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111.
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Shape deformation in continuous map generalization   总被引:2,自引:0,他引:2  
Given a collection of regions on a map, we seek a method of continuously altering the regions as the scale is varied. This is formalized and brought to rigor as well-defined problems in homotopic deformation. We ask the regions to preserve topology, area-ratios, and relative position as they change over time. A solution is presented using differential methods and computational geometric techniques. Most notably, an application of this method is used to provide an algorithm to obtain cartograms.
Rachel WardEmail:

Jeff Danciger   Jeffrey received his undergraduate degree from the College of Creative Studies at UCSB in mathematics and physics. He is currently working on his Ph.D. in mathematics at Stanford University. His research interests include low dimensional topology and geometric analysis. Satyan L. Devadoss   is an Associate Professor of Mathematics at Williams College. His research interests lie in the interplay between topology and geometry, notably in applications to theoretical physics (moduli spaces and string theory) and computer science (cartography and polytopes). John Mugno   received his undergraduate degree from Williams College and is currently continuing his studies in mathematics at the University of Maryland. His areas of interest include combinatorics and topology. Don Sheehy   received his undergraduate degree in Princeton University and is currently pursuing a PhD in Computer Science at Carnegie Mellon University. His research focuses on computational geometry algorithms for meshing. Rachel Ward   received her undergraduate degree at the University of Texas at Austin. She is now a PhD student at Princeton University in the Program in Applied and Computational Mathematics. Her current work is in the area of compressed sensing, combining tools from computational harmonic analysis, probability, and optimization theory.   相似文献   
113.
Cheating is rampant in current gameplay on the Internet. However, it isn't as well understood as we might expect. The authors summarize the various known methods of cheating and define a taxonomy of online game cheating with respect to the underlying vulnerability, consequence, and cheating principal. This taxonomy provides a systematic introduction to the characteristics of cheats in online games and how they can arise. Although cheating in online games is largely due to various security failures, the four traditional aspects of security—confidentiality, integrity, availability, and authenticity—are insufficient to explain it. Instead, fairness becomes a vital additional aspect, and its enforcement provides a convincing perspective for understanding security techniques' role in developing and operating online games.  相似文献   
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Sulfur hexafluoride (SF6) was injected into a 9 km reach of the Santa Ana River in Orange County, CA, over a period of two weeks. The entire flow of this river, which averaged 2.8 m3 s?1, percolated into the ground in the field area. The tracer was monitored at wells near the river to determine subsurface flow patterns and flow times with an accuracy much greater than could be achieved using numerical simulations of ground-water flow. During the experiment, SF6 effectively tagged 3.7 × 106 m3 of water. The tracer plume was mapped in the subsurface for 18 months and indicates that linear ground-water velocities averaged about 2 km year?1. The tracer reached two wells adjacent to the river (about 200 m away) within three weeks, giving evidence that SF6 was not retarded significantly relative to the ground-water flow. This is in agreement with previous laboratory experiments.  相似文献   
116.
Patton  Jeff 《Software, IEEE》2008,25(5):72-73
Design teams rarely consider multiple solution ideas before committing to one. They often forget that an even better idea could be just around the corner, and consider alternative ideas only when they don't like the current one. Using sketchboarding, design studio, or a combination of these two techniques can let teams quickly ideate over many solutions. They then have a chance to arrive at a solution that no one individual had thought of.  相似文献   
117.
Gatekeeper-training programs, designed to increase identification and referral of suicidal individuals, are widespread but largely untested. A group-based randomized trial with 32 schools examined impact of Question, Persuade, Refer (QPR) training on a stratified random sample of 249 staff with 1-year average follow-up. To test QPR impact, the authors introduced and contrasted 2 models of gatekeeper-training effects in a population: gatekeeper surveillance and gatekeeper communication. Intent-to-treat analyses showed that training increased self-reported knowledge (effect size [ES] = 0.41), appraisals of efficacy (ES = 1.22), and service access (ES = 1.07). Training effects varied dramatically. Appraisals increased most for staff with lowest baseline appraisals, and suicide identification behaviors increased most for staff already communicating with students about suicide and distress. Consistent with the communication model, increased knowledge and appraisals were not sufficient to increase suicide identification behaviors. Also consistent with the communication model were results from 2,059 8th and 10th graders surveyed showing that fewer students with prior suicide attempts endorsed talking to adults about distress. Skill training for staff serving as "natural gatekeepers" plus interventions that modify students' help-seeking behaviors are recommended to supplement universal gatekeeper training. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
118.
Three experiments were conducted to test the hypothesis, derived from terror management theory, that reminding people of their mortality increases attraction to those who consensually validate their beliefs and decreases attraction to those who threaten their beliefs. In Study 1, subjects with a Christian religious background were asked to form impressions of Christian and Jewish target persons. Before doing so, mortality was made salient to half of the subjects. In support of predictions, mortality salience led to more positive evaluations of the in-group member (the Christian) and more negative evaluations of the out-group member (the Jew). In Study 2, mortality salience led to especially negative evaluations of an attitudinally dissimilar other, but only among subjects high in authoritarianism. In Study 3, mortality salience led to especially positive reactions to someone who directly praised subjects' cultural worldviews and especially negative reactions to someone who criticized them. The implications of these findings for understanding in-group favoritism, prejudice, and intolerance of deviance are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
119.
The author describes the process that led him to run for election to the Arizona State House of Representatives. His decision was more the result of an interest in the political process and a commitment to the principles of the democratic process than simply a belief that he could effect major changes in the delivery of mental health care to Arizona's citizens. He is now 1 voice out of the 91 in the Arizona State House of Representatives, not 1 voice in about 5 million residents of the state. His training as a psychologist, including training in the scientific method, has helped him become a better representative. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
120.
Research has demonstrated that oral reading fluency probes are reliable and valid for indexing reading achievement. If these probes are to be used for decision making, bias must be examined for various factors, including ethnicity, gender, language background, and socioeconomic status. Data from nearly 4,000 Caucasian and Hispanic students in grades one through three were used to examine potential bias in oral reading fluency scores predicting Stanford Achievement Test-Ninth Edition (SAT-9; Harcourt Brace & Co., 1997a, 1997b) Total Reading scores. Using a series of hierarchical multiple regression models, bias was first examined using concurrent SAT-9 scores as the criterion and then examined using subsequent SAT-9 scores as the criterion. The results reveal that it is the combination of factors, not any one in isolation, that significantly contributes to intercept bias findings. Overall, home language emerged as the strongest factor influencing bias in the prediction of SAT-9 scores from oral reading fluency scores. The implications of these findings are discussed as related to current and proposed uses of oral reading fluency probes. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
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