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91.
The NERC Construct for the development, implementation and enforcement of the NERC reliability standards is analyzed from the perspectives of the economics of the public sector. The public policy solutions to the inherent market failures in providing for electric reliability in the NERC Construct are found to be at odds with the theory of the public sector. Recommendations for change in the NERC Construct are developed and postulated.  相似文献   
92.
Dynamic modeling of processes involving phase changes can be challenging due to changes in the model equations caused by appearance and disappearance of equilibrium phases. Dynamic simulation of these processes requires the ability to detect the change in the number of phases and adapt the model to the new phase regime on the fly. In this work, an easy‐to‐use nonsmooth model for dynamic simulation of processes with vapor‐liquid equilibrium is presented. The presented model does not introduce any auxiliary variables or equations, nor does it require solution of an optimization problem to determine the new phase regime during the dynamic simulation. It can therefore be used for comprehensive simulation of, e.g., distillation columns, where the number of phases present can change during startup and shutdown. The nonsmooth model is illustrated through examples of an evaporator and a distillation column. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3334–3351, 2016  相似文献   
93.
The reaction of sodium hexachloroosmate(IV) hydrate with five equivalents of tetramethylcyclopentadiene (C5Me4H2) in refluxing ethanol yielded the novel coordination compound bis(tetramethylcyclopentadienyl)chloroosmocinium(IV) hexachloroosmate, [(η 5-C5Me4H)2OsCl]2[OsCl6] (1). Compound 1 has been characterized by NMR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The cationic complex of 1 [(η 5-C5Me4H)2OsCl]+, adopts a bent geometry with a ring centroid-osmium-ring centroid angle of 146.2° and an eclipsed conformation of its two tetramethylcyclopentadienyl rings. The addition of zinc powder to sodium hexachloroosmate(IV) hydrate and five equivalents of tetramethylcyclopentadiene in refluxing ethanol produced the known compound, bis(tetramethylcyclopentadienyl)osmium, (η 5-C5Me4H)2Os (2). The crystal structure of 2 has been determined and it reveals an eclipsed arrangement of the tetramethylcyclopentadienyl rings in the solid state. The average Os–Cring bond length in octamethylosmocene 2 (2.187 Å) is in accordance with corresponding bond lengths in osmocene, (η 5-C5H5)2Os (2.19 Å) and decamethylosmocene, (η 5-C5Me5)2Os (2.18 Å).  相似文献   
94.
While peak shaving is commonly used to reduce power costs, chemical process facilities that can reduce power consumption on demand during emergencies (e.g., extreme weather events) bring additional value through improved resilience. For process facilities to effectively negotiate demand response (DR) contracts and make investment decisions regarding flexibility, they need to quantify their additional value to the grid. We present a grid-centric mixed-integer stochastic programming framework to determine the value of DR for improving grid resilience in place of capital investments that can be cost prohibitive for system operators. We formulate problems using both a linear approximation and a nonlinear alternating current power flow model. Our numerical results with both models demonstrate that DR can be used to reduce the capital investment necessary for resilience, increasing the value that chemical process facilities bring through DR. However, the linearized model often underestimates the amount of DR needed in our case studies. Published 2018. This article is a U.S. Government work and is in the public domain in the USA. AIChE J, 65: e16508, 2019  相似文献   
95.
Direct writing is a unique means to align anisotropic particles for the fabrication of textured ceramics by templated grain growth (TGG). We show that alignment of tabular barium titanate (BT) template particles (20–40 μm width and 0.5–2 μm thickness) in a PIN-PMN-PT matrix powder (d50 = 280 nm) is significantly improved during direct writing using anisotropic nozzles at high printing rates. The particle orientation distribution in as-printed filaments, and the texture orientation distribution in sintered ceramic filaments are shown to directly correlate with COMSOL Multiphysics-predicted torque distributions for direct writing with aspect ratio 2, 3 and 5 oval nozzles. Electromechanical strain properties of the textured piezoelectric ceramics significantly improved relative to random ceramics when printed with anisotropic nozzles. Simulations of aspect ratio 20 nozzles and nozzles with interior baffles demonstrate significantly increased torque and near elimination of constant shear stress cores (i.e. plug flow).  相似文献   
96.
Zirconia Nanoparticles Made in Spray Flames at High Production Rates   总被引:1,自引:0,他引:1  
Synthesis of zirconia nanoparticles by flame spray pyrolysis (FSP) at high production rates is investigated. Product powder is collected continuously in a baghouse filter unit that is cleaned periodically by air-pressure shocks. Nitrogen adsorption (BET), X-ray diffractometry (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA) are used to characterize the product powder. The effect of powder production rate (up to 600 g/h), dispersion gas flow rate, and precursor concentration on product particle size, crystallinity, morphology, and purity is investigated. The primary particle size of zirconia is controlled from 6 to 35 nm, while the crystal structure consists of mostly tetragonal phase (80–95 wt%), with the balance monoclinic phase at all process conditions. The tetragonal crystal size is close to the primary particle size, which indicates weak agglomeration of single crystals.  相似文献   
97.
A series of copolyimides were prepared via the polyamide acids (polyamic acids) from the reaction of 2,3,3′,4′-biphenyltetracarboxylic dianhydride (a-BPDA) and pyromellitic dianhydride (PMDA) with 4,4′-oxydianiline (4,4′-ODA) at dianhydride molar ratios of 9:1, 7:3, 1:1, 3:7 and 1:9. Homopolymers and a 1:1 polymer blend were also prepared. Films from the 7:3, 1:1 and 3:7 molar ratio polyamide acids reacted for 5-6 h at ambient temperature were brittle, whereas films from the same polyamide acids reacted for 24-48 h at ambient temperature were fingernail creaseable. The difference was apparently due to the initial formation of incompatible block domains that underway randomization upon longer reaction time. The differential scanning calorimetric (DSC) curves of some of the brittle films quenched after heating to 400 °C had two apparent glass transition temperatures (Tgs), indicative of two block domains. The creaseable films quenched after heating to 400 °C had single Tgs. Wide-angle X-ray diffraction showed all films to be amorphous even though the initial DSC curves showed strong endothermic peaks, generally associated with crystalline melts. These strong endotherms near the Tg region were thought to be due to relaxation of regions in the highly stressed films. Films of copolyamide acids from the reaction of 1:1 molar ratios of 3,3′,4,4′-oxydiphthalic anhydride/a-BPDA and 3,3′,4,4′-biphenyltetracarboxylic dianhydride/a-BPDA with 4,4′-ODA reacted for 6 h were fingernail creaseable. The chemistry and the properties of the copolymers are compared with those of the homopolymers.  相似文献   
98.
To evaluate the effective components of couple relationship education, 59 newlywed couples were randomly assigned to one of two couple relationship programs (CRE): (1) RELATE, which involved receiving feedback on their relationship based on the on-line RELATE assessment; or (2) RELATE + Couple CARE, which was RELATE plus completing the 6 unit Couple CARE relationship skill training program. Relative to RELATE, RELATE + Couple CARE produced more improvement in couple communication, and high relationship satisfaction across the next 12 months in women. Men sustained high and similar relationship satisfaction in either condition. Skill training CRE has additional benefits for couples beyond assessment and feedback. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
99.
This study sought to improve understanding of the persuasive process of emotion-based appeals not only in relation to negative, fear-based appeals but also for appeals based upon positive emotions. In particular, the study investigated whether response efficacy, as a cognitive construct, mediated outcome measures of message effectiveness in terms of both acceptance and rejection of negative and positive emotion-based messages. Licensed drivers (N = 406) participated via the completion of an on-line survey. Within the survey, participants received either a negative (fear-based) appeal or one of the two possible positive appeals (pride or humor-based). Overall, the study's findings confirmed the importance of emotional and cognitive components of persuasive health messages and identified response efficacy as a key cognitive construct influencing the effectiveness of not only fear-based messages but also positive emotion-based messages. Interestingly, however, the results suggested that response efficacy's influence on message effectiveness may differ for positive and negative emotion-based appeals such that significant indirect (and mediational) effects were found with both acceptance and rejection of the positive appeals yet only with rejection of the fear-based appeal. As such, the study's findings provide an important extension to extant literature and may inform future advertising message design.  相似文献   
100.
A case formulation, for a client with depression, based on emotion-focused therapy treatment principles will be presented. The client was seen for 16 sessions in emotion-focused therapy. Based on information provided in the first interview, the therapist discusses how the client’s issues can be formulated in an emotion-focused treatment by attending to different process markers, including markers of characteristic styles of being or ways of treating the self and emotional experience; modes of engagement or ways that emotional experience is processed in terms of whether it is overregulated or underregulated; specific in-session tasks like focusing, two-chair or empty chair work; and micromarkers of nonverbal behaviors including vocal quality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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