全文获取类型
收费全文 | 3493篇 |
免费 | 269篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 36篇 |
儿科学 | 55篇 |
妇产科学 | 120篇 |
基础医学 | 472篇 |
口腔科学 | 52篇 |
临床医学 | 389篇 |
内科学 | 808篇 |
皮肤病学 | 59篇 |
神经病学 | 326篇 |
特种医学 | 70篇 |
外科学 | 373篇 |
综合类 | 15篇 |
一般理论 | 3篇 |
预防医学 | 329篇 |
眼科学 | 126篇 |
药学 | 302篇 |
中国医学 | 2篇 |
肿瘤学 | 230篇 |
出版年
2024年 | 3篇 |
2023年 | 74篇 |
2022年 | 59篇 |
2021年 | 81篇 |
2020年 | 105篇 |
2019年 | 130篇 |
2018年 | 104篇 |
2017年 | 116篇 |
2016年 | 106篇 |
2015年 | 120篇 |
2014年 | 147篇 |
2013年 | 224篇 |
2012年 | 286篇 |
2011年 | 294篇 |
2010年 | 153篇 |
2009年 | 172篇 |
2008年 | 242篇 |
2007年 | 235篇 |
2006年 | 202篇 |
2005年 | 155篇 |
2004年 | 165篇 |
2003年 | 162篇 |
2002年 | 115篇 |
2001年 | 34篇 |
2000年 | 25篇 |
1999年 | 26篇 |
1998年 | 33篇 |
1997年 | 26篇 |
1996年 | 15篇 |
1995年 | 24篇 |
1994年 | 13篇 |
1993年 | 15篇 |
1992年 | 15篇 |
1991年 | 14篇 |
1990年 | 4篇 |
1989年 | 5篇 |
1988年 | 9篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1982年 | 9篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1974年 | 3篇 |
1970年 | 4篇 |
1966年 | 2篇 |
1961年 | 5篇 |
1959年 | 1篇 |
排序方式: 共有3767条查询结果,搜索用时 0 毫秒
21.
Neural classifier construction using regularization, pruning and test error estimation 总被引:1,自引:0,他引:1
Mads Hintz-Madsen Lars Kai Hansen Jan Larsen Morten With Pedersen Michael Larsen 《Neural networks》1998,11(9):1659-1670
In this paper we propose a method for construction of feed-forward neural classifiers based on regularization and adaptive architectures. Using a penalized maximum likelihood scheme, we derive a modified form of the entropic error measure and an algebraic estimate of the test error. In conjunction with optimal brain damage pruning, a test error estimate is used to select the network architecture. The scheme is evaluated on four classification problems. 相似文献
22.
23.
24.
Benign coital headache 总被引:1,自引:0,他引:1
John R Østergaard Morten Kraft 《Cephalalgia : an international journal of headache》1992,12(6):353-355
We studied the natural history of patients with a diagnosis of benign coital headache who presented to a private neurological clinic between the years 1978 and 1991. Thirty-two patients (24M, 8F) were invited to participate and 26 patients (83%) responded. The period of follow-up ranged from six months to 14 years (median 6 years). Thirteen patients (50%) had recurrent attacks of coital headache epochs separated by intervals of up to 10 years. Eleven of these patients suffered a concomitant primary headache whereas this was present in only one of those patients without recurrent attacks of coital headache (p < 0.001). In all but one patient, who had a transient blurred vision, the headache was not accompanied by nausea, vomiting, visual disturbances, sensory/motor disturbances, or unconsciousness. We concluded that benign coital headache can be clearly distinguished from headaches due to cerebral aneurysm or arteriovenous malformation rupture. The presence of a concomitant primary headache syndrome is a risk-factor for recurrence of coital headache. 相似文献
25.
26.
Bruun-Rasmussen M Bernstein K Chronaki C 《International journal of medical informatics》2003,70(2-3):205-214
During the past 10–15 years, Regional Health Care Networks (RHCN) have been established in many regions throughout the world. RHCN build on well-known techniques, methodologies and appropriate standards. Most of the European Countries today have set up IT strategic plans that focus on the establishment of RHCN. The benefits of having access to all relevant information are tremendous and contribute to cost-effective and coherent health services. By the rapid spread and use of Internet, technology has made it possible to interconnect all kinds of applications. In 2000, the most experienced regions in Europe joined PICNIC, a European project to develop the Next Generation Regional Health Care Networks and to support their new ways of providing health and social care. The previous generation of Regional Health Care Networks supported the interconnection of applications by transfer of messages. Messaging is an effective means of integration for isolated high-specialised systems that only need to exchange data. This service will continue to be one of the most important services in the future health care networks. However, tighter coupling may be desirable in some instances to avoid replicating the same functionality in several applications. In other words, certain services can be common and used by a number of applications instead of building that service inside each application. These common services are called middleware services. In PICNIC (http://www.medcom.dk/picnic), a new middleware Collaboration IT service has been identified and developed. This service allows the end users to perform real-time clinical collaboration, with exchange of text, structured data, voice and images across the limits of a single region. A clinical collaboration is associated with the shared clinical context to provide a record of relevant clinical information and facilitates synchronous as well as asynchronous collaboration. This new IT service builds on the increasing popularity of instance messaging and presence systems that facilitate smooth transition between synchronous and asynchronous interaction. The new Collaboration IT service is expected to have a strong impact on the practice of health care in the next generation of Regional Health Care Networks. 相似文献
27.
Consecutively admitted internal medical inpatients (N=294) who were psychiatrically assessed with the Schedules for Clinical Assessment in Neuropsychiatry in a two-phase design were followed up in a review of public files on their use of medical care over 18 months. Self-rated outcome was assessed from health and fitness ratings at admission and after 1 year. ICD-10 mental disorders had a statistically significant impact on the risk (odds ratio) of high use (above the 80th percentile) of primary care, as did ICD-10 anxiety/depression, and worry about illness (as assessed by the Whiteley-7 Scale). The authors found a less-than-significant tendency for mental illness to influence the use of inpatient admissions and self-rated outcome. 相似文献
28.
29.
Geographical and temporal conservation of antibody recognition of Plasmodium falciparum variant surface antigens 下载免费PDF全文
Nielsen MA Vestergaard LS Lusingu J Kurtzhals JA Giha HA Grevstad B Goka BQ Lemnge MM Jensen JB Akanmori BD Theander TG Staalsoe T Hviid L 《Infection and immunity》2004,72(6):3531-3535
The slow acquisition of protection against Plasmodium falciparum malaria probably reflects the extensive diversity of important antigens. The variant surface antigens (VSA) that mediate parasite adhesion to a range of host molecules are regarded as important targets of acquired protective immunity, but their diversity makes them questionable vaccine candidates. We determined levels of VSA-specific immunoglobulin G (IgG) in human plasma collected at four geographically distant and epidemiologically distinct localities with specificity for VSA expressed by P. falciparum isolates from three African countries. Plasma levels of VSA-specific IgG recognizing individual parasite isolates depended on the transmission intensity at the site of plasma collection but were largely independent of the geographical origin of the parasites. The total repertoire of immunologically distinct VSA thus appears to be finite and geographically conserved, most likely due to functional constraints. Furthermore, plasma samples frequently had high IgG reactivity to VSA expressed by parasites isolated more than 10 years later, showing that the repertoire is also temporally stable. Parasites from patients with severe malaria expressed VSA (VSASM) that were better recognized by plasma IgG than VSA expressed by other parasites, but importantly, VSASM-type antigens also appeared to show substantial antigenic homogeneity. Our finding that the repertoire of immunologically distinct VSA in general, and in particular that of VSASM, is geographically and temporally conserved raises hopes for the feasibility of developing VSA-based vaccines specifically designed to accelerate naturally acquired immunity, thereby enhancing protection against severe and life-threatening P. falciparum malaria. 相似文献
30.
In sera from 12 patients with polar tuberculoid leprosy, 12 with subpolar tuberculoid leprosy, and 16 with lepromatous leprosy were demonstrated a total number of 125 anti-BCG precipitins by means of crossed immunoelectrophoresis with intermediate gel. Up to 14 different precipitins were found in individual sera, and the complexity in antibody response was higher than previously realized. The specificity of 69% of the antibodies was defined, and these antibodies were titrated in three arbitrary titer units. A highly significant difference (P < 0.002) was found in antibody response between the tuberculoid and the lepromatous group. Due to simplicity, sensitivity, and high resolution, the method used is a promising tool for providing exact data to be used as guidelines for purification of important individual mycobacterial antigens. The need for reference antisera is emphasized. 相似文献