全文获取类型
收费全文 | 703篇 |
免费 | 23篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 42篇 |
化学工业 | 170篇 |
金属工艺 | 16篇 |
机械仪表 | 20篇 |
建筑科学 | 19篇 |
能源动力 | 26篇 |
轻工业 | 79篇 |
水利工程 | 4篇 |
石油天然气 | 2篇 |
无线电 | 59篇 |
一般工业技术 | 126篇 |
冶金工业 | 51篇 |
原子能技术 | 12篇 |
自动化技术 | 103篇 |
出版年
2022年 | 6篇 |
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 6篇 |
2018年 | 14篇 |
2017年 | 13篇 |
2016年 | 23篇 |
2015年 | 9篇 |
2014年 | 20篇 |
2013年 | 42篇 |
2012年 | 27篇 |
2011年 | 45篇 |
2010年 | 32篇 |
2009年 | 38篇 |
2008年 | 47篇 |
2007年 | 21篇 |
2006年 | 25篇 |
2005年 | 34篇 |
2004年 | 23篇 |
2003年 | 20篇 |
2002年 | 15篇 |
2001年 | 13篇 |
2000年 | 16篇 |
1999年 | 10篇 |
1998年 | 20篇 |
1997年 | 16篇 |
1996年 | 18篇 |
1995年 | 14篇 |
1994年 | 7篇 |
1993年 | 8篇 |
1992年 | 2篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 9篇 |
1985年 | 5篇 |
1984年 | 13篇 |
1983年 | 6篇 |
1982年 | 13篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1976年 | 4篇 |
1974年 | 7篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有729条查询结果,搜索用时 10 毫秒
41.
Physical therapists are trained in manual examination techniques to test the impaired motor functions of patients. In this study, we have introduced a wearable robotic dummy joint to simulate disordered joint resistances or behaviors to support physical therapists in learning such techniques. We developed a discontinuous joint friction model based on a stick-slip phenomenon to simulate knee joint resistances caused by crepitus, a typical symptom accompanied by osteoarthritis. Practicing therapists participated in a reality-based evaluation test and specified acceptable parameter sets to adjust the simulated crepitus for the exoskeletal patient robot. The simulated crepitus and wearable dummy joint are expected to support the training of physical therapists. 相似文献
42.
The authors have been working on natural language understanding based on the knowledge representation language L
md
and its application to robot manipulation by verbal suggestion. The most remarkable feature of L
md
is its capability of formalizing spatiotemporal events in good correspondence with human/robotic sensations and actions,
which can lead to integrated computation of sensory, motory and conceptual information. This paper describes briefly the process
from text to robot action via semantic representation in L
md
and the experimental results of robot manipulation driven by verbal suggestion.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
43.
We report on the use of ultra-thin cross-linked polymer films to coat carbon nanotubes (CNTs). When n-dodecyl glyceryl itaconate, an amphiphilic monomer, and N,N'-methylenebis(acrylamide), a cross-linker, were mixed with CNTs, an ultra-thin cross-linked DGI polymer film formed on the surface of the individual CNTs by self-assembly polymerization. The CNTs modified with the cross-linked DGI polymer film are highly soluble in water with a multi-walled CNT concentration of up to 1 wt.%, providing an attractive approach for preparing stable, mono-dispersed CNT solutions. 相似文献
44.
Shigeki Tasaka Yoshihiro Sato Nobuhito Tateyama Hisahiko Sugimoto Fumihito Fumuro Kaoru Hoshino 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1985,236(2):400-409
A new multiple scanning method is developed and applied to detect cosmic heavy nuclei. The plastic track detectors CR-39 exposed to cosmic heavy nuclei are over-etched in 8.0N NaOH for 94 h at 80°C. We found that the etched cones can easily be scanned on the plastic plates without using an optical microscope. The trajectories of heavy nuclei can be reconstructed with the naked eyes by superposing four or more over-etched plates. The charge detection threshold is obtained by this method, and appears to be 10. The charge resolution is estimated to be 1.0 charge units for iron nuclei. By adopting this method, the scanning time is much shortened and CR-39 plastic chamber size can easily be scaled up. The method is very useful for detecting particles with low flux intensity, like for searching magnetic monopoles or for measuring the high energy spectra of cosmic heavy nuclei. 相似文献
45.
46.
Arakawa Kaoru Fender Derek H. Harashima Hiroshi Miyakawa Hiroshi Saitoh Yoichi 《IEEE transactions on bio-medical engineering》1986,(7):724-726
A new nonlinear digital filter which separates nonstationary waves such as spikes from stationary background waves of the EEG is proposed. This filter is composed of a prediction filter and a simple nonlinear function. Some examples showing the separation of spikes from EEG data of epileptic patients are given. 相似文献
47.
Gozde Unal Susann Bucher Stephane Carlier Greg Slabaugh Tong Fang Kaoru Tanaka 《IEEE transactions on information technology in biomedicine》2008,12(3):335-347
Segmentation of arterial wall boundaries from intravascular images is an important problem for many applications in the study of plaque characteristics, mechanical properties of the arterial wall, its 3-D reconstruction, and its measurements such as lumen size, lumen radius, and wall radius. We present a shape-driven approach to segmentation of the arterial wall from intravascular ultrasound images in the rectangular domain. In a properly built shape space using training data, we constrain the lumen and media-adventitia contours to a smooth, closed geometry, which increases the segmentation quality without any tradeoff with a regularizer term. In addition to a shape prior, we utilize an intensity prior through a nonparametric probability-density-based image energy, with global image measurements rather than pointwise measurements used in previous methods. Furthermore, a detection step is included to address the challenges introduced to the segmentation process by side branches and calcifications. All these features greatly enhance our segmentation method. The tests of our algorithm on a large dataset demonstrate the effectiveness of our approach. 相似文献
48.
49.
Kuwae S Ohda T Tamashima H Miki H Kobayashi K 《Journal of Bioscience and Bioengineering》2005,100(5):502-510
Antithrombin is a serine protease inhibitor that inactivates several coagulation proteases, primarily thrombin and factor Xa. The Chinese hamster ovary (CHO) cell line transfected with a vector expressing recombinant human antithrombin (rAT) and a selectable marker, glutamine synthetase (GS), was cultivated in a 2-l fed-batch culture process using serum-free, glutamine-free medium. To maximize the rAT yield, effects of culture pH, balanced amino acid feeding, and an increased glutamate concentration on cell metabolism and rAT production were investigated. When cells were grown at pH values of 6.6, 6.8, 7.0, and 7.2, the maximum cell density and maximum lactate concentration decreased with decreasing pH. The highest production level of rAT was obtained at culture pH 6.8 due to the extended culture lifetime. Compared to the imbalanced amino acid feeding at culture pH 6.8, the balanced amino acid feeding increased the amount of rAT activity by 30% as a result of an increased viable cell number. A decrease in the specific glucose consumption rate (q(Glc)) with increasing culture time was observed in all the above-mentioned experiments, while the glucose concentration was maintained above 0.7 g l(-1). In addition, a decrease in the specific rAT production rate (q(rAT)) was observed after the depletion of lactate in the late cultivation stage. Taken together, these results suggest that the reduced availability of cellular energy caused by the decrease in q(Glc) and depletion of lactate led to the decrease in q(rAT). This decrease in q(rAT) was partially prevented by increasing the residual glutamate concentration from 1 mM to 7 mM, thus resulting in an additional 30% increase in the amount of rAT activity. The optimized fed-batch culture process yielded 1.0 g l(-1) rAT at 287 h of cultivation. 相似文献
50.
Kubota K Kasuga F Iwasaki E Inagaki S Sakurai Y Komatsu M Toyofuku H Angulo FJ Scallan E Morikawa K 《Journal of food protection》2011,74(10):1592-1598
Most cases of acute gastroenteritis and foodborne disease are not ascertained by public health surveillance because the ill person does not always seek medical care and submit a stool sample for testing, and the laboratory does not always test for or identify the causative organism. We estimated the total burden of acute gastroenteritis in Miyagi Prefecture, Japan, using data from two 2-week cross-sectional, population-based telephone surveys conducted in 2006 and 2007. To estimate the number of acute gastroenteritis illnesses caused by Campylobacter, Salmonella, and Vibrio parahaemolyticus in Miyagi Prefecture, we determined the number of cases for each pathogen from active laboratory-based surveillance during 2005 to 2006 and adjusted for seeking of medical care and submission of stool specimens by using data from the population-based telephone surveys. Monte Carlo simulation was used to incorporate uncertainty. The prevalence of acute gastroenteritis in the preceding 4 weeks was 3.3% (70 of 2,126) and 3.5% (74 of 2,121) in the winter and summer months, yielding an estimated 44,200 episodes of acute gastroenteritis each year in this region. Among people with acute gastroenteritis, the physician consultation rate was 32.0%, and 10.9% of persons who sought care submitted a stool sample. The estimated numbers of Campylobacter-, Salmonella-, and V. parahaemolyticus -associated episodes of acute gastroenteritis were 1,512, 209, and 100 per 100,000 population per year, respectively, in this region. These estimates are significantly higher than the number of reported cases in surveillance in this region. Cases ascertained from active surveillance were also underrepresented in the present passive surveillance, suggesting that complementary surveillance systems, such as laboratory-based active surveillance in sentinel sites, are needed to monitor food safety in Japan. 相似文献