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371.
皮层神经元动作电位不应期和阈电位与神经元动作电位编码的关系 总被引:1,自引:0,他引:1
目的:测量和比较感觉运动皮层Ⅱ/Ⅲ层锥体神经元和中间神经元的内在特性并研究其与动作电位编码频率和精确性的关系。方法:采用全细胞电流钳记录模式,获得的数据输入pClamp和Origin进行处理分析。结果:与锥体神经元相比,中间神经元群集动作电位具有较低的阈电位水平和较短的不应期,从而中间神经元具有较高的动作电位编码频率和精确性。结论:皮层神经元动作电位的阈电位水平和不应期调控动作电位的编码频率和精确性。 相似文献
372.
The ability ofSaccharomyces cerevisiae to transport d-galactose and related sugars with an axial hydroxyl group at C-4, acquired by induction with D-galactose,
was lost either by exposing early exponential-phase cells to an osmotic shock involving incubation in 0.6m NaClO4, 0.66m sucrose and lmm histidine and transfer to 5mm Tris-HCl with 2mm dithiothreitol, or simply by transferring them to
distilled water. The total amount of protein thus released was 0.1–0.35 and 0.1 mg per mg dry wt., respectively. The shock
fluid contained at least six proteins, among them a galactose-binding component. l-Arabinose transport could not be restored
by adding the concentrated shock fluid to depleted cells but cells remained viable after the shock and resynthesized the transport
system if incubated in a galactose-containing growth medium. 相似文献
373.
Federico Baltar Joakim Palovaara Fernando Unrein Philippe Catala Karel Horňák Karel ?imek Dolors Vaqué Ramon Massana Josep M Gasol Jarone Pinhassi 《The ISME journal》2016,10(3):568-581
To test whether protist grazing selectively affects the composition of aquatic bacterial communities, we combined high-throughput sequencing to determine bacterial community composition with analyses of grazing rates, protist and bacterial abundances and bacterial cell sizes and physiological states in a mesocosm experiment in which nutrients were added to stimulate a phytoplankton bloom. A large variability was observed in the abundances of bacteria (from 0.7 to 2.4 × 106 cells per ml), heterotrophic nanoflagellates (from 0.063 to 2.7 × 104 cells per ml) and ciliates (from 100 to 3000 cells per l) during the experiment (∼3-, 45- and 30-fold, respectively), as well as in bulk grazing rates (from 1 to 13 × 106 bacteria per ml per day) and bacterial production (from 3 to 379 μg per C l per day) (1 and 2 orders of magnitude, respectively). However, these strong changes in predation pressure did not induce comparable responses in bacterial community composition, indicating that bacterial community structure was resilient to changes in protist predation pressure. Overall, our results indicate that peaks in protist predation (at least those associated with phytoplankton blooms) do not necessarily trigger substantial changes in the composition of coastal marine bacterioplankton communities. 相似文献
374.
375.
Forty AI bulls were tested for BoLA class I antigens by means of eight specific polyclonal reagents. By means of immobilization and sperm penetration tests these antigens were not detected on sperm cells. Isoimmunization studies with the use of sperm as antigenic stimuli and insemination of frozen spermatozoa diluted in specific reagents did not prove the presence of BoLA class I antigens on bovine spermatozoa. The cytotoxic tests used in this investigation were not reliable. 相似文献
376.
377.
Inhibitors of energy metabolism (3-ohlorophenylhydrazonomalononitrile, antimycin A, iodoacetamide, dicyclohexylcarbodiimide)
but not of transport (uranyl ions) stimulate at low concentrations the uptake ofl-leucine,l-glutamic acid,l-argimne and, to a lesser degree, of 2-aminoisobutyric acid inSaccharomyces cerevisiae. The effect is apparent only after augmenting the energy reserves of cells by preincubation withd-glueose or, more strikingly, with ethanol. It is absent in a mutant (op1) lacking the translocation system for ADP-ATP in mitochondria. The presence of two different energy reserves for amino acid
transport is indicated (one in energy-poor, the other in energy-rich cells). The stimulating effect appears to be caused by
a retarded degradation of the transport proteins as occurs at a lowered level of mitochondria-produced ATP. 相似文献
378.
Karel ?imek Karel Horňák Jan Jezbera Michal Ma?ín Ji?í Nedoma Josep M. Gasol Michael Schauer 《Applied microbiology》2005,71(5):2381-2390
379.
380.
Vibrio vulnificus can be divided into three biotypes, and only biotype 2, which is further divided into serovars, contains eel-virulent strains. We compared the genomic DNA of a biotype 2 serovar E isolate (tester) with the genomic DNAs of three biotype 1 strains by suppression subtractive hybridization and then tested the distribution of the tester-specific DNA sequences in a wide collection of bacterial strains. In this way we identified three plasmid-borne DNA sequences that were specific for biotype 2 strains irrespective of the serovar and three chromosomal DNA sequences that were specific for serovar E biotype 2 strains. These sequences have potential for use in the diagnosis of eel vibriosis caused by V. vulnificus and in the detection of biotype 2 serovar E strains. 相似文献