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N M Maraldi F Marinelli S Papa A Galanzi F A Manzoli 《Basic and applied histochemistry》1987,31(3):421-428
Isolated nuclei represent a suitable model for studying the influence of exogenous phospholipids, normally found as minor chromatin components, on the nuclear structure, which, in turn, could be related to the observed modifications of DNA and RNA synthesis. The morphological modifications induced on chromatin RNP granules and nuclear matrix have been analyzed both with conventional thin sectioning and with an original method based on image analysis of freeze-fractured and replicated nuclear samples. The results obtained support the hypothesis that anionic phospholipids, by removing histone H1, induce a transition of the chromatin from solenoid to nucleosome conformation and favour the RNA polymerizing activity which results in an increased release of RNP particles, while neutral phospholipids, probably affecting the matrix structure, partly impare the RNP maturation and transport, with consequent increase of chromatin condensation. 相似文献
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Emidio Albertini Renzo Torricelli Elena Bitocchi Lorenzo Raggi Gianpiero Marconi Luciano Pollastri Gabriella Di Minco Alfredo Battistini Roberto Papa Fabio Veronesi 《Molecular breeding : new strategies in plant improvement》2011,27(4):533-547
The olive is considered one of the most important fruit crops of the Mediterranean basin where it shows a wide range of variability,
with about 2,000 cultivars. Italy, with about 500 cultivars, plays a fundamental role. The ability to discriminate olive cultivars
and estimate genetic variability are important factors in better management of genetic resources and in helping to understand
how genetic diversity is partitioned among cultivars. The two main objectives of the present investigation were to evaluate
the identity of cultivars grown in Abruzzo region, central Italy, and to study their genetic structure. We applied amplified
fragment length polymorphism (AFLP) methodology on 84 genotypes belonging to the most relevant and oldest varieties cultivated
in Abruzzo and on six unknown genotypes. The information content of data was evaluated using the Marker Ratio index and the
Polymorphic Index Content. Moreover, STRUCTURE software was used to investigate the genetic population structure. The analysis
enabled us to clearly distinguish eight cultivars within seven clusters. Additionally, one cluster was found to have various
minor cultivars and showed a relatively high level of diversity. The partitioning of genetic diversity showed that the largest
amount of molecular variance was within groups. Our data suggest that both sexual and clonal propagation have played an important
role in the evolution of olive cultivars. In our hypothesis, some ancestral population spread in central Italy with a relevant
role of seed propagation, followed by a selection of superior clones from which more traditional varieties originated. In
a few cases, hybridization should be taken into consideration to explain the diffusion of recently developed cultivars. 相似文献
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Paolo Calabresi Veronica Ghiglieri Petra Mazzocchetti Ilenia Corbelli Barbara Picconi 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2015,370(1672)
The long-term replacement therapy with the dopamine (DA) precursor 3,4-dihydroxy-l-phenylalanine (L-DOPA) is a milestone in the treatment of Parkinson''s disease (PD). Although this drug precursor can be metabolized into the active neurotransmitter DA throughout the brain, its therapeutic benefit is due to restoring extracellular DA levels within the dorsal striatum, which lacks endogenous DA as a consequence of the neurodegenerative process induced by the disease. In the early phases of PD, L-DOPA treatment is able to restore both long-term depression (LTD) and long-term potentiation (LTP), two major forms of corticostriatal synaptic plasticity that are altered by dopaminergic denervation. However, unlike physiological DA transmission, this therapeutic approach in the advanced phase of the disease leads to abnormal peaks of DA, non-synaptically released, which are supposed to trigger behavioural sensitization, namely L-DOPA-induced dyskinesia. This condition is characterized by a loss of synaptic depotentiation, an inability to reverse previously induced LTP. In the advanced stages of PD, L-DOPA can also induce non-motor fluctuations with cognitive dysfunction and neuropsychiatric symptoms such as compulsive behaviours and impulse control disorders. Although the mechanisms underlying the role of L-DOPA in both motor and behavioural symptoms are still incompletely understood, recent data from electrophysiological and imaging studies have increased our understanding of the function of the brain areas involved and of the mechanisms implicated in both therapeutic and adverse actions of L-DOPA in PD patients. 相似文献