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101.
102.
Daw-Yang Hwang Stefan Kohl Xueping Fan Asaf Vivante Stefanie Chan Gabriel C. Dworschak Julian Schulz Albertien M. van Eerde Alina C. Hilger Heon Yung Gee Tracie Pennimpede Bernhard G. Herrmann Glenn van de Hoek Kirsten Y. Renkema Christoph Schell Tobias B. Huber Heiko M. Reutter Neveen A. Soliman Natasa Stajic Radovan Bogdanovic Elijah O. Kehinde Richard P. Lifton Velibor Tasic Weining Lu Friedhelm Hildebrandt 《Human genetics》2015,134(8):905-916
103.
Stefanie Wilberts Matthias Suter Nina Walser Peter J. Edwards Harry Olde Venterink Dieter Ramseier 《Journal of Plant Ecology》2014,7(3):276
Aims The volume of soil beyond a plant's roots from which that plant is able to acquire a particular nutrient depends upon the mobility of that nutrient in the soil. For this reason it has been hypothesized that the strength of competitive interactions between plants vary with soil nutrient mobility. We aimed to provide an experimental test of this hypothesis.Methods We devised two experimental systems to investigate specifically the effect of nutrient transport rates upon intraspecific competition. In the first, the exchange of rhizosphere water and dissolved nutrients between two connected pots, each containing one plant, was manipulated by alternately raising and lowering the pots. In the second experiment, the roots systems of two competing plants were separated by partitions of differing porosity, thereby varying the plants' access to water and nutrients in the other plant′s rhizosphere. In this second experiment, we also applied varying amounts of nutrients to test whether higher nutrient input would reduce competition when competition for light is avoided, and applied different water levels to affect nutrient concentrations without changing nutrient supply.Important findings In both experiments, lower mobility reduced competitive effects on plant biomass and on relative growth rate (RGR), as hypothesized. In the second experiment, however, competition was more intense under high nutrient input, suggesting that low nutrient supply rates reduced the strength of the superior competitor. Competitive effects on RGR were only evident under the low water level, suggesting that under lower nutrient concentrations, competitive effects might be less pronounced. Taken together, our results provide the first direct experimental evidence that a reduction in nutrient mobility can reduce the intensity of competition between plants. 相似文献
104.
Gabriel St?lting Stefanie Bungert-Plümke Arne Franzen Christoph Fahlke 《The Journal of biological chemistry》2015,290(51):30406-30416
ClC-K chloride channels are crucial for auditory transduction and urine concentration. Mutations in CLCNKB, the gene encoding the renal chloride channel hClC-Kb, cause Bartter syndrome type III, a human genetic condition characterized by polyuria, hypokalemia, and alkalosis. In recent years, several Bartter syndrome-associated mutations have been described that result in truncations of the intracellular carboxyl terminus of hClC-Kb. We here used a combination of whole-cell patch clamp, confocal imaging, co-immunoprecipitation, and surface biotinylation to study the functional consequences of a frequent CLCNKB mutation that creates a premature stop codon at Trp-610. We found that W610X leaves the association of hClC-Kb and the accessory subunit barttin unaffected, but impairs its regulation by barttin. W610X attenuates hClC-Kb surface membrane insertion. Moreover, W610X results in hClC-Kb channel opening in the absence of barttin and prevents further barttin-mediated activation. To describe how the carboxyl terminus modifies the regulation by barttin we used V166E rClC-K1. V166E rClC-K1 is active without barttin and exhibits prominent, barttin-regulated voltage-dependent gating. Electrophysiological characterization of truncated V166E rClC-K1 demonstrated that the distal carboxyl terminus is necessary for slow cooperative gating. Since barttin modifies this particular gating process, channels lacking the distal carboxyl-terminal domain are no longer regulated by the accessory subunit. Our results demonstrate that the carboxyl terminus of hClC-Kb is not part of the binding site for barttin, but functionally modifies the interplay with barttin. The loss-of-activation of truncated hClC-Kb channels in heterologous expression systems fully explains the reduced basolateral chloride conductance in affected kidneys and the clinical symptoms of Bartter syndrome patients. 相似文献
105.
106.
Girhard M Schuster S Dietrich M Dürre P Urlacher VB 《Biochemical and biophysical research communications》2007,362(1):114-119
Cytochrome P450 monooxygenase from the anaerobic microorganism Clostridium acetobutylicum (CYP152A2) has been produced in Escherichia coli. CYP152A2 was shown to bind a broad range of saturated and unsaturated fatty acids and corresponding methyl esters and demonstrated a high peroxygenase activity of up to 200min(-1) with myristic acid. Although a high concentration of hydrogen peroxide of 200microM was necessary for high activities of the enzyme, it led to a fast enzyme inactivation within 2-4min. This might reflect the natural function of CYP152A2 as a rapid hydrogen peroxide scavenging enzyme. In two different reconstituted systems with NADPH, CYP152A2 was able to convert 10 times more substrate, if provided with flavodoxin and flavodoxin reductase from E. coli and even 30-40 times more substrate with the CYP102A1-reductase from Bacillus megaterium. According to the clear preference for hydroxylation at alpha-position, CYP152A2 can be referred to as fatty acid alpha-hydroxylase. 相似文献
107.
Molecularly imprinted polymer films for reflectometric interference spectroscopic sensors 总被引:2,自引:0,他引:2
Belmont AS Jaeger S Knopp D Niessner R Gauglitz G Haupt K 《Biosensors & bioelectronics》2007,22(12):3267-3272
Reflectometric interference spectroscopic measurements were performed on molecularly imprinted polymer (MIP) films with the herbicide atrazine as the template molecule. A conventional imprinting protocol was used relying on non-covalent interactions between the functional monomers and the template. The MIPs were deposited on glass transducers by two different methods: spin-coating followed by in situ polymerization of thin films of monomers containing a sacrificial polymeric porogen, and autoassembly of MIP nanoparticles with the aid of an associative linear polymer. Reproducible results were obtained upon measurements of atrazine solutions in toluene with both films. Atrazine concentrations as low as 1.7 ppm could be detected with the autoassembled particle film. No or very little analyte adsorption was observed onto non-imprinted control films made by spin-coating and by particle assembly, respectively. We believe that these MIP layers in combination with the general reflectrometric transduction scheme could be a versatile sensing tool for the detection of environmentally important and other analytes. 相似文献
108.
Shirey KA Cole LE Keegan AD Vogel SN 《Journal of immunology (Baltimore, Md. : 1950)》2008,181(6):4159-4167
Francisella tularensis (Ft), the causative agent of tularemia, elicits a potent inflammatory response early in infection, yet persists within host macrophages and can be lethal if left unchecked. We report in this study that Ft live vaccine strain (LVS) infection of murine macrophages induced TLR2-dependent expression of alternative activation markers that followed the appearance of classically activated markers. Intraperitoneal infection with Ft LVS also resulted in induction of alternatively activated macrophages (AA-Mphi). Induction of AA-Mphi by treatment of cells with rIL-4 or by infection with Ft LVS promoted replication of intracellular Ftn, in contrast to classically activated (IFN-gamma plus LPS) macrophages that promoted intracellular killing of Ft LVS. Ft LVS failed to induce alternative activation in IL-4Ralpha(-/-) or STAT6(-/-) macrophages and prolonged the classical inflammatory response in these cells, resulting in intracellular killing of Ft. Treatment of macrophages with anti-IL-4 and anti-IL-13 Ab blunted Ft-induced AA-Mphi differentiation and resulted in increased expression of IL-12 p70 and decreased bacterial replication. In vivo, Ft-infected IL-4Ralpha(-/-) mice exhibited increased survival compared with wild-type mice. Thus, redirection of macrophage differentiation by Ft LVS from a classical to an alternative activation state enables the organism to survive at the expense of the host. 相似文献
109.
Recombination, the precise physical breakage and rejoining of DNA between homologous chromosomes, plays a central role in mediating the orderly segregation of meiotic chromosomes in most eukaryotes. Despite its importance, the factors that control the number and placement of recombination events within a cell remain poorly defined. The rate of recombination exhibits remarkable species specificity, and, within a species, recombination is affected by the physical size of the chromosome, chromosomal location, proximity to other recombination events (i.e., chiasma interference), and, intriguingly, the sex of the transmitting parent. To distinguish between simple genetic and nongenetic explanations of sex-specific recombination differences in mammals, we compared recombination in meiocytes from XY sex-reversed and XO females with that in meiocytes from XX female and XY male mice. The rate and pattern of recombination in XY and XO oocytes were virtually identical to those in normal XX females, indicating that sex, not genotype, is the primary determinant of meiotic recombination patterns in mammals. 相似文献
110.
Gregor Wernet Stefanie Hellweg Konrad Hungerbühler 《The International Journal of Life Cycle Assessment》2012,17(6):720-728