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941.
Human serum albumin (HSA) is the most abundant plasma protein and has an inherent ability to target tumor cells. It is an excellent candidate for drug delivery. However, HSA cannot form complex with DNA or RNA, because it is negatively charged under physiological conditions. In this work, we reported a simple method to prepare HSA/RNA nanoparticles mainly by physical interaction. Firstly, the solution pH is adjusted to 4.0, under which condition HSA is positively charged. It forms complex with RNA via electrostatic interaction. The solution is then heated at 75 oC for 15 min to stabilize the structure and the size of the formed complex. The HSA/RNA nanoparticle prepared by this method has a diameter about 110 nm and a narrow distribution. It is also stable for days under physiological conditions. Cellular essays demonstrate that these particles exhibit a high cellular uptake efficiency and non-toxicity to HeLa cells. 相似文献
942.
Gui-Fang Qin Qiong-Yun Qin Bing-Fan Long Dong-Ping Wei Yan-Hui Xu Shan-Ju Bao Xian-Hong Yin 《Journal of the Iranian Chemical Society》2017,14(6):1227-1234
Copper (Cu)(II) complexes were synthesized by Ind-3-COOH combined with N-containing auxiliary ligands via a combinatorial strategy involving hydrothermal and solvent-evaporation method. The synthesized complexes had the following formulas: [Cu(Ind-3-COO)2] (1), [Cu(PHEN)(Ind-3-COO)]2·2H2O (2), [Cu2(DPP)(Ind-3-COO)2(H2O)]·H2O, (3) and [Cu(BPY)(Ind-3-COO)2]·4H2O (4). Meanwhile, the symbol abbreviations were listed as follows: Ind-3-COOH = 1H-indazole-3-carboxylic acid, 1,3-bis(4-pyridyl)propane (DPP), 1,10-phenanthroline (PHEN) and 4,4′-bipyridine (BPY). The crystalline structure and spectroscopy of each complex were characterized by single-crystal X-ray diffraction, elemental analysis, Fourier transform infrared spectroscopy and powder X-ray diffraction. The redox reactions in the complexes were then investigated by performing cyclic voltammetry under nitrogen conditions at room temperature. Two pairs of distinctive irreversible reduction potentials were identified, which could be attributed to the processes of Cu(II)–Cu(I) and Cu(I)–Cu(0). 相似文献
943.
Ya-sheng Huang Qi-qi Yu Yin Chen Min-jie Cheng Li-ping Xie 《Chemistry Central journal》2017,11(1):120
Background
The plant Alisma plantago-aquatica Linnaeus, which is widely distributed in southwest of China, is the main material of traditional Chinese medicine “Zexie”. It was used as folk medicine for immune-modulation, anti-tumor, anti-inflammatory and antibacterial. Previous chemical studies on A. plantago-aquatica reported the identification of triterpenes, diterpenes, sesquiterpenes, steroids, alkaloids and phenolic acid. Terpenes and phenolic acid were regard as major secondary metabolites from this medicine plant.Results
A new phenolic acid, plantain A (1), along with four known compounds (2–5) were isolated and identified from A. plantago-aquatica by extensive chromatographic and spectrometric methods. In the present study, the levels of TNF-α, IL-1β, COX-2, PEG2 and TGF-β1 were increased in model group rats, whereas on treatment with the isolated compound (1 and 4) at 50 mg/kg, there was a significant decrease in the cytokine levels. Therefore, the anti-CNP effect of 1 and 4 may be related to their anti-inflammatory properties.Conclusions
A new phenolic acid and four known phenolic compounds were isolated from A. plantago-aquatica. Moreover, compounds 1 and 4 shows significant anti-chronic prostatitis activity in rats.944.
In this paper, in terms of the Fréchet normal cone, we establish exact separation results for finitely many disjoint closed sets in an Asplund space, which supplement the extremal principle and some fuzzy separation theorems. As an application, we provide a new optimality condition for a constraint optimization problem in terms of Fréchet subdifferential and Fréchet normal cone. 相似文献
945.
In this paper, we study a nematic liquid crystals system in three-dimensional whole space ?3 and obtain the time decay rates of the higher-order spatial derivatives of the solution by the method of spectral analysis and energy estimates if the initial data belongs to L1?3 additionally. 相似文献
946.
947.
Dang Hai Nguyen George Yin Chao Zhu 《Stochastic Processes and their Applications》2017,127(10):3135-3158
This work is devoted to switching diffusions that have two components (a continuous component and a discrete component). Different from the so-called Markovian switching diffusions, in the setup, the discrete component (the switching) depends on the continuous component (the diffusion process). The objective of this paper is to provide a number of properties related to the well posedness. First, the differentiability with respect to initial data of the continuous component is established. Then, further properties including uniform continuity with respect to initial data, and smoothness of certain functionals are obtained. Moreover, Feller property is obtained under only local Lipschitz continuity. Finally, an example of Lotka–Volterra model under regime switching is provided as an illustration. 相似文献
948.
Infinite Horizon Controlled Diffusions with Randomly Varying and State-Dependent Discount Cost Rates
Xianggang Lu G. Yin Xianping Guo 《Journal of Optimization Theory and Applications》2017,172(2):535-553
This work focuses on optimal controls of diffusions in an infinite horizon. It has several distinct features in contrast to the existing literature. The discount factor is allowed to be randomly varying and state dependent. The existence and uniqueness of the viscosity solution to the associated Hamilton–Jacobi–Bellman equation are established. The verification theorem is also obtained. Because closed-form solutions are virtually impossible to obtain in most cases, we develop numerical methods. Using the Markov chain approximation methods, numerical schemes are constructed; viscosity solution methods are used to prove the convergence of the algorithm. In addition, examples are given for demonstration purpose. 相似文献
949.
Structure-enforced matrix factorization (SeMF) represents a large class of mathematical models appearing in various forms of principal component analysis, sparse coding, dictionary learning and other machine learning techniques useful in many applications including neuroscience and signal processing. In this paper, we present a unified algorithm framework, based on the classic alternating direction method of multipliers (ADMM), for solving a wide range of SeMF problems whose constraint sets permit low-complexity projections. We propose a strategy to adaptively adjust the penalty parameters which is the key to achieving good performance for ADMM. We conduct extensive numerical experiments to compare the proposed algorithm with a number of state-of-the-art special-purpose algorithms on test problems including dictionary learning for sparse representation and sparse nonnegative matrix factorization. Results show that our unified SeMF algorithm can solve different types of factorization problems as reliably and as efficiently as special-purpose algorithms. In particular, our SeMF algorithm provides the ability to explicitly enforce various combinatorial sparsity patterns that, to our knowledge, has not been considered in existing approaches. 相似文献
950.
当二次等参体元用于分析接触问题时,接触面上节点集中接触力不同号给建立接触判据造成困难。本文建立了由节点集中接触力计算接触面上分布接触力节点值的方法,从而可顺利建立接触判据。此方法已成功应用于工程中的弹性固体接触问题分析,文末给出了一个计算实例。 相似文献