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Conidia ofPenicillium variabile P16 were immobilized in polyurethane sponge and used in repeated-batch processes in a fluidized-bed reactor. Optimal conditions for production of glucose oxidase and catalase were: inoculum size, 10%; glucose concentration, 80 g L–1; Ca-carbonate concentration, 15 g L–1; temperature, 28°C and aeration rate, 4 VV–1 min–1. In an extended repeated-batch process, glucose oxidase activity was highest after the fourth batch and catalase activity was highest after the fifth batch. Scanning electron microscopy showed that the fungus grew only in the interior of carrier particles.  相似文献   
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Most green gemmules of Spongilla lacustris survived enclosure in ice at –20 °C for up to 30 days; however, their rate of germination at 20 °C was less rapid than that of control gemmules. The length of time spent at low temperature had little effect on gemmule survival. In contrast, repeated cooling to –20 °C and warming to 4 °C led to a progressive decline in gemmule viability. These results indicate that cold injury occurs primarily during transitions between high and low temperatures.  相似文献   
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下丘脑Kiss1神经元产生的神经肽kisspeptin通过影响促性腺激素释放激素的分泌,参与青春期的启动、生殖系统的成熟以及排卵等过程的神经内分泌调节。Kiss1基因的表达受到包括多种反式调控因子及表观遗传的调控。预测与前期研究表明,miR-92a-3p、miR-25-3p的种子序列能够与Kiss1的3′-UTR直接结合,抑制Kiss1的表达。为进一步研究miR-92a-3p、miR-25-3p在Kiss1表达调控中的作用,本研究分别构建了对miR-92a-3p、miR-25-3p具有抑制作用的特异性吸附海绵载体:sponge-miR-92a和sponge-miR-25,以实现miRNA的功能缺失。流式细胞术和双荧光素酶报告基因系统分别证实,这2个海绵载体均能够非常有效地吸附外源性或内源性靶miRNA。sponge-miR-92a和sponge-miR-25载体被进一步包装成慢病毒LV-sponge-miR-92a和LV-sponge-miR-25。实时荧光定量PCR结果显示,经LV-sponge-miR-92a和LV-sponge-miR-25感染的下丘脑原代神经元细胞中,Kiss1表达水平均显著上调(P<0.05);将LV-sponge-miR-92a注射到下丘脑后,雌性小鼠阴门开启时间明显提前(P<0.05);下丘脑注射LV-sponge-miR-92a和LV-sponge-miR-25扰乱了雌性小鼠的正常动情周期。综上所述,成功构建了能够有效吸附miR-92a-3p、miR-25-3p的海绵载体,证明它们在解除miR-92a-3p、miR-25-3p对Kiss1的抑制中的作用,下丘脑注射海绵对雌性小鼠的阴门开启时间和动情周期均产生一定程度的影响,提示miR-92a-3p、miR-25-3p可能在青春期的启动和生殖成熟过程中发挥重要的作用。  相似文献   
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During evolution, sponges (Porifera) have honed the genetic toolbox and biosynthetic mechanisms for the fabrication of siliceous skeletal components (spicules). Spicules carry a protein scaffold embedded within biogenic silica (biosilica) and feature an amazing range of optical, structural, and mechanical properties. Thus, it is tempting to explore the low-energy synthetic pathways of spiculogenesis for the fabrication of innovative hybrid materials. In this synthetic biology approach, the uptake of multifunctional nonbiogenic nanoparticles (fluorescent, superparamagnetic) by spicule-forming cells of bioreactor-cultivated sponge primmorphs provides access to spiculogenesis. The ingested nanoparticles were detected within intracellular vesicles resembling silicasomes (silica-rich cellular compartments) and as cytosolic clusters where they lent primmorphs fluorescent/magnetic properties. During spiculogenesis, the nanoparticles initially formed an incomplete layer around juvenile, intracellular spicules. In the mature, extracellular spicules the nanoparticles were densely arranged as a surface layer that rendered the resulting composite fluorescent and magnetic. By branching off the conventional route of solid-state materials synthesis under harsh conditions, a new pathway has been opened to a versatile platform that allows adding functionalities to growing spicules as templates in living cells, using nonbiogenic nanoscale building blocks with multiple functionalities. The magnet-assisted alignment renders this composite with its fluorescent/magnetic properties potentially suitable for application in biooptoelectronics and microelectronics (e.g., microscale on-chip waveguides for applications of optical detection and sensing).  相似文献   
6.
The first instar larva of the net-winged midge, Nothohoraia micrognathia Craig, 1969 (Diptera: Blephariceridae) is described. Instead of the primitive ring of eversible hooklets the pseudopods possess stiff apical setae. This character expression suggests that Nothohoraia is more closely related to the advanced Apistomyiini occurring outside New Zealand than to the two other New Zealand genera, Neocurupira and Peritheates.  相似文献   
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Out of some 750 strains of microorganisms, a potent bacterium for lipase production was isolated from soil and was identified as Chromobacterium viscosum.

The bacterium accumulates lipase in culture fluid when grown aerobically at 26°C for 3 days in a medium composed of soluble starch, soy bean meal, lard and inorganic salts.

Chromobacterium lipase had an optimum pH of 7.0 for activity at 37°C, and an optimal temperature of 65°C at pH 7.0. The enzyme retained 80% of the activity when heated for 10 min at 70°C. This lipase was capable of hydrolyzing a variety of natural fats and oils, and it was more active on lard and butter than on olive oil. The activity was stimulated by Ca2+, Mg2+, Mn2+ and inhibited by Cu2+, Hg2+ and Sn2+. It was not diminished but rather stimulated by a high concentration of bile-salts.  相似文献   
9.
A new tribromoiododiphenyl ether ( 1 ) and eight known brominated diphenyl ethers ( 2 – 9 ) were isolated from the MeOH extract of the sponge Arenosclera sp. collected in Vietnam, using repeated open column chromatography and preparative thin layer chromatography. The chemical structure of the new compound 1 was determined by analyses of spectroscopic (1D‐ and 2D‐NMR, and MS) data and by comparison of our data with those reported in the literature. Compounds 1 , 3 , and 8 exhibited strong antibacterial activities against the Gram‐positive bacteria Bacillus subtilis and Staphylococcus aureus and the Gram‐negative bacterium Klebsiella pneumoniae with MIC values ranging from 0.8 to 6.3 μm , while compounds 5 and 7 only displayed activities against Gram‐positive bacteria with MIC values from 0.5 to 3.1 μm . Compound 2 showed activities against the four tested bacteria with MIC values ranging from 0.5 to 6.3 μm .  相似文献   
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