全文获取类型
收费全文 | 712篇 |
免费 | 32篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 73篇 |
金属工艺 | 6篇 |
机械仪表 | 5篇 |
建筑科学 | 20篇 |
能源动力 | 6篇 |
轻工业 | 15篇 |
无线电 | 113篇 |
一般工业技术 | 146篇 |
冶金工业 | 315篇 |
原子能技术 | 1篇 |
自动化技术 | 39篇 |
出版年
2023年 | 6篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 10篇 |
2017年 | 6篇 |
2016年 | 11篇 |
2015年 | 4篇 |
2014年 | 18篇 |
2013年 | 22篇 |
2012年 | 24篇 |
2011年 | 23篇 |
2010年 | 15篇 |
2009年 | 21篇 |
2008年 | 18篇 |
2007年 | 12篇 |
2006年 | 11篇 |
2005年 | 16篇 |
2004年 | 14篇 |
2003年 | 18篇 |
2002年 | 19篇 |
2001年 | 7篇 |
2000年 | 10篇 |
1999年 | 23篇 |
1998年 | 90篇 |
1997年 | 59篇 |
1996年 | 60篇 |
1995年 | 35篇 |
1994年 | 25篇 |
1993年 | 18篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 10篇 |
1989年 | 14篇 |
1988年 | 12篇 |
1987年 | 11篇 |
1986年 | 3篇 |
1985年 | 13篇 |
1984年 | 5篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1978年 | 4篇 |
1977年 | 7篇 |
1976年 | 12篇 |
1974年 | 3篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有744条查询结果,搜索用时 703 毫秒
21.
Y. L. Yip C. C. Leung S. W. Mok K. H. Yip Hin Wing Kui 《Metallurgical and Materials Transactions A》2014,45(3):1457-1469
When undercooled deeply into its undercooling regime, a molten Fe79.5B6.5C14 ingot undergoes spinodal decomposition, splitting into two interpenetrating subnetworks which are denoted by α-(liquid subnetwork) and β-(liquid subnetwork). Transmission electron microscopy results suggest that there are three constraints on crystal growth when the undercooled, decomposed molten ingot solidifies, which are (i) the solidification is due to the advancement of a bulk solid/liquid interface. It consists of a number of α-solid/liquid interfaces moving in the α-(liquid subnetwork) and a number of β-solid/liquid interfaces moving in the β-(liquid subnetwork); (ii) to overcome two long-range composition gradients of C and B atoms; and (iii) the two long-range composition gradients stabilize the bulk solid/liquid interface. The morphology of a solidified or network Fe79.5B6.5C14 ingot is explained in terms of the obtained microscopic results. 相似文献
22.
Currently, foam molding technologies are widely adopted for most bra styles, which demonstrate the incomparable advantages in the contemporary intimate apparel industry. The determination of proper molding conditions, such as molding temperatures and length of time on the basis of cup sizes and styles, is crucial in achieving the required cup shape with high stability, which is regarded as the most challenging part of the molded bra making process. To determine the optimal process parameter settings, numerous process trials are generally required to evaluate the molding variables and their interactions. This study proposes a novel systematic methodology to identify the optimal molding process parameters based on design of experiment (DOE) and a parameterization-based remesh method to evaluate the 3D shape conformity of molded cups. By solving the regression equation obtained from a Box–Behnken design (BBD) and analyzing the response surface plots, the results prove that molding temperature has greater influence than the length of the dwell time on the 3D shape conformity of molded cups. The optimal molding conditions can be determined for the cup depths of different sized mold heads, which are validated by the experimental results. 相似文献
23.
Alberto Carlucci Martin Hooton Hj Mazlan Abd Salim Sammy Yip Kelvin Moneypenny Steve Kite 《Bautechnik》2015,92(3):220-226
The Temburong Bridge Project is a 30 km long dual two‐lane highway crossing over the Brunei Bay. It will connect the relatively isolated Brunei district of Temburong to the other three Brunei districts. The main objective of the project is to stimulate economic growth in the Temburong region by connecting it to the country's airport and ports. The alignment crosses two navigation channels resulting in the need for two cable stayed bridges – the Brunei Channel Bridge (145 m main span) and the Eastern Channel Bridge (260 m main span). The design of these cable stayed bridges is one of the first applications of the Eurocode to a fully concrete cable stayed bridge. Both cable stayed bridges draw on strong Islamic architectural influences from the region to form a tower shape that is unique and instantly recognisable. Temburong Brücke, Brunei – Entwurf von zwei Schrägkabelbrücken Die Temburong Brücke ist eine 30 km lange Verbindung über die Brunei Bucht mit zwei Richtungsfahrbahnen mit je zwei Fahrstreifen. Sie wird den relativ isolierten Distrikt Temburong mit den anderen drei Distrikten Bruneis verbinden. Hauptanliegen des Projekts ist die Stimulierung von ökonomischem Wachstum in der Temburong Region, indem sie an den Flughafen und Seehafen des Landes angebunden wird. Die Trassierung erfordert die Überquerung zweier Schiffahrtsrouten. Dies wird mit der Anordnung zweier Schrägkabelbrücken ermöglicht, der Brunei Channel Brücke (145 m Hauptspannweite) und der Eastern Channel Brücke (260 m Hauptspannweite). Die Bemessung der beiden Brücken stellt eine der ersten Anwendungen des Eurocode auf Schrägkabelbrücken mit Betonüberbau dar. Optisch sind die beiden Brücken geprägt von der islamischen Architektur der Umgebung, die Pylonform ist ein besonderes Erkennungsmerkmal der Brücken. 相似文献
24.
Ozlem Yildiz Johannes Schroth Vittoria Lombardi Valentina Pucino Yoana Bobeva Ping Kei Yip Klaus Schmierer Claudio Mauro Timothy Tree Sian Mari Henson Andrea Malaspina 《International journal of molecular sciences》2022,23(6)
Monocytes expressing the inflammation suppressing active CD11b, a beta2 integrin, may regulate neuroinflammation and modify clinical outcomes in amyotrophic lateral sclerosis (ALS). In this single site, retrospective study, peripheral blood mononuclear cells from 38 individuals living with ALS and 20 non-neurological controls (NNC) were investigated using flow cytometry to study active CD11b integrin classical (CM), intermediate (IM) and non-classical (NCM) monocytes during ALS progression. Seventeen ALS participants were sampled at the baseline (V1) and at two additional time points (V2 and V3) for longitudinal analysis. Active CD11b+ CM frequencies increased steeply between the baseline and V3 (ANOVA repeated measurement, p < 0.001), and the V2/V1 ratio negatively correlated with the disease progression rate, similar to higher frequencies of active CD11b+ NCM at the baseline (R = −0.6567; p = 0.0031 and R = 0.3862; p = 0.0168, respectively). CD11b NCM, clinical covariates and neurofilament light-chain plasma concentration at the baseline predicted shorter survival in a multivariable and univariate analysis (CD11b NCM—HR: 1.05, CI: 1.01–1.11, p = 0.013. Log rank: above median: 43 months and below median: 21.22 months; p = 0.0022). Blood samples with the highest frequencies of active CD11b+ IM and NCM contained the lowest concentrations of soluble CD11b. Our preliminary data suggest that the levels of active CD11b+ monocytes and NCM in the blood predict different clinical outcomes in ALS. 相似文献
25.
W. H. Chow C. C. Leung Y. L. Yip S. W. Mok H. W. Kui 《Metallurgical and Materials Transactions A》2013,44(8):3532-3543
Molten Fe79.5B6.5C14 melts can be cast into ingots of networklike microstructure. According to microstructural classification, a Fe79.5B6.5C14 network specimen can be divided into three zones. Zone A is occupied by a random network, zone B by a uniformly aligned network, and zone C by a severely aligned network that exhibits network patterns. 相似文献
26.
BACKGROUND: To examine the seasonality of suicides in Australia and New Zealand during the period 1981 to 1993. METHODS: A chi-square test and a harmonic analysis were used to detect the seasonality of the suicide data. RESULTS: The reduced amplitude and a smaller proportion of variance accounted for by seasonality suggested the seasonal effect on suicide is greatly diminished. The absence of biseasonal distribution of female suicides was also consistently found in the two countries. The finding was contrary to the reported results in seventies in many Western countries. CONCLUSIONS: The change in living condition, roles of males and females and communication pattern resulted in the reduction of climatic and environment effect in the seasonality of suicides were suggested. LIMITATIONS: The results would be better if a longer series of suicide date were available. 相似文献
27.
28.
29.
Colonization of the nasopharynx by a middle ear pathogen is the first step in the development of otitis media in humans. The establishment of an animal model of nasopharyngeal colonization would therefore be of great utility in assessing the potential protective ability of candidate vaccine antigens (especially adhesins) against otitis media. A chinchilla nasopharyngeal colonization model for nontypeable Haemophilus influenzae (NTHI) was developed with antibiotic-resistant strains. This model does not require coinfection with a virus. There was no significant difference in the efficiency of NTHI colonization between adult (1- to 2-year-old) and young (2- to 3-month-old) animals. However, the incidence of middle ear infection following nasopharyngeal colonization was significantly higher in young animals (83 to 89%) than in adult chinchillas (10 to 30%). Chinchillas that had recovered either from a previous middle ear infection caused by NTHI or from an infection by intranasal inoculation with NTHI were completely protected against nasopharyngeal colonization with a homologous strain and were found to be the best positive controls in protection studies. Systemic immunization of chinchillas with inactivated whole-cell preparations significantly protected animals not only against homologous NTHI colonization but also partially against heterologous NTHI infection. In all protected animals, significant serum anti-P6 and anti-HMW antibody responses were observed. The outer membrane P6 and high-molecular-weight (HMW) proteins appear to be promising candidate vaccine antigens to prevent nasopharyngeal colonization and middle ear infection caused by NTHI. 相似文献
30.
D Josi? H Schwinn A Strancar A Podgornik M Barut YP Lim M Vodopivec 《Canadian Metallurgical Quarterly》1998,803(1-2):61-71
Different ligands with high molecular masses are immobilized on compact, porous separation units and used for affinity chromatography. In subsequent experiments different enzymes are immobilized and used for converting substrates with low and high molecular masses. Disk or tube with immobilized concanavalin A (ConA) are used as model systems for lectin affinity chromatography. The enzyme glucose oxidase is used as a standard protein to test the ConA units. Subsequently glycoproteins from plasma membranes of rat liver are separated, using units with immobilized ConA. The enzyme dipeptidyl peptidase i.v., which is used as a model protein in the experiments, is enriched about 40-fold in a single step, with a yield of over 90%. The results are only slightly better than those obtained with ConA when it is immobilized on bulk supports. The important improvement lies in the reduction of separation time to only 1 h. Experiments concerning the isolation of monoclonal antibodies against clotting factor VIII (FVIII) are carried out on disks, combining anion-exchange chromatography and protein A affinity chromatography as a model for multidimensional chromatography. Both IgG (bound to the protein A disk) and accompanying proteins (bound to the anion-exchange disk) from mouse ascites fluid are retarded and eluted separately. With the immobilized enzymes invertase and glucose oxidase (GOX) the corresponding substrates with low molecular masses, saccharose and glucose, are converted. It is shown that the amount of immobilized enzyme and the concentration of the substrate are responsible for the extent of the conversion, whereas the flow-rates used in the experiments have no effect at all. The influence of immobilization chemistry was investigated with GOX. Indirect immobilization with ConA as spacer proved to be the best alternative. With trypsin, immobilized on a disk, substrates with high molecular masses are digested in flow-through. For optimal digestion the proteins have to be denatured in the buffer for sodium dodecyl sulfate-polyacrlyamide gel electrophoresis prior to application. In contrast to the conversion of substrates with low molecular masses, flow-rates play an important part in conversion of substrates with high molecular masses. With lower flow-rates a higher degree of digestion is achieved. 相似文献