全文获取类型
收费全文 | 3826篇 |
免费 | 160篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 46篇 |
化学工业 | 895篇 |
金属工艺 | 85篇 |
机械仪表 | 51篇 |
建筑科学 | 144篇 |
矿业工程 | 5篇 |
能源动力 | 52篇 |
轻工业 | 443篇 |
水利工程 | 27篇 |
石油天然气 | 7篇 |
无线电 | 282篇 |
一般工业技术 | 595篇 |
冶金工业 | 815篇 |
原子能技术 | 50篇 |
自动化技术 | 496篇 |
出版年
2023年 | 39篇 |
2022年 | 60篇 |
2021年 | 73篇 |
2020年 | 58篇 |
2019年 | 55篇 |
2018年 | 93篇 |
2017年 | 69篇 |
2016年 | 87篇 |
2015年 | 60篇 |
2014年 | 92篇 |
2013年 | 173篇 |
2012年 | 148篇 |
2011年 | 202篇 |
2010年 | 155篇 |
2009年 | 127篇 |
2008年 | 174篇 |
2007年 | 155篇 |
2006年 | 116篇 |
2005年 | 124篇 |
2004年 | 120篇 |
2003年 | 113篇 |
2002年 | 104篇 |
2001年 | 76篇 |
2000年 | 62篇 |
1999年 | 68篇 |
1998年 | 158篇 |
1997年 | 100篇 |
1996年 | 95篇 |
1995年 | 64篇 |
1994年 | 66篇 |
1993年 | 67篇 |
1992年 | 52篇 |
1991年 | 47篇 |
1990年 | 45篇 |
1989年 | 41篇 |
1988年 | 46篇 |
1987年 | 39篇 |
1986年 | 41篇 |
1985年 | 42篇 |
1984年 | 41篇 |
1983年 | 37篇 |
1982年 | 43篇 |
1981年 | 37篇 |
1980年 | 29篇 |
1979年 | 31篇 |
1978年 | 21篇 |
1977年 | 28篇 |
1976年 | 40篇 |
1975年 | 16篇 |
1974年 | 20篇 |
排序方式: 共有3993条查询结果,搜索用时 15 毫秒
41.
JE Max SL Koele SD Lindgren DA Robin WL Smith Y Sato S Arndt 《Canadian Metallurgical Quarterly》1998,79(8):893-899
BACKGROUND: In an effort to intensify osteosarcoma therapy, systemic ifosfamide was added pre- and postoperatively to an already aggressive three-drug regimen. In a subgroup of patients, loco-regional treatment intensification was attempted by using the intraarterial route to give cisplatin. PATIENTS AND METHODS: Patients < or = 40 years at diagnosis of a localised, de novo high-grade central extremity osteosarcoma were eligible for inclusion into study COSS-86 if registered within three weeks from biopsy. Doxorubicin, high-dose methotrexate, and cisplatin were given to all patients. Patients who fulfilled one or more of three defined high-risk criteria received early systemic treatment intensification by adding ifosfamide as the fourth agent. Preoperatively, these high-risk patients received cisplatin either intraarterially or intravenously. RESULTS: 171 eligible patients were entered, of which 128 were stratified into the high-risk group. When all 171 were analysed by intention-to-treat, actuarial overall and event-free survival rates at ten years were 72% and 66%, respectively. No benefit of intraarterial cisplatin application was detected. Cumulative treatment toxicity was considerable. CONCLUSIONS: In a multicenter setting, intensive treatment of osteosarcoma according to protocol COSS-86 led to long-term disease-free survival for two thirds of patients. We saw no benefit of using the intraarterial route to administer cisplatin. 相似文献
42.
R Buchhorn D Bartmus W Siekmeyer M Hulpke-Wette R Schulz J Bürsch 《Canadian Metallurgical Quarterly》1998,81(11):1366-1368
We report on the clinical and neurohumoral effects of adding low-dose propranolol to conventional therapy with digoxin and diuretics in 6 infants with severe congestive heart failure due to large left-to-right shunts. A significant decrease in heart failure scores and a decrease of the highly activated renin-angiotensin-1 aldosterone system by approximately 70% strongly suggests a beneficial effect of this new therapeutic approach. 相似文献
43.
Robin Carr D. H. Thomas T. S. Venkataraman Allan L. Smith Michael A. Gealt R. Quinn M. Tanyel 《工程教育杂志》1995,84(2):137-150
All fields of engineering, whether chemical, civil, electrical, materials, mechanical, etc., encompass a common body of essential mathematics and science. In the freshman year of Drexels E4 program, this common mathematical and scientific foundation is cultivated in the Mathematical and Scientific Foundations of Engineering I, II and III (MSFE I, MSFE II, MSFE III). In an integrated fashion, MSFE I presents the essential calculus, physics and engineering mechanics vital to the freshman engineering student. In the first two quarters, MSFE II presents chemistry with clearly defined engineering applications and significance: in the third quarter, MSFE II presents living systems with the same thrust. Also in the third quarter, MSFE III presents basic circuits and circuit elements, and a brief introduction to electromagnetic theory. 相似文献
44.
45.
Robin N. Santra Sanjoy Roy Anil K. Bhowmick G. B. Nando 《Polymer Engineering and Science》1993,33(20):1352-1359
Blends of ethylene methyl acrylate (EMA) and poly(dimethylsiloxane) rubber (PDMS) are demonstrated to be miscible. The miscibility results in a single and composition-dependent glass transition temperature. IR spectra of the blends provide direct evidence of chemical reaction between EMA and PDMS rubber. 相似文献
46.
Campillo Mauricio Sedaghati Ramin Drew Robin A. L. Alfonso Ismeli Prez Luis 《Engineering with Computers》2021,38(3):1767-1785
Engineering with Computers - In this article, a methodology based on Discrete Element Method (DEM) and Finite Elements Method (FEM) combined with modified Approximate Periodic Boundary Condition... 相似文献
47.
Streit M Schulz HJ Lex A Schmalstieg D Schumann H 《IEEE transactions on visualization and computer graphics》2012,18(6):998-1010
As heterogeneous data from different sources are being increasingly linked, it becomes difficult for users to understand how the data are connected, to identify what means are suitable to analyze a given data set, or to find out how to proceed for a given analysis task. We target this challenge with a new model-driven design process that effectively codesigns aspects of data, view, analytics, and tasks. We achieve this by using the workflow of the analysis task as a trajectory through data, interactive views, and analytical processes. The benefits for the analysis session go well beyond the pure selection of appropriate data sets and range from providing orientation or even guidance along a preferred analysis path to a potential overall speedup, allowing data to be fetched ahead of time. We illustrate the design process for a biomedical use case that aims at determining a treatment plan for cancer patients from the visual analysis of a large, heterogeneous clinical data pool. As an example for how to apply the comprehensive design approach, we present Stack'n'flip, a sample implementation which tightly integrates visualizations of the actual data with a map of available data sets, views, and tasks, thus capturing and communicating the analytical workflow through the required data sets. 相似文献
48.
H. Schulz 《Holz als Roh- und Werkstoff》1985,43(6):215-222
- Sandblasting of hardwood and softwood cross-sections reveals unexpected hardness profiles, which may provide an extension to the conventional division of wood into annual rings, earlywood and latewood or zones of growth.
- Hard wooden parts which occur in cross-sections and which presumably contribute towards its strength, can also be traced in longitudinal cuts in the form of ridges.
- It is assumed that tree species build up different mechanical systems which can be varied during wood formation as the need arises.
49.
Oliver Schmutzler Sebastian Graf Nils Behm Wael Y. Mansour Florian Blumendorf Theresa Staufer Christian Krnig Dina Salah Yanan Kang Jan N. Peters Yang Liu Neus Feliu Wolfgang J. Parak Anja Burkhardt Elisabetta Gargioni Sabrina Gennis Sharah Chandralingam Finn Heg Wolfgang Maison Kai Rothkamm Florian Schulz Florian Grüner 《International journal of molecular sciences》2021,22(7)
Quantitative cellular in vitro nanoparticle uptake measurements are possible with a large number of different techniques, however, all have their respective restrictions. Here, we demonstrate the application of synchrotron-based X-ray fluorescence imaging (XFI) on prostate tumor cells, which have internalized differently functionalized gold nanoparticles. Total nanoparticle uptake on the order of a few hundred picograms could be conveniently observed with microsamples consisting of only a few hundreds of cells. A comparison with mass spectroscopy quantification is provided, experimental results are both supported and sensitivity limits of this XFI approach extrapolated by Monte-Carlo simulations, yielding a minimum detectable nanoparticle mass of just 5 pg. This study demonstrates the high sensitivity level of XFI, allowing non-destructive uptake measurements with very small microsamples within just seconds of irradiation time. 相似文献
50.
Robin Wijngaard Meritxell Perramn Marina Parra-Robert Susana Hidalgo Gina Butrico Manuel Morales-Ruiz Muling Zeng Eudald Casals Wladimiro Jimnez Guillermo Fernndez-Varo Gerald I. Shulman Gary W. Cline Gregori Casals 《International journal of molecular sciences》2021,22(9)
The metabolic ratios lactate/pyruvate and β-hydroxybutyrate/acetoacetate are considered valuable tools to evaluate the in vivo redox cellular state by estimating the free NAD+/NADH in cytoplasm and mitochondria, respectively. The aim of the current study was to validate a gas-chromatography mass spectrometry method for simultaneous determination of the four metabolites in plasma and liver tissue. The procedure included an o-phenylenediamine microwave-assisted derivatization, followed by liquid-liquid extraction with ethyl acetate and silylation with bis(trimethylsilyl)trifluoroacetamide:trimethylchlorosilane 99:1. The calibration curves presented acceptable linearity, with a limit of quantification of 0.001 mM for pyruvate, β-hydroxybutyrate and acetoacetate and of 0.01 mM for lactate. The intra-day and inter-day accuracy and precision were within the European Medicines Agency’s Guideline specifications. No significant differences were observed in the slope coefficient of three-point standard metabolite-spiked curves in plasma or liver and water, and acceptable recoveries were obtained in the metabolite-spiked samples. Applicability of the method was tested in precision-cut liver rat slices and also in HepG2 cells incubated under different experimental conditions challenging the redox state. In conclusion, the validated method presented good sensitivity, specificity and reproducibility in the quantification of lactate/pyruvate and β-hydroxybutyrate/acetate metabolites and may be useful in the evaluation of in vivo redox states. 相似文献