全文获取类型
收费全文 | 492篇 |
免费 | 10篇 |
专业分类
电工技术 | 3篇 |
综合类 | 1篇 |
化学工业 | 56篇 |
金属工艺 | 10篇 |
机械仪表 | 6篇 |
建筑科学 | 8篇 |
矿业工程 | 1篇 |
能源动力 | 11篇 |
轻工业 | 66篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 54篇 |
一般工业技术 | 59篇 |
冶金工业 | 176篇 |
原子能技术 | 1篇 |
自动化技术 | 47篇 |
出版年
2023年 | 3篇 |
2021年 | 7篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 18篇 |
2012年 | 17篇 |
2011年 | 28篇 |
2010年 | 18篇 |
2009年 | 27篇 |
2008年 | 24篇 |
2007年 | 12篇 |
2006年 | 27篇 |
2005年 | 14篇 |
2004年 | 16篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 16篇 |
2000年 | 18篇 |
1999年 | 13篇 |
1998年 | 17篇 |
1997年 | 19篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 14篇 |
1993年 | 8篇 |
1992年 | 3篇 |
1991年 | 7篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1970年 | 5篇 |
1963年 | 5篇 |
排序方式: 共有502条查询结果,搜索用时 0 毫秒
81.
Typically natural resource managers do not consider the implications of climate change even though natural resources depend on specific climatic conditions. This omission stems from the uncertainty associated with climate-change research, and an inability to apply that research to decision-making. This paper suggests that an impact assessment approach can be used to assess the impact that climate change may have on natural resource decisions demonstrating the approach by examining salmon fisheries in the Pacific Northwest. 相似文献
82.
To study the chemotactic response of sperm to an egg and to characterize sperm motility, an annular laser trap based on axicons is designed, simulated with the ray-tracing tool, and implemented. The diameter of the trapping ring can be adjusted dynamically for a range of over 400 microm by simply translating one axicon along the optical axis. Trapping experiments with microspheres and dog sperm demonstrate the feasibility of the system, and the power requirement agrees with theoretical expectation. This new type of laser trapping could provide a prototype of a parallel, objective, and quantitative tool for animal fertility and biotropism study. 相似文献
83.
57 patients with chronic temporomandibular joint (TMJ) pain were randomly assigned to receive either relaxation or biofeedback therapy. 27 Ss (mean age 35.6 yrs) listened to tape-recorded relaxation once a week at the therapist's office for 3 sessions and were encouraged to practice daily. 30 Ss (mean age 43 yrs) participated in biofeedback sessions and were instructed to practice relaxation for 20 min/day between sessions. Results show no significant differences in outcomes. However, successful Ss in the 2 conditions differed from each other. Successful relaxation Ss tended to be younger, had TMJ pain for a shorter period of time, and reported problems with other psychophysiologic disorders. Successful biofeedback Ss were older, married, had TMJ pain for a longer period of time, and had not received prior equilibration treatment. Equilibration and presence of other disorders were related to both short- and long-term outcomes, suggesting they may be useful as predictors of outcome. It is also suggested that knowledge of pretherapy factors may allow for optimal assignment to therapy conditions. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
84.
Polyethylene glycol (PEG) electrolyte solution can induce potentially fatal complications when used as a lavage in preoperative bowel preparation. A 60-year-old man with carcinoma of the esophagogastric junction had a Mallory-Weiss tear after bowel preparation with PEG. He was successfully resuscitated, first with balanced salt solution then by transfusion. The literature on the subject is reviewed and recommendations are made, which include consideration of alternative methods of bowel preparation (e.g., sodium phosphate solution) in patients with esophageal obstruction. 相似文献
85.
Harackiewicz Judith M.; Barron Kenneth E.; Carter Suzanne M.; Lehto Alan T.; Elliot Andrew J. 《Canadian Metallurgical Quarterly》1997,73(6):1284
The authors investigated personality predictors of achievement goals in an introductory psychology class, as well as the consequences of these goals for the motivation and performance of 311 undergraduates. Two dimensions of achievement motivation (workmastery and competitive orientations; J. T. Spence & R. L. Helmreich, 1983) predicted the goals endorsed. Individuals high in workmastery were more likely to adopt mastery goals and less likely to adopt work avoidance goals, whereas competitive individuals were more likely to endorse performance and work avoidance goals. Students adopting mastery goals were more interested in the class, but students adopting performance goals achieved higher levels of performance. These results suggest that both mastery and performance goals can lead to important positive outcomes in college classes. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
86.
Conventional random access memories are capable only of writing data into and reading data from the storage location corresponding to a given address. The availability of VLSI circuits containing hundreds of thousands of switching devices, however, has recently made practical the implementation of active memory chips capable of performing a range of complex operations on their stored data. Such designs are characterized by the extensive intermingling of processing and memory resources within a single chip to achieve the rapid and cost-effective parallel execution of operations relevant to such tasks as image processing, computer graphics, artificial intelligence, and database management.This paper presents a brief survey of a number of active memory chips that have been implemented or proposed, along with a more detailed examination of a particular active memory circuit, the NON-VON 3 primary processing subsystem chip.This research was supported in part by the Defense Advanced Research Projects Agency, under contract N00039-84-C-0165, in part by the New York Center for Advanced Technology in Computers and Information Systems at Columbia University, and in part by an IBM Faculty Development Award. 相似文献
87.
The process-dissociation equations (L. Jacoby, 1991) have been applied to results from inclusion and exclusion tasks to derive quantitative estimates of the influence of controlled and automatic processes on memory. This research has provoked controversies (e.g., T. Curran & D. Hintzman, 1995) regarding the validity of specific assumptions underlying the process-dissociation equations. In this article, the author explores the conclusions one can draw about the ordinal relations between automatic and controlled processes across experimental conditions from results in the inclusion and exclusion tasks. Given relatively neutral assumptions, this article presents and proves 6 theorems that allow investigators to draw conclusions about the ordinal relations between automatic and/or controlled processes across experimental conditions. An illustrative example is presented, and the current approach is compared with the original process-dissociation framework. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
88.
When a response word bearing an orthographic, acoustic, or semantic relation to a stimulus word is generated rather than read, later recall is enhanced. Such "generation effects" have been attributed to the activation or strengthening of response-specific features in memory and to the activation or strengthening of the relation between a stimulus and response. This series of experiments yields evidence suggesting that both mechanisms are involved. The pattern of interactions in the size of the generation effect across type of recall test (cued or free) cannot be accommodated by any one-factor theory. The results of these experiments also suggest that within-subjects manipulations of read and generate study conditions inflate the apparent size of the effect of generation on a given pair by confounding such pair-specific effects with certain whole-list effects, such as differential attention and output interference. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
89.
Berkman Elliot T.; Dickenson Janna; Falk Emily B.; Lieberman Matthew D. 《Canadian Metallurgical Quarterly》2011,30(2):186
Objective: Understanding the psychological processes that contribute to smoking reduction will yield population health benefits. Negative mood may moderate smoking lapse during cessation, but this relationship has been difficult to measure in ongoing daily experience. We used a novel form of ecological momentary assessment to test a self-control model of negative mood and craving leading to smoking lapse. Design: We validated short message service (SMS) text as a user-friendly and low-cost option for ecologically measuring real-time health behaviors. We sent text messages to cigarette smokers attempting to quit eight times daily for the first 21 days of cessation (N-obs = 3,811). Main outcome measures: Approximately every two hours, we assessed cigarette count, mood, and cravings, and examined between- and within-day patterns and time-lagged relationships among these variables. Exhaled carbon monoxide was assessed pre- and posttreatment. Results: Negative mood and craving predicted smoking two hours later, but craving mediated the mood–smoking relationship. Also, this mediation relationship predicted smoking over the next two, but not four, hours. Conclusion: Results clarify conflicting previous findings on the relation between affect and smoking, validate a new low-cost and user-friendly method for collecting fine-grained health behavior assessments, and emphasize the importance of rapid, real-time measurement of smoking moderators. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
90.
Avila Matthew T.; Robles Olalla; Hong L. Elliot; Blaxton Theresa A.; Myers Carol S.; Wonodi Ikwunga; Gold James; Thaker Gunvant K. 《Canadian Metallurgical Quarterly》2006,115(4):771
Individuals with schizophrenia spectrum personality disorders (SSPD) and schizophrenia show similar cognitive impairments. The authors examined the contributions of SSPD symptoms and familial risk for schizophrenia to impairments on the Continuous Performance Test-Identical Pairs Version. Participants included 103 schizophrenia patients, 66 first-degree relatives (29 SSPD), and 103 community controls (26 SSPD) screened for family history of psychosis. Patients and SSPD relatives performed significantly worse than non-SSPD relatives and SSPD and non-SSPD community controls. No differences in performance were observed among non-SSPD relatives and SSPD and non-SSPD community controls. Results suggest a continuum in which risk for schizophrenia-related cognitive impairments is highest among patients and SSPD relatives, intermediate among non-SSPD relatives, and lowest among SSPD and non-SSPD community controls. Results suggest that SSPD in the absence of a family history of psychosis may be a phenocopy. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献