全文获取类型
收费全文 | 2739篇 |
免费 | 104篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 12篇 |
化学工业 | 668篇 |
金属工艺 | 26篇 |
机械仪表 | 24篇 |
建筑科学 | 148篇 |
矿业工程 | 5篇 |
能源动力 | 53篇 |
轻工业 | 510篇 |
水利工程 | 20篇 |
石油天然气 | 6篇 |
无线电 | 107篇 |
一般工业技术 | 419篇 |
冶金工业 | 585篇 |
原子能技术 | 7篇 |
自动化技术 | 255篇 |
出版年
2023年 | 20篇 |
2022年 | 49篇 |
2021年 | 83篇 |
2020年 | 45篇 |
2019年 | 39篇 |
2018年 | 60篇 |
2017年 | 50篇 |
2016年 | 62篇 |
2015年 | 47篇 |
2014年 | 70篇 |
2013年 | 171篇 |
2012年 | 175篇 |
2011年 | 187篇 |
2010年 | 166篇 |
2009年 | 148篇 |
2008年 | 160篇 |
2007年 | 155篇 |
2006年 | 108篇 |
2005年 | 121篇 |
2004年 | 92篇 |
2003年 | 99篇 |
2002年 | 89篇 |
2001年 | 48篇 |
2000年 | 37篇 |
1999年 | 46篇 |
1998年 | 42篇 |
1997年 | 54篇 |
1996年 | 52篇 |
1995年 | 33篇 |
1994年 | 32篇 |
1993年 | 25篇 |
1992年 | 29篇 |
1991年 | 17篇 |
1990年 | 27篇 |
1989年 | 22篇 |
1988年 | 14篇 |
1987年 | 14篇 |
1986年 | 19篇 |
1985年 | 17篇 |
1984年 | 15篇 |
1983年 | 13篇 |
1982年 | 14篇 |
1980年 | 11篇 |
1979年 | 8篇 |
1978年 | 7篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1975年 | 5篇 |
1973年 | 4篇 |
1948年 | 3篇 |
排序方式: 共有2845条查询结果,搜索用时 31 毫秒
171.
172.
Catherine H. Gebotys 《The Journal of VLSI Signal Processing》1995,11(1-2):9-19
An optimization approach to the synthesis of multichip DSP architectures is presented in this paper. This research is important for Industry since it is well known that these early design decisions have a significant impact on the final VLSI implementation. A mathematical programming approach to simultaneously scheduling, partitioning (into multiple chips) and allocating minimum hardware (functional units on each chip) for the DSP application is formulated. Throughput, input/output timing, and latency constraints are supported along with interchip communication delays. By using polyhedral theory, the optimal solution to the integer programming problem can be obtained in fast cpu times. Results show that we can synthesize optimal two-chip, three-chip and four-chip architectures for a realistic Industrial DSP application in reasonable cpu times. This research breaks new ground by simultaneously partitioning, scheduling and allocating multichip DSP architectures with optimal area in fast cpu times. 相似文献
173.
Investigated 89 college students' attributions about the activity preferences of able-bodied vs physically disabled peers and evaluated the effects of imagined empathy on attributional patterns and attitudes toward disabled people. Ss were asked to predict the responses of either a male or a female able-bodied or wheelchair-user college student to items on a 20-item questionnaire offering choices between gregarious–nongregarious activities and between active–passive activities. Results indicate that there was considerable variability in able-bodied students' attributions about disabled peers' activity preferences. Previous contact with disabled people was unrelated either to attitudes toward disabled people or to activity preference attributions. Asking students to imagine empathy for a disabled peer was not an effective technique to change either attributional patterns or attitudes toward disabled people. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
174.
Differences among agents may be constructive in so far as they can bring solution enhancements or conflicts, the second case leading to solution modifications. What is dealt with in this paper is a cooperation involving different rational agents resulting in more than a mere addition of the agents' individual skills, thanks to a process of approval and refutation of the current solution. Lakatos' work is taken as a basis and adapted to a set of cooperating agents, so as to define the concept of supfA-cooperation and the corresponding interaction model. Three case studies are given, involving SuprA-cooperating human or artificial agents. 相似文献
175.
Seidenberg Michael; Hermann Bruce; Wyler Allen R.; Davies Keith; Dohan F. Curtis Jr.; Leveroni Catherine 《Canadian Metallurgical Quarterly》1998,12(2):303
The nature, pattern, and degree of neuropsychological change following anterior temporal lobectomy (ATL) were examined as a function of the presence or absence of the syndrome of mesial temporal lobe epilepsy (MTLE). Fifty-four patients exhibited the syndrome of MTLE, while 34 patients were without the syndrome (non-MTLE). The test-retest performance of a group of 40 epilepsy patients who did not undergo surgery was used to derive regression based estimates of test-retest change. Overall, the MTLE group did not show significant cognitive decline following ATL. In contrast, the left non-MTLE group showed significant declines on verbal memory, confrontation naming, and verbal conceptual ability. Further, verbal memory was the most substantial area of decline, and was independent of seizure outcome. Clinical and theoretical implications of these findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
176.
Millon Theodore; Green Catherine J.; Meagher Robert B. 《Canadian Metallurgical Quarterly》1982,27(1):23
The Millon Behavioral Health Inventory (MBHI), a 150-item self-report inventory, may provide measures relevant to the client's psychological outlook and prognosis. It also appears useful as a guide for treatment planning and psychological counseling. The rationale, development, and uses of the MBHI are briefly described, and the focus of each of the instrument's 20 scales is outlined. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
177.
Catherine Louet 《电信纪事》1977,32(5-6):171-178
The author presents a working method which allows the radioelectric modelization of a complex shape target, to be used whatever the direction of observation may be. The techniques set forth are based upon the geometrical theory of diffractionand its extensions, among which the application to simple and common shapes is classical. The extension of these methods to complicated forms set new problems, such as the research of the rays and the location of the shadow regions, the analysis of which is tackled in this article. The proposed procedure is applied to a planetype target. 相似文献
178.
The structure and the properties of hydrogenated amorphous silicon carbide films produced at room temperature by d.c. and r.f. glow discharge decomposition of silane and ethylene were studied with a systematic control of the ion flux at the surface of the growing film. The composition and structure of the films were monitored by measuring their IR absorption, their refractive index and their optical gap. The ion fluxes were determined from the saturation current of a small grid probe located in the substrate holder.It was found that d.c. cathodic and r.f. films show an inorganic structure with a dispersed carbon phase while d.c. anodic films exhibit mainly hydrogenated carbon clusters. These structural changes are thought to result from differences in the energies of the bombarding ions.The versatility of the r.f. and d.c. proximity discharges in comparison with d.c. discharges (anodic and cathodic films) is also emphasized. 相似文献
179.
Casey PG Butler D Gardiner GE Tangney M Simpson P Lawlor PG Stanton C Ross RP Hill C Fitzgerald GF 《Journal of food protection》2004,67(12):2797-2800
Salmonella carriage in pigs represents a serious health problem that undoubtedly contributes to the spread of human disease. Thus, the efficient and reliable testing of farm animals for bacteria such as Salmonella is an important aspect of any efficient control strategy. Serological analysis of 15 meat juice samples detected antibodies against Salmonella in some. but not all, of the animals identified bacteriologically as harboring the pathogen, indicating a lack of correlation between the bacteriological and serological methods used for Salmonella detection. The results suggest that testing by enzyme-linked immunosorbent assay is appropriate at the herd level, with culture methods preferable for individual animal analysis. A novel culture protocol detected Salmonella in the cecal contents of 15 pigs, whereas a method based on the European Standard identified only 9 pigs as being Salmonella-positive. During the study, an unusual finding was the relatively high incidence of Salmonella London carriage in the pigs tested. 相似文献
180.
The direct measurement of embryogenic volume and nucleo-cytoplasmic ratio during mouse pre-implantation development 总被引:1,自引:0,他引:1
Stringent selection mechanisms, in both internal and external fertilisation systems, reject all but a significant minority of the spermatozoa released at ejaculation. Sperm competition theory provides circumstantial evidence that the selection process involves mechanisms by which the quality of the fertilising spermatozoon is controlled, thereby ensuring that females and their offspring receive high quality genetic material. In this review we examine some of these selection processes to see whether they could be exploited for the improvement of laboratory tests of sperm quality. Such tests are not only required for clinical and agricultural purposes, but are increasingly needed in fields such as reproductive and environmental toxicology where the species requirement is much broader. Despite many years of research, sperm quality assessment methods continue to provide imprecise data about fertility; here we suggest that this may be a consequence of using tests that focus on the spermatozoa that would normally be unable to fertilise under natural conditions. To achieve fertilisation a spermatozoon must be capable of responding appropriately to external signalling stimuli; those involving protein kinase-regulated flagellar function seem especially influential in governing effects ranging from non-Mendelian inheritance in mammals to sperm chemotaxis in sea urchins. Examination of the elicited responses reveals considerable heterogeneity in all species. Here we propose that this level of heterogeneity is meaningful both in terms of understanding how spermatozoa from some individuals possess fertility advantages over spermatozoa from their rivals in sperm competition, and in that the heterogeneity should be exploitable in the development of more accurate laboratory tests. 相似文献