全文获取类型
收费全文 | 344篇 |
免费 | 13篇 |
专业分类
化学工业 | 56篇 |
金属工艺 | 4篇 |
机械仪表 | 5篇 |
建筑科学 | 7篇 |
能源动力 | 6篇 |
轻工业 | 21篇 |
水利工程 | 6篇 |
无线电 | 12篇 |
一般工业技术 | 39篇 |
冶金工业 | 144篇 |
原子能技术 | 5篇 |
自动化技术 | 52篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 16篇 |
2020年 | 2篇 |
2019年 | 11篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 10篇 |
2015年 | 4篇 |
2014年 | 9篇 |
2013年 | 20篇 |
2012年 | 9篇 |
2011年 | 18篇 |
2010年 | 19篇 |
2009年 | 15篇 |
2008年 | 17篇 |
2007年 | 21篇 |
2006年 | 14篇 |
2005年 | 10篇 |
2004年 | 9篇 |
2003年 | 10篇 |
2002年 | 12篇 |
2001年 | 13篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 15篇 |
1997年 | 9篇 |
1996年 | 6篇 |
1995年 | 10篇 |
1994年 | 3篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有357条查询结果,搜索用时 15 毫秒
91.
92.
Naomi H. Bennett Holly R. Chinnery Laura E. Downie Lisa J. Hill Liam M. Grover 《Advanced functional materials》2020,30(14)
Eye drops are the most common and inexpensive approach to topical ocular drug delivery. Eye drops offer a noninvasive treatment strategy; however, this can be detrimental to therapeutic efficacy when compared to invasive methods such as surgeries, implants, and injections. Improvements to the efficacy of the topical delivery of drugs to ocular tissues are currently being explored and much of this work centers on adjusting the formulation of the eye drops and prolonging the bioavailability of the therapeutic agent. This is often in preference to improving other patient‐focused or clinical factors. In this progress report, conventional, commercially available polymer eye drops are explored and the ability for current and future innovations to maintain the existing benefits of eye drops to the patient is assessed. The final materials and form of the drops (liquid, gel, or other) and the immunological implications for the user are explored. There is currently no consensus for how to most effectively improve the ocular retention and drug delivery capabilities of eye drops, but key issues are highlighted in the context of current methods under development, and potential questions and considerations for future innovations are raised. 相似文献
93.
Niobium Doping and Dielectric Anomalies in Bismuth Titanate 总被引:4,自引:1,他引:3
Holly S. Shulman Dragan Damjanovic Nava Setter 《Journal of the American Ceramic Society》2000,83(3):528-532
A study of the complex permittivity in bismuth titanate was conducted to reveal the nature of an anomaly in the real part of the permittivity, which occurs below the Curie temperature. This anomaly is frequency dependent and is caused by a combination of two relaxation phenomena that appear in the imaginary part of the permittivity. One of the relaxations showed classic characteristics of an ion-jump process. Niobium doping suppressed this relaxation and eliminated the nonferroelectric anomaly in permittivity. Niobium is proposed to affect the ion-jump relaxation through a decrease in the concentration and possibly the mobility of oxygen vacancies. 相似文献
94.
Frank Ellen; Swartz Holly A.; Mallinger Alan G.; Thase Michael E.; Weaver Elizabeth V.; Kupfer David J. 《Canadian Metallurgical Quarterly》1999,108(4):579
In a randomized, controlled trial, the authors studied an adjunctive, individual psychotherapy, interpersonal and social rhythm therapy (IPSRT) for bipolar disorder. After stabilizing participants with episode appropriate pharmacotherapy and either IPSRT or intensive clinical management (CM), participants were reassigned to IPSRT or CM in conjunction with pharmacotherapy for 2 years of preventative treatment. Early results (n?=?82) suggest that altering participants' treatment assignment at entry to the preventative phase is related to risk of recurrence. Participants remaining in the same treatment for both acute and preventative phases had lower rates of recurrence (40%) and levels of symptomatology over the subsequent 52 weeks than those reassigned to the alternate modality. This finding, consistent with the authors' philosophy that bipolar patients benefit from stable routines, suggests that disruptions in the psychosocial treatment plan contribute to worse outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
95.
Holly Tuokko Anita Myers Alexandra Jouk Shawn Marshall Malcolm Man-Son-Hing Michelle M. Porter Michel Bédard Isabelle Gélinas Nicol Korner-Bitensky Barbara Mazer Gary Naglie Mark Rapoport Brenda Vrkljan 《Accident; analysis and prevention》2013
The relations among driving-related psychosocial measures (e.g., driving comfort, attitudes toward driving) and measures of self-reported health were examined in the context of driver characteristics (i.e., age and gender) within the Canadian Driving Research Initiative for Vehicular Safety in the Elderly (Candrive II) baseline data, available for the cohort of 928 drivers, 70 years of age and older. Older members of the cohort had lower comfort scores and poorer perceptions of their driving abilities. Men reported significantly higher levels of driving comfort than women. When analyses including health were controlled for age and gender, significant relations with health status were evident for most of the psychosocial measures. These findings extend previous research and suggest that attitudes, beliefs, and perceptions about driving may be influenced by health status and act as mediators in the self-regulation process. 相似文献
96.
97.
Den Hartog DJ Ambuel JR Borchardt MT Falkowski AF Harris WS Holly DJ Parke E Reusch JA Robl PE Stephens HD Yang YM 《The Review of scientific instruments》2010,81(10):10D513
Two standard commercial flashlamp-pumped Nd:YAG (YAG denotes yttrium aluminum garnet) lasers have been upgraded to "pulse-burst" capability. Each laser produces a burst of up to 15 2 J Q-switched pulses (1064 nm) at repetition rates of 1-12.5 kHz. Variable pulse-width drive (0.15-0.39 ms) of the flashlamps is accomplished by insulated gate bipolar transistor (IGBT) switching of electrolytic capacitor banks. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction, and up to four 2 J laser pulses during one flashlamp pulse. These lasers are used in the Thomson scattering plasma diagnostic system on the MST reversed-field pinch to record the dynamic evolution of the electron temperature profile and temperature fluctuations. To further these investigations, a custom pulse-burst laser system with a maximum pulse repetition rate of 250 kHz is now being commissioned. 相似文献
98.
Coherent radiation from undulator beamlines has been used to directly measure the real and imaginary parts of the index of refraction of several materials at both extreme-ultraviolet and soft-x-ray wavelengths. Using the XOR interferometer, we measure the refractive indices of silicon and ruthenium, essential materials for extreme-ultraviolet lithography. Both materials are tested at wavelength (13.4 nm) and across silicon's L2 (99.8 eV) and L3 (99.2 eV) absorption edges. We further extend this direct phase measurement method into the soft-x-ray region, where measurements of chromium and vanadium are performed around their L3 absorption edges at 574.1 and 512.1 eV, respectively. These are the first direct measurements, to our knowledge, of the real part of the index of refraction made in the soft-x-ray region. 相似文献
99.
Spokas EG Spur BW Smith H Kemp FW Bogden JD 《Environmental science & technology》2006,40(21):6852-6858
The fathead minnow is a useful species for evaluating the toxicity of wastewater effluents. While this fish is widely used for "survival" studies of metal toxicity, little or no work has been done on the tissue distribution of metals in fathead minnows. To determine the distribution of tissue lead, aquarium studies were conducted for several weeks with fish maintained in soft synthetic freshwater. Lead- (II) nitrate was added to three aquaria attaining concentrations of 20-30 ppb (aquarium B), 100-140 ppb (aquarium C), and roughly 200 ppb (aquarium D). Results were compared to controls (aquarium A). During the initial week, the majority of aquarium D fish died, whereas few deaths occurred in the other groups. Lead accumulation was dose- and tissue-dependent, with highest uptake by the gills. Gill concentrations of aquarium D fish averaged about 4-fold higherthan in skeleton or skin and muscle. In vitro, lead (2.5-25 ppm) caused dose-dependent reductions in the ratio of reduced glutathione/oxidized glutathione (GSH/GSSG) in gills incubated in physiological buffer. These findings demonstrate that fathead minnow gills bind and accumulate waterborne lead rapidly and preferentially and raise the possibility that gill lipid peroxidation contributes to lead toxicity at low water hardness. 相似文献
100.