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91.
Previously, we demonstrated the utility of a gas chromatography–tandem mass spectrometry (GC–MS/MS) method for the quantitative determination of asymmetric dimethylarginine (ADMA) in biological samples. Here we report the extension of this method to symmetric dimethylarginine (SDMA) in human urine. SDMA and ADMA were simultaneously quantitated in urine by using their in situ prepared trideuteromethyl esters as internal standards. The GC–MS/MS method was validated for SDMA and ADMA in spot urine samples of 19 healthy adults. In these samples, the creatinine-corrected excretion rate was 3.23 ± 0.63 μmol/mmol for SDMA and 3.14 ± 0.98 μmol/mmol for ADMA. 相似文献
92.
Ines Seitl Stephan Wickles Roland Beckmann Andreas Kuhn Dorothee Kiefer 《Molecular microbiology》2014,91(2):408-421
The marine Gram‐negative bacteria Rhodopirellula baltica and Oceanicaulis alexandrii have, in contrast to Escherichia coli, membrane insertases with extended positively charged C‐terminal regions similar to the YidC homologues in mitochondria and Gram‐positive bacteria. We have found that chimeric forms of E. coli YidC fused to the C‐terminal YidC regions from the marine bacteria mediate binding of YidC to ribosomes and therefore may have a functional role for targeting a nascent protein to the membrane. Here, we show in E. coli that an extended C‐terminal region of YidC can compensate for a loss of SRP‐receptor function in vivo. Furthermore, the enhanced affinity of the ribosome to the chimeric YidC allows the isolation of a ribosome nascent chain complex together with the C‐terminally elongated YidC chimera. This complex was visualized at 8.6 Å by cryo‐electron microscopy and shows a close contact of the ribosome and a YidC monomer. 相似文献
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Jochen Ba?ler Helge Paternoga Iris Holdermann Matthias Thoms Sander Granneman Clara Barrio-Garcia Afua Nyarko Gunter Stier Sarah A. Clark Daniel Schraivogel Martina Kallas Roland Beckmann David Tollervey Elisar Barbar Irmi Sinning Ed Hurt 《The Journal of cell biology》2014,207(4):481-498
Eukaryotic ribosome biogenesis involves ∼200 assembly factors, but how these contribute to ribosome maturation is poorly understood. Here, we identify a network of factors on the nascent 60S subunit that actively remodels preribosome structure. At its hub is Rsa4, a direct substrate of the force-generating ATPase Rea1. We show that Rsa4 is connected to the central protuberance by binding to Rpl5 and to ribosomal RNA (rRNA) helix 89 of the nascent peptidyl transferase center (PTC) through Nsa2. Importantly, Nsa2 binds to helix 89 before relocation of helix 89 to the PTC. Structure-based mutations of these factors reveal the functional importance of their interactions for ribosome assembly. Thus, Rsa4 is held tightly in the preribosome and can serve as a “distribution box,” transmitting remodeling energy from Rea1 into the developing ribosome. We suggest that a relay-like factor network coupled to a mechano-enzyme is strategically positioned to relocate rRNA elements during ribosome maturation. 相似文献
95.
Diego V. Beckmann Fabiano B. Carvalho Cinthia M. Mazzanti Rosmarini P. dos Santos Amanda O. Andrades Graciane Aiello Angel Rippilinger Dominguita L. Graça Fátima H. Abdalla Lizielle S. Oliveira Jessié M. Gutierres Maria Rosa C. Schetinger Alexandre Mazzanti 《Life sciences》2014
Aim
The purpose of this study was to investigate whether the flavonoid quercetin can prevent alterations in the behavioral tests and of cholinergic neurotransmission in rats submitted to the ethidium bromide (EB) experimental demyelination model during events of demyelination and remyelination.Main methods
Wistar rats were randomly distributed into four groups (20 animals per group): Control (pontine saline injection and treatment with ethanol), Querc (pontine saline injection and treatment with quercetin), EB (pontine 0.1% EB injection and treatment with ethanol), and EB + Querc (pontine 0.1% EB injection and treatment with quercetin). The groups Querc and Querc + EB were treated once daily with quercetin (50 mg/kg) diluted in 25% ethanol solution (1 ml/kg) and the animals of the control and EB groups were treated once daily with 25% ethanol solution (1 ml/kg). Two stages were observed: phase of demyelination (peak on day 7) and phase of remyelination (peak on day 21 post-injection). Behavioral tests (beam walking, foot fault and inclined plane test), acetylcholinesterase (AChE) activity and lipid peroxidation in pons, cerebellum, hippocampus, hypothalamus, striatum and cerebral cortex were measured.Key findings
The quercetin promoted earlier locomotor recovery, suggesting that there was demyelination prevention or further remyelination velocity as well as it was able to prevent the inhibition of AChE activity and the increase of lipidic peroxidation, suggesting that this compound can protect cholinergic neurotransmission.Significance
These results may contribute to a better understanding of the neuroprotective role of quercetin and the importance of an antioxidant diet in humans to provide benefits in neurodegenerative diseases such as MS. 相似文献96.
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David A. Schaer Richard P. Beckmann Jack A. Dempsey Lysiane Huber Amelie Forest Nelusha Amaladas Yanxia Li Ying Cindy Wang Erik R. Rasmussen Darin Chin Andrew Capen Carmine Carpenito Kirk A. Staschke Linda A. Chung Lacey M. Litchfield Farhana F. Merzoug Xueqian Gong Philip W. Iversen Michael Kalos 《Cell reports》2018,22(11):2978-2994