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61.
62.
通过评估瑞典斯德哥尔摩和巴西圣保罗地铁系统的犯罪活动及扰乱公共秩序行为案例,探讨相关经验教训。对比2个国家地铁系统的时空犯罪模式及上述案例的研究结果,总结环境对犯罪活动及扰乱公共秩序行为的影响。研究中地理信息系统、田野调查和建模等分析过程应用了相应地铁运营商的基础数据。研究发现市中心地铁站及终点站往往比其他站点更容易发生犯罪。除了区位因素,地铁站的环境属性、周边环境及社区环境也会影响站点的犯罪机会。预防犯罪的干预措施必须针对具体犯罪活动、核心地铁站的拥挤情况,特别是易发生犯罪的高峰时段制定。以此总结今后相关研究方向,并提出相应政策建议。 相似文献
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64.
Marco Crisma Giovanni Valle Fernando Formaggio Vania Monaco Claudio Toniolo 《Letters in Peptide Science》1996,3(3):121-126
Summary An X-ray diffraction analysis ofZ-l-Leu-Aib-Gly-l-Ile-l-Leu-OMe, containing the N-acylated tetrapeptide amide sequence-l-Leu-Aib-Gly-l-Ile-, showed that in the crystal state the carbonyl group preceding thel-Leu1 residue acts as the acceptor of two C=OH–N intramolecular H-bonds, which give rise to an-l-Leu1-Aib2-type-III' -turn and an-l-Leu1-Aib2-Gly3-l-Ile4--turn, respectively. A second (type-I') -turn encompasses the-Aib2-Gly3-sequence. This is the third type of folding motif known for that tetrapeptide sequence, considering also those already published for the C-terminal segment of the lipopeptaibol antibiotics trichodecenin I and trichogin A IV. 相似文献
65.
Marco Crisma Vania Monaco Fernando Formaggio Claudio Toniolo Clifford George Judith L. Flippen-Anderson 《Letters in Peptide Science》1997,4(4-6):213-218
An X-ray diffraction analysis of the [Fmoc0,TOAC4,8, Leu-OMe11] analogue of thelipopeptaibol antibiotic trichogin A IV shows that the undecapeptide isfolded in a right-handed, mixed /310-helix. The helicalmolecules are connected in a head-to-tail arrangement along the b-axisthrough C=O···H-N intermolecular H-bonding. Thispacking mode generates a hydrophobic cavity where the FmocN-protecting groups are accommodated. The distances andangles between the nitroxide groups of the two TOAC residues, separated byone turn of the -helix, have been determined. 相似文献
66.
Dora Angelicheva Francesc Calafell Alexey Savov Albena Jordanova Annie Kufardjieva Vania Nedkova Tanya Ivanova Petya Yankova Dimitrina Konstantinova Evgeny Genev Luba Kalaydjieva J. Galeva 《Human genetics》1997,99(4):513-520
We present data on the population genetics of cystic fibrosis (CF) in Bulgaria, obtained by comprehensive mutation analysis
and the construction of intragenic microsatellite haplotypes. The sample of 262 CF alleles analysed is representative of the
patients diagnosed during the period of referral and of the three main ethnic groups in the country. ΔF508 accounted for 100%
of Gypsy CF alleles, which thus differed significantly from both Bulgarians and ethnic Turks. In Bulgarian and Turkish CF
patients, 92% of the mutant alleles were identified, yielding a total of 25 different mutations, of which only 7 occurred
at frequencies higher than 1%. The findings were compared to other European populations and to the distribution of phenylketonuria
mutations. Genetic distances and population trees demonstrated that in the south-eastern tip of Europe, the overall distribution
of CF mutations and polymorphic haplotypes is very close to that of Mediterranean populations, with a high frequency of N1303K
and G542X, a large number of rare mutations and a prevalence of the 23 31 13 haplotype in association with ΔF508. These findings
are consistent with a main role for the Neolithic expansion in the shaping of the CF mutation spectrum in Bulgaria and southern
Europe.
Received: 1 September 1996 相似文献
67.
Vania Cristina Desoti Danielle Lazarin-Bidóia Fabianne Martins Ribeiro Solange Cardoso Martins Jean Henrique da Silva Rodrigues Tania Ueda-Nakamura Celso Vataru Nakamura Valdecir Farias Ximenes Sueli de Oliveira Silva 《PloS one》2015,10(12)
Chagas’ disease is an infection that is caused by the protozoan Trypanosoma cruzi, affecting millions of people worldwide. Because of severe side effects and variable efficacy, the current treatments for Chagas’ disease are unsatisfactory, making the search for new chemotherapeutic agents essential. Previous studies have reported various biological activities of naphthoquinones, such as the trypanocidal and antitumor activity of vitamin K3. The combination of this vitamin with vitamin C exerted better effects against various cancer cells than when used alone. These effects have been attributed to an increase in reactive oxygen species generation. In the present study, we evaluated the activity of vitamin K3 and vitamin C, alone and in combination, against T. cruzi. The vitamin K3 + vitamin C combination exerted synergistic effects against three forms of T. cruzi, leading to morphological, ultrastructural, and functional changes by producing reactive species, decreasing reduced thiol groups, altering the cell cycle, causing lipid peroxidation, and forming autophagic vacuoles. Our hypothesis is that the vitamin K3 + vitamin C combination induces oxidative imbalance in T. cruzi, probably started by a redox cycling process that leads to parasite cell death. 相似文献
68.
Regulation of trehalose metabolism in Saccharomyces cerevisiae mutants during temperature shifts 总被引:1,自引:0,他引:1
Temperature shifts from 23 degrees C to 36 degrees C resulted in trehalose accumulation in Saccharomyces independently of genetic lesions in the cAMP-protein kinase cascade. In parallel, trehalose 6-phosphate synthase activity increased about 3-fold in all strains; the increase could be inhibited by cycloheximide, suggesting that protein synthesis was required. Heat shock treatment after the temperature shift led to a drastic increase in trehalose activity, and deactivation of the biosynthetic enzyme with a consequent drop in trehalose. Up to now no definite correlation between acquisition of thermotolerance and trehalose accumulation has been made. 相似文献
69.
70.
Ruijie Liu Biswarathan Ramani Dagoberto Soto Vania De Arcangelis Yang Xiang 《The Journal of biological chemistry》2009,284(47):32279-32287
Adrenoceptors receptors (ARs) play a pivotal role in regulating cardiovascular response to catecholamines during stress. β2ARs, prototypical G protein-coupled receptors (GPCRs), expressed in animal hearts, display dual coupling to both Gs and Gi proteins to control the adenylyl cyclase-cAMP dependent protein kinase A (PKA) pathway to regulate contraction responses. Here, we showed that the β2AR coupling to Gi proteins was agonist dose-dependent and occurred only at high concentrations in mouse cardiac myocytes. Both the β2AR-induced PKA activity, measured by fluorescence resonance energy transfer (FRET) imaging, and the increase in myocyte contraction rate displayed sensitivity to the Gi inhibitor pertussis toxin (PTX). Further studies revealed that activated β2ARs underwent PKA phosphorylation at a broad range of agonist concentrations. Disruption of the PKA phosphorylation sites on the β2AR blocked receptor/Gi coupling. However, a sufficient β2AR/Gi coupling was also dependent on the G protein-coupled receptor kinase (GRK)-mediated phosphorylation of the receptors, which only occurred at high concentrations of agonist (≥100 nm). Disruption of the GRK phosphorylation sites on the β2AR blocked receptor internalization and coupling to Gi proteins, probably by preventing the receptor''s transportation to access Gi proteins. Furthermore, neither PKA nor GRK site mutated receptors displayed sensitivity to the Gi-specific inhibitor, GiCT. Together, our studies revealed distinct roles of PKA and GRK phosphorylation of the β2AR for agonist dose-dependent coupling to Gi proteins in cardiac myocytes, which may protect cells from overstimulation under high concentrations of catecholamines. 相似文献