全文获取类型
收费全文 | 10188篇 |
免费 | 740篇 |
国内免费 | 393篇 |
专业分类
电工技术 | 173篇 |
综合类 | 619篇 |
化学工业 | 1303篇 |
金属工艺 | 622篇 |
机械仪表 | 1175篇 |
建筑科学 | 320篇 |
矿业工程 | 133篇 |
能源动力 | 287篇 |
轻工业 | 2244篇 |
水利工程 | 168篇 |
石油天然气 | 1313篇 |
武器工业 | 54篇 |
无线电 | 746篇 |
一般工业技术 | 692篇 |
冶金工业 | 429篇 |
原子能技术 | 181篇 |
自动化技术 | 862篇 |
出版年
2024年 | 30篇 |
2023年 | 88篇 |
2022年 | 195篇 |
2021年 | 278篇 |
2020年 | 242篇 |
2019年 | 265篇 |
2018年 | 195篇 |
2017年 | 305篇 |
2016年 | 344篇 |
2015年 | 327篇 |
2014年 | 496篇 |
2013年 | 695篇 |
2012年 | 674篇 |
2011年 | 804篇 |
2010年 | 569篇 |
2009年 | 608篇 |
2008年 | 547篇 |
2007年 | 687篇 |
2006年 | 628篇 |
2005年 | 489篇 |
2004年 | 489篇 |
2003年 | 417篇 |
2002年 | 355篇 |
2001年 | 268篇 |
2000年 | 244篇 |
1999年 | 177篇 |
1998年 | 162篇 |
1997年 | 125篇 |
1996年 | 110篇 |
1995年 | 97篇 |
1994年 | 77篇 |
1993年 | 79篇 |
1992年 | 46篇 |
1991年 | 41篇 |
1990年 | 36篇 |
1989年 | 24篇 |
1988年 | 19篇 |
1987年 | 16篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 10篇 |
1983年 | 12篇 |
1982年 | 5篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1965年 | 2篇 |
1962年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
1.
Today, utility meters for water are tested for measurement behavior at stable operating conditions at specified flow rates as part of the approval process. The measurement error that occurs during start and stop or when changing between flow rates may not be taken into account. In addition, there are new technologies whose measuring behavior under real-world conditions is only known to a limited extend. To take these facts into account, a new method has been developed and tested to determine the measurement behavior of water meters under dynamic load profiles as they occur in the real application. For this purpose, a test rig for flow rate measurement was extended by a cavitation nozzle apparatus and the generation of dynamic load profiles was validated. For the cavitation nozzles used, possible factors influencing the flow rate, such as temperature and purity of the water as well as the upstream pressure were investigated. Using different types of domestic water meters, the applicability of the dynamic test procedure was demonstrated and the measurement behavior of the meters was characterised. 相似文献
2.
3.
Yana Jorge Polizer-Rocha José M. Lorenzo Daniel Pompeu Isabela Rodrigues Juliana Cristina Baldin Manoela A. Pires Maria Teresa A. Freire Francisco Jose Barba Marco Antonio Trindade 《International Journal of Food Science & Technology》2020,55(3):1018-1024
This study aimed to evaluate the physicochemical characteristics and sensory attributes of beef burgers with the addition of pea fibre as a partial substitute of meat or fat. Three formulations were prepared: control (CON) – similar to the commercial formulation; fibre/less meat (FLM)—5% meat reduction and addition of 1% pea fibre; fibre/less fat (FLF)—7% fat reduction and addition of 1% pea fibre. Non-significant differences were obtained for pH, colour parameters (L* and b*), texture profile, cooking loss and size reduction among formulations. Moreover, sensory analysis with consumers of beef burgers did not indicate differences among the formulations for all the analysed attributes. Therefore, pea fibre is a promising partial replacer for meat and fat in beef burgers due to the preservation of technological parameters and sensory acceptance. 相似文献
4.
5.
Effects of breed and age at slaughter on degradation of muscle lipids during processing of dry‐cured hams 下载免费PDF全文
Linda Storrustløkken Hanne Marie Devle Lars Erik Gangsei Carl Fredrik Naess‐Andresen Bjørg Egelandsdal Ole Alvseike Dag Ekeberg 《International Journal of Food Science & Technology》2015,50(8):1933-1943
Hams from Landrace, Duroc and Hampshire pigs slaughtered at ages 6, 7.5 and 9 months were processed to generate Norwegian Parma‐style hams. Lipid contents and the compositions of fatty acid classes (ΣSFA, ΣMUFA, ΣPUFA) within neutral lipids, phospholipids and free fatty acids were determined. Small differences in lipid degradation and composition of the classes were revealed. However, significant sensory differences related to lipids were observed. Breed was more important than age. Dry‐cured Hampshire hams gave a more intense mature odour that may be associated with higher overall lipid degradation. Unexpectedly, these hams also demonstrated high juiciness and tenderness, which could be related to the melting characteristics of the fat. Dry‐cured Duroc hams showed a higher susceptibility towards rancidity, presumably associated with preferential oxidation of n‐6 fatty acids relative to C18:1 n‐9. Dry‐cured Landrace hams showed the lowest juiciness and tenderness, likely due to their lower fat content (marbling). 相似文献
6.
Eight datasets of 1-h black carbon (BC) concentrations measured in Warsaw agglomeration (Poland), at urban background and sub-urban sites, and in Racibórz, a small town in Upper Silesia district (regional background site) were analyzed to evaluate BC levels, daily profiles and statistical distributions of concentrations in Central-Eastern European region. The observed mean levels ranged from 1483 ng m−3 in suburban site during summer to 3358 ng m−3 in regional background site in winter. Observed diurnal patterns were bimodal in the locations dominated by traffic emissions, but unimodal, with elevated evening peak in individually heated residential area. Three theoretical frequency distributions were applied to fit analyzed datasets separately. The lognormal distribution was the most appropriate to represent the middle-range values, while the high concentrations were satisfactorily predicted by the type I two-parameter exponential distribution which was used to estimate the return periods of extreme concentrations for winter months. 相似文献
7.
Dr. Emrah Kara Dr. Nis Valentin Nielsen Bergrun Eggertsdottir Dr. Bernd Thiede Dr. Sandip M. Kanse Dr. Geir Åge Løset 《Chembiochem : a European journal of chemical biology》2020,21(13):1875-1884
We describe a novel, easy and efficient combinatorial phage display peptide substrate-mining method to map the substrate specificity of proteases. The peptide library is displayed on the pVII capsid of the M13 bacteriophage, which renders pIII necessary for infectivity and efficient retrieval, in an unmodified state. As capture module, the 3XFLAG was chosen due to its very high binding efficiency to anti-FLAG mAbs and its independency of any post-translational modification. This library was tested with Factor-VII activating protease (WT-FSAP) and its single-nucleotide polymorphism variant Marburg-I (MI)-FSAP. The WT-FSAP results confirmed the previously reported Arg/Lys centered FSAP cleavage site consensus as dominant, as well as reinforcing MI-FSAP as a loss-of-function mutant. Surprisingly, rare substrate clones devoid of basic amino acids were also identified. Indeed one of these peptides was cleaved as free peptide, thus suggesting a broader range of WT-FSAP substrates than previously anticipated. 相似文献
8.
In this study, we have proposed an automated classification approach to identify meaningful patterns in wind field data. Utilizing an extensive simulated wind database, we have demonstrated that the proposed approach can identify low‐level jets, near‐uniform profiles, and other patterns in a reliable manner. We have studied the dependence of these wind profile patterns on locations (eg, offshore vs onshore), seasons, and diurnal cycles. Furthermore, we have found that the probability distributions of some of the patterns depend on the underlying planetary boundary layer schemes in a significant way. The future potential of the proposed approach in wind resource assessment and, more generally, in mesoscale model parameterization improvement is touched upon in this paper. 相似文献
9.
Advanced protein-based nanomaterials and nanosystems (PNNS) have attracted considerable scientific interest in recent decades due to their potential in bio-applications. Nowadays, the constructed PNNS exhibit different properties for various special applications based on the characteristics of different proteins. Herein, in this review article, a systematic summary and discussion focusing on designing multi-functional PNNS are presented. The latest developments in unique synthesis strategies and detailed classification of PNNS are reviewed. The functions of proteins in PNNS for biomedical applications, such as targeting proteins, carriers, enzymes, and fluorescent indicators, are summarized. Finally, the challenges and forward-looking perspectives of PNNS research are provided. 相似文献
10.