全文获取类型
收费全文 | 25954篇 |
免费 | 1898篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 297篇 |
儿科学 | 1112篇 |
妇产科学 | 638篇 |
基础医学 | 3385篇 |
口腔科学 | 281篇 |
临床医学 | 2483篇 |
内科学 | 5054篇 |
皮肤病学 | 511篇 |
神经病学 | 2868篇 |
特种医学 | 725篇 |
外国民族医学 | 4篇 |
外科学 | 3523篇 |
综合类 | 234篇 |
一般理论 | 23篇 |
预防医学 | 2890篇 |
眼科学 | 482篇 |
药学 | 1460篇 |
1篇 | |
中国医学 | 27篇 |
肿瘤学 | 1894篇 |
出版年
2023年 | 363篇 |
2022年 | 556篇 |
2021年 | 1108篇 |
2020年 | 635篇 |
2019年 | 938篇 |
2018年 | 1044篇 |
2017年 | 723篇 |
2016年 | 740篇 |
2015年 | 754篇 |
2014年 | 959篇 |
2013年 | 1183篇 |
2012年 | 1809篇 |
2011年 | 1827篇 |
2010年 | 940篇 |
2009年 | 805篇 |
2008年 | 1284篇 |
2007年 | 1224篇 |
2006年 | 1082篇 |
2005年 | 1113篇 |
2004年 | 890篇 |
2003年 | 797篇 |
2002年 | 738篇 |
2001年 | 457篇 |
2000年 | 493篇 |
1999年 | 390篇 |
1998年 | 204篇 |
1997年 | 166篇 |
1996年 | 159篇 |
1995年 | 133篇 |
1994年 | 137篇 |
1993年 | 122篇 |
1992年 | 293篇 |
1991年 | 270篇 |
1990年 | 256篇 |
1989年 | 285篇 |
1988年 | 247篇 |
1987年 | 247篇 |
1986年 | 213篇 |
1985年 | 228篇 |
1984年 | 193篇 |
1983年 | 163篇 |
1982年 | 114篇 |
1981年 | 107篇 |
1979年 | 154篇 |
1978年 | 113篇 |
1976年 | 82篇 |
1975年 | 74篇 |
1974年 | 106篇 |
1973年 | 98篇 |
1972年 | 74篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
TG Berger F Kiesewetter C Maczek N Bauer M Lueftl G Schuler M Simon Jr 《Journal of the European Academy of Dermatology and Venereology》2006,20(2):178-183
Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis. 相似文献
23.
Michael Berger 《Child and Adolescent Mental Health》2006,11(2):64-75
The number and range of computer-based assessment procedures for children and young people have increased greatly over the past few years. Over this time as well, other technological advances have occurred with a potential for application in services for young people. This paper provides an overview of the range of applications of relevance to practitioners, with a focus on assessment. Some of the benefits and disadvantages of computerised procedures for test administration and report writing are considered. The paper concludes with an examination of the issue of access to tests and some of the implications of the introduction of other new technologies. 相似文献
24.
Paul A Dabisch Emily A Davis Michael S Horsmon Robert J Mioduszewski 《Journal of ocular pharmacology and therapeutics》2006,22(5):323-332
The organophosphorous nerve agent sarin (GB) and the carbamate pyridostigmine bromide (PB) both inhibit acetylcholinesterase (AChE), leading to overstimulation of muscarinic receptors. Both GB and PB produce miosis through stimulation of ocular muscarinic receptors. This study investigated 2 hypotheses: (1) that the miotic response to PB would decrease following repeated injections; and (2) that repeated administration of PB would result in tolerance to the miotic effect of GB vapor. Rats were injected intramuscularly with saline, 0.04 mg/kg, 0.5 mg/kg, or 1.4 mg/kg of PB twice daily for 8 consecutive days. After day 3, animals injected with 1.4 mg/kg PB developed miotic tolerance. Twenty-four (24) h following the final PB injection, the rats were exposed to GB vapor (4.0 mg/m(3)). A similar magnitude of miosis was observed in all groups after GB exposure. However, the rate of recovery of pupil size in animals pretreated with 0.5 and 1.4 mg/kg PB was significantly increased. Twenty (20) h following exposure to GB vapor, the pupils of animals pretreated with 1.4 mg/kg PB had recovered to 77% +/- 4% of their pre-exposure baseline, whereas the saline-injected controls had recovered to only 52% +/- 2% of their pre-exposure baseline. The increased rate of recovery does not appear to be a result of protection of pupillary muscarinic receptors by the higher doses of PB, as there was no longer PB present in the animal at the time of GB exposure. These results demonstrate the development of tolerance to the miotic effect of PB following repeated exposures, and also suggest that cross-tolerance between PB and GB occurs. However, because the magnitude of the response was not reduced, the PB pretreatment and its associated miotic cross-tolerance does not appear to diminish the effectiveness of miosis as a biomarker of acute exposure to nerve agent vapor. 相似文献
25.
26.
27.
Matthias Müller Joachim Berger Nikolaus Gersdorff Francesco Cecconi Rainer Herken Fabio Quondamatteo 《Developmental dynamics》2005,234(1):215-221
Apoptosis is an essential ubiquitous process that controls the duration of the life span of cells, thus playing a crucial role in morphogenetic, histogenetic, and phylogenetic developmental processes. Apaf1 (apoptosis protease activating factor 1) is one of the central mediators of the intrinsic apoptotic pathway and a part of the apoptosome, which activates procaspase-3 and promotes cell death. Gene knockout of Apaf1 in mice leads to late embryonic lethality with malformations such as the persistence of interdigital webs and hyperplasia of brain and retina. Therefore, Apaf1 is generally believed to play a crucial role in developmental apoptosis and have a widespread expression. However, its pattern of expression in early development remains unknown. To specify whether Apaf1 indeed plays this key role, we investigated the pattern of gene expression for Apaf1 in mouse embryos on day 7, 9, and 12 of development. Our results show, that gene expression for Apaf1 first occurs within the embryo between day 7 and 9 of development, becoming more widespread toward day 12 and then includes structures, such as yolk sac, mesenchyme, cartilage, heart anlage, otic vesicle, peridermis, and anlagen of the spinal ganglia and vertebral bodies. Our results also show that gene expression for Apaf1 is not ubiquitous in early mouse development. This finding indicates that cell death processes are independent of or less dependent on Apaf1 during this time. Of interest, an active gene expression for Apaf1 is also present in organ anlagen such as heart or intestine, in which no obvious phenotype is seen after Apaf1 deletion. This finding suggests a possible role for Apaf1 in such anlagen as a putative alternative compensatory pathway, which could be switched on in the case of defects in the mediators that are normally involved in such organs. 相似文献
28.
J. E. Hammond R. G. Berger T. S. Carey R. Rutledge T. J. Cleveland J. P. Kichak C. F. Ayscue 《Journal of medical systems》1991,15(3):257-267
Many hospitals today have implemented widely disparate information systems on mainframe and mini-computer hardware. The advent of network technology in hospitals has made it possible to access information in these systems. Unfortunately, the user interfaces to applications on these systems are unique and difficult to learn, which makes them unsuitable for use by clinical services. In this paper we describe the development of a Physician's Workstation which integrates information from multiple existing information systems and discuss how the workstation makes it possible to move from the departmental systems of the present to the computer-based medical record system of the future. 相似文献
29.
30.
The influence of different levels of dietary fat on the incidence and growth of MNU-induced mammary carcinoma in rats 总被引:1,自引:0,他引:1
This study describes the influence of isocalorically fed diets (containing different amounts of fat) on tumor incidence and parameters of fat metabolism in female Sprague-Dawley rats. Comparisons are made between rats induced with methylnitrosourea (25 mg/kg body wt) and untreated controls (Group I). The animals received either control diets (3.9% fat by weight, Groups I and II) or fat-enriched diets (10.7%, Group III; 15.6%, Group IV; 21.4%, Group V) over a period of 180 days. At the termination of the experiment, intake of the diet containing 10.7% fat by weight (24% fat per total calories) was associated with the highest tumor incidence. Comparing the different diets, liver lipid concentrations in the individual groups increased with increasing dietary fat, whereas the total lipid in plasma decreased. During the feeding period, total lipid of the liver and plasma, and plasma cholesterol, increased in all groups, but triglycerides of plasma decreased. However, when plasma cholesterol and triglycerides were calculated as a relative amount of total lipid in plasma, cholesterol was found to be significantly decreased in Groups III and IV, and triglycerides were increased in Group III but decreased significantly in Groups I, II, and V at the end of the experiment. 相似文献