全文获取类型
收费全文 | 6747篇 |
免费 | 13篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 6篇 |
综合类 | 1篇 |
化学工业 | 142篇 |
金属工艺 | 5篇 |
机械仪表 | 4篇 |
建筑科学 | 19篇 |
能源动力 | 8篇 |
轻工业 | 47篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 46篇 |
一般工业技术 | 68篇 |
冶金工业 | 6363篇 |
原子能技术 | 6篇 |
自动化技术 | 44篇 |
出版年
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 11篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 13篇 |
2014年 | 7篇 |
2013年 | 16篇 |
2012年 | 15篇 |
2011年 | 19篇 |
2010年 | 17篇 |
2009年 | 12篇 |
2008年 | 15篇 |
2007年 | 14篇 |
2006年 | 10篇 |
2005年 | 17篇 |
2004年 | 11篇 |
2003年 | 25篇 |
2002年 | 12篇 |
2001年 | 7篇 |
2000年 | 10篇 |
1999年 | 212篇 |
1998年 | 2022篇 |
1997年 | 1103篇 |
1996年 | 799篇 |
1995年 | 417篇 |
1994年 | 341篇 |
1993年 | 374篇 |
1992年 | 47篇 |
1991年 | 95篇 |
1990年 | 58篇 |
1989年 | 74篇 |
1988年 | 74篇 |
1987年 | 72篇 |
1986年 | 73篇 |
1985年 | 58篇 |
1983年 | 7篇 |
1982年 | 27篇 |
1981年 | 43篇 |
1980年 | 68篇 |
1979年 | 11篇 |
1978年 | 22篇 |
1977年 | 140篇 |
1976年 | 320篇 |
1975年 | 11篇 |
1972年 | 2篇 |
1955年 | 5篇 |
1903年 | 2篇 |
排序方式: 共有6762条查询结果,搜索用时 15 毫秒
71.
DL Zealear CL Rainey GD Herzon JL Netterville RH Ossoff 《Canadian Metallurgical Quarterly》1996,105(9):689-693
This study represents the first attempt to electrically pace the paralyzed human larynx. The goal was to determine if electrical stimulation of the posterior cricoarytenoid muscle could produce functional abduction of the vocal fold in pace with inspiration. An external apparatus was used to sense inspiration and reanimate the unilaterally paralyzed larynx of a thyroplasty patient. Stimuli were delivered through a needle electrode to locate and pace the abductor muscle. The magnitude of electrically induced abduction was comparable to spontaneous movement on the normal side. The abduction was appropriately timed with inspiration: this finding demonstrated that this simple pacing system could effectively modulate stimulation with patient respiration. 相似文献
72.
The reduction of nitric oxide with ammonia on an unsupported iron oxide catalyst has been studied in a continuous-flow recycle reactor using simulated flue gas. The responses of the employed reactor system to step and pulse inputs of tracer indicate that the system could be regarded as a continuous stirred tank reactor (CSTR). Preliminary tests were carried out to determine the effect of temperature and particle size on the measured reaction rates. Additional experiments were performed in order to study the influence of oxygen and water concentration on these rates. A gas chromatographic system has been developed to analyze the gas components NO, N2O, NO2, NH3, H2O, O2, CO2 and N2. In addition, the concentrations of NO and NO2 were measured with a nondisperse infrared (NDUV/NDIR) analyzer. 相似文献
73.
A method of posterior mitral annulus remodeling is presented. The posterior annulus is divided into three segments, each segment encircled by a suture that is passed in a tourniquet. Coaptation of the leaflets can be achieved by tightening the tourniquets while the ventricle is being filled. This technique is simple and quick, avoids the use of foreign material, and requires less expertise and judgment than traditional annuloplasties. 相似文献
74.
A new principle and arrangement for directly determining the angle of incidence of an optical beam on an object are proposed and demonstrated. The novelty of the approach lies in the realization of a ‘smart object’, which extracts a portion of the incident beam's power into an optical waveguide attached to the object's surface or embedded in its body for converting the angle of incidence into the position of a guided beam with finite lateral extent. This ‘integrated optical light pointer’ beam is accomplished by means of creating additional degrees of freedom on the target in two different ways. While a first type is based on introducing spatial variations of the waveguide thickness, a second type makes use of a chirp of the grating periodicity. The feasibility for practical applications has been experimentally demonstrated by a direct comparison with a commercial high-resolution encoder, resulting in an r.m.s. error of <30′'. Measurements have been performed for chips fabricated based on replicated polycarbonate substrates and with no external optics, showing the great potential of this approach for realizing low-cost yet high-performance miniature goniometers. 相似文献
75.
76.
Y Munakata JL McClelland MH Johnson RS Siegler 《Canadian Metallurgical Quarterly》1997,104(4):686-713
Infants seem sensitive to hidden objects in habituation tasks at 3.5 months but fail to retrieve hidden objects until 8 months. The authors first consider principle-based accounts of these successes and failures, in which early successes imply knowledge of principles and failures are attributed to ancillary deficits. One account is that infants younger than 8 months have the object permanence principle but lack means-ends abilities. To test this, 7-month-olds were trained on means-ends behaviors and were tested on retrieval of visible and occluded toys. Means-ends demands were the same, yet infants made more toy-guided retrievals in the visible case. The authors offer an adaptive process account in which knowledge is graded and embedded in specific behavioral processes. Simulation models that learn gradually to represent occluded objects show how this approach can account for success and failure in object permanence tasks without assuming principles and ancillary deficits. 相似文献
77.
The benefits of using a comprehensive annotation strategy (employing underlining/circling, making connections, asking questions, and making comments) with knowledge maps (spatial/verbal arrays) and traditional, linear text to improve free recall scores for learners with individual differences in vocabulary and comprehension ability were examined. Types and frequencies of annotations generated were also examined for each stimulus format condition. Multiple regression analyses indicate that the frequency of use of two component annotation strategies, asking questions and making connections, were significant predictors of recall scores, while frequency of underlining/circling and generating elaborations failed to predict recall scores. Text users generated more underlining/circling, while knowledge map users generated more connections between ideas, suggesting that knowledge maps may facilitate the application of more productive annotation strategies. Also examined were the interrelationships between vocabulary ability, comprehension ability, and free recall scores. Copyright 1997Academic Press 相似文献
78.
LB Corbeil RP Gogolewski I Kacskovics KH Nielsen RR Corbeil JL Morrill R Greenwood JE Butler 《Canadian Metallurgical Quarterly》1997,61(3):207-213
AIMS/BACKGROUND: To characterise clinically a large kindred segregating retinitis pigmentosa and sensorineural hearing impairment in an autosomal dominant pattern and perform genetic linkage studies in this family. Extensive linkage analysis in this family had previously excluded the majority of loci shown to be involved in the aetiologies of RP, some other forms of inherited retinal degeneration, and inherited deafness. METHODS: Members of the family were subjected to detailed ophthalmic and audiological assessment. In addition, some family members underwent skeletal muscle biopsy, electromyography, and electrocardiography. Linkage analysis using anonymous microsatellite markers was performed on DNA samples from all living members of the pedigree. RESULTS: Patients in this kindred have a retinopathy typical of retinitis pigmentosa in addition to a hearing impairment. Those members of the pedigree examined demonstrated a subclinical myopathy, as evidence by abnormal skeletal muscle histology, electromyography, and electrocardiography. LOD scores of Zmax = 3.75 (theta = 0.10), Zmax = 3.41 (theta = 0.10), and Zmax = 3.25 (theta = 0.15) respectively were obtained with the markers D9S118, D9S121, and ASS, located on chromosome 9q34-qter, suggesting that the causative gene in this family may lie on the long arm (q) of chromosome 9. CONCLUSIONS: These data indicate that the gene responsible for the phenotype in this kindred is located on chromosome 9 q. These data, together with evidence that a murine deafness gene is located in a syntenic area of the mouse genome, should direct the research community to consider this area as a candidate region for retinopathy and/or deafness genes. 相似文献
79.
80.