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101.
Automated flow-based anion-exchange method for high-throughput isolation and real-time monitoring of RuBisCO in plant extracts 总被引:1,自引:0,他引:1
In this work, a miniaturized, completely enclosed multisyringe-flow system is proposed for high-throughput purification of RuBisCO from Triticum aestivum extracts. The automated method capitalizes on the uptake of the target protein at 4 °C onto Q-Sepharose Fast Flow strong anion-exchanger packed in a cylindrical microcolumn (105 × 4 mm) followed by a stepwise ionic-strength gradient elution (0-0.8 mol/L NaCl) to eliminate concomitant extract components and retrieve highly purified RuBisCO. The manifold is furnished downstream with a flow-through diode-array UV/vis spectrophotometer for real-time monitoring of the column effluent at the protein-specific wavelength of 280 nm to detect the elution of RuBisCO. Quantitation of RuBisCO and total soluble proteins in the eluate fractions were undertaken using polyacrylamide gel electrophoresis (PAGE) and the spectrophotometric Bradford assay, respectively. A comprehensive investigation of the effect of distinct concentration gradients on the isolation of RuBisCO and experimental conditions (namely, type of resin, column dimensions and mobile-phase flow rate) upon column capacity and analyte breakthrough was effected. The assembled set-up was aimed to critically ascertain the efficiency of preliminary batchwise pre-treatments of crude plant extracts (viz., polyethylenglycol (PEG) precipitation, ammonium sulphate precipitation and sucrose gradient centrifugation) in terms of RuBisCO purification and absolute recovery prior to automated anion-exchange column separation. Under the optimum physical and chemical conditions, the flow-through column system is able to admit crude plant extracts and gives rise to RuBisCO purification yields better than 75%, which might be increased up to 96 ± 9% with a prior PEG fractionation followed by sucrose gradient step. 相似文献
102.
Leandro Chaves Rêgo Andrea Maria dos Santos 《European Journal of Operational Research》2019,272(2):587-594
We generalize a network formation model for co-authorship introducing the possibility of the connections having different link strengths. Different link strengths represent the fact that authors may put different efforts into different collaborations. To evaluate the model, we consider the notions of efficiency and pairwise stability, which are based on a utility function that measures the benefits for an author to belonging to a certain network structure. We divide the analysis in two cases, considering that link strengths are unbounded or bounded. In the first case, we show that if there are more than two authors in the network, then there is no pairwise stable network. In the second case, we show that the pairwise stable networks consist of completely connected disjoint components where essentially all link strengths are maximal. Regarding efficiency, in both cases, if the number of authors is even, then the unique efficient network structure consists of pairs of connected authors. 相似文献
103.
Harold J. Kushner 《Queueing Systems》2006,54(4):317-329
Consider a communications network consisting of mobiles and random external data processes, each destined to a particular
destination. Each mobile can serve as a node in the multi-hop path from source to destination. At each mobile the data is
queued according to the source destination pair. The quality of the connecting channels are randomly varying. Time is divided
into small scheduling intervals. At the beginning of each interval, the channels are estimated and this information is used
for the decisions concerning allocation of transmission power and/or time, bandwidth, and perhaps antennas, in a queue and
channel-state dependent way. Under a natural (and “almost” necessary) “average flow” condition, stochastic stability methods
are used to develop scheduling policies that assure stability. The policies are readily implementable and allow a range of
tradeoffs between current rates and queue lengths, under very weak conditions. Because of the non-Markovian nature of the
problem, we use the perturbed Stochastic Liapunov function method. The choice of Liapunov function allows a choice of the
effective performance criteria. All essential factors are incorporated into a “mean rate” function, so that the results cover
many different systems. Extensions concerning acknowledgments, multicasting, non-unique routes, and others are given to illustrate
the versatility of the method, and a useful method for getting the a priori routes is discussed. 相似文献
104.
小角散射实验应用成像板探测器测量绝对强度的方法 总被引:1,自引:0,他引:1
利用衰减法,设计了以第一电离室的计数归一化入射光束强度,用成像板计数单位记录入射光束强度的方案,并用Si片衰减进行了实验,结果表明本文提出的方案能够获得合理的绝对强度. 相似文献
105.
106.
107.
单程大气传输的能量衰减研究 总被引:4,自引:0,他引:4
本文对激光束在大气传输中能量衰减的主要原因进行了分析,给现单程水平,垂直和斜路径大气传输的能量衰减表达式。 相似文献
108.
109.
A random graph Gn(x) is constructed on independent random points U1,…,Un distributed uniformly on [0,1]d, d1, in which two distinct such points are joined by an edge if the l∞-distance between them is at most some prescribed value 0<x<1. The connectivity distance cn, the smallest x for which Gn(x) is connected, is shown to satisfy For d2, the random graph Gn(x) behaves like a d-dimensional version of the random graphs of Erdös and Rényi, despite the fact that its edges are not independent: cn/dn→1, a.s., as n→∞, where dn is the largest nearest-neighbor link, the smallest x for which Gn(x) has no isolated vertices. 相似文献
110.
为搞好洞庭湖区洪涝灾害的预测和防灾减灾,促进湖区经济建设,本文对洞庭湖区洪涝灾害的形成机制进行了分析研究.结果表明:80 %特大洪涝灾害的发生在厄尔尼诺年的次年,其内在机制是厄尔尼诺事件所导致的全球气候异常.大气环流的异常是洪涝发生的根本原因,主要表现在有特大洪涝年汛期,位于110°~120°E的西太平洋副高脊线位置都稳定处于19°~24°N之间,且越过24°N的时间大致与城陵矶年最高水位出现时间相吻合;西风带形势稳定;印度低压偏强并持续稳定.洞庭湖区洪涝与湖区、四水流域、长江上游东部区和西部区等广泛地域的降水密切相关,汛期在这4个区域第一次大范围的强降水过程以后20 天各代表站降水量总和的平均值对洞庭湖的洪涝预测具有决定性意义. 相似文献