全文获取类型
收费全文 | 1761篇 |
免费 | 111篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 116篇 |
妇产科学 | 20篇 |
基础医学 | 346篇 |
口腔科学 | 39篇 |
临床医学 | 183篇 |
内科学 | 389篇 |
皮肤病学 | 8篇 |
神经病学 | 172篇 |
特种医学 | 62篇 |
外科学 | 193篇 |
综合类 | 17篇 |
预防医学 | 170篇 |
眼科学 | 18篇 |
药学 | 53篇 |
肿瘤学 | 81篇 |
出版年
2023年 | 7篇 |
2022年 | 31篇 |
2021年 | 33篇 |
2020年 | 26篇 |
2019年 | 25篇 |
2018年 | 18篇 |
2017年 | 39篇 |
2016年 | 34篇 |
2015年 | 48篇 |
2014年 | 55篇 |
2013年 | 75篇 |
2012年 | 122篇 |
2011年 | 122篇 |
2010年 | 55篇 |
2009年 | 67篇 |
2008年 | 130篇 |
2007年 | 113篇 |
2006年 | 136篇 |
2005年 | 87篇 |
2004年 | 105篇 |
2003年 | 127篇 |
2002年 | 106篇 |
2001年 | 34篇 |
2000年 | 16篇 |
1999年 | 24篇 |
1998年 | 27篇 |
1997年 | 16篇 |
1996年 | 9篇 |
1995年 | 16篇 |
1994年 | 11篇 |
1993年 | 10篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 12篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1977年 | 6篇 |
1972年 | 9篇 |
1971年 | 4篇 |
1969年 | 2篇 |
1967年 | 3篇 |
排序方式: 共有1878条查询结果,搜索用时 15 毫秒
1.
Epilepsy After Stroke 总被引:48,自引:4,他引:44
A retrospective follow-up of 200 consecutive stroke patients [ischemic brain infarction (IBI) 157, intracerebral hemorrhage (ICH) 20, subarachnoid hemorrhage (SAH) 23] who were in need of ambulatory rehabilitation was conducted for a mean period of 40 months after stroke. Epilepsy developed in 33 (17%) patients. The occurrence of epilepsy was 14% in IBI, 15% in ICH, and 35% in SAH. Significantly more patients developed epilepsy in the SAH group than in the IBI group (8 of 23 vs. 22 of 157, p less than 0.05). Of the 33 patients, 15% had their first seizures within the first 2 weeks after stroke, and 55% developed epilepsy in 6 months. Forty-eight percent of the patients had generalized seizures. Antiepileptic drug (AED) treatment was started in 28 of 33 patients, of whom 17 still had seizures during follow-up. Epilepsy was an important consequence of stroke among patients who needed rehabilitation, especially in SAH patients. In most, this was due to arterial spasm leading to IBI. 相似文献
2.
Evaluation of serological methods for diagnosis of Puumala hantavirus infection (nephropathia epidemica). 总被引:4,自引:2,他引:2
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
K B Sjlander F Elgh H Kallio-Kokko O Vapalahti M Hgglund V Palmcrantz P Juto A Vaheri B Niklasson A Lundkvist 《Journal of clinical microbiology》1997,35(12):3264-3268
Nephropathia epidemica (NE), Puumala (PUU) virus infection, is a febrile disease which is commonly associated with acute renal impairment. To differentiate NE from other acute febrile illnesses, a rapid and reliable serological diagnosis is important, and a number of different protocols have recently been introduced. In the present report we describe a comparative evaluation of six PUU virus immunoglobulin M (IgM) and seven IgG enzyme-linked immunosorbent assay (ELISA) protocols based on native, Escherichia coli-expressed, or baculovirus-expressed nucleocapsid protein (N). Neutralization and immunofluorescence assays were included for comparison. Equally high sensitivities and specificities were obtained with three mu-capture-based IgM ELISAs using native, baculovirus-expressed, and E. coli-expressed N antigens, respectively, and by an ELISA based on purified E. coli-expressed full-length N adsorbed to solid phase. The assays based on truncated amino-terminal N proteins, including a commercially available PUU virus IgM ELISA, all showed lower sensitivities. For detection of PUU virus-specific IgG, ELISAs based on monoclonal antibody-captured native or baculovirus-expressed N antigens showed optimal sensitivities and specificities, while the assays based on E. coli-expressed N did not detect all PUU virus IgG-positive serum samples. A commercially available PUU virus IgG ELISA based on E. coli-expressed amino-terminal N showed a significantly lower sensitivity than those of all other IgG assays. 相似文献
3.
Petri S. Mattila Jan Schugk Hongyan Wu Olli Mkel 《European journal of immunology》1995,25(9):2578-2582
During the initial stages of B lymphocyte differentiation heavy chain variable (VH), diversity (DH) and joining (JH) gene segments recombine to form a functional heavy chain variable region (VDJ) gene. Evidence for genetic polymorphism of the human JH gene segments has been obtained from mature rearranged VDJ sequences. We conducted an analysis of the published rearranged JH gene sequences and found that the JH alleles present in the two published germ-line JH region sequences were rare (approx. 2%) in the rearranged sequences. As an attempt to explain this discrepancy a 2.5-kb strech of DNA containing all the six heavy chain JH region genes and the most 3' DH gene segment, DHQ52, was amplified by the polymerase chain reaction from 39 individuals and analyzed for restriction fragment length polymorphism. Five new JH region haplotypes were found and sequenced. These new haplotypes contained the coding segment alleles that were frequent in antibody genes. Surprisingly, a high number of interallelic differencies in the non-coding sequence was found between the new and the two previously published haplotypes implying that the haplotypes had been separated early in evolution. In this respect the JH locus resembles HLA loci. 相似文献
4.
HEALTH CARE RESEARCH: WHAT IS IT ABOUT? 总被引:1,自引:0,他引:1
5.
Several V genes participate in the early phenyloxazolone response in various combinations 总被引:4,自引:0,他引:4
Seventeen monoclonal anti-2-phenyloxazolone antibodies from the early (day 7) primary response were partially sequenced with an mRNA method. Ten antibodies expressed the VH-Ox1 gene. The remaining seven express at least four but probably six different germ-line VH genes belonging to Dildrop's groups 1, 5, 6 and 7 (Immunol. Today 1984. 5: 85). Two of them have been met before in other antibodies, one (group 6) in J606 and the other (group 7) in antibodies to the influenza virus hemagglutinin. Eleven kappa chains were partially sequenced and five of them (all VH-Ox1 antibodies) express the V kappa-Ox1 gene. One expresses another germ-line gene of the V kappa-Ox1 family, one the V kappa 89.4 gene, three the V kappa 45.1 gene and one a new V kappa gene. The V kappa 45.1 gene was found to form anti-phOx antibodies with two new VH genes. The frequency of somatic mutations in day 7 antibodies was estimated by comparing germ-line sequences and antibody sequences. It is low (one mutation per 2500 nucleotides sequenced), twenty times lower than in antibodies obtained a week later. Two anti-idiotype antisera (495 and 260) are useful in the typing of monoclonal antibodies. 260 bound only to antibodies coded by both VH-Ox1 and V kappa-Ox1 genes. 495 bound strongly to antibodies coded by the VH-Ox1 gene and weakly to antibodies coded by the (related) VH101 gene regardless of the light chain partner. 相似文献
6.
Estimation of genetic risk for type 1 diabetes 总被引:8,自引:0,他引:8
Ilonen J Sjöroos M Knip M Veijola R Simell O Akerblom HK Paschou P Bozas E Havarani B Malamitsi-Puchner A Thymelli J Vazeou A Bartsocas CS 《American journal of medical genetics》2002,115(1):30-36
The most important gene loci defining risk of type 1 diabetes mellitus (T1DM) are located within the HLA gene region. HLA-DQ molecules are of primary importance but HLA-DR gene products modify the risk conferred by HLA-DQ. The risk associated with an HLA genotype is defined by the particular combination of susceptible and protective alleles. The highest risk is associated with a combination of two different risk haplotypes (7% risk to develop T1DM in Finland) whereas protective genotypes covering 69% of population have a risk of less than 0.2%). The complicated analysis of HLA genotypes is simplified by strong linkage disequilibrium between HLA-DRB1, -DQA1 and -DQB1 loci. In many cases one can deduce the alleles of other loci based on determination of the alleles in one locus. Differences between various populations in the frequency of marker alleles and in the linkages between them has to be taken into account. We have developed PCR based typing methods that utilize blood spot samples, microtiter plate format and lanthanide labeled oligonucleotide probes to define HLA-DQ and -DR alleles relevant for T1DM risk. Typing is run stepwise so that after initial HLA-DQB1 typing only those samples will be further analyzed in which -DQA1 or -DRB1 typing is informative and expected to contribute to the risk estimation. This method has been used to screen more than 50,000 newborn infants in Finland over a time period of 6 years, and it has been able to identify most children who have developed T1D during the follow-up period. The efficiency of the procedure has also been tested in Finnish and Greek populations. 相似文献
7.
Summary The human fetal carotid body was studied using both histochemical and electron microscopic methods. The glomus cells of a mid term fetal carotid body evidently contain catecholamines. This was demonstrated both by formaldehyder-induced fluorescence of the cells and by the presence of typical dense-cored vesicles (diameter 1430–3200 Å) in the cytoplasm of the chief cells. The glomus cells were densely innervated and the synapses found on their surface were probably cholinergic in type, containing agranular synaptic vesicles measuring 400–700 Å in diameter with a few dense-cored vesicles measuring 900 to 1300 Å. Synapses were not found in any other cell type within the glomus caroticum. The prominent feature of the glomus cell cytoplasm was the presence of the dense-cored vesicles. The density of the vesicular core varied only slightly from cell to cell. There were no perceptible differences in vesicular size between the different cells. The glomus cells were mostly surrounded by the processes of the sustentacular cells, which usually also surrounded the capillary walls. No glomus cells were ever found in direct contact with the capillary wall. The capillaries were wide and very numerous over the restricted area of the organ. They formed sinusoidal loops, probably anastomosing with each other. Finally, the features of the fine structure are discussed, correlating the present findings with our knowledge about the adult functional carotic body. 相似文献
8.
Hemagglutination by BK Virus, a Tentative New Member of the Papovavirus Group 总被引:5,自引:0,他引:5
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Some characteristics of hemagglutination (HA) by the BK virus, a new candidate for the papovavirus group, have been studied. Hemagglutinin prepared from cell cultures was found to be partially masked by inhibitors which could be dissociated from the virus by incubation at 37 C or by fluorocarbon extraction. Optimal conditions for HA are outlined. In routine tests, 0.5% human erythrocytes were used. The reaction was carried out at pH 7.0 on ice-water slurry. BK hemagglutinin receptors on human erythrocytes were found to be more resistant to neuraminidase than polyoma receptors. By gradient centrifugation analysis, two types of particles were found to be responsible for HA: (i) full, deoxyribonucleic acid-containing particles with a density of 1.325 g/cm(3) and (ii) empty capsids with a density 1.29 g/cm(3). Based on particle counting, one HA unit was calculated to correspond to 3 x 10(6) virus particles. 相似文献
9.
Solid-phase immunoassay-derived antibody titers are often converted to weight unit concentrations with the aid of standard sera containing known antibody concentrations. Systematic studies justifying this procedure have not yet been published. We therefore investigated the magnitude of errors associated with this conversion. Antibody concentrations of thirteen sera or ascites fluids were determined by quantitative precipitation or equlibrium dialysis, and one was then used as a “standard antibody” for the others in solid-phase radioimmunoassay (SP-RIA) or enzyme-linked immunosorbent (ELISA) assays. Antibody concentrations determined by the conventional solid-phase assay (the “standard serum” has the same specificity as the “sample”) had up to fourfold errors. These errors could be reduced by basing the conversion on the combination of two standard sera instead of one. The possibility was studied of whether the conversion to weight units could be done with the aid of a standard serum directed to a different antigen than the sample antibody. Errors associated with the use of such a heterologous standard were not significantly greater than those found using the conventional conversion. A combination of two reference sera again reduced the errors. The use of such heterologous standard(s), however, requires checking the binding capacity of the antigen coats. 相似文献
10.