全文获取类型
收费全文 | 1576篇 |
免费 | 172篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 12篇 |
妇产科学 | 2篇 |
基础医学 | 406篇 |
口腔科学 | 38篇 |
临床医学 | 110篇 |
内科学 | 337篇 |
皮肤病学 | 15篇 |
神经病学 | 98篇 |
特种医学 | 19篇 |
外科学 | 266篇 |
综合类 | 4篇 |
预防医学 | 32篇 |
眼科学 | 10篇 |
药学 | 149篇 |
中国医学 | 5篇 |
肿瘤学 | 232篇 |
出版年
2021年 | 42篇 |
2020年 | 14篇 |
2019年 | 11篇 |
2018年 | 13篇 |
2017年 | 11篇 |
2016年 | 22篇 |
2015年 | 25篇 |
2014年 | 41篇 |
2013年 | 35篇 |
2012年 | 44篇 |
2011年 | 64篇 |
2010年 | 28篇 |
2009年 | 21篇 |
2008年 | 37篇 |
2007年 | 61篇 |
2006年 | 51篇 |
2005年 | 43篇 |
2004年 | 56篇 |
2003年 | 58篇 |
2002年 | 49篇 |
2001年 | 74篇 |
2000年 | 56篇 |
1999年 | 60篇 |
1998年 | 26篇 |
1997年 | 27篇 |
1996年 | 15篇 |
1995年 | 15篇 |
1994年 | 17篇 |
1993年 | 10篇 |
1992年 | 56篇 |
1991年 | 57篇 |
1990年 | 67篇 |
1989年 | 58篇 |
1988年 | 61篇 |
1987年 | 69篇 |
1986年 | 60篇 |
1985年 | 50篇 |
1984年 | 39篇 |
1983年 | 40篇 |
1982年 | 19篇 |
1981年 | 15篇 |
1980年 | 12篇 |
1979年 | 29篇 |
1978年 | 9篇 |
1977年 | 15篇 |
1973年 | 7篇 |
1971年 | 7篇 |
1969年 | 10篇 |
1967年 | 7篇 |
1966年 | 7篇 |
排序方式: 共有1763条查询结果,搜索用时 15 毫秒
1.
Nagai Masahiro Nishikawa Noriko Yabe Hayato Moritoyo Hiroyoko Moritoyo Takashi Shigematsu Yuji Nomoto Masahiro 《Journal of neurology》2007,254(4):IV54-IV57
Journal of Neurology - A high incidence of valvular heart disease in Parkinson's disease (PD) patients treated with ergot-derived dopamine agonists, such as cabergoline and pergolide, has been... 相似文献
2.
OBJECTIVE: The aim of this study was to evaluate the relationship between the degree of conversion (DC) of composites and the light intensity using LED-curing units and also to determine the amount of exposure required to achieve optimal curing. METHOD: The light outputs of light-curing units and the depths of cure of composites exposed to these units were determined using the methods outlined in modified ISO standards, ISO/TS10650 and ISO 4049, respectively. The distributions of DC in composites were investigated by IR spectra of microareas obtained at various depths from the irradiated surface of thin specimens cut out from the cured composites. IR spectra were measured using a Fourier transform infrared spectrometer equipped with a microscopic unit. DC was calculated from the changes in the amount of C=C double bonds in the IR spectra. RESULTS: The light intensity at various depths through the cured composite was calculated from the attenuation coefficient of each material, obtained from the linear relationship between the depth of cure and the logarithm of the amount of exposure, which is defined as the product of the irradiance and irradiation time. There was a third or fourth order regression relationship between DC and the logarithm of total light energy at a particular depth. SIGNIFICANCE: The minimum light energy required to produce a saturated DC was about 1000 s mW/cm2. 相似文献
3.
Transient depletion of nucleus accumbens dopamine content may contribute to initial akinesia induced by MPTP in common marmosets 总被引:2,自引:0,他引:2
Acute treatment of common marmosets with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) caused an initial profound akinesia and other motor deficits. However, over the following months akinesia gradually disappeared although the animals remained clumsy and poorly coordinated. At 10 days following MPTP treatment there was a profound decrease in the dopamine, HVA and DOPAC content of the caudate nucleus, putamen and nucleus accumbens. By 3-4 months following MPTP treatment the animals had largely recovered from their akinesia, but the caudate nucleus and putamen dopamine, HVA and DOPAC content remained low. In contrast, the dopamine content of the nucleus accumbens had returned towards normal and the metabolite levels were higher than at 10 days. No overall alterations in 5HT or 5HIAA levels were observed at either time point. The transient and reversible nature of dopamine loss in the nucleus accumbens may contribute to the initial profound akinesia exhibited by common marmosets treated with MPTP. The restoration of dopamine levels in the nucleus accumbens may be partially responsible for the subsequent recovery of motor function that occurs in MPTP-treated marmosets. 相似文献
4.
A Nomoto 《Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan》1989,109(9):622-635
Molecular genetic studies of the antigenicity and the attenuation phenotype of type 1 poliovirus were described. Antigenic sites were identified on the genome of type 1 poliovirus by the determination of nucleotide sequence of the genome of variants that were not neutralized by the neutralizing monoclonal antibodies. The solution of the crystal structure of poliovirus revealed that all mutations found as above are located at the surface of the virion and cluster into three distinct sites. These regions probably represent distinct antibody binding sites. To study expression of the attenuation phenotype of type 1 poliovirus, a number of recombinant polioviruses were constructed in vitro by using infectious complementary deoxyribonucleic acid clones of the virulent Mahoney and attenuated Sabin 1 strains of type 1 poliovirus. Biological tests including a monkey neurovirulence test were performed on the recombinants. The results indicated that the 5' noncoding region harbors a relatively strong determinant influencing the attenuation. Further studies revealed that an adenine residue (Mahoney type) at nucleotide position 480 importantly contribute to the expression of the neurovirulence phenotype. However, a guanine residue (Sabin 1 type) at position 480 was not sufficient for full expression of the attenuation phenotype encoded by this genome region. These results suggested that the expression of the attenuation phenotype depends on the highly ordered structure formed in the 5' noncoding sequence and that the formation of such a structure is possibly influenced by the nucleotide position 480. To investigate the structure and function of the 5' noncoding region, many insertion and deletion sequences were introduced into the genome region. Replication processes of the mutants were analysed and second-site mutations in the genome of the variants that partially restored the phenotypes of the parental viruses were identified. The results indicated that interactions between different loci, for example at around positions 200 and 500, are important for maintaining the viral replication efficiency. 相似文献
5.
Kohji Nagata Michiko Horinouchi Miyuki Saitou Michiyo Higashi Mitsuharu Nomoto Masamichi Goto Suguru Yonezawa 《Journal of hepato-biliary-pancreatic sciences》2007,14(3):243-254
In this review article, we demonstrate the mucin expression profile in normal tissue, invasive ductal carcinoma (IDC), two subtypes of intraductal papillary–mucinous neoplasm (IPMN dark cell type and IPMN clear cell type), pancreatic intraepithelial neoplasia (PanIN), and mucinous cystic neoplasm (MCN) of the pancreas. In MUC1, there are various glycoforms, such as poorly glycosylated MUC1, sialylated MUC1, and fully glycosylated MUC1. IDCs showed high expression of all the glycoforms of MUC1. IPMNs dark cell type showed no expression or low expression of all the glycoforms of MUC1. IPMNs clear cell type showed low expression of poorly glycosylated MUC1, but expression of sialylated MUC1 and fully glycosylated MUC1. Expression of MUC2 was negative in IDCs, high in IPMNs dark cell type and low in IPMNs clear cell type. MUC5AC was highly expressed in IDCs, IPMNs dark cell type, and IPMNs clear cell type. MUC6 expression was higher in IPMNs clear cell type than in IDCs and IPMNs dark cell type. Our recent study demonstrated that high expression of MUC4 in IDCs is correlated with a poor outcome for patients. In PanINs, expression of both MUC5AC and MUC6 are an early event, whereas up-regulation of MUC1 is a late event. MCNs do not look as if they will show a specific mucin expression profile according to the literature review. 相似文献
6.
Long-term effect of urokinase therapy in IgA nephropathy 总被引:4,自引:0,他引:4
Effects of urokinase (UK) therapy in patients with moderate to advanced degrees of IgA nephropathy (IgAN) were examined. Twenty-seven patients were treated by "two weeks" UK administration, 14 patients were treated by "consecutive" UK administration and 16 patients were treated by antiplatelet drugs. There were marked improvements in urinary protein concentration, serum creatinine and blood urea nitrogen after UK therapy, especially in patients treated by "consecutive" UK administration which was performed by "single shot" UK injection. Clinical prognosis was favorable in patients treated by UK administration compared with those given antiplatelet treatment. It was concluded that "consecutive" UK administration might be useful for treatment of IgAN with moderate to advanced renal injuries. 相似文献
7.
Detection of polymeric IgA in glomeruli from patients with IgA nephropathy. 总被引:4,自引:8,他引:4
下载免费PDF全文
![点击此处可从《Clinical and experimental immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A study on the detection of polymeric IgA in glomeruli from renal biopsy specimens in patients with IgA nephropathy is described. Renal biopsy specimens were obtained from patients with IgA nephropathy. These specimens were stained with FITC-labelled anti-human J chain antisera and then examined with a fluorescent microscope. The J chain was observed in the glomerular mesangium by immunofluorescent staining. In parallel studies, renal biopsy specimens were treated with citrate buffer (pH 3.2) and the 'eluate' was neutralized by sodium hydroxide. The eluate was labelled with iodine-125, and the radiolabelled 'eluate' was fractionated by sucrose density-gradient ultracentrifugation. Polymerized IgA in the 'eluate' obtained from patients with IgA nephropathy was found to sediment predominantly as 9S to 11S using a sucrose density gradient analysis. Polymeric IgA in the fractions of the density gradient analysis was determined by anti-human IgA and anti-human J chain antisera. It was demonstrated that IgA and J chain were eluted from the glomeruli in some patients with IgA nephropathy. It is concluded that IgA deposited in the glomeruli is composed of dimers and/or larger polymers of circulating IgA in some patients with IgA nephropathy. 相似文献
8.
Ontogeny of macrophage-mediated protection against Listeria monocytogenes. 总被引:1,自引:3,他引:1
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)
We investigated the ontogenic development of macrophage functions which are important in the expression of host defense against infection by Listeria monocytogenes. Macrophage functions, including accumulation in response to local stimuli, chemotaxis in vitro, and intracellular killing, as well as number of macrophages, were examined by using mice 1, 2, 3, 4, and 8 weeks old. The number of peritoneal macrophages was extremely low in younger mice even when their body weights were taken into consideration. Macrophage accumulation in response to infectious stimulus with viable listeria was poor in younger mice and showed an age-dependent development. In younger groups, chemotaxis in vitro was as immature as chemotaxis in vivo. In 1- and 2-week-old mice, macrophages did not show any intracellular killing activity against L. monocytogenes, but killing was observed in mice over 3 weeks of age. These functions developed in an age-dependent manner and reached the 8-week-old adult level after the mice were 4 weeks of age. In adult mice, these macrophage functions were shown to be enhanced after immunization with viable listeria; however, such an immunization-induced enhancement was very poor in the younger groups of mice. Protection judged by mortality and in vivo bacterial growth was weaker in the younger groups against both primary and secondary challenges. In vivo protection against L. monocytogenes seemed to develop in the same age-dependent manner as the development of macrophage functions. These results indicate that age-dependent immaturity of macrophage functions mainly comprises the age-dependent immaturity of protection against L. monocytogenes. 相似文献
9.
Molecular cloning and complete nucleotide sequence of the genome of Japanese encephalitis virus Beijing-1 strain 总被引:5,自引:0,他引:5
Hiroshi Hashimoto Akio Nomoto Koji Watanabe Takayuki Mori Toshiyuki Takezawa Chikara Aizawa Tsutomu Takegami Keiichi Hiramatsu 《Virus genes》1988,1(3):305-317
The genomic RNA of the Japanese encephalitis virus (JEV) Beijing-1 strain was reversely transcribed and the synthesized cDNA was molecularly cloned. Six continuous cDNA clones that cover the entire virus genome were established and sequenced to determine the complete nucleotide sequence of the JEV RNA. The precise genomic size was estimated as 10,965 bases long. With flanking 95 bases at the 5 and 583 bases at the 3 non-coding regions, one long open reading frame (ORF) was revealed encoding a virus polyprotein with 3,429 amino acid residues. Because of sequence homologies observed between JEV and other flaviviruses, the genome organization of JEV appears to be identical with other flaviviruses. Genetic variation detected among flavivirus genomes is consistent with the established serological relatedness between JEV and other members of flaviviruses. The secondary structure of the JEV genome is deduced and discussed concerning its involvement in genome replication. 相似文献
10.