全文获取类型
收费全文 | 718篇 |
免费 | 21篇 |
国内免费 | 2篇 |
学科分类
工业技术 | 741篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2021年 | 19篇 |
2020年 | 7篇 |
2019年 | 11篇 |
2018年 | 8篇 |
2017年 | 13篇 |
2016年 | 14篇 |
2015年 | 11篇 |
2014年 | 25篇 |
2013年 | 34篇 |
2012年 | 29篇 |
2011年 | 39篇 |
2010年 | 36篇 |
2009年 | 34篇 |
2008年 | 49篇 |
2007年 | 35篇 |
2006年 | 39篇 |
2005年 | 42篇 |
2004年 | 20篇 |
2003年 | 21篇 |
2002年 | 21篇 |
2001年 | 18篇 |
2000年 | 9篇 |
1999年 | 11篇 |
1998年 | 30篇 |
1997年 | 18篇 |
1996年 | 23篇 |
1995年 | 15篇 |
1994年 | 16篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 14篇 |
1990年 | 11篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有741条查询结果,搜索用时 46 毫秒
11.
Inflammatory pseudotumor of the liver is a rare lesion characterized by proliferating fibrovascular tissue admixed with inflammatory cells. A 50-yr-old Japanese man was hospitalized because of upper abdominal pain and high fever. Computed tomography revealed a poorly demarcated, low density mass in the left lobe of the liver, and abnormal laboratory findings included WBC 9340/mm3, CRP 10.5 mg/dl, and marked elevation of CA19-9 to 1167.9 U/ml. Endoscopic retrograde cholangiography showed irregularity of the intrahepatic bile duct of the left lateral segment, and the lateral segmental branches of the portal vein were not visualized on the venous phase of abdominal angiography. Ultrasound-guided liver biopsy was performed, but malignant disease, including intrahepatic cholangiocarcinoma, could not be completely ruled out. The patient underwent left hepatic lobectomy with lymph node dissection. Histopathological examination yielded a definitive diagnosis of inflammatory pseudotumor. The lesion was immunohistochemically stained for CA19-9 by the ABC method, and the biliary epithelium in severely inflamed portal canals was found to be positive. The markedly elevated preoperative level of CA 19-9 decreased to almost within the normal range and the patient remains well 2 yr 9 months after surgery, without any complications. 相似文献
12.
In this paper, we propose a multi-agent learning system for the control of an intelligent robot, based on a model of the human
consciousnesses, including the ego. We pay attention to the intelligent learning processes of human beings. We try to give
a robot a high learning ability by modeling the roles of the human consciousnesses, including the ego. In most ordinary methods,
the instructions for learning are given from outside the system only. In the proposed method, the instructions are given not
only from outside, but also from inside (from other agents in the system). Therefore, the robot can learn efficiently because
it has more instructions than usual. The learning is also more flexible, since an agent learns by instructions from other
agents while the learning agent and one of the instructing agents exchange roles according to changes in the environment.
We experimentally verified that the proposed method is efficient by using an actual robot. 相似文献
13.
Toshihide Miyagi Norihiro Abe Yoshimasa Kinoshita Tatsushi Tokuyasu Hirokazu Taki Shoujie He 《Artificial Life and Robotics》2009,14(2):237-241
In this article, a system is proposed for a simulated operation which would help a trainee surgeon to perform a medical operation
to ensure that a cerebral aneurysm does not burst. The physician will have acquired empirical medical technologies from operations
in traditional clinical teaching. However, there is a problem with safety and the burden to the patient. Therefore, recently
a new training approach for a simulated medical operation using virtual reality has been explored. With the aim of developing
a simulated system for a medical operation for a cerebral aneurysm, we considered the necessary functions such as detecting
the brain aneurysm that is the target of the operation, and searching for a suitable blood vessel to make a plan for the operation. 相似文献
14.
Yuki Takenaka Norihiro Abe Yoshihiro Tabuchi Hirokazu Taki Shoujie He 《Artificial Life and Robotics》2009,14(2):224-227
This research was aimed at making a robot that can go and get an object designated by the user. We produced a robot control
system that uses pointing and voice control. This control system is composed of two systems. One system is the object instruction
system that uses pointing, and the other is the object instruction system that uses voice. The approximate position of a designated
object is recognized by the object instruction system that uses pointing, and information about the object and instructions
about the operation are conveyed by the object instruction system that uses voice. This time, the object instruction system
that uses pointing has been designed and verified as the first step. A calculation resource to calculate the approximate position
of the designated object is obtained when the user points directly at the object. A robot can be moved around a designated
object by using this system. The object instruction system that uses voice will be constructed in future work. 相似文献
15.
We propose to redesign a neural network used as a motion generator with bimanual coordination for upper limb prosthesis in
order to improve its learning capability. We assumed that the wearer of the prosthesis was a unilateral amputee. In our previous
work, we proposed a prosthesis control system using a neural network that learned bimanual coordination in order to implement
smooth motion with both hands. However, the previously proposed system has the problem that a neural network cannot generate
the desired motion of the prosthesis in special cases. The reason is that the motion generator calculates the desired posture
of the prosthesis from the current posture of the healthy arm only, regardless of the current posture of the prosthesis. We
propose to use the current posture of both the healthy arm and the prosthesis as neural network inputs in order to solve this
problem. In this article, we show that a single neural network whose input was the current posture of both arms could learn
the relationships of the coordinated motions of holding boxes of different sizes, and the newly proposed system can calculate
the desired motion of the prosthesis in special cases through computer simulations. 相似文献
16.
Kensuke Yokoi 《Computer Physics Communications》2009,180(7):1145-1149
We propose a simple and robust numerical algorithm to deal with multi-phase motion of gas, liquid and solid based on the level set method [S. Osher, J.A. Sethian, Front propagating with curvature-dependent speed: Algorithms based on Hamilton-Jacobi formulation, J. Comput. Phys. 79 (1988) 12; M. Sussman, P. Smereka, S. Osher, A level set approach for capturing solution to incompressible two-phase flow, J. Comput. Phys. 114 (1994) 146; J.A. Sethian, Level Set Methods and Fast Marching Methods, Cambridge University Press, 1999; S. Osher, R. Fedkiw, Level Set Methods and Dynamics Implicit Surface, Applied Mathematical Sciences, vol. 153, Springer, 2003]. In Eulerian framework, to simulate interaction between a moving solid object and an interfacial flow, we need to define at least two functions (level set functions) to distinguish three materials. In such simulations, in general two functions overlap and/or disagree due to numerical errors such as numerical diffusion. In this paper, we resolved the problem using the idea of the active contour model [M. Kass, A. Witkin, D. Terzopoulos, Snakes: active contour models, International Journal of Computer Vision 1 (1988) 321; V. Caselles, R. Kimmel, G. Sapiro, Geodesic active contours, International Journal of Computer Vision 22 (1997) 61; G. Sapiro, Geometric Partial Differential Equations and Image Analysis, Cambridge University Press, 2001; R. Kimmel, Numerical Geometry of Images: Theory, Algorithms, and Applications, Springer-Verlag, 2003] introduced in the field of image processing. 相似文献
17.
This paper presents an algebraic approach to polynomial spectral factorization, an important mathematical tool in signal processing and control. The approach exploits an intriguing relationship between the theory of Gröbner bases and polynomial spectral factorization which can be observed through the sum of roots, and allows us to perform polynomial spectral factorization in the presence of real parameters. It is discussed that parametric polynomial spectral factorization enables us to express quantities such as the optimal cost in terms of parameters and the sum of roots. Furthermore an optimization method over parameters is suggested that makes use of the results from parametric polynomial spectral factorization and also employs two quantifier elimination techniques. This proposed approach is demonstrated in a numerical example of a particular control problem. 相似文献
18.
Fieldbus-based control systems (FCS) have been increasingly used in process automation. Some processes and dynamic specifications need higher control frequencies to avoid instability. The aim of this paper is to analyze the temporal characteristics of communication and computation tasks and the configuration of the function blocks in a FCS and to allow the control interval to be shortened. An FCS for a water tank process is used as a case study. The experimental results show that the execution time of function blocks and the margin time are dominant over communication delays, and optimizing configuration by reducing the number of external links can contribute to increasing the control frequency. 相似文献
19.
Site-specific electronic structures were investigated by electron energy loss spectroscopy (EELS) under electron channeling conditions. The Al-K and Mn-L(2,3) electron energy loss near-edge structure (ELNES) of, respectively, NiAl2O4 and Mn3O4 were measured. Deconvolution of the raw spectra with the instrumental resolution function restored the blunt and hidden fine features, which allowed us to interpret the experimental spectral features by comparing with theoretical spectra obtained by first-principles calculations. The present method successfully revealed the electronic structures specific to the differently coordinated cationic sites. 相似文献
20.
Tetsu Ando Hirokazu Ohsawa Tadahiro Ueno Hideki Kishi Yutaka Okamura Satoshi Hashimoto 《Journal of chemical ecology》1993,19(4):787-798
Although several sex pheromones of the family Geometridae have been characterized, investigations on Japanese species are limited. In order to obtain more information, screening using known sex pheromones and their analogs was carried out. The (Z,Z,Z)-3,6,9-triunsaturated and (Z,Z)-6,9-diunsaturated hydrocarbons with straight C19-C21 chains were synthesized by the Grignard coupling reaction as a key step starting from linolenic and linoleic acids, respectively. Oxidation of the homoconjugated trienes withm-chloroperoxybenzoic acid yielded a 111 mixture of three monoepoxy derivatives that could be separated by silica gel chromatography. The chemical structure of each positional isomer was confirmed using two-dimensional NMR techniques and MS measurements, which enabled characteristic fragment ions from the isomers to be identified. Field tests using lures incorporating only one of the above six hydrocarbons or nine epoxides were carried out in a forest in Tokyo. Consequently, attraction of male moths of 14 geometrid species in addition to four species in another family, the Noctuidae, was observed. It was concluded that hydrocarbons with a homoconjugated polyene system and the monoepoxy derivatives are important components of sex pheromones produced by Japanese lepidopterous insects, particularly the geometrid moths. 相似文献