全文获取类型
收费全文 | 1810篇 |
免费 | 66篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 65篇 |
综合类 | 2篇 |
化学工业 | 452篇 |
金属工艺 | 41篇 |
机械仪表 | 49篇 |
建筑科学 | 30篇 |
矿业工程 | 1篇 |
能源动力 | 68篇 |
轻工业 | 82篇 |
水利工程 | 5篇 |
石油天然气 | 2篇 |
无线电 | 176篇 |
一般工业技术 | 353篇 |
冶金工业 | 321篇 |
原子能技术 | 50篇 |
自动化技术 | 182篇 |
出版年
2023年 | 24篇 |
2022年 | 26篇 |
2021年 | 64篇 |
2020年 | 31篇 |
2019年 | 38篇 |
2018年 | 39篇 |
2017年 | 51篇 |
2016年 | 50篇 |
2015年 | 39篇 |
2014年 | 56篇 |
2013年 | 124篇 |
2012年 | 82篇 |
2011年 | 112篇 |
2010年 | 96篇 |
2009年 | 99篇 |
2008年 | 70篇 |
2007年 | 72篇 |
2006年 | 69篇 |
2005年 | 46篇 |
2004年 | 39篇 |
2003年 | 38篇 |
2002年 | 20篇 |
2001年 | 23篇 |
2000年 | 25篇 |
1999年 | 27篇 |
1998年 | 116篇 |
1997年 | 64篇 |
1996年 | 50篇 |
1995年 | 33篇 |
1994年 | 32篇 |
1993年 | 32篇 |
1992年 | 22篇 |
1991年 | 15篇 |
1990年 | 10篇 |
1989年 | 16篇 |
1988年 | 14篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 11篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 13篇 |
1981年 | 8篇 |
1980年 | 9篇 |
1979年 | 9篇 |
1977年 | 9篇 |
1976年 | 11篇 |
1974年 | 4篇 |
1971年 | 4篇 |
1970年 | 4篇 |
排序方式: 共有1879条查询结果,搜索用时 593 毫秒
111.
Yusuke Tanimura Tsutomu Ikegami Hidemoto Nakada Yoshio Tanaka Satoshi Sekiguchi 《Journal of Grid Computing》2006,4(2):145-157
A task parallel application is implemented with Ninf-G, a GridRPC system. A series of experiments are conducted on the Grid testbed in Asia Pacific for three months. Through tens of long executions, typical fault patterns were collected, and instability of the network throughput was determined to be a major reason of the faults. Several important points are stressed to avoid task throughput decline due to the fault-recovery operations: Timeout minimization for fault detection, background recovery, redundant task assignments, and so on. This study also issues a steer for design of the automated fault-tolerant mechanism in an upper layer of the GridRPC framework. 相似文献
112.
Keisuke Hachisuka Teruhito Takeda Yusuke Terauchi Ken Sasaki Hiroshi Hosaka Kiyoshi Itao 《Microsystem Technologies》2005,11(8-10):1020-1027
Intra-body communication is a wireless means of exchanging information within a personal area network (PAN) between wearable electronic sensors and devices. The feasibility of intra-body communication is confirmed through several experiments on signal propagation within the human body, and a human phantom is designed and used to obtain reproducible results over repeated experiments. Based on the results of these experiments, a prototype transmission system is constructed using aluminum electrodes powered by 3 V DC and operating in the 10.7 MHz frequency modulation (FM) band. This prototype is demonstrated to be capable of transmitting analog signals through the human subjects in the presence of external noise. Digital data transmission at 9600 bps is also achieved using newly fabricated 10.7 MHz frequency shift keying (FSK) transmitter and receiver devices. The carrier frequency of 10.7 MHz is the intermediate frequency of FM radio receivers, meaning that the proposed system can make use of a wide selection of inexpensive, commercial radio frequency devices. 相似文献
113.
Naoyuki Kubota Yusuke Nojima Fumio Kojima Toshio Fukuda 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2006,10(10):891-901
The purpose of this study is to develop partner robots that can obtain and accumulate human-friendly behaviors. To achieve this purpose, the entire architecture of the robot is designed, based on a concept of structured learning which emphasizes the importance of interactive learning of several modules through interaction with its environment. This paper deals with a trajectory planning method for generating hand-to-hand behaviors of a partner robot by using multiple fuzzy state-value functions, a self-organizing map, and an interactive genetic algorithm. A trajectory for the behavior is generated by an interactive genetic algorithm using human evaluation. In order to reduce human load, human evaluation is estimated by using the fuzzy state-value function. Furthermore, to cope with various situations, a self-organizing map is used for clustering a given task dependent on a human hand position. And then, a fuzzy state-value function is assigned to each output unit of the self-organizing map. The robot can easily obtain and accumulate human-friendly trajectories using a fuzzy state-value function and a knowledge database corresponding to the unit selected in the self-organizing map. Finally, multiple fuzzy state-value functions can estimate a human evaluation model for the hand-to-hand behaviors. Several experimental results show the effectiveness of the proposed method. 相似文献
114.
The effect of the dispersing procedure on the aggregate size, membrane fluidity and the pharmacokinetics were evaluated for the lipid A analog E5531. The size of the aggregates prepared by the pH-jump method (pH 11.0 → 7.3) was decreased, reaching 20 nm with increasing dispersing time in 0.003 N NaOH (pH 11.0). The membrane fluidity of the aggregates increased with increasing dispersing time. When prepared by the normal dilution method (pH 7.3 → 7.3), the size of the aggregates remained constant at 150 nm and the membrane fluidity was smaller compared to samples prepared by the pH-jump method. Using samples with different degrees of hydration and different membrane fluidities prepared by the pH-jump method, the pharmacokinetics after intravenous administration into rats were evaluated, and the data obtained confirmed that the membrane fluidity was correlated with the pharmacokinetics in rat. In addition, E5531 vials were stable for 24 months at room temperature when used within 24 hr after reconstitution. 相似文献
115.
Pulse responses of top-illuminated GaAs metal-semiconductor-metal photodetectors (MSM PDs) are evaluated by using a two-dimensional ensemble Monte Carlo technique. Fundamental assumptions and the model used for the evaluation are detailed. Pulsewidths for MSM PDs are presented as functions of the gap length between metal electrodes and the photon energy of optical pulses. It is also shown that reducing the thickness of the absorption region is very effective for shortening the pulsewidth of MSM PDs 相似文献
116.
K Ueda M Konishi K Maeda K Hamada M Sakamoto E Yoshimoto T Majima K Mikasa E Kita R Sano T Masutani N Narita 《Canadian Metallurgical Quarterly》1998,72(12):1325-1329
A 78-year-old female was admitted with complaints of malaise and fatigue in the legs. The patient was diagnosed as severe aplastic anemia and treatment was started with metenolone and steroid pulse therapy. Administration of antibiotics and granulocyte-colony stimulating factor which led to a resolution of the high fever. About four months after admission, the patient developed vomiting and abdominal pain with a spiking fever. The next day after suddenly losing consciousness, she died. B. cereus was isolated from blood cultures. Autopsy specimens of the liver, cardiac muscle and lung showed changes due to B. cereus. This pathogen is widely distributed in nature. We should not overlook B. cereus as a contamination, but rather should consider it a potential pathogen in immunocompromised hosts, when it is isolated from blood cultures. 相似文献
117.
The pathogenic mechanism of drug allergy was investigated by determining leucocyte migration activating factor (LMAF), interleukin-1 alpha (IL 1 alpha) and 1 beta (IL-1 beta), and tumor necrosis factor-alpha (TNF-alpha) levels in 13 patients with suspected hypersensitivity to drugs, following with the relevant agents. LMAF was detected in 10 out of 11 patients in the absence of serum and in 8 out of 9 patients in the presence of serum by means of the leucocyte migration inhibition test (LMIT). The drug-stimulated group had a significantly higher level of IL-1 alpha production than a non-stimulated group, both without serum (p < 0.05) and with serum (p < 0.05), among patients positive for LMAF. Moreover, the LMAF-positive group had a significantly higher level of IL-1 alpha production than the LMIT-negative group, both without serum (p < 0.05) and with serum (p < 0.05). In contrast, the level of IL-1 beta production showed no significant difference, either without or with serum, between drug-stimulated and non-drug-stimulated patients who were positive for LMAF. The production of TNF-alpha in the LMAF-positive group was significantly greater in drug-stimulated patients than in non-drug-stimulated patients, but only in the presence of serum (p < 0.05). However, the level of TNF-alpha production showed no significant difference, either without or with serum, between the LMAF-positive group and the control group. Our findings suggest that IL-1 alpha may be prominently involved in the production of LMAF in allergic reactions to drugs and that the production of TNF-alpha may be enhanced in the presence of serum. 相似文献
118.
To more completely describe acromion morphology and its relationship to impingement syndrome, we performed three-dimensional magnetic resonance imaging (N = 111) or computed tomography (N = 27) on 132 symptomatic shoulders. The mean patient age was 46.2 years (range, 14 to 86). Four parameters were evaluated: the angle of anterior slope of the acromion in the midsagittal and lateral-sagittal planes, lateral acromial angulation in the coronal plane, and the presence or absence of medial encroachment in the acromioclavicular joint. Twenty-five asymptomatic age-matched shoulders were used as controls. All imaging data were combined because no significant differences existed between the two imaging techniques. The mean acromion angle was 19.4 degrees in the midsagittal plane and 20 degrees in the lateral-sagittal plane. In the coronal plane, 97 (73%) acromions were neutral and 35 (27%) were downward sloping. Medial encroachment was present in 31 (24%) shoulders. Age distribution from the 2nd to 8th decade demonstrated a consistent and gradual transition from a flat acromion in the younger decades to a more hooked acromion in the older decades that was significant in both the midsagittal and lateral-sagittal planes. Furthermore, a greater percentage of patients were found to have downward angulating acromions with increasing age. Ninety-eight patients (74%) had stage II or III impingement. Of these shoulders, 39 (40%) had type I acromions, 51 (52%) type II, and 8 (8%) type III. Twenty-eight of 33 acromions with coronal lateral downward sloping had impingement, and all 31 shoulders with medial encroachment had impingement. 相似文献
119.
Sang Chul Shim Fumitaka Tsukihashi Nobuo Sano 《Metallurgical and Materials Transactions B》1993,24(2):333-337
Although a great number of works on BaO-bearing fluxes for refining Fe-Cr and Fe-Mn alloys have been carried out, there still
remain several unresolved problems on using them in the refining process. The principal aim of the present study is to understand
the thermodynamic properties of the BaO-MnO system, which has been shown to be very effective for dephosphorization of Fe-Mn
alloys. The activity of manganese oxide in the BaO-MnO flux was measured at 1573 and 1673 K by equilibrating the flux, a Ag-Mn
alloy, and a gas mixture of CO and CO2 as functions of the flux composition and temperature. The influence of BaF2, which is an effective additive for lowering the melting temperature of the flux, on the thermodynamics of the BaO-MnO system,
including the solubility of MnO in the BaO-BaF2 system, was also investigated. 相似文献
120.
High-voltage power distribution systems are connected in a branch configuration so as to meet the need for highly reliable power service. When service is interrupted the faulty section is automatically isolated and the power supply is rerouted from an adjacent power distribution system thereby minimizing the service interruption area. The faulty section in the power distribution system is quickly located by means of time relays installed in the switchgears. The settings of those time relays, however, must be monitored constantly. For this reason, we have proposed a “section management method” which can supervise each section of the power distribution system. From this method, we developed a prototype automated distribution system for overall management of time relays through the use of internal software, facilities and customer feedback. This paper describes the section management of power distribution systems. 相似文献