全文获取类型
收费全文 | 1927篇 |
免费 | 85篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 17篇 |
妇产科学 | 52篇 |
基础医学 | 217篇 |
口腔科学 | 38篇 |
临床医学 | 105篇 |
内科学 | 381篇 |
皮肤病学 | 13篇 |
神经病学 | 163篇 |
特种医学 | 21篇 |
外科学 | 537篇 |
综合类 | 2篇 |
一般理论 | 1篇 |
预防医学 | 16篇 |
眼科学 | 175篇 |
药学 | 159篇 |
中国医学 | 5篇 |
肿瘤学 | 111篇 |
出版年
2023年 | 11篇 |
2022年 | 19篇 |
2021年 | 50篇 |
2020年 | 10篇 |
2019年 | 30篇 |
2018年 | 35篇 |
2017年 | 30篇 |
2016年 | 25篇 |
2015年 | 45篇 |
2014年 | 54篇 |
2013年 | 59篇 |
2012年 | 90篇 |
2011年 | 82篇 |
2010年 | 56篇 |
2009年 | 54篇 |
2008年 | 113篇 |
2007年 | 110篇 |
2006年 | 100篇 |
2005年 | 89篇 |
2004年 | 74篇 |
2003年 | 77篇 |
2002年 | 82篇 |
2001年 | 70篇 |
2000年 | 85篇 |
1999年 | 78篇 |
1998年 | 25篇 |
1997年 | 17篇 |
1996年 | 8篇 |
1994年 | 9篇 |
1993年 | 10篇 |
1992年 | 42篇 |
1991年 | 35篇 |
1990年 | 25篇 |
1989年 | 35篇 |
1988年 | 23篇 |
1987年 | 26篇 |
1986年 | 32篇 |
1985年 | 17篇 |
1984年 | 11篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1979年 | 19篇 |
1977年 | 7篇 |
1976年 | 10篇 |
1975年 | 11篇 |
1973年 | 7篇 |
1972年 | 12篇 |
1971年 | 10篇 |
1969年 | 7篇 |
1968年 | 19篇 |
排序方式: 共有2017条查询结果,搜索用时 15 毫秒
21.
Shigemitsu Iwai MD Kei Torikai MD Chris M. Coppin MD Yoshiki Sawa MD 《Journal of artificial organs》2007,10(1):29-35
Currently used bioprosthetic valves have several limitations such as calcification and functional deterioration, and revitalization
through cellular ingrowth is impossible. To overcome these obstacles, we have developed a minimally immunogenic tissue-engineered
valve that consists of an unfixed, decellularized porcine valve scaffold capable of being spontaneously revitalized in vivo
after implantation. Porcine aortic root tissue was decellularized using detergents such as sodium lauryl sulfate and Triton
X-100. The porcine valve was treated very gently and plenty of time was allowed for constituents to diffuse in and out of
the matrix. In a preliminary study, a piece of decellularized porcine valve tissue was implanted into the rat subdermal space
for 14 and 60 days and the structural integrity and calcification were evaluated. As an in vivo valve replacement model, the
decellularized porcine valve was implanted in the pulmonary valve position in dogs and functional and histological evaluation
was performed after 1, 2, and 6 months. Histological examination showed that the newly developed detergent treatment effectively
removed cellular debris from the porcine aortic tissue. Decellularized porcine valve tissue implanted subdermally in rats
showed minimal inflammatory cell infiltration and calcification. In the valve replacement model, spontaneous reendothelialization
and repopulation of the medial cells were observed within 2 months, and good valve function without regurgitation was observed
by echocardiography up to 6 months. The minimally immunogenic decellularized porcine valve proved effective in mitigating
postimplant calcification and provided a suitable matrix for revitalizing prostheses through in situ recellularization, cellular
ingrowth, and tissue remodeling. 相似文献
22.
Quantitation of varicella-zoster virus DNA in patients with Ramsay Hunt syndrome and zoster sine herpete 总被引:3,自引:0,他引:3 下载免费PDF全文
Varicella-zoster virus (VZV) reactivation causes facial nerve palsy in Ramsay Hunt syndrome (RHS) and zoster sine herpete (ZSH) with and without zoster rash, respectively. In the present study, we analyzed the VZV DNA copy number in saliva samples from 25 patients with RHS and 31 patients with ZSH using a TaqMan PCR assay to determine differences in the viral load between the two diseases. VZV copy number in saliva peaked near the day of the appearance of zoster in patients with RHS. Consequently, VZV DNA was less frequently detected in patients with RHS who exhibited facial palsy several days after the appearance of zoster. These findings suggest that the VZV load in saliva samples reflects the kinetics of viral reactivation in patients with RHS. In addition, VZV DNA was equally detected in saliva from patients with RHS and ZSH, and there was no significant difference in the highest viral copy number between patients with RHS and those with ZSH. The VZV load does not appear to reflect a major difference between RHS and ZSH. 相似文献
23.
IL-6-STAT3 controls intracellular MHC class II alphabeta dimer level through cathepsin S activity in dendritic cells 总被引:1,自引:0,他引:1
Kitamura H Kamon H Sawa S Park SJ Katunuma N Ishihara K Murakami M Hirano T 《Immunity》2005,23(5):491-502
We found IL-6-STAT3 pathway suppresses MHC class II (MHCII) expression on dendritic cells (DCs) and attenuates T cell activation. Here, we showed that IL-6-STAT3 signaling reduced intracellular MHCII alphabeta dimmer, Ii, and H2-DM levels in DCs. IL-6-mediated STAT3 activation decreased cystatin C level, an endogenous inhibitor of cathepsins, and enhanced cathepsin activities. Importantly, cathepsin S inhibitors blocked reduction of MHCII alphabeta dimer, Ii, and H2-DM in the IL-6-treated DCs. Overexpression of cystatin C suppressed IL-6-STAT3-mediated increase of cathepsin S activity and reduction of MHCII alphabeta dimer, Ii, and H2-DM levels in DCs. Cathepsin S overexpression in DCs decreased intracellular MHCII alphabeta dimer, Ii, and H2-DM levels, LPS-mediated surface expression of MHCII and suppressed CD4(+) T cell activation. IL-6-gp130-STAT3 signaling in vivo decreased cystatin C expression and MHCII alphabeta dimer level in DCs. Thus, IL-6-STAT3-mediated increase of cathepsin S activity reduces the MHCII alphabeta dimer, Ii, and H2-DM levels in DCs, and suppresses CD4(+) T cell-mediated immune responses. 相似文献
24.
A common approach to the analysis of gene expression data is to define clusters of genes that have similar expression. A critical step in cluster analysis is the determination of similarity between the expression levels of two genes. We introduce a neural network-based similarity index as a non-linear similarity index and compare the results with other proximity measures for Saccharomyces cerevisiae gene expression data. We show that the clusters obtained using Euclidean distance, correlation coefficients, and mutual information were not significantly different. The clusters formed with the neural network-based index were more in agreement with those defined by functional categories and common regulatory motifs. 相似文献
25.
Inducible expression of mutant alpha-synuclein decreases proteasome activity and increases sensitivity to mitochondria-dependent apoptosis 总被引:23,自引:0,他引:23
Tanaka Y Engelender S Igarashi S Rao RK Wanner T Tanzi RE Sawa A L Dawson V Dawson TM Ross CA 《Human molecular genetics》2001,10(9):919-926
Parkinson's disease (PD) is a common progressive neurodegenerative disorder caused by the loss of dopaminergic neurons in the substantia nigra. Although mutations in alpha-synuclein have been identified in autosomal dominant PD, the mechanism by which dopaminergic neural cell death occurs remains unknown. Proteins encoded by two other genes in which mutations cause familial PD, parkin and UCH-L1, are involved in regulation of the ubiquitin-proteasome pathway, suggesting that dysregulation of the ubiquitin-proteasome pathway is involved in the mechanism by which these mutations cause PD. We established inducible PC12 cell lines in which wild-type or mutant alpha-synuclein can be de-repressed by removing doxycycline. Differentiated PC12 cell lines expressing mutant alpha-synuclein showed decreased activity of proteasomes without direct toxicity. Cells expressing mutant alpha-synuclein showed increased sensitivity to apoptotic cell death when treated with sub-toxic concentrations of an exogenous proteasome inhibitor. Apoptosis was accompanied by mitochondrial depolarization and elevation of caspase-3 and -9, and was blocked by cyclosporin A. These data suggest that expression of mutant alpha-synuclein results in sensitivity to impairment of proteasome activity, leading to mitochondrial abnormalities and neuronal cell death. 相似文献
26.
Action of strychnine to cortical neurons 总被引:1,自引:0,他引:1
27.
Many antimicrobial peptides and proteins were discovered recently in various animals. Cecropins are insect-derived antimicrobial peptides which contain 35-39 amino acid residues. Magainins are amphibian-derived antimicrobial peptides with 21-27 amino acid residues. In mammals, defensins, 29-35 amino acid peptides, were identified in the granules of neutrophils and various epithelial cells. In addition, the granules of neutrophils in the mammal have been shown to have several antimicrobial proteins. Among them, bactericidal/permeability increasing protein (BPI) and cationic antimicrobial peptide-18 (CAP 18) have been found to have potent bactericidal activity against gram-negative bacteria and strong lipopolysaccharide-neutralizing function. The recombinant BPIs (recombinant BPI, 23-kDa N-terminal fragment of BPI, and lipopolysaccharide-binding protein-BPI fusion protein) and synthetic peptides derived from C-terminal of CAP 18 are now under investigation for the application to the therapy of sepsis or septic shock. 相似文献
28.
Formation of biologically active prostanoids from PGH2 occurs through a set of synthases for PGD, PGE, PGF, PGI and TXA2, following the cyclooxygenase reaction. Over the past few years, the genes of several prostanoid synthases have been cloned and the characteristics of the enzymes are now determined. In addition, receptors for prostanoids were also cloned and their structures were determined as G-protein coupled seven-transmembrane domain types belonging to the rhodopsin-type receptor superfamily. Based on these molecular biological findings, the mechanism of the diverse effects of prostanoids are being clarified. Selective inhibitors against the synthases and the selective agonists and antagonists for the prostanoid receptors are now being investigated rapidly for clinical application. 相似文献
29.
Inagaki M Yabuki H Hashimoto M Maguchi M Kino S Sawa M Ojima H Tokusashi Y Miyokawa N Kusano M Kasai S 《Surgery today》1999,29(12):1260-1263
We describe herein the case of a 51-year-old woman in whom metastatic tumor seeding of the percutaneous transhepatic biliary
drainage tract occurred following a pancreatoduodenectomy for carcinoma of the distal common bile, duct. An abdominal computed
tomography scan done 6 months after the initial operation detected a hepatic lesion located at the site of the previous percutaneous
transhepatic biliary drainage tract. Implantation of bile duct carcinoma in the drainage tract was diagnosed, and the recurrent
tumor was successfully resected by performing a subsegmentectomy of segment 3 and removal of the adjacent abdominal wall.
At present, 5 years and 4 months after the second resection, the patient is in good health without any signs of recurrence.
This case report demonstrates that an aggressive surgical approach should be performed for tumor seeding of a transhepatic
biliary catheter tract. 相似文献
30.
N Matsumoto T Tsuchida H Nakamura R Sawa Y Takahashi H Naganawa H Iinuma T Sawa T Takeuchi M Shiro 《The Journal of antibiotics》1999,52(3):276-280
The absolute structure of a new antibiotic lactonamycin is described. The NMR studies deduced one of four possible structures for the aglycon attached by a rhodinose through glycosidic bond. The stereochemistry of the sugar obtained by an acid hydrolysis was determined to be L-form by measuring optical rotation. The stereochemistry of the aglycon was determined by X-ray crystallographic analysis. 相似文献