全文获取类型
收费全文 | 939篇 |
免费 | 68篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 31篇 |
妇产科学 | 11篇 |
基础医学 | 151篇 |
口腔科学 | 16篇 |
临床医学 | 122篇 |
内科学 | 247篇 |
皮肤病学 | 10篇 |
神经病学 | 91篇 |
特种医学 | 37篇 |
外科学 | 113篇 |
综合类 | 5篇 |
预防医学 | 45篇 |
眼科学 | 9篇 |
药学 | 101篇 |
肿瘤学 | 17篇 |
出版年
2023年 | 21篇 |
2022年 | 31篇 |
2021年 | 49篇 |
2020年 | 35篇 |
2019年 | 52篇 |
2018年 | 53篇 |
2017年 | 25篇 |
2016年 | 41篇 |
2015年 | 35篇 |
2014年 | 47篇 |
2013年 | 54篇 |
2012年 | 62篇 |
2011年 | 61篇 |
2010年 | 31篇 |
2009年 | 32篇 |
2008年 | 56篇 |
2007年 | 50篇 |
2006年 | 35篇 |
2005年 | 39篇 |
2004年 | 26篇 |
2003年 | 23篇 |
2002年 | 20篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 15篇 |
1998年 | 8篇 |
1997年 | 5篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1975年 | 3篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1969年 | 2篇 |
1965年 | 1篇 |
1961年 | 1篇 |
1879年 | 1篇 |
排序方式: 共有1008条查询结果,搜索用时 15 毫秒
1.
Bente E. Moen Bjrg E. Hollund Morten Berntsen Ragnar Flo Knut Rasmus Kyvik Trond Riise 《American journal of industrial medicine》1995,27(4):555-564
Occupational exposure to carcinogenic agents on the decks on six Norwegian crude oil tankers was examined in five harbors. The purpose of the study was to evaluate the need for improving the working environment on deck on these tankers. Technical arrangments and the work itself on the deck were observed during loading or unloading. Occupational monitoring was performed by active sampling of benzene, polyaromatic hydrocarbons, and some aldehydes. The crew answered a questionnaire concerning their work, use of protective equipment, and occurrence of acute symptoms. The levels of air-borne carcinogenic agents were low, probably due to closed loading systems on all tankers. However, the seamen reported discomfort during the work that may be related to other chemical agents in the cargo. The seamen were frequently painting with lead chromate paint without using personal protective equipment. This type of chemical exposure should be evaluated. 相似文献
2.
Jan Sollenberg Rasmus Bjurström Kent Wrangskog Olof Vesterberg 《International archives of occupational and environmental health》1988,60(5):365-370
Summary Styrene exposure of 18 workers in fiber-glass reinforced plastic industries was measured for 30-min periods throughout each workday for a week. The styrene uptake was estimated using pulmonary ventilation measurements. All urine voidings were collected separately and the styrene metabolites, mandelic acid (MA) and phenylglyoxylic acid (PGA) were determined. The relationship between both exposure and uptake versus excretion of these metabolites was studied. Styrene metabolite concentrations and excretion rates (with 95% tolerance limits) were calculated to correspond to a constant 8-h exposure at the Swedish exposure limit level (25 ppm) or an uptake of an exposure limit related styrene dose (6.3 mmol). The tightest tolerance limits were obtained for excretion rate of MA + PGA per 24 h. The calculated biological exposure limit was 3.4 (± 0.7) mmol MA + PGA/24 h for a dose of 6.3 mmol styrene. 相似文献
3.
Kläning U Laursen TM Licht RW Kyvik KO Skytthe A Mortensen PB 《Journal of affective disorders》2004,81(2):141-145
BACKGROUND: A previous study demonstrated a higher rate of schizophrenia in dizygotic twins than in the general population, and a higher rate of schizophrenia in siblings of dizygotic twins than in siblings of monozygotic twins and singletons, pointing to a common genetic predisposition for dizygotic twinning and schizophrenia. The aim of the present study was to investigate whether these findings also apply to bipolar disorder. METHODS: Through record linkage between The Danish Twin Register, The Danish Psychiatric Central Register and The Danish Civil Registration System, the rate of bipolar disorder (diagnosed for the first time during admission to hospital) in dizygotic and monozygotic twins was compared with the rate in singletons, and the rate in siblings and parents of twins was compared with the rate in siblings and parents of singletons. RESULTS: The rate of bipolar disorder was the same in dizygotic twins, monozygotic twins and singletons as well as for parents and siblings of dizygotic twins, monozygotic twins and singletons. LIMITATIONS: The study is a register-based study, only including hospitalized patients. CONCLUSION: This study shows that there is an equal rate of bipolar disorder in twins and in singletons. Assuming that DZ twinning is under some genetic influence, a differential relationship between schizophrenia and DZ twinning on one hand and bipolar disorder and DZ twinning on the other hand may suggest differences in the genetic basis of the two diseases. The finding that the rate of bipolar disorder in monozygotic twins is the same as the rate of bipolar disorder in singletons supports studies finding no association between bipolar disorder and obstetric complications. 相似文献
4.
5.
High frequency of Coxsackie-B-virus-specific IgM in children developing type I diabetes during a period of high diabetes morbidity 总被引:2,自引:0,他引:2
G Frisk J Fohlman M Kobbah U Ewald T Tuvemo H Diderholm G Friman 《Journal of medical virology》1985,17(3):219-227
Twenty-four consecutive children with newly diagnosed insulin-dependent (type I) diabetes mellitus (IDDM) were investigated for a history of infectious disease. Thirteen of the 24 (54%) patients reported symptoms of acute infection within two months before diabetes was diagnosed. The mean age was 8.5 years and 15 (63%) of the patients were girls. No clear seasonal variation in onset was seen. Coxsackie B (CB)-virus-specific IgM responses were detected by reverse radioimmunoassay (RIA) in 16 of the 24 (67%) patients on the day of diagnosis of IDDM. The highest titre was usually recorded at that time, but with some the highest titre was found with a second serum obtained three to seven weeks after diagnosis. Thereafter the titres declined, and after six months IgM was detected only in a few patients. Thirteen patients displayed monotypic IgM responses, whereas three patients showed ditypic responses. Among the former, IgM was recorded against Coxsackie B4 (CB4) in four, B5 (CB5) in three, B1 (CB1) in two, B2 (CB2) in two, and B3 (CB3) in two patients. The ditypic responses were against CB2 and CB3, CB3 and CB4, and CB5. No CB-virus-specific IgM was detected in sera, found during the same period, from age-matched nondiabetic children without evidence of infection. In neutralisation (NT) tests, antibodies to the homotypic virus were found in 12 of the 16 diabetic patients showing CB-virus-specific at the time of diagnosis. A significant rise in NT titre was demonstrated in three of these patients. No significant clinical difference was noted between IgM positive and IgM negative patients.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
6.
Maurizio Severino Anja F. Pedersen Viktorija Trajkovska Ellen Christensen Rasmus Lohals Lone M. Veng Gitte M. Knudsen Susana Aznar 《Neuroscience letters》2007
Although loss of cholinergic neurons in the basal forebrain is considered a key initial feature in Alzheimer's disease (AD), changes in other transmitter systems, including serotonin and 5-HT2A receptors, are also associated with early AD. The aim of this study was to investigate whether elimination of the cholinergic neurons in the basal forebrain directly affects 5-HT2A receptor levels. For this purpose intraventricular injection of the selective immunotoxin 192 IgG-Saporin was given to rats in doses of either 2.5 or 5 μg. The rats were sacrificed after 1, 2, 4 and 20 weeks. 5-HT2A protein levels were determined by western techniques in frontal cortex and hippocampus. A significant 70% downregulation in frontal cortex and a 100% upregulation in hippocampus of 5-HT2A receptor levels were observed 20 weeks after the cholinergic lesion when using the highest dose of 192 IgG-Saporin. Our results show that cholinergic deafferentation leads to decreased frontal cortex and increased hippocampal 5-HT2A receptor levels. This is probably a consequence of the interaction between the serotonergic and the cholinergic system that may vary depending on the brain region. 相似文献
7.
8.
Wolf Rasmus Trap Ratcliffe Julie Chen Gang Jeppesen Pia 《Quality of life research》2021,30(6):1747-1756
Quality of Life Research - The Child Health Utility 9D (CHU9D) currently represents the only preference-based health-related quality-of-life instrument designed exclusively from its inception for... 相似文献
9.
Rasmus W. Licht Jytte O. Larsen Donald Smith Hans Brændgaard 《Psychopharmacology》1994,115(3):371-374
The present study used stereological methods to determine whether long-term administration of lithium, with or without haloperidol, affects the number and average volume of neocortical neurons. Twenty-five rats were divided into three groups and given no treatment, lithium, or lithium combined with haloperidol. Serum lithium levels ranged from 0.5 to 0.8 mmol/l. Haloperidol was injected intraperitoneally at a daily dose of 1 mg/kg. After 30 weeks of treatment, the animals were killed and the brains were prepared. Neocortical volume, density of neurons, total number of neurons and mean volume of neurons were estimated. As no differences were found between the groups, the present study provides no evidence for quantitative morphological changes in the cerebral cortex due to long-term therapeutic levels of lithium, with or without haloperidol. 相似文献
10.
Rasmus
. Thorsen Christiaan N. Hulleman Bernd Rieger Sjoerd Stallinga 《Biomedical optics express》2022,13(5):2835
Combining orientation estimation with localization microscopy opens up the possibility to analyze the underlying orientation of biomolecules on the nanometer scale. Inspired by the recent improvement of the localization precision by shifting excitation patterns (MINFLUX, SIMFLUX), we have adapted the idea towards the modulation of excitation polarization to enhance the orientation precision. For this modality two modes are analyzed: i) normally incident excitation with three polarization steps to retrieve the in-plane angle of emitters and ii) obliquely incident excitation with p-polarization with five different azimuthal angles of incidence to retrieve the full orientation. Firstly, we present a theoretical study of the lower precision limit with a Cramér-Rao bound for these modes. For the oblique incidence mode we find a favorable isotropic orientation precision for all molecular orientations if the polar angle of incidence is equal to degrees. Secondly, a simulation study is performed to assess the performance for low signal-to-background ratios and how inaccurate illumination polarization angles affect the outcome. We show that a precision, at the Cramér-Rao bound (CRB) limit, of just 2.4 and 1.6 degrees in the azimuthal and polar angles can be achieved with only 1000 detected signal photons and 10 background photons per pixel (about twice better than reported earlier). Lastly, the alignment and calibration of an optical microscope with polarization control is described in detail. With this microscope a proof-of-principle experiment is carried out, demonstrating an experimental in-plane precision close to the CRB limit for signal photon counts ranging from 400 to 10,000. 相似文献