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91.
The axisymmetric Laplace equation is solved numerically to extract contact-angle data for a flat liquid/vapor interface contacting a submerged hemispherical solid. The liquid/vapor interface is treated as a membrane, with a membrane tension equal to the surface energy of the liquid. By measuring the vertical displacement of the membrane and the projected contact area the membrane makes with the hemisphere, the contact angle and correspondingly the driving force for motion of the contact line can be measured. We show that characteristic receding and advancing contact angles can be obtained by measuring the contact radii formed upon initial contact between the interface and hemisphere and final contact just prior to detachment of the interface, respectively. Use of the technique is illustrated with a model experiment involving the contact of an air/water interface with a poly(methyl methacrylate) surface. 相似文献
92.
M. Muhr S. Pack S. Jaufer H. Lugschitz 《e & i Elektrotechnik und Informationstechnik》2006,123(12):537-543
New developments in diagnostic tools and systems are necessary for a reliable and economic evaluation of the condition of
equipment in power systems. In a research project a tool for the condition of contacts of centre break disconnector, which
is used under normal operation by the aid of a thermography measurement system, has been developed. In this paper, an overview
about the laboratory investigation of the temperature load behaviour and the environmental influence on-site for new and aged
disconnector contacts are given. A condition evaluation tool for contacts, which was the aim of the project, has been created.
The basic method for the evaluation is presented, and also two additional easements for a fast identification of suspect contacts
are presented. With this evaluation tool and the usage of a thermography based measuring system, a condition based maintenance
strategy can be applied, whereby an early detection of damages is possible and so power quality and reliability increase.
相似文献
93.
The grafting of acrylic acid onto electron beam‐irradiated polypropylene was carried out using preirradiation method. The stability of peroxy radicals was investigated by electron spin resonance. It was found that the decay of peroxy radicals is much faster at 70°C than at 40°C and ambient temperature. The grafting has been observed to be strongly dependent on the monomer dilution in the reaction medium. The grafting was ascertained by attenuated total reflectance (ATR). The distribution of grafts across the samples was monitored by infrared microscopy. It was found that the graft management is considerably influenced by composition of the grafting medium. The grafting involving pure monomer leads to the surface enrichment with the polyacrylic acid chains. The samples grafted in pure monomer led to much lower contact angles as compared to the diluted monomer solution. The swelling of the grafted samples also showed a trend that was governed by the graft management. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 546–553, 2006 相似文献
94.
在非AWGN环境下,针对CW,AM,FM,OOK,PSK,QPSK,16QAM,FSK,MSK,SSB十种混合调制信号,对调制类型特征提取方法和自动识别算法进行了分析、综合、设计和计算机仿真。提出了梯层电平分析方法、频率瞬时信号分析、剔除载波的归一化能量分析、平方后信号的频谱分析、四次方后的信号频谱分析等方法。当SNR=10dB时,计算机仿真结果是正确识别率不低于95%,自动识别的平均处理时间为不超过10s。 相似文献
95.
共聚物水凝胶的合成及其溶胀性能研究 总被引:3,自引:1,他引:2
以过氧化二苯甲酰(BPO)为引发剂,合成了N-乙烯基吡咯烷酮(NVP)-甲基丙烯酸肛羟乙酯(HEMA)-甲基丙烯酸丁酯(BMA)共聚物水凝胶,可作为软性角膜接触镜材料。探讨了不同比例的NVP、HEMA、BMA对材料溶胀性能的影响。 相似文献
96.
This paper presents some results from a totally new and powerful fusion between automated, digital photoelastic techniques and mathematical analysis of a crack experiencing closure. In essence, real-time photoelastic stress field data is acquired and fitted to a Muskhelishvili complex potential model of a loaded crack experiencing closure. The fit entails optimisation of multiple variables via a memetic algorithm, which combines a genetic algorithm and a local search. From observations made in this work, it is proposed that the plastic enclave around a crack tip will shield the crack from the full influence of the applied stress field. Furthermore, the effects of this ‘back stress’ are overcome by the applied tensile load in a way that, often, cannot be readily correlated with crack contact length, wake contact force, or with compliance. 相似文献
97.
To confirm the reliability of the theory of phase equibria of multicomponent polymer 1/multicomponent polymer 2 systems (i.e. quasi-binary systems) and the method of computer experiment based on this theory (Brit. Polym. J., 23 (1990)285; 23 (1990)299; Polym. Int., 29 (1992)219), could point curves (CPC), two-phase volume ratios ( R ) and critical solution points (CSP) have been determined experimentally for the quasi-binary mixtures of poly(ethylene oxide) (M¯w = 647, M¯w/M¯n = 1.15; M¯w and M¯n, the weight-average and numberaverage molecular weights, respectively) and poly(propylene oxide) (M¯w = 2028, M¯w/M¯n = 1.08; and Mw = 2987, Mw/Mn = 1.13). The hydroxyl end groups of both polymers were methoxylated in advance by the Cooper & Booth method (Polymer, 18 (1977)164). The thermodynamic interaction parameter between both polymers, χ12, and the concentration dependence parameters for the above quasi-binary systems were determined by the method proposed in a previous paper (Brit. Polym. J., 23 (1990)299). CPC, R and CSP values calculated on the basis of the theory are in good agreement with the values determined experimentally. 相似文献
98.
99.
Reviews the book, The concept of structure in psychoanalysis by Theodore Shapiro (see record 1991-97355-000). The present volume is a hardcover edition of a previous supplement to the Journal of the American Psychoanalytic Association based on a series of panels presented at meetings of the American on the role of the concept of structure in current psychoanalytic theory and practice. The result can be taken as a more or less authoritative expression of current thinking about structure in orthodox analytic circles. As such, the volume is informative and in many regards thought provoking. But if readers are looking for a coherent, consistent, and consensually endorsed presentation of the idea of structure, or for a uniform conceptualization of the nature of psychic structure and its role in psychoanalytic praxis, they will have to look elsewhere. The volume is more remarkable for its diversity and often contradictory views on the nature of structure and the relevance of structure to clinical work in the analytic setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
100.
According to D. E. Broadbent's (1958) selective filter theory, people do not process unattended stimuli beyond the analysis of basic physical properties. This theory was later rejected on the basis of numerous findings that people identify irrelevant (and supposedly unattended) stimuli. A careful review of this evidence, however, reveals strong reasons to doubt that these irrelevant stimuli were in fact unattended. This review exposed a clear need for new experiments with tight control over the locus of attention. The authors present 5 such experiments using a priming paradigm. When steps were taken to ensure that irrelevant stimuli were not attended, these stimuli produced no priming effects. Hence, the authors found no evidence that unattended stimuli can be identified. The results support a modern version of Broadbent's selective theory, updated to reflect recent research advances. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献