全文获取类型
收费全文 | 2274篇 |
免费 | 76篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 20篇 |
综合类 | 19篇 |
化学工业 | 833篇 |
金属工艺 | 37篇 |
机械仪表 | 35篇 |
建筑科学 | 138篇 |
矿业工程 | 4篇 |
能源动力 | 53篇 |
轻工业 | 128篇 |
水利工程 | 5篇 |
石油天然气 | 3篇 |
无线电 | 90篇 |
一般工业技术 | 423篇 |
冶金工业 | 267篇 |
原子能技术 | 24篇 |
自动化技术 | 272篇 |
出版年
2021年 | 23篇 |
2019年 | 29篇 |
2018年 | 27篇 |
2017年 | 25篇 |
2016年 | 43篇 |
2015年 | 50篇 |
2014年 | 58篇 |
2013年 | 88篇 |
2012年 | 101篇 |
2011年 | 106篇 |
2010年 | 97篇 |
2009年 | 87篇 |
2008年 | 106篇 |
2007年 | 89篇 |
2006年 | 82篇 |
2005年 | 71篇 |
2004年 | 68篇 |
2003年 | 46篇 |
2002年 | 55篇 |
2001年 | 53篇 |
2000年 | 49篇 |
1999年 | 56篇 |
1998年 | 50篇 |
1997年 | 38篇 |
1996年 | 42篇 |
1995年 | 40篇 |
1994年 | 37篇 |
1993年 | 23篇 |
1992年 | 36篇 |
1991年 | 40篇 |
1990年 | 34篇 |
1989年 | 47篇 |
1988年 | 27篇 |
1987年 | 31篇 |
1986年 | 18篇 |
1985年 | 21篇 |
1984年 | 20篇 |
1983年 | 29篇 |
1982年 | 25篇 |
1981年 | 23篇 |
1980年 | 24篇 |
1979年 | 20篇 |
1978年 | 35篇 |
1977年 | 27篇 |
1976年 | 25篇 |
1975年 | 31篇 |
1974年 | 35篇 |
1973年 | 32篇 |
1971年 | 17篇 |
1970年 | 21篇 |
排序方式: 共有2351条查询结果,搜索用时 15 毫秒
991.
Carl-Philipp?FederolfEmail authorView authors OrcID profile Matthias?Westerschulte Hans-Werner?Olfs Gabriele?Broll Dieter?Trautz 《Nutrient Cycling in Agroecosystems》2017,107(1):19-31
Using pig slurry as starter fertilizer for maize (Zea mays L.), injected below the row prior to planting is a reasonable way to omit application of additional mineral fertilizer in areas with intensive animal farming. However, delayed early growth and a lack of knowledge on nutrient availability limit the interest of farmers. To extenuate farmers concerns a field trial was conducted in 2014 and 2015 to get detailed information on nitrogen (N) uptake, the subsequent influences on crop growth at different vegetative growth stages and final yield of silage maize. Besides an unfertilized control, two liquid manure injection treatments (without and with nitrification inhibitor [NI]) were compared to slurry broadcast application + mineral N and phosphorus (P) starter fertilizer at planting (MSF). In 2014, NI treatment yields increased (+16.5%) and N uptake increased (+9.6%) compared to broadcast treatment. In 2015, cold and dry conditions during early growth limited P plant availability and reduced crop growth in treatments without MSF. However, when a NI was added to the slurry prior to application, plants showed less P deficiency symptoms and better growth. At harvest no differences between the fertilized treatments were observed. In both years apparent N recovery was increased when manure was injected (48% without, and 56% with NI, respectively) compared to broadcast application of manure (43%) indicating that N losses were lower. However, further knowledge on soil N transformation and N loss pathways in systems with slurry injection is needed. 相似文献
992.
Dieter B. J. Herrmann Herbert A. Neumann Wolfgang E. Berdel Manfred E. Heim Michael Fromm Dietmar Boerner Uwe Bicker 《Lipids》1987,22(11):962-966
BM 41.440 (1-hexadecylmercapto-2-methoxymethyl-rac-glycero-3-phosphocholine) is a new thioether phospholipid, which has been shown to possess antineoplastic, antimetastatic, anti-invasive and immunomodulating properties in serveral tumor models. The mechanism whereby this compound exerts its direct antineoplastic effect is thought to be related to specific interference with the normal phospholipid metabolism, preferentially of neoplastic cells. BM 41.440 was evaluated in a multicenter phase I study in patients (pts) with refractory cancers. In phase I A, 34 pts were orally treated with doses ranging from 0.5 to 7.0 mg/kg body weight (bw). Three different formulations were tested. The maximum-tolerated dose (MTD) was ca. 5 mg/kg bw. The limiting side effects were nausea and vomiting. There was no evidence for systemic toxicities like myelosuppression, nephro-, neuro-, hepatotoxicity or hematological side effects. The current phase I B is designed to determine the MTD of BM 41.440 administered orally on a daily schedule for at least eight weeks. So far, 19 pts have entered this trial at dose levels ranging from 1.0 to 5.0 mg/kg bw/day. Some pts receiving 1.0 and 2.5 mg/kg bw/day, respectively, have been treated, up to now, for more than nine months. Clinical progress was followed with at-least-weekly blood counts, chemistry profiles, urine analysis, liver function tests and recordings of side effects. Tumor parameters were evaluated at eight-week intervals. In parallel, pharmacokinetic investigations were performed in some pts in phase I A and IB. First results on tolerability and therapeutic efficacy of the long-term BM 41.440 treatment are reported in this intermediate evaluation. 相似文献
993.
Summary Poly(ether amide) dendrimers with different molar masses were investigated using Size Exclusion Chromatography (SEC) with
linear standard calibration and Matrix Assisted Laser Desorption/Ionization – Time-of-Flight – Mass Spectroscopy (MALDI-TOF-MS).
The SEC behaviour of the dendrimers was investigated in different column systems, in pure and in mixed N,N-dimethylacetamide
with water and LiCl. This behaviour was compared to linear poly(styrene) and poly(2-vinyl pyridine) standards. Kuhn-Mark-Houwink-Sakurada
relationship yielded evidence about the molecular shapes of the polymers in solution and explained the different solution
behaviour of the polymers. The universal calibration method was tested for its application to molar mass determination of
poly(ether amide) dendrimers. 相似文献
994.
Ernst Dieter Gilles 《化学,工程师,技术》1987,59(9):715-726
Model-based process control engineering in chemical engineering production . Modern process control engineering nowadays provides almost ideal tools for the implementation of even highly sophisticated control concepts. The very reluctant acceptance of these tools is due to the following bottlenecks:
- – insufficient understanding of chemical engineering control processes;
- – limitations in the acquisition of sensorial primary information;
- – insufficient performance of control engineering concepts.
995.
996.
Nanocomposites: Glassomer—Processing Fused Silica Glass Like a Polymer (Adv. Mater. 22/2018)
下载免费PDF全文
![点击此处可从《Advanced materials (Deerfield Beach, Fla.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
997.
B. Bode W. Wessel A. Brueckner‐Foit J. Mildner M. Wollenhaupt T. Baumert 《Fatigue & Fracture of Engineering Materials & Structures》2016,39(2):227-237
The relation is studied between crack initiation from micro‐notches in a fully lamellar intermetallic γ‐TiAl alloy and the local strain field. These micro‐notches were introduced using femtosecond‐laser ablation and had dimensions below the average colony size. The specimen under investigation was then subjected to fatigue loading. Continuous monitoring using a travelling optical microscope allowed detecting microcracks at an early stage. Prior to fatigue loading, a sustained load was applied and the local strain field was determined using digital image correlation. This was supplemented by a Finite Element analysis of the notches and their neighbourhood. It was found that a crack was initiated from a notch causing high normal strains in lamella direction, whereas no crack was initiated from notches with high shear strains. 相似文献
998.
High resolution photolithography for direct view active matrix organic light‐emitting diode augmented reality displays
下载免费PDF全文
![点击此处可从《Journal of the Society for Information Display》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Paweł E. Malinowski Tung‐Huei Ke Atsushi Nakamura Ya‐Han Liu Dieter Vander Velpen Erwin Vandenplas Nikolas Papadopoulos Auke Jisk Kronemeijer Jan‐Laurens van der Steen Soeren Steudel Che‐Cheng Kuo Yen‐Yu Huang Yu‐Hsien Chen Ming‐Hua Yeh Gerwin Gelinck Paul Heremans 《Journal of the Society for Information Display》2018,26(3):128-136
High‐resolution RGB organic light‐emitting diode frontplane is a key enabler for direct‐view transparent augmented reality displays. In this paper, we demonstrate 1250 ppi passive displays and semi‐transparent active displays. Organic light‐emitting diode photolithography can provide pixel density above 1000 ppi while keeping effective emission area high because of high aperture ratio. Patterns with 2 μm line pitch were successfully transferred to emission layers, indicating possible further pixel density scaling. Lifetime after patterning, key parameter enabling industrialization, is above 150 h (T90 at 1000 nit). 相似文献
999.
Bayesian filtering is a general framework for recursively estimating the state of a dynamical system. Key components of each
Bayes filter are probabilistic prediction and observation models. This paper shows how non-parametric Gaussian process (GP)
regression can be used for learning such models from training data. We also show how Gaussian process models can be integrated
into different versions of Bayes filters, namely particle filters and extended and unscented Kalman filters. The resulting
GP-BayesFilters can have several advantages over standard (parametric) filters. Most importantly, GP-BayesFilters do not require
an accurate, parametric model of the system. Given enough training data, they enable improved tracking accuracy compared to
parametric models, and they degrade gracefully with increased model uncertainty. These advantages stem from the fact that
GPs consider both the noise in the system and the uncertainty in the model. If an approximate parametric model is available,
it can be incorporated into the GP, resulting in further performance improvements. In experiments, we show different properties
of GP-BayesFilters using data collected with an autonomous micro-blimp as well as synthetic data.
相似文献
Dieter FoxEmail: |
1000.
Position‐Sensitive Array Photodetector Based on Comb‐Like CdS Nanostructure with Cone‐Shape Branches
Yan Hao Shuai Guo Dieter Weller Min Zhang Chunjie Ding Ke Chai Lingling Xie Ruibin Liu 《Advanced functional materials》2019,29(1)
2D microscale position‐sensitive detectors (PSDs) are highly desirable with the degree of integration increase and the size reduction of nanodevices, which are still unavailable. Multichannel devices with outstanding photoelectric properties attract considerable interest as powerful building blocks to be applied in on‐chip systems. Here, based on a highly ordered comb‐like CdS nanowire array with cone‐shape branches through a one‐step synthesis strategy, a high‐resolution 2D position‐sensitive photodetector is realized through variable resistance in different transportation routes and variable optical responses at different parts of the cone‐shape branches, which enable accurate position identification of incident light in various zones of nanowire arrays according to photocurrent changes. In a broadband from 310 to 560 nm, the PSD exhibits high sensitivity with 85 and 58 KΩ µm?1 in the trunk and branch part, respectively, and an ultrafast optical response shorter than tens of millisecond. Moreover, a lower conductivity change rate per unit temperature of the PSD (1.625 × 10?9 A V?1 K?1) than that of commercial Si‐based PSDs (≈6.67 × 10?7 A V?1 K?1) reveals outstanding low‐temperature performance. Finally, the multichannel nanostructure based PSD with nanoscale resolution is applied to high‐accuracy quadrant photodetectors. 相似文献