全文获取类型
收费全文 | 773篇 |
免费 | 35篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 63篇 |
综合类 | 4篇 |
化学工业 | 242篇 |
金属工艺 | 9篇 |
机械仪表 | 10篇 |
建筑科学 | 23篇 |
能源动力 | 36篇 |
轻工业 | 89篇 |
水利工程 | 3篇 |
石油天然气 | 6篇 |
无线电 | 51篇 |
一般工业技术 | 159篇 |
冶金工业 | 12篇 |
原子能技术 | 15篇 |
自动化技术 | 89篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 15篇 |
2020年 | 8篇 |
2019年 | 9篇 |
2018年 | 11篇 |
2017年 | 18篇 |
2016年 | 16篇 |
2015年 | 11篇 |
2014年 | 13篇 |
2013年 | 39篇 |
2012年 | 44篇 |
2011年 | 37篇 |
2010年 | 48篇 |
2009年 | 42篇 |
2008年 | 43篇 |
2007年 | 37篇 |
2006年 | 30篇 |
2005年 | 32篇 |
2004年 | 34篇 |
2003年 | 30篇 |
2002年 | 24篇 |
2001年 | 21篇 |
2000年 | 14篇 |
1999年 | 13篇 |
1998年 | 18篇 |
1997年 | 18篇 |
1996年 | 11篇 |
1995年 | 8篇 |
1994年 | 12篇 |
1993年 | 7篇 |
1992年 | 12篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 11篇 |
1985年 | 15篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有811条查询结果,搜索用时 31 毫秒
141.
Jong-Heun Lee Toshiyuki Mori Ji-Guang Li Takayasu Ikegami Manabu Komatsu Hajime Haneda 《Journal of the American Ceramic Society》2000,83(5):1273-1275
The scavenging of a resistive siliceous phase via the addition of Al2 O3 was studied, using imaging secondary-ion mass spectroscopy (SIMS), given the improved grain-boundary conductivity in 8-mol%-yttria-stabilized zirconia (8YSZ). The grain-boundary resistivity in 8YSZ decreased noticeably with the addition of 1 mol% of Al2 O3 . Strong SiO2 segregation at the grain boundaries was observed in a SIMS map of pure 8YSZ that contained 120 ppm of SiO2 (by weight). The addition of 1 mol% of Al2 O3 caused the SiO2 to gather around the Al2 O3 particles. The present observations provided direct and visual evidence of SiO2 segregation at the grain boundaries (which had a deleterious effect on grain-boundary conductivity) and the scavenging of SiO2 via Al2 O3 addition. 相似文献
142.
Shuzo KOBAYASHI Mitsuko MIYAMOTO Hajime KURUMATANI Machiko OKA Kyoko MAESATO Tsutomu MANO Ryota IKEE Hidekazu MORIYA Takayasu OHTAKE 《Hemodialysis international. International Symposium on Home Hemodialysis》2009,13(3):286-292
Little data are available on the role of blood rheology in atherosclerosis in hemodialysis (HD) patients. This study sought to assess the relationship between leukocytes conjugated with platelets (leukocyte aggregates [LA]) and atherosclerosis in patients with HD. The present study included 118 patients on HD. As surrogate markers of atherosclerosis, aortic stiffness measured by brachial-ankle pulse wave velocity, and carotid intima-media thickness (IMT) were measured. As an assessment of LA, a method, microchannel array flow analyzer, which makes it possible to directly observe the flow of blood cell elements through the microchannel, was used. We measured a number of LA during 50 μL flow of whole blood through microchannels. In 12 age-matched healthy individuals, a number of LA during 50 μL flow of whole blood was 25.7±5.4, whereas in HD patients it was significantly increased up to 48.2±16.4 (P<0.001). Flow cytometry demonstrated that LA were predominantly monocytes. Leukocyte aggregates were positively associated with plasma levels of fibrinogen (P<0.01), or serum high-sensitive C-reactive protein (P<0.01). Moreover, LA had highly significant associations with brachial-ankle pulse wave velocity (P<0.001) and IMT (P<0.001). In conclusion, we demonstrated hemorheologically that monocyte-platelet conjugates play an important role in aortic stiffness and IMT in HD patients. 相似文献
143.
一阶迎风差分格式的精度问题 总被引:10,自引:4,他引:6
通过对一维线性对流方程和一维非线性对流方程的数值求解 ,对一阶迎风差分格式的精度作了较详细的分析 .当计算如悬移质泥沙、污染物等质量输移方程时 ,应避免用其离散其中的对流项 ;而当计算水流动量方程时 ,用其离散其中的对流项可以获得较高精度结论 .最后给出了算例 ,计算结果与精确解和实验符合良好 相似文献
144.
Polyacene capacitors 总被引:2,自引:0,他引:2
Shizukuni Yata Eiji Okamoto Hisashi Satake Hidekazu Kubota Masanori Fujii Tomohiro Taguchi Hajime Kinoshita 《Journal of power sources》1996,60(2):207-212
We fabricated two types of polyacene capacitor with extremely stable polyacenic semiconductor (PAS) as the positive and negative electrodes. The first one is a coin-type PAS capacitor (six different sizes), which possesses large capacity with high reliability. Its capacity is much larger than that of the conventional electric double-layer capacitor which uses activated carbon as electrode. PAS capacitor can maintain more than 70% of the initial capacity even after 100 000 cycles. Moreover, this capacitor can be charged and discharged in a few minutes as well as at low rate. The second one is a cylinder-type PAS capacitor (diameter: 18 mm, height: 65 mm) which shows high capacity of 100 F and can discharge at the extremely high rate of 80 C. The coin-type PAS capacitor is currently used for memory back-up of electrical and communication equipment, and the cylinder-type is considered to be useful as power back-up for starting drive parts of electric equipment which needs high power density. 相似文献
145.
Kazama Haruna Ohata Yuto Ishiguri Yoichi Ono Hajime Mori Naoki Yoshinaga Naoko 《Journal of chemical ecology》2022,48(5-6):583-587
Journal of Chemical Ecology - TXIB (2,2,4-trimethyl-1,3-pentanediol diisobutyrate), a common plasticizer, inhibits the peach fruit moth, Carposina sasakii from ovipositing on young apple fruits.... 相似文献
146.
Isao Sakaguchi Varanasi Srikanth Takayasu Ikegami Hajime Haneda 《Journal of the American Ceramic Society》1995,78(9):2557-2559
The volume and grain boundary diffusion coefficients (Dv and δDgb ) of oxygen at 1673 K in pure and Mg-doped alumina were studied by using a resistive anode encoder of SIMS. The effect of Mg-doping on Dv , was observed clearly. The differences on δDgb in pure and Mg-doped alumina were about 3 orders and 1 order of magnitude, respectively. The Mg-doping in alumina is useful for homogenizing grain boundary diffusion. 相似文献
147.
Chikara Tsutsumi Katsuhiko Nakagawa Hiroyuki Shirahama Hajime Yasuda 《Polymer International》2003,52(3):439-447
Syntheses and biodegradation of statistical copolymers of D ,L ‐lactide (D ,L ‐LA) with trimethylene carbonate (TMC), rac‐1‐methyltrimethylene carbonate (1‐MTMC) and 2,2‐dimethyltrimethylene carbonate (2,2‐DTMC) were investigated at various monomer ratios using SmMe(C5Me5)2THF as an initiator at 80 °C for 24 h in toluene. Biodegradations of poly(D ,L ‐LA‐co‐racemo‐1‐MTMC) (95/5) and poly(D ,L ‐LA‐co‐2,2‐DTMC) (98/2) with a compost at 60 °C proceed rapidly. Enzymatic degradations of these polymers were also performed using cholesterol esterase, lipoprotein lipase and proteinase K. Only poly(D ,L ‐LA‐co‐TMC) was biodegraded with cholesterol esterase, while poly(TMC), poly(1‐MTMC), poly(2,2‐DTMC) and poly(D ,L ‐LA) were barely degraded with these enzymes. Biodegradations of poly(D ,L ‐LA‐co‐TMC) (87/13) and poly(D ,L ‐LA‐co‐racemo‐1‐MTMC) (95/5) are rapid using proteinase K. Physical properties of these copolymers were also described. © 2003 Society of Chemical Industry 相似文献
148.
Koichiro Asano & Hajime Nakagawa 《Computer-Aided Civil and Infrastructure Engineering》1998,13(6):425-432
This article presents an analytical approach to estimating the seismic random response of MDOF elastoplastic structural systems with bilinear hysteretic characteristics under saturation control force. Active saturation control is used for both seismic safety and vibration mitigation under severe earthquake excitation. Numerical calculations are carried out for five‐degree-of-freedom systems, and the efficiency of the theoretical saturation control approach is examined from two viewpoints of random seismic response and energy response. Considering the inability to install a saturation control system in actual structural systems, much more realistic nonlinear control systems are developed and examined from the control efficiency viewpoint through simulation analysis based on the earthquake accelerogram recorded during the Hyogo-ken Nanbu earthquake. 相似文献
149.
We fabricated ZnO micropatterns by a novel process in an aqueous solution at low temperatures. Photo-patterned self-assembled monolayer with phenyl/OH-surface functional groups was used as a template. Site-selective electroless deposition of ZnO was realized on Pd catalyst adhered only to the phenyl-surfaces. The as-deposited ZnO shows 500-800 nm visible light photoluminescence, which would be related to OH ions introduced during deposition process. Patterned monochromatic cathodoluminescence image was successfully demonstrated for 1 μm-width lines. 相似文献
150.
Yuichi Nakazato Akiyoshi Sekine Hajime Miyazawa Sadao Takeuchi Yukinori Ariga Masao Murakawa 《Microsystem Technologies》2005,11(8-10):997-1004
In this study we focus on diamond as a structural material for micromechanisms. Diamond is the hardest material on the earth, and has superior antifriction and anticorrosion characteristics. If diamond were applied to a micromechanism, an almost maintenance-free component which requires only a few component exchanges could be fabricated. In addition, since it has a superior anticorrosion characteristic, it can be used in chemical substances and organic tissue; thus, micromechanical components made of diamond have many advantages. Furthermore, when diamond is applied to a micromanipulator, we can expect accurate gripping to be realized because its deformation is small. We have already developed a diamond end effector for micromanipulators, and have obtained several promising results. In this study, we added a reversal mechanism to the positioning unit of this micromanipulator to increase efficiency in assembly tasks, and modified the design of the diamond end effector accordingly. Major modifications were examined through finite element analysis of fabricated shapes and amount of movement. A modified effector was experimentally fabricated based on the analytical results, and its features were examined experimentally. The starting material was 2-μm-thick flat-plate diamond, whichwas processed by laser into a designated shape. A shape-memory-alloy actuator which memorizes the linear shape was used to realize a driving amount larger than those of electrostatic actuators and piezoelectric devices. 相似文献