全文获取类型
收费全文 | 21558篇 |
免费 | 1878篇 |
国内免费 | 787篇 |
专业分类
耳鼻咽喉 | 209篇 |
儿科学 | 400篇 |
妇产科学 | 233篇 |
基础医学 | 1922篇 |
口腔科学 | 652篇 |
临床医学 | 2513篇 |
内科学 | 2946篇 |
皮肤病学 | 195篇 |
神经病学 | 1064篇 |
特种医学 | 1031篇 |
外国民族医学 | 26篇 |
外科学 | 2588篇 |
综合类 | 3577篇 |
现状与发展 | 5篇 |
一般理论 | 2篇 |
预防医学 | 2001篇 |
眼科学 | 361篇 |
药学 | 2167篇 |
23篇 | |
中国医学 | 1184篇 |
肿瘤学 | 1124篇 |
出版年
2024年 | 55篇 |
2023年 | 212篇 |
2022年 | 493篇 |
2021年 | 662篇 |
2020年 | 534篇 |
2019年 | 386篇 |
2018年 | 387篇 |
2017年 | 478篇 |
2016年 | 379篇 |
2015年 | 656篇 |
2014年 | 885篇 |
2013年 | 1133篇 |
2012年 | 1489篇 |
2011年 | 1674篇 |
2010年 | 1404篇 |
2009年 | 1249篇 |
2008年 | 1461篇 |
2007年 | 1344篇 |
2006年 | 1229篇 |
2005年 | 1036篇 |
2004年 | 800篇 |
2003年 | 785篇 |
2002年 | 666篇 |
2001年 | 547篇 |
2000年 | 536篇 |
1999年 | 330篇 |
1998年 | 143篇 |
1997年 | 120篇 |
1996年 | 98篇 |
1995年 | 108篇 |
1994年 | 77篇 |
1993年 | 65篇 |
1992年 | 183篇 |
1991年 | 177篇 |
1990年 | 174篇 |
1989年 | 157篇 |
1988年 | 155篇 |
1987年 | 143篇 |
1986年 | 142篇 |
1985年 | 142篇 |
1984年 | 103篇 |
1983年 | 87篇 |
1982年 | 71篇 |
1981年 | 60篇 |
1979年 | 65篇 |
1978年 | 63篇 |
1977年 | 58篇 |
1976年 | 58篇 |
1974年 | 68篇 |
1973年 | 57篇 |
排序方式: 共有10000条查询结果,搜索用时 22 毫秒
101.
H. Leysieffer J. W. Baumann R. Mayer D. Müller G. Müller T. Schön A. Volz H. P. Zenner 《HNO》1998,46(10):853-863
Zusammenfassung
Kürzlich wurde über die Entwicklung eines elektromechanischen, piezoelektrischen Wandlers und eines Mikrofons zum subkutanen
Einbau in die hintere Geh?rgangswand als Komponenten eines zukünftigen vollst?ndig implantierbaren H?rsystems für Innenohrschwerh?rige
berichtet (HNO 45, 1997, 792–880). Zwischenzeitlich konnte die Entwicklung eines elektronischen Hauptmoduls zur Implantation
auf dem Planum mastoideum abgeschlossen werden, das diese Mikrofone und Wandler zu dem kompletten H?rimplantat TICA? LZ 3001
erg?nzt. Dieses Hauptmodul enth?lt neben der signalverarbeitenden Elektronik eine spezielle Batterie, die transkutan mit einem
portablen Ladeger?t nachgeladen wird. Nach einer Volladung, die ca. 2 h ben?tigt, ist das Implantat für rund 50 h kontinuierlich
betriebsbereit. Das Ladeger?t wird ?hnlich wie bei Mobiltelefonen in einer netzbetriebenen Station nachgeladen. L?sbare Steckverbindungen
zu Mikrofon und Wandler erm?glichen den einfachen operativen Austausch des Hauptmoduls, wenn die Batterielebensdauer erreicht
ist. Dies wird nach ca. 3–5 Jahren erwartet. Dem Patienten steht eine kleine, drahtlose Fernbedienung zur Verfügung, mit der
Lautst?rke, Ein/Aus sowie 4 H?rprogramme für unterschiedliche H?rsituationen eingestellt werden k?nnen. Die grundlegenden
audiologischen Eigenschaften sind durch ein flexibel digital programmierbares 3-Kanal-AGC-System mit Peak-clipping-Funktion
gegeben. Die gesamte übertragungsbandbreite betr?gt ca. 10 kHz. Das vollimplantierbare H?rsystem wurde im Rahmen der klinischen
Erprobung Anfang Juni 1998 erstmals am Menschen angewendet.
相似文献
102.
Zusammenfassung. Die Klonierung, Sequenzierung und Produktion von hochreinen Allergenen bietet die Möglichkeit, perfekt standardisierte Allergenpräparate herzustellen. Die Entwicklung eines neuen Klonierungssystems, das auf filamentösen Phagen basiert, führte zu einer schnellen Isolierung und Charakterisierung von Aspergillus fumigatus-Allergenen. Die auf diesem Weg rekombinant hergestellten Proteine wurden serologisch und klinisch geprüft und ihr routinemä-ßiger Einsatz im ImmunoCAP-System evaluiert. Es gelang eine quantitative Übereinstimmung zwischen Hauttestergebnissen und Serologie nachzuweisen, welche das Potential rekombinanter Allergene in der Diagnostik allergischer Krankheiten aufzeigt. Darüber hinaus trägt die Charakterisierung der Pilzallergene wesentlich zum Verständnis der moiekularen Natur der allergieauslösenden Komponenten bei Zum jetzigen Zeitpunkt können, abgesehen von Proteinen mit unbekannten biologischen Funktionen, die Pilzallergene in zwei Klassen eingeteilt werden: 1. Spezies-spezifische sezcrnierte Allergene und 2. cytoplasmatische, hoch konservierte Proteine. Diese letztgenannten Pilzallergene zeigen auch zu Proteinen aus phylogenetisch weit entfernten Organismen weitreichende Sequenzhomologien. Neben der daraus zu erwartenden IgE-Kreuzreaktivität findet man in einigen Fällen auch eine Kreuzreaktivität mit den homologen humanen Proteinen, was auf Autoimmunreaktionen, bei Pilzalleigien hindeutet. Summary. Cloning, sequencing and production of highly pure recombinant allergens allows to produce perfectly standardised allergen preparations. The development of a new cloning system based on filamentous phage allowed the fast isolation and characterisation of allergens from the fungus Aspergillus fumigatus. The produced recombinant allergens were tested in serological and clinical studies as well as for their performance for routine assessments in the ImmunoCAP-system. Thereby, a perfect correlation between skin test results and serology was found showing the potential of recombinant allergens for the diagnosis of allergic diseases. Moreover, the characterisation of fungal allergens substantially contributes to our understanding of the molecular nature of proteins involved in the elication of allergic reactions. Apart from allergenic proteins with unknown biological function, fungal allergens can be subdivided into two classes: 1. Species-specific, secreted proteins and 2. cytoplasmic, even in phylogenetically distant organisms, well conserved proteins. These fungal allergens show extended sequence similarity, a high level of IgE cross-reactivity and in some cases also cross-reactivity with homologous human proteins indicating autoimmune reactions involved in fungal allergy. 相似文献
103.
脂蛋白脂肪酶基因突变的研究 总被引:4,自引:2,他引:4
目的:筛查国人脂蛋白脂肪酶(LPL)基因的突变,并探讨其与高甘油三酯血症的关系。方法:对高甘油三酯血症组(48例)和正常甘油三酯对照组(121例)的各扩增片段进行分析,电泳图谱异常者进行PCR产物测序。对于频率较高的多态性位点,引入限制性核酸内切酶位点利用PCR-RFLP进行鉴定。结果:在高甘油三酯血症人群中,检出2例内含子3受位剪接点上游6bp的C→T转换的突变杂合子,1例外显子5Pm^207→Leu突变杂合子,在全部样品中检出1例Ser^447→stop突变纯合子,50例Ser^447→stop杂合子。结论:天津地区人群中存在着LPL基因突变,除Ser^447→stop外,内含子3和外显子5的突变多与高甘油三酯血症相关,可能是高甘油三酯血症的遗传易感因子。 相似文献
104.
Stamm C Friehs I Moran AM Zurakowski D Bacha E Mayer JE Jonas RA Del Nido PJ 《The Journal of thoracic and cardiovascular surgery》2000,120(4):755-763
OBJECTIVE: A number of patients with Williams syndrome or other forms of elastin arteriopathy have stenoses of pulmonary arteries in addition to supravalvular aortic stenosis. We sought to investigate the effect of the degree of pulmonary arterial stenosis on the prognosis after an operation for supravalvular aortic stenosis to help define the optimal treatment strategy for patients with severe forms of elastin arteriopathy. METHODS: Between 1960 and 1999, 33 patients underwent operations for supravalvular aortic stenosis while having significant stenoses of the pulmonary arteries. We retrospectively reviewed patient charts, obtained current follow-up information, and determined risk factors for survival and reoperation. RESULTS: Fifteen patients with moderate right-sided obstructions (confirmed by pulmonary artery Z-scores and right ventricular/descending aortic pressure ratio) underwent operations for supravalvular aortic stenosis only. Eighteen patients had more severe right-sided obstructions and underwent surgical relief of pulmonary arterial stenoses or right ventricular outflow tract obstruction in addition to operations for supravalvular aortic stenosis. Eight patients had undergone preoperative balloon dilations of stenotic pulmonary arteries. There were 6 early deaths and 1 late death in our series. Survival at 10 and 20 years was 76% (70% confidence interval, 68%-84%) and freedom from reintervention was 59% (70% confidence interval, 46%-71%) at 10 years and 49% (70% confidence interval, 35%-62%) at 20 years. Multivariate analysis revealed that patients with a right ventricular/descending aortic pressure ratio of 1.0 or more were at higher risk for reintervention but not for death. CONCLUSIONS: Surgical treatment of pulmonary artery obstructions in elastin arteriopathy is palliative but, in conjunction with balloon dilation of peripheral pulmonary arteries, offers good long-term survival to patients with the severest form of elastin arteriopathy. 相似文献
105.
106.
Twenty-five-year experience with rastelli repair for transposition of the great arteries 总被引:12,自引:0,他引:12
Kreutzer C De Vive J Oppido G Kreutzer J Gauvreau K Freed M Mayer JE Jonas R del Nido PJ 《The Journal of thoracic and cardiovascular surgery》2000,120(2):211-223
OBJECTIVE: Our purpose was to describe the outcome of the Rastelli repair in D -transposition of the great arteries and to determine the risk factors associated with unfavorable events. METHODS: From March 1973 to April 1998, 101 patients with D -transposition of the great arteries and ventricular septal defect underwent a Rastelli type of repair. Median age and weight were 3.1 years (10th to 90th percentiles 0.3-9.9 years) and 12.8 kg (5.9-28.2). Pulmonary stenosis was present in 73 patients and pulmonary atresia in 18; 10 patients had no left ventricular outflow tract obstruction. RESULTS: There were 7 early deaths (7%) and no operative deaths in the last 7 years of the study. Risk factors for early death, by univariable analysis, included straddling tricuspid valve (P =.04) and longer aortic crossclamping times (P =.04). At a median follow-up of 8.5 years, there were 17 late deaths and 1 patient had undergone heart transplantation. Forty-four patients had reoperations for conduit stenosis, 11 for left ventricular outflow tract obstruction, and 28 had interventional catheterization to relieve conduit stenosis. Nine patients had late arrhythmias, and there were 5 sudden deaths. Overall freedom from death or transplantation (Kaplan-Meier) was 82%, 80%, 68%, and 52% at 5, 10, 15, and 20 years, respectively. Freedom from death or reintervention (catheterization or surgical treatment) was 53%, 24%, and 21% at 5, 10, and 15 years of follow-up, respectively. CONCLUSIONS: The Rastelli repair can be performed with low early mortality. However, substantial late morbidity and mortality are associated with conduit obstruction, left ventricular outflow tract obstruction, and arrhythmia. 相似文献
107.
将岩虫匀浆液经反相浓缩、凝胶过滤和亲和柱层析获得活性组分,在体外用MTS/PMS(氮兰四唑盐/吩嗪硫酸甲酯)方法筛选抗菌肽,再分别用MTS/PMS方法和ELISA—AFP(甲胎蛋白)方法检测其对人肝癌细胞株HepG2增殖、AFP分泌及对正常大鼠成骨细胞株MC3T3-E1增殖的影响。结果表明,纯化的岩虫抗菌肽为组成型碱性蛋白(MW8.1kDa,pI8.6),不同浓度抗菌肽对肝癌细胞增殖和AFP的分泌均有抑制作用,抑制作用大小与抗菌肽浓度呈正相关性;对正常成骨细胞未见明显的抑制和杀伤作用。 相似文献
108.
河北省部分高校大学生结核菌素试验结果分析 总被引:3,自引:0,他引:3
目的了解结核菌在大学生群体中的感染状况及PPD试验过程中存在的问题,为采取相应的干预措施提供依据。方法随机抽取河北省8所高校,对其在2001~2004年新入学大学生的PPD试验记录及监测报表进行统计分析。结果河北省部分高校大学生接种人口数量明显增多;经χ2检验,2001~2004年PPD试验的阳性率、强阳性率差异有统计学意义(P<0.005),阳性率随时间呈明显下降趋势、强阳性率随时间呈缓慢上升趋势。结论高校应进一步加强PPD试验的监测力度,提高PPD的监测质量。 相似文献
109.
Erdtmann-Vourliotis M Mayer P Riechert U Höllt V 《Brain research. Molecular brain research》2000,77(1):55-64
Repeated morphine application usually leads to the development of tolerance but under certain circumstances sensitization may arise simultaneously. This phenomenon becomes obvious in behavioral tests as increasing locomotor activity and increasing drug self-administration during a course of chronic morphine application. It was suggested recently that sensitization could contribute to addiction. The molecular mechanisms of sensitization may include the long lasting increase in neuronal responsiveness to morphine which was observed in defined brain areas after repeated morphine injections. In this work, we studied whether morphine-sensitized Wistar rats also display an enhanced neuronal activity in response to other drugs of abuse (so called co-sensitization). The substances to be tested were injected as single doses 4 weeks after completion of a 10-day morphine pretreatment. MDMA (3, 4-methylenedioxymethamphetamine, 6 mg/kg) as a single test dose yielded a c-fos response in a wide range of brain areas. In the caudate putamen, the expression pattern of c-fos was clearly altered if the rats had received repeated morphine application previously. In this case, the MDMA-induced c-fos expression was markedly confined to the centromedial, mesolimbic aspect of the striatum whereas it had a diffuse appearance in rats not exposed to the opiate earlier. Cocaine application (50 mg/kg) elicited an intense c-fos expression in the medial striatum if the animals were morphine-pretreated; it was virtually absent in drug-naive rats after the same cocaine dose. Ten mg/kg cocaine had a similar but weaker effect. No difference in the c-fos expression pattern between morphine and saline pretreated animals was observed in the case of a THC (Delta(9)-tetrahydrocannabinol, 25 mg/kg) or an LSD (lysergic acid diethylamide, 1 mg/kg) test application. These findings imply that morphine sensitizes the brain towards other addicting drugs. In consequence, morphine sensitization obviously does not solely reflect alterations in mu-opioid receptor signaling. Rather, it seems to reflect further rearrangements within the mesolimbic system. 相似文献
110.
WANG Li-feng LIU Ming ZHU Hong HAN Wei HU Cheng-yi QI Ji-ping MEI Huan-lin GE Re-le ZHOU Min 《中华医学杂志(英文版)》2006,119(11):966-968
Primary cardiac hemangioendothelioma is extremely rare.1-3 Up to now less than twenty cases have been reported in English literature, the data about this kind of cardiac tumors are scanty. In this report, a case of a huge hemangio-endothelioma that arose from the right atrium and was successfully resected is presented. 相似文献