全文获取类型
收费全文 | 1887篇 |
免费 | 14篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 79篇 |
金属工艺 | 16篇 |
机械仪表 | 9篇 |
建筑科学 | 10篇 |
矿业工程 | 1篇 |
能源动力 | 12篇 |
轻工业 | 49篇 |
水利工程 | 8篇 |
石油天然气 | 1篇 |
无线电 | 87篇 |
一般工业技术 | 70篇 |
冶金工业 | 1492篇 |
原子能技术 | 5篇 |
自动化技术 | 56篇 |
出版年
2022年 | 9篇 |
2021年 | 10篇 |
2020年 | 6篇 |
2019年 | 9篇 |
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 4篇 |
2013年 | 27篇 |
2012年 | 11篇 |
2011年 | 25篇 |
2010年 | 10篇 |
2009年 | 17篇 |
2008年 | 13篇 |
2007年 | 17篇 |
2006年 | 15篇 |
2005年 | 21篇 |
2004年 | 17篇 |
2003年 | 17篇 |
2002年 | 18篇 |
2001年 | 10篇 |
2000年 | 11篇 |
1999年 | 54篇 |
1998年 | 400篇 |
1997年 | 230篇 |
1996年 | 163篇 |
1995年 | 91篇 |
1994年 | 82篇 |
1993年 | 89篇 |
1992年 | 19篇 |
1991年 | 26篇 |
1990年 | 29篇 |
1989年 | 33篇 |
1988年 | 32篇 |
1987年 | 41篇 |
1986年 | 31篇 |
1985年 | 20篇 |
1983年 | 6篇 |
1982年 | 19篇 |
1981年 | 11篇 |
1980年 | 30篇 |
1979年 | 8篇 |
1978年 | 10篇 |
1977年 | 36篇 |
1976年 | 111篇 |
1975年 | 7篇 |
1974年 | 4篇 |
1970年 | 4篇 |
1964年 | 3篇 |
排序方式: 共有1902条查询结果,搜索用时 62 毫秒
41.
Weixia Zhong Omar Shahbaz Garrett Teskey Abrianna Beever Nala Kachour Vishwanath Venketaraman Nissar A. Darmani 《International journal of molecular sciences》2021,22(11)
Nausea and vomiting are common gastrointestinal complaints that can be triggered by diverse emetic stimuli through central and/or peripheral nervous systems. Both nausea and vomiting are considered as defense mechanisms when threatening toxins/drugs/bacteria/viruses/fungi enter the body either via the enteral (e.g., the gastrointestinal tract) or parenteral routes, including the blood, skin, and respiratory systems. While vomiting is the act of forceful removal of gastrointestinal contents, nausea is believed to be a subjective sensation that is more difficult to study in nonhuman species. In this review, the authors discuss the anatomical structures, neurotransmitters/mediators, and corresponding receptors, as well as intracellular emetic signaling pathways involved in the processes of nausea and vomiting in diverse animal models as well as humans. While blockade of emetic receptors in the prevention of vomiting is fairly well understood, the potential of new classes of antiemetics altering postreceptor signal transduction mechanisms is currently evolving, which is also reviewed. Finally, future directions within the field will be discussed in terms of important questions that remain to be resolved and advances in technology that may help provide potential answers. 相似文献
42.
Garrett BC Dixon DA Camaioni DM Chipman DM Johnson MA Jonah CD Kimmel GA Miller JH Rescigno TN Rossky PJ Xantheas SS Colson SD Laufer AH Ray D Barbara PF Bartels DM Becker KH Bowen KH Bradforth SE Carmichael I Coe JV Corrales LR Cowin JP Dupuis M Eisenthal KB Franz JA Gutowski MS Jordan KD Kay BD Laverne JA Lymar SV Madey TE McCurdy CW Meisel D Mukamel S Nilsson AR Orlando TM Petrik NG Pimblott SM Rustad JR Schenter GK Singer SJ Tokmakoff A Wang LS Wettig C Zwier TS 《Chemical reviews》2005,105(1):355-390
43.
44.
Driving a Wedge Between Evidence and Beliefs: How Online Ideological News Exposure Promotes Political Misperceptions
下载免费PDF全文
![点击此处可从《Journal of Computer-Mediated Communication》网站下载免费的PDF全文](/ch/ext_images/free.gif)
R. Kelly Garrett Brian E. Weeks Rachel L. Neo 《Journal of Computer-Mediated Communication》2016,21(5):331-348
This article has 2 goals: to provide additional evidence that exposure to ideological online news media contributes to political misperceptions, and to test 3 forms this media‐effect might take. Analyses are based on representative survey data collected during the 2012 U.S. presidential election (N = 1,004). Panel data offer persuasive evidence that biased news site use promotes inaccurate beliefs, while cross‐sectional data provide insight into the nature of these effects. There is no evidence that exposure to ideological media reduces awareness of politically unfavorable evidence, though in some circumstances biased media do promote misunderstandings of it. The strongest and most consistent influence of ideological media exposure is to encourage inaccurate beliefs regardless of what consumers know of the evidence. 相似文献
45.
Ali Hashmi Garrett Heiman Gan Yu Mark Lewis Hyuck-Jin Kwon Jie Xu 《Microfluidics and nanofluidics》2013,14(3-4):591-596
Microstreaming generated from oscillating microbubbles has great potential in microfluidic applications for localized flow control. In this study, we explore the use of teardrop-shaped cavities for trapping microbubbles. Upon acoustic actuation, these microbubbles confined in teardrop cavities can be utilized to generate a directional microstreaming flow. We further show that by altering the acoustic excitation frequency, a flow-switch for altering flow direction in microfluidic environments can be achieved using two oppositely arranged teardrop cavities with different sizes. In the end, we show that an array of such bubble-filled teardrop cavities can act as a fixated microfluidic transport system allowing for on-chip particle manipulation in complex flow patterns. This inexpensive method to create flows to switch and transport elements based on teardrop cavities can be widely employed for microfluidic applications such as drug delivery systems. 相似文献
46.
Single channel currents were activated by GABA (0.5 to 5 microM) in cell-attached and inside-out patches from cells in the dentate gyrus of rat hippocampal slices. The currents reversed at the chloride equilibrium potential and were blocked by bicuculline (100 microM). Several different kinds of channel were seen: high conductance and low conductance, rectifying and "nonrectifying." Channels had multiple conductance states. The open probability (Po) of channels was greater at depolarized than at hyperpolarized potentials and the relationship between Po and potential could be fitted with a Boltzmann equation with equivalent valency (z) of 1. The combination of outward rectification and potential-dependent open probability gave very little chloride current at hyperpolarized potentials but steeply increasing current with depolarization, useful properties for a tonic inhibitory mechanism. 相似文献
47.
Antony Jan Benjamin A. Reeves Yoeri van de Burgt Garrett J. Hayes Bruce M. Clemens 《Advanced Engineering Materials》2018,20(1)
48.
Saliva is considered to be the conduit by which pathogens are transmitted from blood-sucking arthropod vectors to their vertebrate hosts, but supporting evidence for this is fragmentary. To determine if Thogoto (THO) virus, a tick-borne member of the influenza virus family, is transmitted via tick saliva, and whether virus replication is a prerequisite for such transmission, two experimental conditions were compared: (1) "biological transmission" and (2) "mechanical transmission." In (1), THO virus was allowed to infect and replicate in a natural vector, Amblyomma variegatum: virus was detected in saliva collected from 3/22 (14%) ticks. In (2), virus was inoculated directly into the hemocoel with the drug used to induce salivation and saliva was collected immediately to preclude the possibility of virus replication: virus was detected in saliva collected from 31/170 (18%) ticks. The results demonstrate that THO virus is secreted in tick saliva and that virus can pass from the hemolymph to the salivary glands independently of viral replication within the tick. The comparatively low numbers of ticks that yielded virus-positive saliva samples together with the results from assays of serial saliva samples suggested that virus secretion may not be a continuous process during salivation. Ticks in which THO virus had established an infection showed an impaired secretory response compared with uninfected ticks and ticks used for mechanical transmission. 相似文献
49.
This paper presents two examples of how impedance cardiography may be used to interpret the hemodynamic influences on blood pressures measured during behavioral stress. In Study 1, blood pressure changes which were similar during two tasks were shown to have important differences in their cardiac output and vascular resistance components. During work on a reaction time task having aversive incentives compared with a neutral task, the blood pressure changes were seen to be associated with lowered vascular resistance and raised cardiac activity, a "fight-flight" pattern. In Study 2, blood pressure response differences between two subject groups working on an identical task were found to have blood pressure changes differing in their underlying cardiac and vascular components as measured by impedance. Such uses impedance cardiography have widespread potential application in psychophysiological research with humans. 相似文献
50.