全文获取类型
收费全文 | 92012篇 |
免费 | 29941篇 |
国内免费 | 1056篇 |
专业分类
耳鼻咽喉 | 2370篇 |
儿科学 | 2474篇 |
妇产科学 | 2219篇 |
基础医学 | 1869篇 |
口腔科学 | 4979篇 |
临床医学 | 25437篇 |
内科学 | 23530篇 |
皮肤病学 | 3205篇 |
神经病学 | 11740篇 |
特种医学 | 3456篇 |
外科学 | 17253篇 |
综合类 | 97篇 |
现状与发展 | 40篇 |
预防医学 | 12934篇 |
眼科学 | 2056篇 |
药学 | 802篇 |
中国医学 | 5篇 |
肿瘤学 | 8543篇 |
出版年
2024年 | 540篇 |
2023年 | 4999篇 |
2022年 | 1050篇 |
2021年 | 2609篇 |
2020年 | 5245篇 |
2019年 | 1892篇 |
2018年 | 6740篇 |
2017年 | 7226篇 |
2016年 | 7793篇 |
2015年 | 7871篇 |
2014年 | 10227篇 |
2013年 | 11861篇 |
2012年 | 3371篇 |
2011年 | 3119篇 |
2010年 | 6594篇 |
2009年 | 8911篇 |
2008年 | 3147篇 |
2007年 | 2070篇 |
2006年 | 3262篇 |
2005年 | 1819篇 |
2004年 | 1232篇 |
2003年 | 936篇 |
2002年 | 866篇 |
2001年 | 1777篇 |
2000年 | 1106篇 |
1999年 | 1642篇 |
1998年 | 2034篇 |
1997年 | 1871篇 |
1996年 | 1926篇 |
1995年 | 1665篇 |
1994年 | 1063篇 |
1993年 | 895篇 |
1992年 | 727篇 |
1991年 | 616篇 |
1990年 | 494篇 |
1989年 | 505篇 |
1988年 | 489篇 |
1987年 | 366篇 |
1986年 | 342篇 |
1985年 | 284篇 |
1984年 | 243篇 |
1983年 | 292篇 |
1982年 | 219篇 |
1981年 | 192篇 |
1980年 | 116篇 |
1978年 | 119篇 |
1977年 | 114篇 |
1976年 | 83篇 |
1974年 | 70篇 |
1972年 | 70篇 |
排序方式: 共有10000条查询结果,搜索用时 812 毫秒
981.
R. Langevin PhD P. Wright MA L. Handy 《Sexual abuse : a journal of research and treatment》1989,2(3):227-253
From a data bank of 479 sex offenders, a comparison was undertaken of those reporting any childhood sexual abuse versus those reporting none. A total of 201 men (42.0%) reported abuse, 261 (54.5%) did not and for 17 (3.5%), information was unavailable. The Abused and Nonabused Groups were compared on demographic information, the MMPI, Clarke Sex History Questionnaire and the Clarke Parent Child Relations Questionnaire. The Abused and Nonabused groups were similar in age, marital status, income, and criminal history, but the Abused Group had significantly less education. The Abused Group showed sexualization of their childhood, not only in the number of contacts with adults but also with age peers and siblings of both sexes. They tended to have wider ranging and more frequent sexual experiences as adults both with men and women. They more often raped. The Abused Group tended to show more emotional instability than the Nonabused Group in more frequent suicidal ideation and suicide attempts, as well as in elevated Mania Scale Scores on the MMPI. The family background of the Abused Group was more disturbed than the Nonabused Group's; especially father-son relations. They reported more alcohol use and abuse in their parents and more parent-child aggression than nonabused offenders did. Although it is unlikely that child sexual abuse causes sexual anomalies, the results of the present study suggest that childhood sexual victimization in the lives of adult sex offenders merits further investigation and has implications for treatment. 相似文献
982.
Finite-element models of the human head 总被引:9,自引:0,他引:9
L. Voo PhD S. Kumaresan F. A. Pintar N. Yoganandan A. Sances Jr. 《Medical & biological engineering & computing》1996,34(5):375-381
A review is presented of the existing finite-element (FE) models for the biomechanics of human head injury. Finite element
analysis can be an important tool in describing the injury biomechanics of the human head. Complex geometric and material
properties pose challenges to FE modelling. Various assumptions and simplifications are made in model development that require
experimental validation. More recent models incorporate anatomic details with higher precision. The cervical vertebral column
and spinal cord are included. Model results have been more qualitative than quantitative owing to the lack of adequate experimental
validation. Advances include transient stress distribution in the brain tissue, frequency responses, effects of boundary conditions,
pressure release mechanism of the foramen magnum and the spinal cord, verification of rotation and cavitation theories of
brain injury, and protective effects of helmets. These theoretical results provide a basic understanding of the internal biomechanical
responses of the head under various dynamic loading conditions. Basic experimental research is still needed to determine more
accurate material properties and injury tolerance criteria, so that FE models can fully exercise their analytical and predictive
power for the study and prevention of human head injury. 相似文献
983.
Johannes W. G. Jacobs MD PhD Agnes van der Heide MD Johannes J. Rasker MD PhD Johannes W. J. Bijlsma MD PhD 《Patient education and counseling》1993,20(2-3):121-132
Chronic arthritis may have great impact on the patient but also on his or her family, relatives and friends. The assessment of the consequences of chronic arthritis and the effect of therapy not only in terms of physical, but also psychological and social dimensions deserves more attention. Functional ability and health status can be measured using a questionnaire or ‘instrument’, high-lighting important aspects not quantified with more traditional measurements. In this paper, arguments to apply such instruments more frequently are given. Health status instruments can be used not only to assess beneficial but also deleterious (side-)effects of therapeutic interventions. The properties are summarized of the most frequently used instruments assessing functional ability and health status. Many of these instruments have been evaluated sufficiently for validity and reliability; their sensitivity to detect change seems to be satisfactory. Therefore it is advisable to choose an internationally accepted, frequently used instrument, reflecting the area of interest. 相似文献
984.
985.
Ichiya Yamazaki MD PhD Norihisa Karube MD PhD Tamitaro Soma MD Yasuharu Noishiki MD PhD Yukio Ichikawa MD PhD 《Journal of artificial organs》2005,8(1):67-70
The aim of this study was to test the safety and efficacy of fragmented autologous adipose tissue (FAT) grafts for revascularization in aortoiliac occlusive disease. Twenty-seven patients with atherosclerotic aortoiliac occlusive disease underwent surgical treatment using FAT grafts. A piece of adipose connective tissue was obtained from the operative wound, cut into small pieces, and pressed into the wall of a fabric vascular prosthesis. Cumulative primary patency rates were 92% at 1 year, 92% at 3 years, and 86% at 6 years. Cumulative secondary patency rates were 96%, 96%, and 90% for the same intervals. In this clinical study, the FAT grafts demonstrated good long-term patency rates and no particular problems. This is the first clinical report of long-term outcomes using FAT grafts for aortofemoral or aortoiliac bypasses. FAT grafts are thus safe for revascularization in aortoiliac occlusive disease. 相似文献
986.
987.
Benjamin B. Gelman MD PhD Dwayne A. Wolf MD PhD Juan Pablo Olano MD Lannette C. Linthicum MD 《Human pathology》1996,27(12):1282-1287
The Texas Department of Criminal Justice (TDCJ) houses many subjects with acquired immunodeficiency syndrome (AIDS) who receive medical care in a comprehensive AIDS treatment center. In this case-control autopsy survey, we compared pathological outcomes of TDCJ inmates treated at the center (n = 155) with nonincarcerated patients who died during the same period (n = 155). Using multiple regression analysis and a proportional hazards model, survival time in the prisoners was equivalent to that in the controls. With few exceptions, the prevalences of opportunistic viral, fungal, protozoal, and bacterial infections contributing to mortality were equivalent between groups. Mycobacterium tuberculosis was isolated more frequently in the inmates, and M avium intracellulare was isolated less frequently (P < .0001). The inmates had a higher prevalence of bacterial infection of the central nervous system (CNS) (9.1% v 1.4%; P < .006); half of all CNS bacterial infections were caused by M tuberculosis. Inmates had significantly lower prevalences of vacuolar myelopathy (P < .006) and severe wasting disease (P < .0009). We conclude that survival of prison inmates with AIDS treated in a comprehensive AIDS treatment center was equivalent to that of nonincarcerated subjects with AIDS. Prevalences of certain complications of AIDS differed in the inmates, showing that the prison environment influenced some of the underlying causes of AIDS morbidity and mortality. 相似文献
988.
We have developed a Joint Photographic Experts Group (JPEG) compatible image compression scheme tailored to the compression of digitized mammographic images. This includes a preprocessing step that segments the tissue area from the background, replaces the background pixels with a constant value, and applies a noise-removal filter to the tissue area. The process was tested by performing a just-noticeable difference (JND) study to determine the relationship between compression ratio and a reader's ability to discriminate between compressed and noncompressed versions of digitized mammograms. We found that at compression ratios of 15∶1 and below, image-processing experts are unable to detect a difference, whereas at ratios of 60∶1 and above they can identify the compressed image nearly 100% of the time. The performance of less specialized viewers was significantly lower because these viewers seemed to have difficulty in differentiating between artifact and real information at the lower and middle compression ratios. This preliminary study suggests that digitized mammograms are very amenable to compression by techniques compatible with the JPEG standard. However, this study was not designed to address the efficacy of image compression process for mammography, but is a necessary first step in optimizing the compression in anticipation of more elaborate reader performance (ROC) studies. 相似文献
989.
Core biopsies of the bone marrow are indispensable in the evaluation of fever of unknown etiology in human immunodeficiency virus-positive patients. We report two patients in whom visceral leishmaniasis was diagnosed based on the typical morphology, staining characteristics, and ultrastructure of the organisms. 相似文献
990.
The role of the complement system in innate immunity 总被引:4,自引:0,他引:4
Complement is a major component of innate immune system involved in defending against all the foreign pathogens through complement
fragments that participate in opsonization, chemotaxis, and activation of leukocytes and through cytolysis by C5b-9 membrane
attack complex. Bacterias and viruses have adapted in various ways to escape the complement activation, and they take advantage
of the complement system by using the host complement receptors to infect various cells. Complement activation also participates
in clearance of apoptotic cells and immune, complexes. Moreover at sublytic dose, C5b-9 was shown to promote cell survival.
Recently it was also recognized that complement plays a key role in adaptive immunity by modulating and modifying the T cell
responses. All these data suggest that complement activation constitutes a critical link between the innate and acquired immune
responses. 相似文献