全文获取类型
收费全文 | 1390篇 |
免费 | 24篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 18篇 |
综合类 | 4篇 |
化学工业 | 298篇 |
金属工艺 | 33篇 |
机械仪表 | 22篇 |
建筑科学 | 163篇 |
矿业工程 | 3篇 |
能源动力 | 41篇 |
轻工业 | 56篇 |
水利工程 | 5篇 |
石油天然气 | 14篇 |
武器工业 | 1篇 |
无线电 | 87篇 |
一般工业技术 | 229篇 |
冶金工业 | 119篇 |
原子能技术 | 15篇 |
自动化技术 | 307篇 |
出版年
2024年 | 16篇 |
2023年 | 32篇 |
2022年 | 21篇 |
2021年 | 71篇 |
2020年 | 46篇 |
2019年 | 53篇 |
2018年 | 46篇 |
2017年 | 35篇 |
2016年 | 56篇 |
2015年 | 42篇 |
2014年 | 70篇 |
2013年 | 65篇 |
2012年 | 74篇 |
2011年 | 96篇 |
2010年 | 71篇 |
2009年 | 72篇 |
2008年 | 63篇 |
2007年 | 56篇 |
2006年 | 35篇 |
2005年 | 49篇 |
2004年 | 34篇 |
2003年 | 18篇 |
2002年 | 20篇 |
2001年 | 24篇 |
2000年 | 8篇 |
1999年 | 17篇 |
1998年 | 28篇 |
1997年 | 31篇 |
1996年 | 21篇 |
1995年 | 17篇 |
1994年 | 10篇 |
1993年 | 15篇 |
1992年 | 10篇 |
1991年 | 4篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1986年 | 4篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1981年 | 7篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1971年 | 4篇 |
1970年 | 3篇 |
1969年 | 3篇 |
1968年 | 5篇 |
排序方式: 共有1415条查询结果,搜索用时 15 毫秒
61.
DK Ball GA Surveyor JR Diehl CL Steffen M Uzumcu MA Mirando DR Brigstock 《Canadian Metallurgical Quarterly》1998,59(4):828-835
62.
Steffen Astrid Christine; Rockstroh Brigitte; Jansma Bernadette 《Canadian Metallurgical Quarterly》2009,2(1):32
Emotion is usually not discussed as a relevant variable in rational models of decision making—but may be one. The present electroencephalographic study demonstrates the influence of emotional primes (angry, happy faces) on purchase decisions. In a within-subject design, pictures of an apartment were shown to participants who then had to make Go/NoGo decisions on whether to rent it. Their decision should be based either on its price or on its brightness. In two thirds of the trials, emotional prime pictures of happy versus unhappy faces preceded the purchase target (apartment); in one third of the trials no prime was given. Response certainty was evaluated by means of reaction times (RT) and peak amplitude of the event-related potential N200. Facial primes accelerated decisions (RT) irrespective of affective expression. Positive face primes elicited larger N200 amplitudes during purchase decision compared to negative ones. Price-based decisions were made faster and elicited larger N200 than brightness-based decisions. These results support the cognitive-tuning model of decision making and validate the N200 as sensitive measure for the interplay of cognitive and affective aspects in decision making. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
63.
The microsegregation of titanium and manganese and the precipitation of titanium nitride during dendritic solidification were investigated on an Fe-0.051%Ti-0.77%Mn alloy. Carbon and nitrogen were introduced into the liquid sample via the gas phase. The material solidifies as delta ferrite at a carbon mass content of about 0.08% but predominantly as austenite at ≥ 0.3%. At ferritic solidification, an about 3fold enrichment of the titanium in the residual melt between secondary dendrite arms is attained by segregration, whereas in the corners between some dendrites or grains in maximum a 10fold enrichment was detected. TiN particles of 0.5 to 1.0 μm size are formed only in the regions of maximum segregation where the supersaturation is higher than 15fold. An equal supersaturation has been calculated for homogeneous nucleation in the melt. The number of particles is moderate at 0.016% nitrogen but low at 0.008%. At austenitic solidification, the titanium content in the residual melt increases to more than the 30fold of the starting value. Particles formed in the melt grow to diameters in the 2 μm range. 相似文献
64.
Junction Adhesion: Nanostructured Si/Organic Heterojunction Solar Cells with High Open‐Circuit Voltage via Improving Junction Quality (Adv. Funct. Mater. 28/2016)
下载免费PDF全文

Shan Wu Wei Cui Nabi Aghdassi Tao Song Steffen Duhm Shuit‐Tong Lee Baoquan Sun 《Advanced functional materials》2016,26(28):5192-5192
65.
Johannes Schemmel Steffen Hohmann Karlheinz Meier Felix Schürmann 《Analog Integrated Circuits and Signal Processing》2004,38(2-3):233-244
A hardware neural network is presented that combines digital signalling with analog computing. This allows a high amount of parallelism in the synapse operation while maintaining signal integrity and high transmission speed throughout the system. The presented mixed-mode implementation achieves a synapse density of 4 k per mm2 in 0.35 μm CMOS. The current-mode operation of the analog core combined with differential neuron inputs reaches an analog precision sufficient for 10 bit parity while running at a speed of 0.8 Teraconnections per second. 相似文献
66.
In many fields of materials science it is important to know how densely a particle mixture can be packed. The “packing density” is the ratio of the particle volume and the volume of the surrounding container needed for a random close packing of the particles. We present a method for estimating the packing density for spherical particles based on computer simulations only, i.e. without the need for additional experiments. Our method is particularly suited for particle mixtures with an extremely wide range of particle diameters as they occur e.g. in modern concrete mixtures. A single representative sample from such mixtures would be much larger than can be handled on present standard computers. In our hierarchical approach the diameter range is therefore divided into smaller intervals. Samples from these limited diameter intervals are drawn and their packing density is estimated from a simulated packing. The results are used to “fill” the interstices in the sample from the next larger particle interval. To account for the interaction between particles of different sizes we include larger particles into the sample of smaller ones. The larger ones act as part of the boundary during the packing. Thus we obtain more realistic estimates of how dense a fraction of particles can be packed within the whole mixture. The focus of this paper is on the divide-and-conquer approach and on how the simulation results from the fractions can be collected into an overall estimate of the packing density. We do not go into details of the simulation technique for the single packing. We compare our results to some experimental data to show that our method works at least as good as the classical analytical models like CPM without the need for any experiments. 相似文献
67.
The extent to which technical barriers to international trade caused by non-acceptance of chemical measurement results can be removed, largely depends on the success in building up national and international traceability structures also in metrology in chemistry. Achieving metrological comparability of measurement results requires the definition of metrological calibration hierarchies providing metrological traceability chains which enable the establishment of metrological traceability of measured quantity values to a common metrological reference [1]. For pH, over the last decade, work has been carried out in a number of countries to build up meteorological calibration hierarchies within a national framework. An overview on the metrological traceability chain for pH is given with focus on the primary measurement procedure of pH. 相似文献
68.
Peter Steffen 《Circuits, Systems, and Signal Processing》1986,5(2):187-210
The concept of smoothing noisy data using appropriate polynomials turns out to be equivalent to the application of suitable nonrecursive digital filters having the following properties: They process the data in such a way that the moments are conserved up to a desired order while the energy of their impulse response is minimum. Flatness constraints of their frequency response at =0 are equivalent to the moment condition. By using orthogonal polynomials, an explicit solution is known from the literature. A second approach which uses a special decomposition also yields closed form solutions. The realization is simplified, especially in the case where a large number of moments is supposed to be conserved. 相似文献
69.
M Kay R Wyllie W Michener M Caulfield R Steffen 《Canadian Metallurgical Quarterly》1993,60(6):473-478
We report two young men with clinical and laboratory evidence of macroscopic ulcerative colitis, sclerosing cholangitis, and insulin-dependent diabetes mellitus. The first patient presented at age 15 with vomiting, abdominal pain, weight loss, and abnormal liver function test results. Liver biopsy and endoscopic retrograde cholangiopancreatography (ERCP) demonstrated sclerosing cholangitis. Colonoscopy with biopsy revealed ulcerative colitis which responded to sulfasalazine. Diabetes occurred at age 18 and insulin therapy was begun. The second patient was 19 at presentation with diarrhea, hematochezia, and weight loss. Proctosigmoidoscopy revealed ulcerative colitis, and sulfasalazine led to clinical remission. Three months later he developed diabetes requiring insulin therapy. At age 28, he developed elevated alkaline phosphatase, and ERCP revealed sclerosing cholangitis. At age 37 he expired from adenocarcinoma that metastasized to the liver. Literature review revealed only one possible case report of this association with microscopic asymptomatic ulcerative colitis in that patient. Statistical analysis suggests that this association is real rather than a chance occurrence. An autoimmune process may be involved and a specific histocompatibility locus antigen (HLA) type may exert a regulatory influence. 相似文献
70.
Fe2O3/FeO-Verhältnisse im Quasivierstoffsystem CaO'–FeO'ges.-P2O5'–SiO2' im Gleichgewicht mit flüssigem Eisen. Beeinflussung der Sättigungskonzentrationen durch höhere Fe2O3/FeO-Verhältnisse. Bedeutung für die Schlacken der Stahlerzeugungsverfahren. 相似文献