全文获取类型
收费全文 | 5198篇 |
免费 | 123篇 |
国内免费 | 27篇 |
专业分类
电工技术 | 412篇 |
综合类 | 17篇 |
化学工业 | 1500篇 |
金属工艺 | 136篇 |
机械仪表 | 138篇 |
建筑科学 | 189篇 |
矿业工程 | 1篇 |
能源动力 | 244篇 |
轻工业 | 506篇 |
水利工程 | 19篇 |
石油天然气 | 7篇 |
无线电 | 286篇 |
一般工业技术 | 917篇 |
冶金工业 | 180篇 |
原子能技术 | 214篇 |
自动化技术 | 582篇 |
出版年
2023年 | 30篇 |
2022年 | 59篇 |
2021年 | 96篇 |
2020年 | 52篇 |
2019年 | 63篇 |
2018年 | 75篇 |
2017年 | 63篇 |
2016年 | 112篇 |
2015年 | 79篇 |
2014年 | 151篇 |
2013年 | 320篇 |
2012年 | 185篇 |
2011年 | 306篇 |
2010年 | 257篇 |
2009年 | 279篇 |
2008年 | 314篇 |
2007年 | 262篇 |
2006年 | 203篇 |
2005年 | 220篇 |
2004年 | 176篇 |
2003年 | 161篇 |
2002年 | 165篇 |
2001年 | 105篇 |
2000年 | 96篇 |
1999年 | 97篇 |
1998年 | 104篇 |
1997年 | 73篇 |
1996年 | 71篇 |
1995年 | 55篇 |
1994年 | 82篇 |
1993年 | 69篇 |
1992年 | 56篇 |
1991年 | 75篇 |
1990年 | 52篇 |
1989年 | 77篇 |
1988年 | 65篇 |
1987年 | 39篇 |
1986年 | 73篇 |
1985年 | 56篇 |
1984年 | 53篇 |
1983年 | 57篇 |
1982年 | 60篇 |
1981年 | 47篇 |
1980年 | 42篇 |
1979年 | 41篇 |
1978年 | 41篇 |
1977年 | 28篇 |
1976年 | 28篇 |
1975年 | 18篇 |
1973年 | 17篇 |
排序方式: 共有5348条查询结果,搜索用时 15 毫秒
101.
Human behaviors consist of both voluntary and involuntary motions. Almost all behaviors of task-oriented robots, however, consist solely of voluntary motions. Involuntary motions are important for generating natural motions like those of humans. Thus, we propose a natural behavior generation method for humanoid robots that is a hybrid generation between voluntary and involuntary motions. The key idea of our method is to control robots with a hybrid controller that combines the functions of a communication behavior controller and body balancing controllers. We also develop a wheeled inverted pendulum type of humanoid robot, named “Robovie-III”, in order to generate involuntary motions like oscillation. By applying our method to this robot and conducting preliminary experiments, we verify its validity. Experimental results show that the robot generates both voluntary and involuntary motions. 相似文献
102.
Zhang Ming CHEN Haiyan Chen Xiaosong Dai Shaojun Inoue Shinich OKAMOTO Hiroshi 《中国稀土学报(英文版)》2004,22(Z3)
Acrylic acid rare earth complex was prepared. Its chemical composition was determined by chemical and elemental analysis, and its structure as well as properties was characterized using IR, Fluorescence and UV spectrum, and its solubility was also investigated. Meanwhile a kind of elastic functional polymer with rare earth units in the side chains was produced. It is confirmed by IR spectrum that the Si-H bonds really react with acrylic acid rare earth. 相似文献
103.
Hiroshi Fujita 《Microscopy research and technique》1986,3(3):243-304
High voltage electron microscopy has shown numerous advantages for the study of natural science, including biology, but it is especially useful in materials science. The most important advantage for materials science is in-situ experiments on detailed processes of the same phenomena that occur in bulk materials. For such in-situ experiments, the specimens should be thicker than a few microns to observe the behavior of lattice effect. The maximum observable thickness of the specimens and other advantages markedly increase with increasing accelerating voltage, and since 1965, two 3 MV instruments have been installed. The present paper is mainly concerned with these 3 MV electron microscopes and their applications to new research fields. 相似文献
104.
Atsushi Kubota Shogo Tatsumi Toshihiko Tanaka Masahiro Goshima Shin-Ichiro Mori Hiroshi Nakashima Shinji Tomita 《International journal of parallel programming》1999,27(2):97-109
Optimizing inter-processor (PE) communication is crucial for parallelizing compilers for message-passing parallel machines to achieve high performance. In this paper, we propose a technique to eliminate redundant inter-PE messages. This technique utilizes data-flow analysis to find a definition point that corresponds to a use point where the definition and the use occur in different PEs. If several read accesses occurred in the same PE use the data defined at the same definition point in another PE, redundant inter-PE messages are eliminated as follows: only one inter-PE communication is performed for the earliest read access and the previously received data are used for the following read. In order to guarantee the consistency of the data, a valid flag and a sent flag are provided for each chunk of received data. The control of these flags is equivalent to the coherence control by the self invalidation on a compiler aided cache coherence scheme. 相似文献
105.
106.
In this study, the damage evolution behavior was evaluated considering the effect of the textile structure and water absorption. Damage observation was conducted by the integration of non-destructive and direct observation methods. Candidate textile reinforcements were T300-3k plain woven fabric (PW) and T700S-12k multi-axial knitted fabric (MA). The effect of water absorption on the performances of compression after impact (CAI) and PIF were small in PW CFRP laminates. Conversely, PIF properties of water-absorbed MA CFRP laminates drastically decreased than that of dry ones. CAI strength was not affected by water absorption. PIF performance of dry MA CFRP was fairly higher than that of the others. From the precise observation, some evidences of interfacial deterioration caused by water absorption were confirmed in both PW and MA CFRP laminates. 相似文献
107.
Sota H Yoshimine H Whittier RF Gotoh M Shinohara Y Hasegawa Y Okahata Y 《Analytical chemistry》2002,74(15):3592-3598
Despite high theoretical sensitivity, low-cost manufacture, and compactness potentially amenable to lab-on-a-chip use, practical hurdles have stymied the application of the quartz crystal microbalance (QCM) for aqueous applications such as detection of biomolecular interactions. The chief difficulty lies in achieving a sufficiently stable resonance signal in the presence of even minute fluctuations in hydrostatic pressure. In this work, we present a novel versatile planar sensor chip design (QCM chip) for a microliter-scale on-line biosensor. By sealing the quartz resonator along its edges to a flat, solid support, we provide uniform support for the crystal face not exposed to solvent, greatly decreasing deformation of the crystal resonator under hydrostatic pressure. Furthermore, this cassette design obviates the need for direct handling when exchanging the delicate quartz crystal in the flow cell. A prototype 27-MHz sensor signal exhibited very low noise over a range of flow rates up to 100 microL/min. In contrast, signals obtained from a conventional QCM sensor employing an O-ring-based holder were less stable and deteriorated even further with increasing flow rate. Additional control designs with intermediate amounts of unsupported undersurface yielded intermediate levels of stability, consistent with the interpretation that deformation of the crystal resonator under fluctuating hydraulic pressure is the chief source of noise. As a practical demonstration of the design's high effective sensitivity, we readily detected interaction between myoglobin and surface-bound antibody. 相似文献
108.
Single-heterostructure crystals of a series of halogen-bridged quasi-one- dimensional mixed-valence transition metal complexes (HMMCs) were fabricated by selective coordination epitaxial growth (SCE growth). The overgrowth crystals of the HMMC were grown on the columnar crystals of the substrate HMMC in solution. The single-heterostructure crystals were epitaxially grown only when the two HMMCs had similar crystal structures. If their crystal structures were different, no heterostructure crystal was grown. This result suggests that the degree of mismatch between the crystal structures of the substrate and the overgrowth is the predominant factor which determines the SCE growth of the HMMCs. 相似文献
109.
Shunpei Yamazaki Takuya Hirohashi Masahiro Takahashi Shunsuke Adachi Masashi Tsubuku Junichi Koezuka Kenichi Okazaki Yohsuke Kanzaki Hiroshi Matsukizono Seiji Kaneko Shigeyasu Mori Takuya Matsuo 《Journal of the Society for Information Display》2014,22(1):55-67
Our crystalline In–Ga–Zn oxide (IGZO) thin film has a c‐axis‐aligned crystal (CAAC) structure and maintains crystallinity even on an amorphous base layer. Although the crystal has c‐axis alignment, its a‐axis and b‐axis have random arrangement; moreover, a clear grain boundary is not observed. We fabricated a back‐channel‐etched thin‐film transistor (TFT) using the CAAC‐IGZO film. Using the CAAC‐IGZO film, more stable TFT characteristics, even with a short channel length, can be obtained, and the instability of the back channel, which is one of the biggest problems of IGZO TFTs, is solved. As a result, we improved the process of manufacturing back‐channel‐etched TFTs. 相似文献
110.
Galactose and N-acetyl-D-galactosamine-inhibitable lectin of Entamoeba histolytica have roles in the pathogenicity of intestinal amoebiasis. Igl1, the intermediate subunit lectin-1 of E. histolytica, has been shown to have both hemolytic and cytotoxic activities that reside in the C-terminus of the protein. To identify the amino acid regions responsible for these activities, recombinant proteins were prepared and used in hemolytic and cytotoxic assays. The results revealed that Igl1 has multiple domains with hemolytic and cytotoxic activities and that amino acids 787-846, 968-1028 and 1029-1088 are involved in these activities. The hemolytic activities of the fragments were partly inhibited by mannose, galactose and N-acetylgalactosamine, and glucose showed lower or negligible inhibitory effects for the activities. This is the first report of a protozoan protein with hemolytic and cytotoxic activities in multiple domains. 相似文献