全文获取类型
收费全文 | 578篇 |
免费 | 36篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 47篇 |
综合类 | 6篇 |
化学工业 | 155篇 |
金属工艺 | 23篇 |
机械仪表 | 22篇 |
建筑科学 | 18篇 |
矿业工程 | 9篇 |
能源动力 | 31篇 |
轻工业 | 52篇 |
水利工程 | 1篇 |
石油天然气 | 16篇 |
武器工业 | 4篇 |
无线电 | 41篇 |
一般工业技术 | 79篇 |
冶金工业 | 34篇 |
原子能技术 | 19篇 |
自动化技术 | 64篇 |
出版年
2024年 | 3篇 |
2023年 | 7篇 |
2022年 | 24篇 |
2021年 | 41篇 |
2020年 | 17篇 |
2019年 | 16篇 |
2018年 | 14篇 |
2017年 | 20篇 |
2016年 | 28篇 |
2015年 | 21篇 |
2014年 | 17篇 |
2013年 | 33篇 |
2012年 | 32篇 |
2011年 | 44篇 |
2010年 | 23篇 |
2009年 | 30篇 |
2008年 | 22篇 |
2007年 | 29篇 |
2006年 | 14篇 |
2005年 | 14篇 |
2004年 | 16篇 |
2003年 | 11篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 2篇 |
1998年 | 11篇 |
1997年 | 10篇 |
1996年 | 14篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 7篇 |
1977年 | 7篇 |
1976年 | 3篇 |
1973年 | 2篇 |
1971年 | 2篇 |
排序方式: 共有621条查询结果,搜索用时 15 毫秒
611.
Unregulated emissions from a heavy-duty diesel engine with various fuels and emission control systems 总被引:1,自引:0,他引:1
Tang S Frank BP Lanni T Rideout G Meyer N Beregszaszy C 《Environmental science & technology》2007,41(14):5037-5043
This study evaluated the effects of various combinations of fuels and emission control technologies on exhaust emissions from a heavy-duty diesel engine tested on an engine dynamometer. Ten fuels were studied in twenty four combinations of fuel and emission control technology configurations. Emission control systems evaluated were diesel oxidation catalyst (DOC), continuously regenerating diesel particulate filter (CRDPF), and the CRDPF coupled with an exhaust gas recirculation system (EGRT). The effects of fuel type and emission control technology on emissions of benzene, toluene, ethylbenzene, xylene (BTEX), and 1,3-butadiene, elemental carbon and organic carbon (EC/OC), carbonyls, polycyclic aromatic hydrocarbons (PAHs), and nitro-PAHs (n-PAHs) are presented in this paper. Regulated gaseous criteria pollutants of total hydrocarbons (THC), carbon monoxide (CO), oxides of nitrogen (NO(x)) and particulate matter (PM) emissions have been reported elsewhere. In general, individual unregulated emission with a CRDPF or an EGRT system is similar (at very low emission level) or much lower than that operating solely with a DOC and choosing a "best" fuel. The water emulsion PuriNO(x) fuel exhibited higher BTEX, carbonyls and PAHs emissions compared to other ultralow sulfur diesel (ULSD) fuels tested in this study while n-PAH emissions were comparable to that from other ULSD fuels. Naphthalene accounted for greater than 50% of the total PAH emissions in this study and there was no significant increase of n-PAHs with the usage of CRDPF. 相似文献
612.
Shida K Kiyoshima-Shibata J Nagaoka M Watanabe K Nanno M 《Journal of dairy science》2006,89(9):3306-3317
Some strains of lactobacilli can stimulate macrophages and dendritic cells to secrete IL-12, which plays a key role in activating innate immunity. We examined the IL-12-inducing ability of 47 Lactobacillus strains belonging to 10 species in mouse peritoneal macrophages, and characterized the properties important for the induction of IL-12. Although considerable differences in IL-12-inducing ability were observed among the strains tested, almost all strains belonging to the Lactobacillus casei group (L. casei, Lactobacillus rhamnosus, and Lactobacillus zeae) or to Lactobacillus fermentum induced high levels of IL-12. Phagocytosis of lactobacilli was necessary for IL-12 induction, and the strains with strong IL-12 induction were relatively resistant to lysis in the macrophages. The sensitivity of Lactobacillus strains to in vitro treatment with M-1 enzyme, a member of the N-acetylmuramidases, was negatively correlated with IL-12-inducing ability. Using a probiotic strain, L. casei strain Shirota (LcS), we showed that the cell wall of LcS could be digested by long-term treatment with a high dose of M-1 enzyme and that the IL-12-inducing ability was diminished according to the duration of the enzyme treatment. The soluble polysaccharide-peptidoglycan complex released from the cell wall of LcS did not induce IL-12, whereas the insoluble intact cell wall of LcS induced IL-12. These results suggest that the intact cell wall structure of lactobacilli is an important element in the ability to induce IL-12 and that Lactobacillus strains having a rigid cell wall resistant to intracellular digestion effectively stimulate macrophages to induce IL-12. 相似文献
613.
Hiroaki Tsurumaki Chihiro Mogi Haruka Aoki-Saito Masayuki Tobo Yosuke Kamide Masakiyo Yatomi Koichi Sato Kunio Dobashi Tamotsu Ishizuka Takeshi Hisada Masanobu Yamada Fumikazu Okajima 《International journal of molecular sciences》2015,16(12):28931-28942
Acute lung injury is characterized by the infiltration of neutrophils into lungs and the subsequent impairment of lung function. Here we explored the role of TDAG8 in lung injury induced by lipopolysaccharide (LPS) administrated intratracheally. In this model, cytokines and chemokines released from resident macrophages are shown to cause neutrophilic inflammation in the lungs. We found that LPS treatment increased TDAG8 expression in the lungs and confirmed its expression in resident macrophages in bronchoalveolar lavage (BAL) fluids. LPS administration remarkably increased neutrophil accumulation without appreciable change in the resident macrophages, which was associated with increased penetration of blood proteins into BAL fluids, interstitial accumulation of inflammatory cells, and damage of the alveolar architecture. The LPS-induced neutrophil accumulation and the associated lung damage were enhanced in TDAG8-deficient mice as compared with those in wild-type mice. LPS also increased several mRNA and protein expressions of inflammatory cytokines and chemokines in the lungs or BAL fluids. Among these inflammatory mediators, mRNA and protein expression of KC (also known as CXCL1), a chemokine of neutrophils, were significantly enhanced by TDAG8 deficiency. We conclude that TDAG8 is a negative regulator for lung neutrophilic inflammation and injury, in part, through the inhibition of chemokine production. 相似文献
614.
Yosuke Kayama Uwe Raaz Ann Jagger Matti Adam Isabel N. Schellinger Masaya Sakamoto Hirofumi Suzuki Kensuke Toyama Joshua M. Spin Philip S. Tsao 《International journal of molecular sciences》2015,16(10):25234-25263
Cardiovascular disease (CVD) is the leading cause of morbidity and mortality among patients with diabetes mellitus (DM). DM can lead to multiple cardiovascular complications, including coronary artery disease (CAD), cardiac hypertrophy, and heart failure (HF). HF represents one of the most common causes of death in patients with DM and results from DM-induced CAD and diabetic cardiomyopathy. Oxidative stress is closely associated with the pathogenesis of DM and results from overproduction of reactive oxygen species (ROS). ROS overproduction is associated with hyperglycemia and metabolic disorders, such as impaired antioxidant function in conjunction with impaired antioxidant activity. Long-term exposure to oxidative stress in DM induces chronic inflammation and fibrosis in a range of tissues, leading to formation and progression of disease states in these tissues. Indeed, markers for oxidative stress are overexpressed in patients with DM, suggesting that increased ROS may be primarily responsible for the development of diabetic complications. Therefore, an understanding of the pathophysiological mechanisms mediated by oxidative stress is crucial to the prevention and treatment of diabetes-induced CVD. The current review focuses on the relationship between diabetes-induced CVD and oxidative stress, while highlighting the latest insights into this relationship from findings on diabetic heart and vascular disease. 相似文献
615.
In this article, we propose a behavior generation approach with human instruction to improve the strategy of the RoboCup soccer
3D simulation team. Many teams implement their strategies based on the programmer’s own knowledge about soccer. That is, the
programmers have to write action rules that cover any situation on the soccer field. Although it is clear that this is not
the best approach, there are only a few researchers who have tackled this problem. Here, we solve the problem using human
instruction to improve the manually implemented behavior of soccer robots. It is shown that the team performance is improved
by the rules generated by this approach. 相似文献
616.
Yosuke YamadaTakayuki Doi Ichiro TanakaShigeto Okada Jun-ichi Yamaki 《Journal of power sources》2011,196(10):4837-4841
Highly dispersed NaFeF3 particles were prepared at 280 °C by liquid-phase synthesis using high-boiling-point organic solution, and their electrochemical properties were studied by charge and discharge measurements. TEM observation clarified that the resultant NaFeF3 particles had uniform particle sizes of ca. 10-20, 100-200, and 500-600 nm, which could be controlled by the composition of the synthetic solution. The discharge capacities were higher for NaFeF3 that had smaller particle sizes, particularly at a rate of 0.1 C or higher, while the discharge capacities obtained at a rate of 0.01 C between 1.5 and 4.5 V were almost the same in the range 170-181 mAh g−1 regardless of the particle size of NaFeF3. These results clearly indicate that the use of well-dispersed nano-sized NaFeF3 particles should effectively improve the rate performance of NaFeF3. 相似文献
617.
Masashi KotobukiKiyoshi Kanamura Yosuke SatoToshihiro Yoshida 《Journal of power sources》2011,196(18):7750-7754
Li7La3Zr2O12 (LLZ) solid electrolyte is one of the promising electrolytes for all-solid-state battery due to its high Li ion conductivity and stability against Li metal anode. However, high calcination temperature for LLZ preparation promotes formation of La2Zr2O7 impurity phase. In this paper, an effect of Al2O3 addition as sintering additive on LLZ solid electrolyte preparation and electrochemical properties of Al2O3-added LLZ were examined. By the Al2O3 addition, sintered LLZ pellet could be obtained after 1000 °C calcination, which is 230 °C lower than that without Al2O3 addition. Chemical and electrochemical properties of the Al2O3-added LLZ, such as stability against Li metal and ion conductivity, were comparable with the LLZ without Al2O3 addition, i.e. σbulk and σtotal were 2.4 × 10−4 and 1.4 × 10−4 S cm−1 at 30 °C, respectively. All-solid-state battery with Li/Al2O3-added LLZ/LiCoO2 configuration was fabricated and its electrochemical properties were tested. In cyclic voltammogram, clear redox peaks were observed, indicating that the all-solid-state battery with Li metal anode was successfully operated. The redox peaks were still observed even after one year storage of the all-solid-state battery in the Ar-filled globe-box. It can be inferred that the Al2O3-added LLZ electrolyte would be a promising candidate for all-solid-state battery because of facile preparation by the Al2O3 addition, relatively high Li ion conductivity, and good stability against Li metal and LiCoO2 cathode. 相似文献
618.
This paper proposes a torque control method for interior permanent magnet synchronous motors (IPMSMs). The proposed method uses state feedback control based on a new n‐t coordinate system and controls the voltage amplitude and phase based on the coordinate system. The t‐axis is a tangent line of the constant voltage ellipse, and the n‐axis is a normal line of the ellipse. The n‐axis current is utilized to place the poles of the transfer function at the desired position and reduce the mutual coupling between the voltage amplitude controller and phase controller. The proposed method realizes a high torque response even under parameter variation for the linear range and over‐modulation range of the inverter, including a 6‐step mode. The effectiveness of the proposed method was verified by simulation and experimental results. 相似文献
619.
620.