全文获取类型
收费全文 | 302篇 |
免费 | 3篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 38篇 |
金属工艺 | 2篇 |
机械仪表 | 12篇 |
建筑科学 | 13篇 |
能源动力 | 6篇 |
轻工业 | 23篇 |
水利工程 | 5篇 |
石油天然气 | 5篇 |
无线电 | 12篇 |
一般工业技术 | 32篇 |
冶金工业 | 117篇 |
原子能技术 | 8篇 |
自动化技术 | 30篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2013年 | 25篇 |
2012年 | 10篇 |
2011年 | 6篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 10篇 |
2007年 | 6篇 |
2006年 | 3篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 11篇 |
1998年 | 26篇 |
1997年 | 14篇 |
1996年 | 6篇 |
1995年 | 12篇 |
1994年 | 11篇 |
1993年 | 6篇 |
1992年 | 10篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 9篇 |
1976年 | 11篇 |
1975年 | 2篇 |
1973年 | 6篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1969年 | 3篇 |
1967年 | 3篇 |
1965年 | 2篇 |
1924年 | 1篇 |
排序方式: 共有307条查询结果,搜索用时 31 毫秒
1.
Gastric bacteria from cheetahs with gastritis were used to inoculate specific-pathogen free kittens and conventional mice. Helicobacter sp. and Gastrospirillum sp. colonized kittens, while only Gastrospirillum sp. colonized mice. In kittens, both bacterial species induced mild lymphofolliclar gastritis which did not change over the course of the 11 months observation period. In mice, Gastrospirillum sp. induced lymphoplasmacytic and follicular gastritis which increased in severity over 6 months and persisted for the 12 month observation period. Gastric ulcers and gastric mucosal hypertrophy were present in chronically infected mice. These results indicate that host but not bacterial factors influence the severity of gastritis, and that in mice, bacterial gastritis increases in severity with time and may lead to gastric ulceration in some individuals. 相似文献
2.
Eaton P. Ragusa A. Clavel C. Rojas C.T. Graham P. Duran R.V. Penades S. 《IEEE transactions on nanobioscience》2007,6(4):309-318
Glyconanoparticles which present carbohydrate and amino groups motifs at their surface were produced. These particles were highly stable and soluble in aqueous solutions. The presence of the carbohydrate groups also allowed the inclusion of more strongly binding groups, without affecting solubility. The binding of a model DNA, plasmid by these nanoparticles was studied by atomic force microscopy, transmission electron microscopy, and gel electrophoresis. Significant differences between the nanoparticles based on their affinities for the DNA were found, with implications for their potential use as nonviral gene delivery agents. 相似文献
3.
Peter Eaton Andrea Ragusa Caroline Clavel Cristina T Rojas Paul Graham Raúl V Durán Soledad Penadés 《IEEE transactions on nanobioscience》2007,6(4):309-318
Glyconanoparticles which present carbohydrate and amino groups motifs at their surface were produced. These particles were highly stable and soluble in aqueous solutions. The presence of the carbohydrate groups also allowed the inclusion of more strongly binding groups, without affecting solubility. The binding of a model DNA, plasmid by these nanoparticles was studied by atomic force microscopy, transmission electron microscopy, and gel electrophoresis. Significant differences between the nanoparticles based on their affinities for the DNA were found, with implications for their potential use as nonviral gene delivery agents. 相似文献
4.
An analytic solution of the diffusion equation for a hemisphere of fissile or non-fissile material is presented which contains a spatially uniform neutron source. Numerical results are given for the flux distribution for one-speed fast neutrons in 235U and also for a non-fissile element of similar scattering properties. We use these results to check the accuracy of the finite element code EVENT. The procedure is also developed for multigroup calculations. In an Appendix we outline the procedure required when the hemisphere contains a source and is also irradiated by an external current of neutrons. 相似文献
5.
S. Boyd Eaton 《Lipids》1992,27(10):814-820
The genetically ordered physiology of contemporary humans was selected over eons of evolutionary experience for a nutritional
pattern affording much less fat, particularly less saturated fat. Current dietary recommendations do not accord exactly with
those generated by an understanding of prior hominoid/hominid evolution. Similarly, widely advocated standards for serum cholesterol
values fail to match those observed in recently studied hunter-gatherers, whose experience represents the closest living approximation
of “natural” human lipid metabolism. The evolutionary paradigm suggests that fats should comprise 20–25% of total energy intake,
that the ratio of polyunsaturated to saturated fat should exceed 1.0, and that total serum cholesterol levels should be below
150 mg/dL (∼4 mM/L).
Based on a paper presented at the Symposium on Lipids in Cancer held at the AOCS Annual Meeting, Baltimore, MD, April 1990. 相似文献
6.
Amitava Roy Harvill C. Eaton Frank K. Cartledge Marty E. Tittlebaum 《Journal of hazardous materials》1992,30(3):297-316
The effect of sodium sulfate on the solidification/stabilization of a large quantity of a synthetic electroplating sludge in cementitious binders was s 相似文献
7.
8.
FJ de Sauvage K Carver-Moore SM Luoh A Ryan M Dowd DL Eaton MW Moore 《Canadian Metallurgical Quarterly》1996,183(2):651-656
Thrombopoietin (TPO) has recently been cloned and shown to regulate megakaryocyte and platelet production by activating the cytokine receptor c-mpl. To determine whether TPO is the only ligand for c-mpl and the major regulator of megakaryocytopoiesis, TPO deficient mice were generated by gene targeting. TPO-/- mice have a >80% decrease in their platelets and megakaryocytes but have normal levels of all the other hematopoietic cell types. A gene dosage effect observed in heterozygous mice suggests that the TPO gene is constitutively expressed and that the circulating TPO level is directly regulated by the platelet mass. Bone marrow from TPO-/- mice have decreased numbers of megakaryocyte-committed progenitors as well as lower ploidy in the megakaryocytes that are present. These results demonstrate that TPO alone is the major physiological regulator of both proliferation and differentiation of hematopoietic progenitor cells into mature megakaryocytes but that TPO is not critical to the final step of platelet production. 相似文献
9.
A new mode of operation of a balanced magnetic circuit is described. With this new mode of operation, which utilizes pulsed current excitation, the detection sensitivity of the magnetic modulator circuit is combined with the high-speed amplification of parametric buildup. This combination permits detection of low-level current pulses applied during a specified time interval of the excitation sequence and provides subsequent amplification of the detected signal. Matched square-loop toroids are used. Signal currents which are a small fraction of the coercive MMF have been successfully detected. The limit of detection sensitivity depends upon the matching of the two cores. The parametric buildup has been made to occur for pump cycle times of 30 μs to 120 μs, depending upon the magnetic material used. The signal information is retained when the pulse excitation sequence is interrupted during buildup because the signal information is stored as a flux unbalance in the two cores during the time interval between excitation pulses. The use of this circuit mode as a sense amplifier for the detection and amplification of sense winding currents in magnetic memories is suggested. 相似文献
10.
Bethany Anderson Fynnette Eaton Scott W. Schwartz 《New Review of Information Networking》2015,20(1-2):3-15
The digital revolution has changed the daily work of archivists. As a result, archivists have refined their analog practices and initiated new ones to accommodate the unique information creation and access needs of users. While limitless storage and technological obsolescence may be surmountable challenges, appraisal continues to be a necessary component of this preservation enterprise. Macro-appraisal—a top-down functional assessment of an organization’s high-level decision making that defines the enduring value of specific bodies of documentary evidence of these creative or administrative processes—is used to facilitate the management of diverse bodies of born-digital records in archives and special collections. 相似文献