全文获取类型
收费全文 | 227篇 |
免费 | 9篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 10篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 12篇 |
2014年 | 10篇 |
2013年 | 19篇 |
2012年 | 24篇 |
2011年 | 15篇 |
2010年 | 12篇 |
2009年 | 5篇 |
2008年 | 10篇 |
2007年 | 12篇 |
2006年 | 14篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1987年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有236条查询结果,搜索用时 15 毫秒
91.
Mahmud H Silljé HH Cannon MV van Gilst WH de Boer RA 《Journal of cellular and molecular medicine》2012,16(4):722-729
The (pro)renin-renin receptor [(P)RR] was discovered as an important novel component of the renin-angiotensin system (RAS). The functional significance of (P)RR is widely studied in renal and vascular pathologies and has sparked interest for a potential role in cardiovascular disease. To investigate the role of (P)RR in cardiac pathophysiology, we aimed to assess (P)RR regulation in adverse cardiac remodelling of the failing heart. In particular, we evaluated the expression of (P)RR in different models of heart failure and across different species. Significantly increased levels of (P)RR mRNA were found in post-myocardial infarcted (MI) hearts of rats (1.6-fold, P < 0.05) and mice (5-fold, P < 0.01), as well as in transgenic rats with overexpression of the mouse renin gene (Ren2) (2.2-fold, P < 0.01). Moreover, we observed a strong increase of (P)RR expression in hearts of dilated cardiomyopathy (DCM) patients (5.3-fold, P < 0.001). Because none of the tested commercially available antibodies appeared to detect endogenous (P)RR, a (P)RR-specific polyclonal antibody was generated to study (P)RR protein levels. (P)RR protein levels were significantly increased in the post-MI rat heart (1.4-fold, P < 0.05) as compared to controls. Most interestingly in DCM patients, a significant 8.7-fold (P < 0.05) increase was observed. Thus, protein expression paralleled gene expression. These results demonstrate that (P)RR expression is strongly up-regulated both in rodent models of heart failure and in the failing human heart, hinting to a potential role for (P)RR in cardiac pathophysiology. 相似文献
92.
Aims The study of deciduous phenology over boreal forest is important for understanding forest ecology and better management. In this paper, our objective was to determine the phenological stages of deciduous leaf out (DLO) over the deciduous-dominant [i.e. trembling aspen (Populus tremuloides)] stands in the Canadian Province of Alberta.Methods During the period 2006–2008, we used Moderate Resolution Imaging Spectroradiometer (MODIS)-based 8-day surface temperature (T S) images to calculate accumulated growing degree days (AGDD: a favourable temperature regime for plant growth). The temporal dynamics of AGDD in conjunction with in situ DLO observations were then analysed in determining the optimal threshold for DLO in 2006 (i.e. 80 degree days).Important findings The implementation of the above-mentioned optimal threshold revealed reasonable agreements (i.e. on an average 91.9% of the DLO cases within ±2 periods or ±16 days of deviations during 2007–2008) in comparison to the in situ observed data. The developments could be useful in various forestry-related applications, e.g. plant growth and its ability of exchanging atmospheric carbon dioxide, forest ecohydrology, risk of insect infestation, forest fire and impact of climate change, among others. 相似文献
93.
Occurrence, seasonality and genetic diversity of Vibrio vulnificus in coastal seaweeds and water along the Kii Channel, Japan 总被引:1,自引:0,他引:1
Mahmud ZH Neogi SB Kassu A Mai Huong BT Jahid IK Islam MS Ota F 《FEMS microbiology ecology》2008,64(2):209-218
Vibrio vulnificus is a ubiquitous toxigenic bacterium found in a coastal environment but little is known about its occurrence and seasonality among seaweeds, which are widely consumed as seafood in Japan. Therefore, we have observed the bacterium's abundance in seawater and seaweed samples from three areas of the Kii Channel, Japan, during June 2003 to May 2004. A total of 192 samples were collected: 24 from each source in summer, autumn, winter and spring. The samples were selectively cultivated following the most probable number (MPN) technique. Vibrio vulnificus population ranged from 0 to 10(3) MPN 100 mL(-1) seawater or 10 g seaweeds; higher counts were observed during summer. The optimum temperature, salinity and pH for the bacterium were 20-24 degrees C, 24-28 p.p.t. and 7.95-8.15, respectively. However, seaweeds always contained higher V. vulnificus than seawater. Among 280 V. vulnificus strains, detected by species-specific colony hybridization and PCR, 78, 74, 11 and 16 were from seaweeds and 46, 42, 2 and 11 were from seawater during summer, autumn, winter and spring, respectively. Ribotyping of 160 selected strains revealed a higher genotypic diversity (18 patterns) among strains from seaweeds than from seawater (10 patterns). Seaweeds can thus act as a potential habitat for V. vulnificus and are more unsafe for consumption during summer. 相似文献
94.
Muhammad Shaiq Ali Shaukat Mahmud Shaista Perveen Viqar Uddin Ahmad Ghazala Hafeez Rizwani 《Phytochemistry》1999,50(8):441
The ethanolic extract of the fresh leaves of Calophyllum inophyllum afforded a pair of new epimers named as inophynone and isoinophynone. Their structures were elucidated with the aid of spectroscopic techniques. Some known constituents, cholesterol, friedelin, canophyllol and canophyllic acid, were also isolated from the same source. 相似文献
95.
Gobindo Kumar Paul Shafi Mahmud Md. Mehedi Hasan Shahriar Zaman Md. Salah Uddin Md. Abu Saleh 《Saudi Journal of Biological Sciences》2021,28(11):6592-6605
Aphanamixis polystachya may be a natural, renewable resource against antibiotic-resistant bacterial infections. The antibacterial activity of A. polystachya leaf and bark extracts was investigated against three antibiotic-resistant bacterial species and one fungus. Methanolic leaf extract showed only limited antibacterial activity but both methanolic and aqueous bark extract showed high antimicrobial activity. In an antioxidant activity test, leaf and bark extracts exhibited 50% free radical scavenging at a concentration of 107.14 ± 3.14 μg/mL and 97.13 ± 3.05 μg/mL, respectively, indicating that bark extracts offer more antioxidative activity than leaf extracts. Bark extracts also showed lower toxicity than leaf extracts. This suggests that bark extracts may offer greater development potential than leaf extracts. The molecular dynamics were also investigated through the simulated exploration of multiple potential interactions to understand the interaction dynamics (root-mean-square deviation, solvent-accessible surface area, radius of gyration, and the hydrogen bonding of chosen compounds to protein targets) and possible mechanisms of inhibition. This molecular modeling of compounds derived from A. polystachya revealed that inhibition may occur by binding to the active sites of the target proteins of the tested bacterial strains. A. polystachya bark extract may be used as a natural source of drugs to control antibiotic-resistant bacteria. 相似文献
96.
Katayoon Pakravan Ehsan Razmara Bashdar Mahmud Hussen Fatemeh Sattarikia Majid Sadeghizadeh Sadegh Babashah 《Journal of cellular and molecular medicine》2022,26(1):1
Different cellular and molecular mechanisms contribute to chondrocyte and osteocyte development. Although vital roles of the mothers against decapentaplegic homolog 4 (also called ‘SMAD4’) have been discussed in different cancers and stem cell‐related studies, there are a few reviews summarizing the roles of this protein in the skeletal development and bone homeostasis. In order to fill this gap, we discuss the critical roles of SMAD4 in the skeletal development. To this end, we review the different signalling pathways and also how SMAD4 defines stem cell features. We also elaborate how the epigenetic factors—ie DNA methylation, histone modifications and noncoding RNAs—make a contribution to the chondrocyte and osteocyte development. To better grasp the important roles of SMAD4 in the cartilage and bone development, we also review the genotype‐phenotype correlation in animal models. This review helps us to understand the importance of the SMAD4 in the chondrocyte and bone development and the potential applications for therapeutic goals. 相似文献
97.
98.
Ishtiaq Mahmud Mineko Asanagi Yoshiaki Miura 《Biochemical and biophysical research communications》1980,93(3):661-667
In rats, feeding protein free diet for 4 days followed by starvation and then high protein diet induced a biphasic ornithine decarboxylase (EC 4.1.1.17) activity, prolonged thymidine kinase (EC 2.7.1.21) activity and DNA synthesis. In contrast feeding a diet containing casein-equivalent amino acid mixture induced a monophasic ornithine decarboxylase activity, short-lived thymidine kinase activity and DNA synthesis. To maintain prolonged thymidine kinase activity and DNA synthesis high protein diet must be given in the early part of the prereplicative period. 相似文献
99.
Allozyme variation in a population of the common mussel Mytilus edulis in Mumbles, South Wales, has been studied by starch gel electrophoresis. On the basis of data obtained for 34 loci, we estimate the proportion of loci polymorphic to be 30%. Using only the 29 loci for which individual genotypes can be accurately typed, the average heterozygosity is estimated to be 9.5 +/- 3.6%. The calculated expected average heterozygosity based on Hardy-Weinberg expectations is identical with the observed value. Allele frequency data at six polymorphic loci are given for several other British populations. There is no significant geographic heterogeneity. The results are discussed in relation to genetic adaptive strategies and are shown to be inconsistent with the predictions of the neutral hypothesis. 相似文献
100.