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911.
Due to the relative movement between space debris and background stars, the blending of objects and stars is ineluctable through observation. It brings down position accuracy of objects and even makes the tracking break down in worse conditions. In view of the difference of geometry between stars and objects in space debris observation, a technique for separating blended objects based on mathematical morphology is presented. It’s sufficiently flexible to be applied in image processing, and the blending images can be separated effectively with a high degree of centroid precision.
相似文献912.
Laburnine’s dissolution behaviors in glucose and saline solution were studied by a micro-calorimetry method. The measured
integral and differential heats of solution were utilized to build equations of the solute and the heat, so that dissolution
thermodynamic equations and half-time periods, Δsol
H
m, Δsol
G
m, and Δsol
S
m were obtained. The results show that this study does not only provide a simple method for the determination of the half-life
period for a drug but also offer a theoretical reference for the clinical application of laburnine. 相似文献
913.
914.
Deqing Zhao Kefu Chen Fei Yang Guanglin Feng Yufeng Sun Ya Dai 《Cellulose (London, England)》2013,20(6):3205-3217
Accurate determination of the thermal properties of cellulose is of particular significance in studying the mechanism of cellulosic cigarette paper combustion. This paper probes into the influence of four kinds of potassium carboxylates on the thermal degradation kinetics and the heat properties of cigarette paper through simultaneous thermogravimetric analysis (TGA) coupled with differential scanning calorimetry (DSC) measurement under air atmosphere. Reduced mass loss and mass loss rate, and increased solid residue for samples containing four potassium salts implied that potassium carboxylates may retard the formation of levoglucosan and volatiles by inhibiting the depolymerization reaction and simultaneously accelerate char formation by catalyzing the dehydration reaction. Kinetic parameters were analyzed based on three non-isothermal models available in literature. The results indicated that three modeling methods exhibit good consistency. A global activation energy range of 106–155 kJ mol?1 was proposed for cigarette paper with potassium carboxylates. The four potassium salts studied considerably reduced the activation energy in the following descending order: potassium 1,2,3,4-butane tetracarboxylate (PBTCA) > citrate > gluconate > ascorbate. The heat properties of cigarette paper were also determined by integrating the DSC curves. The results demonstrated that both cellulose degradation and char oxidation have strong exothermic peaks. Cigarette paper samples with potassium salts have lower exothermic cellulose degradation process and higher exothermic char oxidation process, which were further confirmed by greater differences as the amounts of salt citrate or PBTCA increased. 相似文献
915.
We propose a new stochastic SIRS model under regime switching in which both white and color environmental noises are taken into account. We show that white noise suppresses explosions in the model and the disease-free equilibrium of the model is stochastically asymptotically stable under certain conditions. Moreover, we show that the model is stochastically ultimately bounded and the moment average in time of the model solution is bounded. An example illustrates the boundedness of the moment average in time of the model solution. 相似文献
916.
A Monte Carlo particle tracking (MCPT) code has been developed and coupled to hydrodynamic simulations to generate and track primary and scattered neutrons in addition to scattered charged particles by post-processing. This code uses one dimensional (1-D) deuterium-tritium implosion profiles, and the computed down-scattered neutron and knock-on deuteron spectra are analyzed for different areal densities. The mixing effects on the spectra of down-scattered neutron and knock-on deuteron are also investigated. The implementation of the numerical scheme is analyzed, and the particle splitting technique is adopted, which is proven to efficiently reduce computational effort. 相似文献
917.
918.
Dr. Yuling Zhao Yue Zhao Dr. Cailing Wu Dr. Jikuan Qiu Dr. Huiyong Wang Dr. Zhiyong Li Prof. Yang Zhao Prof. Jianji Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(36):9391-9397
As an important member of crystalline porous polymers, acylhydrazone-linked covalent organic frameworks (COFs) have gained much attention in recent years. However, the low structural stability imparts a limit on their practical applications. To tackle this problem, we report a simple strategy to increase the chemical stability of acylhydrazone-linked COFs by incorporating azobenzene groups in the conjugated framework. Through reinforcing the π-π stacking interactions between the adjacent layers with increased π-surface, it is surprising to find that the resulting materials exhibit extreme stability in harsh environments, such as in strong acid, strong base, aqueous educing agent and boiling water, even exposed to air for one year. As a proof-of-concept, such frameworks have been used to remove various organic micropollutants such as antibiotics, plastic components, endocrine disruptors, and carcinogens from water with high capacity, fast speed and excellent reusability over a wide pH range at environmentally relevant concentrations. The results provide a new avenue to significantly enhance the stability of COFs for practical applications. 相似文献
919.
920.