012年 | 176篇 |
2011年 | 225篇 |
2010年 | 176篇 |
2009年 | 208篇 |
2008年 | 240篇 |
2007年 | 244篇 |
2006年 | 209篇 |
2005年 | 190篇 |
2004年 | 134篇 |
2003年 | 137篇 |
2002年 | 84篇 |
2001年 | 92篇 |
2000年 | 62篇 |
1999年 | 73篇 |
1998年 | 53篇 |
1997年 | 95篇 |
1996年 | 55篇 |
1995年 | 65篇 |
1994年 | 55篇 |
1993年 | 45篇 |
1992年 | 49篇 |
1991年 | 58篇 |
1990年 | 45篇 |
1989年 | 31篇 |
1988年 | 29篇 |
1987年 | 34篇 |
1986年 | 39篇 |
1985年 | 33篇 |
1984年 | 32篇 |
1983年 | 22篇 |
1982年 | 25篇 |
1981年 | 25篇 |
1980年 | 13篇 |
1979年 | 18篇 |
1978年 | 15篇 |
1977年 | 13篇 |
1976年 | 16篇 |
1974年 | 6篇 |
1973年 | 8篇 |
排序方式: 共有5067条查询结果,搜索用时 15 毫秒
61.
Summary Two hundred twenty five patients with intracranial lesions underwent diagnostic and therapeutic stereotactic surgery during the period 1978–1985. In the first 98 cases target coordinates were determined by transferring the information from the CT images to the standard stereotactic films. In the remainder, a simple, CT adapted stereotactic system has been used. Operations were as a rule performed under local anaesthesia. Positive histological diagnosis using paraffin embedding was achieved in 96% of the patients (biopsy success rate). Therapeutic procedures included abscess and cyst aspiration, cyst shunting, interstitial (Ir 192) or intracavitary (Y 90) irradiation and ventriculocisternostomy. Stereotactic surgery implied a refinement of the eventual therapeutic management in 90% of the cases. Transient neurological deficit occurred in 5.7% of the patients and there were three deaths (mortality rate 1.3%). Infection or other complications were not seen. The rationale and indications for non-functional stereotaxis are discussed. 相似文献
62.
Ad F. Roffel Willy G. in't Hout Rokus A. de Zeeuw Johan Zaagsma 《Naunyn-Schmiedeberg's archives of pharmacology》1987,335(5):593-595
Summary We have characterized the muscarine receptors in bovine tracheal and left ventricular membranes using 3H-dexetimide/pirenzepine and 3H-dexetimide/AF-DX 116 competition studies. Pirenzepinc exhibited low (M2) affinity binding to both preparations; K
d was 590 nM in left ventricle and 463 nM in trachea. AF-DX 116 exhibited high (M2) affinity binding to left ventricle (K
d = 95.6 nM); in tracheal membranes it bound with high (M2) affinity (K
d = 40.7 nM) to 74% of the receptors and with low (M3) affinity (K
d = 2.26 M) to 26% of the receptors. It is concluded that bovine tracheal muscle membranes contain a heterogeneous population of muscarine binding sites, the majority having M2 (heart) subtype characteristics and being located on the smooth muscle membranes; a minority having M3 (exocrine gland) subtype characteristics and presumed to be located in submucosal glands. This is the first report of high affinity binding of AF-DX 116 to non-cardiac peripheral muscarine receptors.
Send offprint requests to A. F. Roffel at the above address 相似文献
63.
目的 :建立便于推广、功能齐全、价廉的三维医学图像重建系统及进行三维重建。方法 :利用目前较先进的数码摄片技术和自行编制的软件系统 ,对层距 1.0 mm的人体头部断面共 2 4 0层进行侧脑室的三维重建 ,同时对头部整体行三维重建以其进行相对定位和比较。结果 :重建后的侧脑室可和头部进行参照显示 ,行旋转、透明处理和不同方向的任意剖割。结论 :较以 CT、MRI断面图像重建的模型增加了轮廓的准确性和器官内组织的鲜明色彩 相似文献
64.
Antonio M. Calafiore Antonio Totaro Nicola Testa Cosimo Sacra Gaetano Castellano Stefano Guarracini Massimo Di Marco Sotirios Prapas Mario Gaudino Roberto Lorusso Domenico Paparella Michele Di Mauro 《Journal of cardiac surgery》2021,36(1):247-259
In secondary mitral regurgitation, the concept that the mitral valve (MV) is an innocent bystander, has been challenged by many studies in the last decades. The MV is a living structure with intrinsic plasticity that reacts to changes in stretch or in mechanical stress activating biohumoral mechanisms that have, as purpose, the adaptation of the valve to the new environment. If the adaptation is balanced, the leaflets increase both surface and length and the chordae tendineae lengthen: the result is a valve with different characteristics, but able to avoid or to limit the regurgitation. However, if the adaptation is unbalanced, the leaflets and the chords do not change their size, but become stiffer and rigid, with moderate or severe regurgitation. These changes are mediated mainly by a cytokine, the transforming growth factor‐β (TGF‐β), which is able to promote the changes that the MV needs to adapt to a new hemodynamic environment. In general, mild TGF‐β activation facilitates leaflet growth, excessive TGF‐β activation, as after myocardial infarction, results in profibrotic changes in the leaflets, with increased thickness and stiffness. The MV is then a plastic organism, that reacts to the external stimuli, trying to maintain its physiologic integrity. This review has the goal to unveil the secret life of the MV, to understand which stimuli can trigger its plasticity, and to explain why the equation “large heart = moderate/severe mitral regurgitation” and “small heart = no/mild mitral regurgitation” does not work into the clinical practice. 相似文献
65.
心血管参数对动脉中压力和流量的影响 总被引:2,自引:0,他引:2
本文从建立心室-血管优化耦合模型出发,通过求解优化耦合所对应主动脉根部的压力和流量所满足方程,详细讨论动脉中压力和流量随心血管参数的变化规律,所得结果与血液循环系统的生理事实一致。 相似文献
66.
目的探讨侧脑室室管膜囊肿的MRI表现。方法回顾性分析10例侧脑室室管膜囊肿患者的临床及MRI影像学资料。结果10例中有明显症状者3例,其余7例症状不明显。MRI表现为侧脑室三角区和/或体部内单发椭圆形囊样病灶,边界清晰、光滑、锐利,信号均匀,在MRI所有序列上均与脑脊液信号相同,5例增强扫描病灶无增强,邻近的脉络丛受压移位。4例合并同侧颞角轻度扩大,1例合并同侧颞角明显扩大。双侧脑室前角无明显扩大。邻近脑实质无水肿带。结论侧脑室室管膜囊肿MRI表现具有一定特征性,为该病的诊断及鉴别诊断提供重要依据。 相似文献
67.
68.
M. Fleischer W. Wippo H. Themann R. -S. Achatzy 《Virchows Archiv : an international journal of pathology》1980,389(2):205-210
Summary 15 biopsies of dilated and hypertrophied human left ventricles in mitral insufficient hearts were morphometrically investigated. On light and electron microscopical level the results were compared with those received from normally loaded human left ventricles and from hypertrophied human left ventricles found in hearts with aortic valve disease. The results demonstrate alterations when compared with the results from normally loaded left ventricles. The differences between normally loaded and volume loaded left ventricles are smaller than those in pressure loaded left ventricles from aortic valve diseased hearts.This work was supported gratefully by the Deutsche Forschungsgemeinschaft, SFB 104 相似文献
69.
狗左冠状动脉结扎后左、右心室和肺循环功能的动态演变及其相互关系 总被引:1,自引:0,他引:1
用麻醉开胸狗,观察了左冠状动脉前降支(LAD)结扎后2小时内,左,右心室舒缩性能、泵功能及肺循环压力和阻力的动态变化,并分析其相互关系。结扎LAD所造成的心肌缺血范围占左心室(LV)重量的35.2±1.4%。LAD结扎后,依次出现LV舒缩性能、肺动脉压、左、右心室泵功能、LV收缩性船、右心室(RV)舒张性能和肺血管阻力的改变,而RV收缩性能则无明显变化。结果表明,较大范围的LV心肌梗塞(MI)早期,LV功能降低可直接导致RV舒张性能降低,还可直接和通过肺循环压力和阻力升高间接使RV泵功能降低。但对RV收缩性能无明显影响。因子分析提示,LV收缩性能与两心室泵功能的改变是LVMI后心功能改变的主要方面;依次为两心室舒张性能和肺循环功能的改变。 相似文献
70.
目的 :探索手术切除侧脑室肿瘤的方法。方法 :15例侧脑室肿瘤分别为室管膜瘤、脑膜瘤、室管膜下瘤、胶样囊肿、胶质细胞瘤、脉络丛乳头状瘤及脑血管畸形 ,其中 7例侧脑室额角肿瘤经额中回皮质入路 ,2例侧脑室体部肿瘤经胼胝体前部入路 ,5例侧脑室三角区肿瘤经顶枕部皮质入路 ,1例侧脑室颞角肿瘤经颞叶皮质入路。结果 :除 1例侧脑室额角胶质细胞瘤次全切除术后行放疗和化疗外 ,其余肿瘤均手术全切 ,所有病人术后随访 6个月至 1年 ,术后恢复良好 ,参加日常工作。结论 :侧脑室肿瘤绝大多数可行全切除且预后良好 相似文献