全文获取类型
收费全文 | 3520篇 |
免费 | 297篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 107篇 |
妇产科学 | 77篇 |
基础医学 | 566篇 |
口腔科学 | 36篇 |
临床医学 | 382篇 |
内科学 | 823篇 |
皮肤病学 | 49篇 |
神经病学 | 329篇 |
特种医学 | 115篇 |
外科学 | 400篇 |
综合类 | 32篇 |
一般理论 | 4篇 |
预防医学 | 262篇 |
眼科学 | 78篇 |
药学 | 219篇 |
中国医学 | 12篇 |
肿瘤学 | 309篇 |
出版年
2024年 | 9篇 |
2023年 | 36篇 |
2022年 | 89篇 |
2021年 | 147篇 |
2020年 | 79篇 |
2019年 | 104篇 |
2018年 | 130篇 |
2017年 | 94篇 |
2016年 | 122篇 |
2015年 | 140篇 |
2014年 | 159篇 |
2013年 | 195篇 |
2012年 | 302篇 |
2011年 | 276篇 |
2010年 | 169篇 |
2009年 | 145篇 |
2008年 | 209篇 |
2007年 | 173篇 |
2006年 | 183篇 |
2005年 | 195篇 |
2004年 | 170篇 |
2003年 | 165篇 |
2002年 | 141篇 |
2001年 | 40篇 |
2000年 | 26篇 |
1999年 | 28篇 |
1998年 | 36篇 |
1997年 | 23篇 |
1996年 | 18篇 |
1995年 | 19篇 |
1994年 | 19篇 |
1993年 | 13篇 |
1992年 | 20篇 |
1991年 | 12篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 11篇 |
1986年 | 12篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1979年 | 4篇 |
1978年 | 13篇 |
1977年 | 9篇 |
1976年 | 8篇 |
1975年 | 12篇 |
1974年 | 5篇 |
1968年 | 5篇 |
排序方式: 共有3832条查询结果,搜索用时 25 毫秒
71.
Ultrafine grained sheets were prepared from a twin-roll cast AA8006 aluminium alloy using accumulative roll-bonding process at room temperature. The evolution of microstructure of sheets after three accumulative roll-bonding passes during isochronal annealing with a constant step of 20 °C/20 min was studied by light and electron microscopy. The influence of the resulting microstructure on mechanical properties was monitored by microhardness measurements. The microhardness increases when the material is annealed up to 160 °C. Above this temperature a fast drop of microhardness occurs followed by a negligible variation at annealing temperatures exceeding 300 °C. In order to map continuously the microstructure changes during annealing, the in situ TEM experiments in the heating stage were performed as a supplement to post-mortem TEM observations. 相似文献
72.
Background
Longitudinal studies are of aetiological and public health relevance but can be undermined by attrition. The aim of this paper was to identify effective retention strategies to increase participation in population-based cohort studies. 相似文献73.
Mathieu Collette Carlo Palombo Carmela Morizzo Sara Sbragi Michaela Kozakova Georges Leftheriotis 《Ultrasound in medicine & biology》2017,43(6):1187-1194
Described here is a new method for determination of carotid–femoral pulse wave velocity (PWV) based on arterial diameter waveform recording by an ultrasound system. The study was carried out on 120 consecutive patients. Carotid–femoral PWV was determined using a tonometric technique (PWVpp, PulsePen, DiaTecne, Milan, Italy) and an echotracking ultrasound system (PWVet, E-Track, Aloka, Tokyo, Japan). The relationship between PWVpp and PWVet was evaluated by linear regression and Bland–Altman analysis. There was excellent agreement between PWVet and PWVpp (Pearson's r = 0.94, 95% confidence interval: 0.91–0.96, p < 0.0001; PWVet = 0.88 × PWVpp + 0.57). The Bland–Altman plot revealed an offset of ?0.33 m/s with limits of agreement from ?2.21 to 1.54 m/s. The coefficients of variation for within-subject repeatability between PWVet and PWVpp had were 5.79% and 8.47%, respectively, without significant differences in the Bland–Altman analysis. The results suggest that echotracking technology can provide a reliable estimate of aortic stiffness comparable to that of the tonometric techniques. 相似文献
74.
Human Secretory IgM Antibodies Activate Human Complement and Offer Protection at Mucosal Surface
下载免费PDF全文
![点击此处可从《Scandinavian journal of immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
T. E. Michaelsen S. Emilsen R. H. Sandin B. K. Granerud D. Bratlie O. Ihle I. Sandlie 《Scandinavian journal of immunology》2017,85(1):43-50
IgM molecules circulate in serum as large polymers, mainly pentamers, which can be transported by the poly‐Ig receptor (pIgR) across epithelial cells to mucosal surfaces and released as secretory IgM (SIgM). The mucosal SIgM molecules have non‐covalently attached secretory component (SC), which is the extracellular part of pIgR which is cleaved from the epithelial cell membrane. Serum IgM antibodies do not contain SC and have previously been shown to make a conformational change from ‘a star’ to a ‘staple’ conformation upon reaction with antigens on a cell surface, enabling them to activate complement. However, it is not clear whether SIgM similarly can induce complement activation. To clarify this issue, we constructed recombinant chimeric (mouse/human) IgM antibodies against hapten 5‐iodo‐4‐hydroxy‐3‐nitro‐phenacetyl (NIP) and in addition studied polyclonal IgM formed after immunization with a meningococcal group B vaccine. The monoclonal and polyclonal IgM molecules were purified by affinity chromatography on a column containing human SC in order to isolate joining‐chain (J‐chain) containing IgM, followed by addition of excess amounts of soluble SC to create SIgM (IgM J+ SC+). These SIgM preparations were tested for complement activation ability and shown to be nearly as active as the parental IgM J+ molecules. Thus, SIgM may offer protection against pathogens at mucosal surface by complement‐mediated cell lysis or by phagocytosis mediated by complement receptors present on effector cells on mucosa. 相似文献
75.
Ralf Jürgens Jonathan Cohen Edwin Cameron Scott Burris Michaela Clayton Richard Elliott Richard Pearshouse Anne Gathumbi Delme Cupido 《Reproductive Health Matters》2009,17(34):163-172
Recent years have seen a push to apply criminal law to HIV exposure and transmission, often driven by the wish to respond to concerns about the ongoing rapid spread of HIV in many countries. Particularly in Africa, some groups have begun to advocate for criminalization in response to the serious phenomenon of women being infected with HIV through sexual violence or by partners who do not reveal their HIV diagnoses to them. While these issues must be urgently addressed, a closer analysis of the complex issues raised by criminalization of HIV exposure or transmission reveals that criminalization is unlikely to prevent new infections or reduce women's vulnerability to HIV. In fact, it may harm women rather than assist them, and have a negative impact on public health and human rights. This paper is a slightly revised version of a document originally released in December 2008 by a coalition of HIV, women's and human rights organizations. It provides ten reasons why criminalizing HIV exposure or transmission is generally an unjust and ineffective public policy. The obvious exception involves cases where individuals purposely or maliciously transmit HIV with the intent to harm others. In these rare cases, existing criminal laws – rather than new, HIV-specific laws – can and should be used. 相似文献
76.
Niehues T Horneff G Michels H Höck MS Schuchmann L;Working Groups Pediatric Rheumatology Germany 《Rheumatology international》2005,25(3):169-178
Juvenile idiopathic arthritis (JIA) is the most common diagnosis in children and adolescents with rheumatic disorders. In many children and adolescents, JIA is successfully treated with non-steroidal anti-inflammatory drugs (NSAID) and physiotherapy. However, in a significant number of cases the disease is resistant to this therapy, and treatment with second line disease-modifying antirheumatic drugs (DMARDs) is required. Methotrexate (MTX) is frequently referred to as first-choice second-line agent for the treatment of JIA. To increase drug safety, the Working Groups for Children and Adolescents with Rheumatic Diseases in Germany (AGKJR) and Pediatric Rheumatology Austria have initiated the formulation of evidence-based recommendations. Evidence is based on consensus expert meetings, a MEDLINE search with the key words Methotrexate and juvenile arthritis limited to age 0–18 years, standard textbooks and review articles, data from the central registry of the German Research Center for Rheumatic Diseases (Deutsches Rheumaforschungszentrum Berlin DRFZ), experience with MTX in adults with rheumatoid arthritis (RA), and recommendations of the German Society of Rheumatology (DGRh). Based on these data, evidence and recommendations are graded, and evidence-based recommendations for the use of MTX in children and adolescents with rheumatic disease are presented.Section Pharmacotherapy of the Working Group Pediatric Rheumatology Germany and Austria: I. Foeldvari; J.P. Haas, A. Haeffner, D. Hobusch,G. Horneff, A. Hospach, R. Keitzer, G. Klaus, M. Metzler, H. Michels, T. Niehues, I. Pilz, M. Sailer Höck, M. Schöntube, L. Schuchmann, K. Schumacher, H.W. Seyberth, E. Siemers, A. Urban, E. Weißbarth-Riedl. Working Group Pediatric Rheumatology North-Rhine-Westfalia: S. Benseler, G. Bürk, S. Fahl, I. Foeldvari, D. Föll, M. Frosch, G. Ganser, S. Kastner, I. Kleine, E. Lainka, K. Mönkemöller, J. Neubert, U. Neudorf, T. Niehues, J. Roth, S. Seeliger, N. Wagner, R. Wieland, H. Winowski. 相似文献
77.
78.
Stamm TA Cieza A Coenen M Machold KP Nell VP Smolen JS Stucki G 《Arthritis and rheumatism》2005,53(3):431-439
OBJECTIVE: To validate the International Classification of Functioning, Disability and Health (ICF) Comprehensive Core Set for Rheumatoid Arthritis (RA) from the patient perspective. METHODS: Patients with RA were interviewed about their problems in daily functioning. Interviews were tape recorded and transcribed verbatim. Interview texts were divided into meaning units. The concepts contained in these meaning units were linked to the ICF according to 10 established linking rules. Of the transcribed data, 15% were analyzed and linked by a second health professional. The degree of agreement was calculated using the kappa statistic. RESULTS: Twenty-one patients were interviewed. Two hundred twenty different concepts contained in 367 meaning units were identified in the qualitative analysis of the interviews and linked to 109 second-level ICF categories. Of the 76 second-level categories from the ICF RA Core Set, 63 (83%) were also found in the interviews. Twenty-five second-level categories, which are not part of the current ICF RA Core Set, were identified in the interviews. The result of the kappa statistic for agreement was 0.62 (95% boot-strapped confidence interval 0.59-0.66). CONCLUSION: The validity of the ICF RA Core Set was supported by the perspective of individual patients. However, some additional issues raised in this study but not covered in the current ICF RA Core Set need to be investigated. 相似文献
79.
80.
Simunek T Sterba M Popelova O Kaiserova H Potacova A Adamcova M Mazurova Y Ponka P Gersl V 《Hemoglobin》2008,32(1-2):207-215
The risk of cardiotoxicity is the main drawback of anthracycline antibiotics. However, these drugs remain among the most effective and frequently used anti cancer drugs. In this study we aimed to assess the cardioprotective effects of aroylhydrazone iron (FE) chelators: pyridoxal isonicotinoyl hydrazone (PIH) and its two analogs: salicyladehyde isonicotinoyl hydrazone (SIH) and pyridoxal o-chlorbenzoyl hydrazone (o-108). In rabbits, chronic treatment with daunorubicin (DAU) (3 mg/kg weekly for 10 weeks) induced mortality (33%) as well as left ventricular (LV) dysfunction. Co-administrations of PIH (25 mg/kg, i.p.), SIH hydrochloride [1 mg/kg, iv] as well as o-108 (10 mg/kg, i.p.), fully prevented premature deaths and most of the DAU-induced functional impairments were significantly suppressed. However, when 2- to 2.5-fold higher doses of the chelators were used, they led to rather paradoxical and mostly negative results regarding both cardioprotection and overall mortality. 相似文献