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991.
José Alberto Rodríguez‐Castillo Jennifer Quantius Susanne Herold Elie El Agha Saverio Bellusci Isabelle Salwig Thomas Braun Robert Voswinckel Werner Seeger Rory E. Morty Katrin Ahlbrecht 《Genesis (New York, N.Y. : 2000)》2017,55(12)
Pulmonary diseases such as chronic obstructive pulmonary disease, lung fibrosis, and bronchopulmonary dysplasia are characterized by the destruction or malformation of the alveolar regions of the lung. The underlying pathomechanisms at play are an area of intense interest since these mechanisms may reveal pathways suitable for interventions to drive reparative processes. Lipid‐laden fibroblasts (lipofibroblasts) express the Perilipin 2 (Plin2) gene‐product, PLIN2, commonly called adipose‐differentiation related protein (ADRP). These cells are also thought to play a role in alveolarization and repair after injury to the alveolus. Progress in defining the functional contribution of lipofibroblasts to alveolar generation and repair is hampered by a lack of in vivo tools. The present study reports the generation of an inducible mouse Cre‐driver line to target cells of the ADRP lineage. Robust Cre‐mediated recombination in this mouse line was detected in mesenchymal cells of the postnatal lung, and in additional organs including the heart, liver, and spleen. The generation and validation of this valuable new tool to genetically target, manipulate, and trace cells of the ADRP lineage is critical for assessing the functional contribution of lipofibroblasts to lung development and repair. 相似文献
992.
Population history and life history influence the migration rate of female Glanville fritillary butterflies 总被引:4,自引:0,他引:4
Ilkka Hanski Casper J. Breuker Katrin Schps Rosemary Setchfield Marko Nieminen 《Oikos》2002,98(1):87-97
This study examines the causes of emigration from small fragments of suitable habitat in a species that has a distinct metapopulation structure, frequent turnover of local populations, and substantial migration among local populations and currently unoccupied habitat fragments. We conducted a field experiment in which 727 individuals of the Glanville fritillary butterfly ( Melitaea cinxia ) originating from four regions were marked and released simultaneously in a natural environment. In three of the four source regions, larvae for the experiment were collected from dozens of small local populations, some of which had been established in the previous summer (new populations), whereas the remaining populations were older. In two of the source regions, female butterflies prefer a host plant ( Veronica spicata ) that is not present in the release area, where there is only Plantago lanceolata , the preferred host plant of females from the other two source regions. We found that migration rate of males was unrelated to any of the factors studied in this experiment. In contrast, two factors influenced the migration rate of females. First, Veronica -preferring females had higher emigration rate than Plantago- preferring females from the Plantago -containing release patches, demonstrating that the individual perception of habitat quality significantly influences the migration rate of females. Second, females from newly-established populations were more dispersive than females from older populations, supporting the notion that metapopulation processes (recurrent colonizations) select for increased migration. The observed migration rate was not correlated with any body size measurements, and thus the observed differences in migration rate were apparently caused by differences in the behaviour of female butterflies rather than in their flight capacity. 相似文献
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994.
The previously unclear taxonomic status of the high-Antarctic bivalve Limatula ovalis Thiele, 1912 and the sub-Antarctic L. pygmaea (Philippi, 1845) was investigated using molecular techniques (18S rDNA, 16S rDNA, ITS-1). L. ovalis and L. pygmaea were recovered as sister taxa, and L. hodgsoni (Smith, 1907) as their sister, supporting the subgenus Antarctolima Habe, 1977. Various different molecular clock calculations placed the timing of the L. ovalis/pygmaea divergence (1.36-8.03 MYA with 16S rDNA, 6.81-19.12 MYA with 18S rDNA, 0.24-2.87 MYA with ITS-1) well after the formation of the Antarctic Polar Front (23.5 MYA, APF), indicating a more recent speciation process. The vicariance hypothesis that the APF is a barrier for geneflow favouring speciation processes in the Southern Ocean has to be questioned. 相似文献
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A general strategy for the synthesis of Fmoc protectednucleobase modified amino acids is presented. Fmoc protected nucleo amino acidsbearing a natural purine (guanine) as well as an artificial purine(isoadenine) in the side chain have been synthesized and incorporated into cyclicpentapeptides. The structure of the cyclic peptides is based on the well knownRGD peptides, which act as selective integrin antagonists. Thenucleo amino acids serve as conformationally constrained arginine mimeticswith a reduced basicity of the guanidino moiety. 相似文献
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1000.
Katrin Reimer 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1987,161(2):305-313
Summary Single neuron responses to sinusoidally amplitude modulated (SAM) signals were studied in the inferior colliculus of the horseshoe bat,Rhinolophus rouxi.57% of the neurons responded to SAM stimuli with periodical discharges synchronized to the modulation cycle. The proportion of cells driven by amplitude modulated signals was independent of the best frequency of the neurons. Best modulation frequencies were at or below 100 Hz in about 70% of the neurons. Synchronized activity could be elicited by modulation frequencies up to 400 Hz.Best SAM responses were observed at stimulus intensities 10 dB above threshold. Generally the BMF of a neuron did not change with intensity. The BMF decreased with decreasing modulation depth of the amplitude modulation.A trend for a topographical organization of neurons according to best modulation frequencies was detected. The results did not reveal any significant specialization of the bat's auditory system for coding of amplitude modulations as compared to other mammals.Abbreviations
BF
best frequency
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BMF
best modulation frequency
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CF
constant frequency
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FM
frequency modulation
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IC
inferior colliculus
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SAM
sinusoidal amplitude modulation
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SFM
sinusoidal frequency modulation 相似文献