全文获取类型
收费全文 | 5881篇 |
免费 | 0篇 |
专业分类
综合类 | 1篇 |
化学工业 | 30篇 |
金属工艺 | 3篇 |
机械仪表 | 1篇 |
建筑科学 | 1篇 |
矿业工程 | 2篇 |
能源动力 | 2篇 |
轻工业 | 18篇 |
无线电 | 3篇 |
一般工业技术 | 10篇 |
冶金工业 | 5807篇 |
自动化技术 | 3篇 |
出版年
2020年 | 5篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 3篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2010年 | 4篇 |
2008年 | 2篇 |
2007年 | 4篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 6篇 |
2003年 | 12篇 |
2002年 | 1篇 |
2000年 | 1篇 |
1999年 | 184篇 |
1998年 | 1915篇 |
1997年 | 1096篇 |
1996年 | 701篇 |
1995年 | 377篇 |
1994年 | 275篇 |
1993年 | 358篇 |
1992年 | 42篇 |
1991年 | 42篇 |
1990年 | 53篇 |
1989年 | 44篇 |
1988年 | 36篇 |
1987年 | 38篇 |
1986年 | 35篇 |
1985年 | 44篇 |
1984年 | 1篇 |
1983年 | 9篇 |
1982年 | 19篇 |
1981年 | 37篇 |
1980年 | 52篇 |
1979年 | 2篇 |
1978年 | 14篇 |
1977年 | 129篇 |
1976年 | 291篇 |
1975年 | 13篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1965年 | 1篇 |
1963年 | 1篇 |
1955年 | 4篇 |
排序方式: 共有5881条查询结果,搜索用时 15 毫秒
1.
2.
AM Pollock 《Canadian Metallurgical Quarterly》1995,310(6994):1580-1584
The Association of Metropolitan Authorities has recently proposed that responsibility for the NHS should pass from health authorities to local authorities. One of the fiercest debates at the outset of the NHS was whether the hospitals should be run by local authorities. In the end the minister for health, Aneurin Bevan, decided against local democracy and in favour of a national health service. His arguments included the fact that equality of treatment could not be guaranteed if facilities varied with local finances and that even the largest authorities were not big enough to pool risks and expertise. All these arguments still apply today, and the recent changes in community care provide an insight into how a market model of local authority control might work. The changes have been accompanied by a shift from public to private sector provision and the introduction of charges for services that the NHS once provided free. As important, the willingness and ability of local authorities to raise extra revenue from local taxes and charges affect the service they can provide, so leading to inequalities of provision. Local authorities have yet to make the case that they can preserve the fundamental principles and benefits of the NHS, including its reliance on central taxation and unified funding formulas. 相似文献
3.
Comparison of protein adsorption isotherms and uptake rates in preparative cation-exchange materials
Adsorption isotherms and effective diffusivities of lysozyme in a set of six preparative cation-exchange stationary phases were determined from batch uptake data in a stirred vessel. Both a pore diffusion and a homogeneous diffusion model were used in estimating diffusivities, with the isotherms fitted to a non-Langmuirian analytical isotherm equation. The capacities inferred from the isotherms are found to be correlated with the surface area accessible to lysozyme, the effective surface concentrations obtained being in agreement with values measured by different methods in various non-chromatographic systems. The pore diffusivities show systematic trends with protein and salt concentration, and effects of pore size and connectivity are also evident. Some trends in the homogeneous diffusivities are quite different to those in the pore diffusivities, but these differences largely disappear when the homogeneous diffusivities are rescaled to account for adsorption equilibrium behavior. Additional information is required to elucidate further the mechanisms of coupled diffusion and adsorption in stationary phases. 相似文献
4.
Oligonucleotide N3'-->P5' phosphoramidates (3'-phosphoramidates) are DNA analogs that are presently under investigation as potential therapeutic agents. These compounds may also hold promise as a diagnostic tool. Here, we describe a rapid method for the analysis of single-stranded RNA fragments utilizing 3'-phosphoramidate oligonucleotides as probes in conjunction with capillary gel electrophoresis (CGE). 3'-Phosphoramidate 9-mers were mixed with complimentary RNA, and CGE was used to monitor duplex formation. Complimentary strands of RNA and 3'-phosphoramidate formed duplexes that gave unique relative mobilities based on an internal standard. The ability of CGE to discriminate between perfect duplexes and duplexes that contain a base mismatch was also investigated. However, the primary focus of this work was to determine CGE's ability to detect the presence of the 3'-phosphoramidates/RNA duplex under routine electrophoretic running conditions. Polyacrylamide gel electrophoresis analysis was utilized to verify duplex formation. 相似文献
5.
As with other forms of stress, surgery is a time of fluctuating haemodynamics, physiological shifts, intense metabolic changes, and protein catabolism and anabolism. At times, these changes can occur within hours. There is a reasonable body of literature concerning the adverse effects of surgery on gastric emptying, but not on the effects of surgery on the distribution, metabolism and excretion of drugs. Gastric emptying is diminished or absent following major procedures, which prevent the delivery of orally administered drugs to their major site of absorption, the small bowel. Changes in the paracellular absorption of drugs may occur postoperatively, although transcellular absorption appears to be unimpaired. Distribution is affected by changes in blood volume, alterations in circulation, increases in the extracellular fluid and changes in the circulating plasma protein levels, such as albumin and alpha 1-acid glycoprotein. Little is known about alterations in drug metabolism following surgery. However, it has been shown that systemic hypoxia alters the function of some of the cytochrome P450 (CYP) system and increased levels of cytokines have an effect on the metabolism of at least 1 drug. In addition, the renal elimination of drugs is affected in patients postoperatively, although the effects of biliary clearance in this period are difficult to determine. Despite the lack of research into pharmacokinetics during the postoperative period, and given the immense and often sudden changes observed in patients post-surgery, it is reasonable to recommend vigilance with respect to drug therapy during this period. 相似文献
6.
AM al-Senaidy 《Canadian Metallurgical Quarterly》1996,66(3):210-216
"Holistic therapy" can be just a slogan, a catchword. Two examples--the combination of behaviour therapy and pharmacotherapy on one side, the use of biofeedback in psychiatry on the other--shall present the possible integration of different therapeutic strategies into a holistic concept. The quality of different therapeutic concepts may be influenced by their possible combination. No more any therapeutic method (except some eclectic ones) can see itself as the one and only cure for everything. Of course this view has a consequence on psychopathology and diagnosis, which have to be more exact under these premisses. A holistic treatment requires more knowledge about details in psychopathology and diagnosis as well as about therapeutic methods. 相似文献
7.
8.
AM Malashenko 《Canadian Metallurgical Quarterly》1976,12(3):163-165
Diethylsulphate solution was injected intraperitoneally twice a week to male mice B10.C3H having the wild-type colour at a 5 mg/kg dose. The treatment lasted 10 weeks, so that the total dose administered was 5-20 = 100 mg/kg. In fifth week after the end of the treatment these males were crossed to YT females homozygous for seven recessive mutant genes. In the control group all the F1 descendants were of wild-type colour, while in the experimental group among 5042 F1 mice derived from DES-treated spermatogonia there was one mutant d and 4 mosaics (3 with respect to the locus c and 1 with respect to the locusa). These results are interpreted as the evidence of the mutagenic effect of DES. 相似文献
9.
10.