全文获取类型
收费全文 | 20691篇 |
免费 | 1060篇 |
国内免费 | 58篇 |
专业分类
电工技术 | 196篇 |
综合类 | 38篇 |
化学工业 | 4344篇 |
金属工艺 | 414篇 |
机械仪表 | 379篇 |
建筑科学 | 1188篇 |
矿业工程 | 74篇 |
能源动力 | 580篇 |
轻工业 | 1715篇 |
水利工程 | 269篇 |
石油天然气 | 72篇 |
武器工业 | 1篇 |
无线电 | 1341篇 |
一般工业技术 | 4007篇 |
冶金工业 | 3749篇 |
原子能技术 | 77篇 |
自动化技术 | 3365篇 |
出版年
2023年 | 132篇 |
2022年 | 272篇 |
2021年 | 436篇 |
2020年 | 331篇 |
2019年 | 379篇 |
2018年 | 475篇 |
2017年 | 416篇 |
2016年 | 561篇 |
2015年 | 433篇 |
2014年 | 703篇 |
2013年 | 1381篇 |
2012年 | 1109篇 |
2011年 | 1558篇 |
2010年 | 1131篇 |
2009年 | 1049篇 |
2008年 | 1216篇 |
2007年 | 1159篇 |
2006年 | 967篇 |
2005年 | 899篇 |
2004年 | 753篇 |
2003年 | 633篇 |
2002年 | 696篇 |
2001年 | 400篇 |
2000年 | 376篇 |
1999年 | 335篇 |
1998年 | 334篇 |
1997年 | 308篇 |
1996年 | 257篇 |
1995年 | 313篇 |
1994年 | 268篇 |
1993年 | 252篇 |
1992年 | 227篇 |
1991年 | 104篇 |
1990年 | 169篇 |
1989年 | 163篇 |
1988年 | 154篇 |
1987年 | 156篇 |
1986年 | 118篇 |
1985年 | 191篇 |
1984年 | 172篇 |
1983年 | 122篇 |
1982年 | 107篇 |
1981年 | 89篇 |
1980年 | 72篇 |
1979年 | 73篇 |
1978年 | 63篇 |
1977年 | 45篇 |
1976年 | 52篇 |
1975年 | 33篇 |
1974年 | 35篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Dr. Laurent David Dr. Mark Wenlock Dr. Patrick Barton Dr. Andreas Ritzén 《ChemMedChem》2021,16(17):2669-2685
Chameleonic properties, i. e., the capacity of a molecule to hide polarity in non-polar environments and expose it in water, help achieving sufficient permeability and solubility for drug molecules with high MW. We present models of experimental measures of polarity for a set of 24 FDA approved drugs (MW 405-1113) and one PROTAC (MW 1034). Conformational ensembles in aqueous and non-polar environments were generated using molecular dynamics. A linear regression model that predicts chromatographic apparent polarity (EPSA) with a mean unsigned error of 10 Å2 was derived based on separate terms for donor, acceptor, and total molecular SASA. A good correlation (R2=0.92) with an experimental measure of hydrogen bond donor potential, Δlog Poct-tol, was found for the mean hydrogen bond donor SASA of the conformational ensemble scaled with Abraham's A hydrogen bond acidity. Two quantitative measures of chameleonic behaviour, the chameleonic efficiency indices, are introduced. We envision that the methods presented herein will be useful to triage designed molecules and prioritize those with the best chance of achieving acceptable permeability and solubility. 相似文献
2.
3.
Carolyn A. Grimley Stephen Funni Christopher Green Elizabeth C. Dickey 《Journal of the European Ceramic Society》2021,41(4):2807-2817
In flash sintering experiments, the thermal history of the sample is key to understanding the mechanisms underlying densification rate and final properties. By combining robust temperature measurements with current-ramp-rate control, this study examined the effects of the thermal profile on the flash sintering of yttria-stabilized zirconia, with experiments ranging from a few seconds to several hours. The final density was maximized at slower heating rates, although processes slower than a certain threshold led to grain growth. The amount of grain growth observed was comparable to a similar conventional thermal process. The bulk electrical conductivity correlated with the maximum temperature and cooling rate. The only property that exhibited behavior that could not be attributed to solely the thermal profile was the grain boundary conductivity, which was consistently higher than conventional in flash sintered samples. These results suggest that, during flash sintering, athermal electric field effects are relegated to the grain boundary. 相似文献
4.
5.
A method is proposed to generate categorical colour observer functions (individual colour matching functions) for any field size based on the CIE 2006 system of physiological observer functions. The method combines proposed categorical observer techniques of Sarkar et al with a physiologically-based individual observer model of Asano et al and a clustering technique to produce the optimal set of categorical observers. The number of required categorical observers varies depending on an application with as many as 50 required to predict individual observers' matches when a laser projector is viewed. However, 10 categorical observers are sufficient to represent colour-normal populations for personalized colour imaging. The proposed and recommended categorical observers represent a robust and inclusive technique to examine and quantify observer metamerism in any application of colorimetry. 相似文献
6.
7.
8.
9.
Cerebral microbleeds and cognitive decline in a hemodialysis patient: Case report and review of literature
下载免费PDF全文
![点击此处可从《Hemodialysis international. International Symposium on Home Hemodialysis》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Lin Li Mark Fisher Wei‐Ling Lau Hamid Moradi Alexander Cheung Gaby Thai Jason Handwerker Kamyar Kalantar‐Zadeh 《Hemodialysis international. International Symposium on Home Hemodialysis》2015,19(3):E1-E7
Cerebral microbleeds (CMBs) are small hemosiderin deposits indicative of prior cerebral microscopic hemorrhage and previously thought to be clinically silent. Recent population‐based cross‐sectional studies and prospective longitudinal cohort studies have revealed association between CMB and cognitive dysfunction. In the general population, CMBs are associated with age, hypertension, and cerebral amyloid angiopathy. In the chronic kidney disease (CKD) population, diminished estimated glomerular filtration rate has been found to be an independent risk factor for CMB, raising the possibility that a uremic milieu may predispose to microbleeds. In the end‐stage renal disease (ESRD) population on hemodialysis, the incidence of microbleeds is significantly higher compared with a control group without history of CKD or stroke. We present an ESRD patient on chronic hemodialysis with a history of gradual cognitive decline and progressive CMBs. Through this case and literature review, we illustrate the need to develop detection and prediction models to treat this frequent development in ESRD patients. 相似文献
10.
Jonas Ort Benedikt Kremer Linda Grüßer Romy Blaumeiser-Debarry Hans Clusmann Mark Coburn Anke Hllig Ute Lindauer 《International journal of molecular sciences》2020,21(23)
Effective pharmacological neuroprotection is one of the most desired aims in modern medicine. We postulated that a combination of two clinically used drugs—nimodipine (L-Type voltage-gated calcium channel blocker) and amiloride (acid-sensing ion channel inhibitor)—might act synergistically in an experimental model of ischaemia, targeting the intracellular rise in calcium as a pathway in neuronal cell death. We used organotypic hippocampal slices of mice pups and a well-established regimen of oxygen-glucose deprivation (OGD) to assess a possible neuroprotective effect. Neither nimodipine (at 10 or 20 µM) alone or in combination with amiloride (at 100 µM) showed any amelioration. Dissolved at 2.0 Vol.% dimethyl-sulfoxide (DMSO), the combination of both components even increased cell damage (p = 0.0001), an effect not observed with amiloride alone. We conclude that neither amiloride nor nimodipine do offer neuroprotection in an in vitro ischaemia model. On a technical note, the use of DMSO should be carefully evaluated in neuroprotective experiments, since it possibly alters cell damage. 相似文献