全文获取类型
收费全文 | 993篇 |
免费 | 32篇 |
专业分类
电工技术 | 4篇 |
综合类 | 6篇 |
化学工业 | 182篇 |
金属工艺 | 8篇 |
机械仪表 | 6篇 |
建筑科学 | 87篇 |
矿业工程 | 1篇 |
能源动力 | 10篇 |
轻工业 | 156篇 |
水利工程 | 20篇 |
石油天然气 | 4篇 |
无线电 | 34篇 |
一般工业技术 | 123篇 |
冶金工业 | 289篇 |
原子能技术 | 1篇 |
自动化技术 | 94篇 |
出版年
2024年 | 5篇 |
2023年 | 8篇 |
2022年 | 18篇 |
2021年 | 32篇 |
2020年 | 14篇 |
2019年 | 18篇 |
2018年 | 31篇 |
2017年 | 22篇 |
2016年 | 26篇 |
2015年 | 10篇 |
2014年 | 18篇 |
2013年 | 50篇 |
2012年 | 41篇 |
2011年 | 89篇 |
2010年 | 59篇 |
2009年 | 54篇 |
2008年 | 68篇 |
2007年 | 63篇 |
2006年 | 55篇 |
2005年 | 56篇 |
2004年 | 47篇 |
2003年 | 43篇 |
2002年 | 42篇 |
2001年 | 18篇 |
2000年 | 14篇 |
1999年 | 10篇 |
1998年 | 14篇 |
1997年 | 15篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 8篇 |
1993年 | 7篇 |
1992年 | 8篇 |
1991年 | 1篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1972年 | 1篇 |
排序方式: 共有1025条查询结果,搜索用时 0 毫秒
31.
Mary W. Stoertz Heather Bourne Christa Knotts Matthew M. White 《Mine Water and the Environment》2002,21(2):60-72
Isolated headwater streams in mined watersheds may have good water quality and fish habitat, yet be disconnected from immigration
sources by stream segments impaired by acid mine drainage (AMD). Studies of fish and macroinvertebrate communities, habitat,
and a number of hydrochemical parameters in Monday Creek, Ohio, show that AMD eliminates fish communities and severely limits
macroinvertebrate communities in directly affected tributaries. Isolated headwaters in the heavily mined Monday Creek watershed
have relatively good water quality and habitat, but poor fish communities. Comparison of isolated Monday Creek headwaters
with non-isolated reaches in unmined watersheds indicates that differences in fish communities are attributable to isolation.
Fish communities in isolated headwaters have lower Indices of Biotic Integrity (IBI) than comparable non-isolated communities,
reduced species numbers, and lower numbers of individuals, despite suitable habitat as measured by the Qualitative Habitat
Evaluation Index (QHEI). Comparison of macroinvertebrate communities shows higher Invertebrate Community Indices (ICI), and
no apparent species loss, which can be attributed to the obligate flight stage in the life cycle of many macroinvertebrates,
which enables them to overcome aquatic barriers. The implication of this research is that there is an opportunity for recovery
of depleted fish communities in large AMD-isolated areas with good water quality, suitable habitat, and intact macroinvertebrate
communities, by downstream treatment or source control of AMD to create aquatic corridors for fish immigration. 相似文献
32.
正Ground control is the science of studying and controlling the behavior of rock strata in response to mining operations.Ground-control-related research has seen significant advancements over the last 40 years, and these accomplishments are well documented in the proceedings of the annual International Conference on Ground Control in Mining (ICGCM)[1]. 相似文献
33.
Heather D. Ots Jovanna A. Tracz Katherine E. Vinokuroff Alberto E. Musto 《International journal of molecular sciences》2022,23(8)
Immune-inflammatory conditions in the central nervous system (CNS) rely on molecular and cellular interactions which are homeostatically maintained to protect neural tissue from harm. The CD40–CD40L interaction upregulates key proinflammatory molecules, a function best understood in the context of infection, during which B-cells are activated via CD40 signaling to produce antibodies. However, the role of CD40 in neurological disease of non-infectious etiology is unclear. We review the role of CD40–CD40L in traumatic brain injury, Alzheimer’s Disease, Parkinson’s Disease, stroke, epilepsy, nerve injury, multiple sclerosis, ALS, myasthenia gravis and brain tumors. We also highlight therapeutic advancements targeting the CD40 system to either attenuate the neuroinflammatory response or leverage the downstream effects of CD40 signaling for direct tumor cell lysis. 相似文献
34.
Corrigendum: Discovery of a Potent BTK Inhibitor with a Novel Binding Mode by Using Parallel Selections with a DNAEncoded Chemical Library 下载免费PDF全文
35.
Sharon Hausman-Cohen William LaValley Heather Way Emily Gutierrez Jordan Reeder 《International journal of molecular sciences》2022,23(4)
Molecular biology combined with genomics can be a powerful tool for developing potential intervention strategies for improving outcomes in children with autism spectrum disorders (ASD). Monogenic etiologies rarely cause autism. Instead, ASD is more frequently due to many polygenic contributing factors interacting with each other, combined with the epigenetic effects of diet, lifestyle, and environment. One limitation of genomics has been identifying ways of responding to each identified gene variant to translate the information to something clinically useful. This paper will illustrate how understanding the function of a gene and the effects of a reported variant on a molecular level can be used to develop actionable and targeted potential interventions for a gene variant or combinations of variants. For illustrative purposes, this communication highlights a specific genomic variant, SHANK3. The steps involved in developing molecularly genomically targeted actionable interventions will be demonstrated. Cases will be shared to support the efficacy of this strategy and to show how clinicians utilized these targeted interventions to improve ASD-related symptoms significantly. The presented approach demonstrates the utility of genomics as a part of clinical decision-making. 相似文献
36.
Jackson I Schijns H Schmitt DR Mu J Delmenico A 《The Review of scientific instruments》2011,82(6):064501
Novel laboratory equipment has been modified to allow both torsional and flexural oscillation measurements at sub-microstrain amplitudes, thereby providing seismic-frequency constraints on both the shear and compressional wave properties of cylindrical rock specimens within the linear regime. The new flexural mode capability has been tested on experimental assemblies containing fused silica control specimens. Close consistency between the experimental data and the results of numerical modelling with both finite-difference and finite-element methods demonstrates the viability of the new technique. The capability to perform such measurements under conditions of independently controlled confining and pore-fluid pressure, with emerging strategies for distinguishing between local (squirt) and global (specimen-wide) fluid flow, will have particular application to the study of frequency-dependent seismic properties expected of cracked and fluid-saturated rocks of the Earth's upper crust. 相似文献
37.
Schoener CA Hutson HN Fletcher GK Peppas NA 《Industrial & engineering chemistry research》2011,50(22):12556-12561
To investigate the delivery of hydrophobic therapeutic agents, a novel class of interpenetrating networks (IPNs) were synthesized and composed of two networks: methacrylic acid grafted with poly(ethylene glycol) tethers, P(MAA-g-EG), and poly(n-butyl acrylate) (PBA). The hydrophilic P(MAA-g-EG) networks are pH-responsive hydrogels capable of triggered release of an encapsulated therapeutic agent, such as a low molecular weight drug or a protein, when it passes from the stomach (low pH) to upper small intestine (neutral pH). PBA is a hydrophobic homopolymer that can affect the IPN swelling behavior, the therapeutic agent loading efficiencies in IPNs, and solute release profiles from IPNs. In dynamic swelling conditions, IPNs had greater swelling ratios than P(MAA-g-EG), but in equilibrium swelling conditions the IPN swelling ratio decreased with increasing PBA content. Loading efficiencies of the model therapeutic agent fluorescein ranged from 21 - 44%. Release studies from neat P(MAA-g-EG) and the ensuing IPNs indicated that the transition from low pH (2.0) to neutral pH (7.0) triggered fluorescein release. Maximum fluorescein release depended on the structure and hydrophilicity of the carriers used in these studies. 相似文献
38.
Gabriel S.Esterhuizen I.Berk Tulu Dave F.Gearhart Heather Dougherty Mark Van Dyke 《矿业科学技术学报(英文版)》2021,31(1):103-110
Longwall gateroad entries are subject to changing horizontal and vertical stress induced by redistribution of loads around the extracted panel. The stress changes can result in significant deformation of the entries that may include roof sag, rib dilation, and floor heave. Mine operators install different types of supports to control the ground response and maintain safe access and ventilation of the longwall face. This paper describes recent research aimed at quantifying the effect of longwall-induced stress changes on ground stability and using the information to assess support alternatives. The research included monitoring of ground and support interaction at several operating longwall mines in the U.S., analysis and calibration of numerical models that adequately represent the bedded rock mass, and observation of the support systems and their response to changes in stress. The models were then used to investigate the impact of geology and stress conditions on ground deformation and support response for various depths of cover and geologic scenarios. The research results were summarized in two regression equations that can be used to estimate the likely roof deformation and height of roof yield due to longwall-induced stress changes. This information is then used to assess the ability of support systems to maintain the stability of the roof. The application of the method is demonstrated with a retrospective analysis of the support performance at an operating longwall mine that experienced a headgate roof fall. The method is shown to produce realistic estimates of gateroad entry stability and support performance, allowing alternative support systems to be assessed during the design and planning stage of longwall operations. 相似文献
39.
Mahendra Pakala Heather Walls Ray Y. Lin 《Journal of the American Ceramic Society》1997,80(6):1477-1484
Calcia-stabilized zirconia films were deposited on the surface of silicon 111 wafers using radio frequency (rf) magnetron sputter deposition. Deposition was conducted at substrate temperatures that varied in the range of 80°–900°C. X-ray diffractometry results showed that all the films consisted of cubic zirconia. The fracture surface morphology and etched surfaces of the films were studied using scanning electron microscopy (SEM). Depending on the deposition temperature, the structure of the film was either columnar or equiaxed. The transition temperature from the columnar structure to the equiaxed structure was at a ratio of deposition temperature to melting temperature of } 0.42. The microhardness of the films was evaluated using a developed model that is based on the plastic zone analysis below a diamond (Vickers) indentor. From this model, the microhardness was found to increase as the deposition temperature increased, which was probably because the hardness of ceramic materials decreases as the defect concentration increases. 相似文献
40.
Dr. Vimary Vázquez‐Dorbatt Juneyoung Lee En‐Wei Lin Prof. Heather D. Maynard 《Chembiochem : a European journal of chemical biology》2012,13(17):2478-2487
Natural saccharides are involved in numerous biological processes. It has been shown that these carbohydrates play a role in cell adhesion and proliferation, as well as protein stabilization, organization, and recognition. Certain carbohydrates also serve as receptors for viruses and bacteria. They are over expressed in diseases such as cancer. Hence, a lot of effort has been focused on mimicking these sugars. Polymers with pendent saccharide groups, also known as glycopolymers, are studied as oligo‐ and polysaccharide mimics. Controlled radical polymerization (CRP) techniques such as atom transfer radical polymerization (ATRP), reversible addition–fragmentation chain transfer (RAFT) polymerization, and nitroxide‐mediated polymerization (NMP), as well as cyanoxyl‐mediated free radical polymerization have allowed chemists to synthesize well‐defined glycopolymers that, in some cases, have particular end‐group functionalities. This review focuses on the synthesis of glycopolymers by these methods and the applications of glycopolymers as natural saccharide mimics. 相似文献