全文获取类型
收费全文 | 3350篇 |
免费 | 12篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 18篇 |
化学工业 | 225篇 |
金属工艺 | 20篇 |
机械仪表 | 32篇 |
建筑科学 | 42篇 |
矿业工程 | 5篇 |
能源动力 | 18篇 |
轻工业 | 110篇 |
水利工程 | 10篇 |
石油天然气 | 10篇 |
无线电 | 175篇 |
一般工业技术 | 230篇 |
冶金工业 | 2313篇 |
原子能技术 | 11篇 |
自动化技术 | 144篇 |
出版年
2021年 | 10篇 |
2020年 | 8篇 |
2019年 | 7篇 |
2018年 | 13篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 17篇 |
2013年 | 54篇 |
2012年 | 40篇 |
2011年 | 46篇 |
2010年 | 30篇 |
2009年 | 39篇 |
2008年 | 47篇 |
2007年 | 36篇 |
2006年 | 34篇 |
2005年 | 35篇 |
2004年 | 31篇 |
2003年 | 24篇 |
2002年 | 22篇 |
2001年 | 40篇 |
2000年 | 36篇 |
1999年 | 80篇 |
1998年 | 663篇 |
1997年 | 394篇 |
1996年 | 273篇 |
1995年 | 134篇 |
1994年 | 124篇 |
1993年 | 168篇 |
1992年 | 44篇 |
1991年 | 45篇 |
1990年 | 47篇 |
1989年 | 52篇 |
1988年 | 69篇 |
1987年 | 52篇 |
1986年 | 44篇 |
1985年 | 48篇 |
1984年 | 27篇 |
1983年 | 23篇 |
1982年 | 31篇 |
1981年 | 42篇 |
1980年 | 35篇 |
1979年 | 20篇 |
1978年 | 17篇 |
1977年 | 83篇 |
1976年 | 153篇 |
1975年 | 20篇 |
1974年 | 8篇 |
1973年 | 20篇 |
1972年 | 10篇 |
1967年 | 6篇 |
排序方式: 共有3363条查询结果,搜索用时 15 毫秒
91.
92.
U Carcassi GS Del Giacco A Pintus G Perpignano F Locci M Loy MG Batzella G Piludu L Cengiarotti G Ibba AL Leone 《Canadian Metallurgical Quarterly》1977,54(3):285-287
Wind enhances the carcinogenic effect of chronic Iltraviolet radiation (UVL). This was demonstrated in hairless mice that were irradiated for 42 weeks with mercury are lamps. One group of animals was exposed to continuous wind flow of 2.7 m/s except for the daily I-2 min time interval when they were removed from the wind tunnel and irradiated. Another group of animals received identical irradiation but were protected from wind. The first tumour appeared in the UVL and wind group after 105 days of irradiation, and at 164 days of irradiation all surviving mice in the group had developed tumours. The group of mice receiving identical irradiation but protected from wind had their first tumour appear at 154 days of irradiation, and by 164 days of irradiation only 40% of the mice had developed tumours. 相似文献
93.
The contribution from impurities in chlorine to levels of chlorinated organics found in potable water after chlorination was investigated. Techniques for sampling of chlorine and gas chromatography (GC) determination of chlorinated organics in chlorine are described. The detection limits were better than 1 ppm for each of chloromethane, dichloromethane, chloroform, carbon tetrachloride, trichloroethylene, tetrachloroethylene, hexachloroethane, hexachloropropane and hexachlorobenzene in chlorine. With the exception of chloroform which occasionally accounted for nearly 1 μg l−1 in water, the levels of the nine compounds in chlorine accounted for less than 0.1 μg l−1 of each compound in chlorinated water from 10 Canadian treatment plants. The occurrence of these nine and 28 additional chlorinated organics previously detected in water supplies was determined by aid of liquid-liquid extraction of water samples. Seven compounds, including chloroform, carbon tetrachloride, trichloroethylene and tetrachloroethylene were detected, usually at levels ranging from 0.1 to 1 μg l−1 in chlorinated water from the treatment plant. 相似文献
94.
C. Deslouis O. Gil B. Tribollet G. Vlachos B. Robertson 《Journal of Applied Electrochemistry》1992,22(9):835-842
The reduction of dissolved oxygen has been studied over a wide conductivity range for use in steady or nonsteady hydrodynamic measurements. Mass transfer fluctuations can be analysed statistically to obtain the power spectra of hydrodynamic fluctuations. This requires a consideration of the proton reduction, which prevents diffusion from limiting the current. The transfer function for deducing the hydrodynamic spectra from mass transfer spectra includes not only transport effects but also kinetic effects which account for the finite rate of the reaction. The experimental study was performed using electrohydrodynamic (EHD) impedance. 相似文献
95.
Bor‐Sen Chiou George H. Robertson LuAnn E. Rooff Trung Cao Haani Jafri Kay S. Gregorski Syed H. Imam Greg M. Glenn William J. Orts 《应用聚合物科学杂志》2010,116(5):2638-2644
Wheat gluten films of various thicknesses formed at 30–70°C were treated with cold sulfuric acid to produce sulfated gluten films. Chemical, thermal, thermal stability, and water uptake properties were characterized for neat and sulfated films. The sulfated gluten films were able to absorb up to 30 times their weight in deionized water. However, this value dropped to 3.5 when the film was soaked in a 0.9% (w/w) NaCl solution. The films were also soaked 4 times in deionized water, and each soaking resulted in a reduced water uptake capacity. The temperature of film formation had no effect on the final water uptake properties. Also, thinner films had higher concentrations of sulfate groups than thicker films; this resulted in higher water uptake values. In addition, sulfated gluten films had comparable glass‐transition temperatures but lower thermal stabilities than the neat gluten films. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
96.
Increased Prostaglandin Response to Oxytocin in Ewes Fed a Diet High in Omega-6 Polyunsaturated Fatty Acids 总被引:1,自引:1,他引:0
Catherine E. Gulliver Michael A. Friend Belinda J. King Susan M. Robertson John F. Wilkins Edward H. Clayton 《Lipids》2013,48(2):177-183
Diets high in omega-6 polyunsaturated fatty acids (n-6) are associated with increased prostaglandin F2α (PGF2α) synthesis in cattle, however, the specific effects on the potential prostaglandin response to an oxytocin challenge in sheep have not been reported. The aim of the current study was to determine whether oxytocin-stimulated PGF2α was significantly increased when ewes were fed a diet high in n-6 compared with a control diet low in n-6. Merino x Border Leicester ewes (n = 30) received one of two dietary treatments, either high in n-6 (70 % oat grain) or low in n-6 (control diet, 100 % cereal/legume silage). Ewes consumed the diets for 44 days prior to two consecutive oxytocin challenges. Plasma n-6 and PGF2α metabolite (PGFM) concentrations following oxytocin challenge were greater (P < 0.05) when ewes were fed a diet high in n-6 compared with the control diet. A higher availability of n-6 may have lead to an increased in vivo synthesis of PGF2α, however, further research is required to determine the exact mechanisms involved. 相似文献
97.
Bor‐Sen Chiou Haani Jafri Trung Cao George H. Robertson Kay S. Gregorski Syed H. Imam Greg M. Glenn William J. Orts 《应用聚合物科学杂志》2013,129(6):3192-3197
Wheat gluten was reacted with citric acid to produce natural superabsorbent materials able to absorb up to 78 times its weight in water. The properties of the modified gluten samples were characterized using Fourier Transform Infra‐red (FTIR) spectroscopy, thermogravimetric analysis, and water uptake. The reaction between gluten and citric acid was examined for gluten : citric acid ratios of 0.38 : 1 to 0.75 : 1 at temperatures from 100 to 130°C. More citric acid reacted for samples containing higher citric acid concentrations and at higher temperatures. FTIR analyses indicated the presence of carboxylate groups on the modified gluten samples, which resulted in modified samples having higher water uptake values than neat gluten. The sample with a gluten:citric acid ratio of 0.5 : 1 and reaction temperature of 120°C had the largest water uptake value. Also, all modified gluten samples had lower thermal stability than neat gluten. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
98.
John A. Robertson Jean Théberge Julie Weller Dick J. Drost Frank S. Prato Alex W. Thomas 《Journal of the Royal Society Interface》2010,7(44):467-473
Extremely low-frequency magnetic fields (from DC to 300 Hz) have been shown to affect pain sensitivity in snails, rodents and humans. Here, a functional magnetic resonance imaging study demonstrates how the neuromodulation effect of these magnetic fields influences the processing of acute thermal pain in normal volunteers. Significant interactions were found between pre- and post-exposure activation between the sham and exposed groups for the ipsilateral (right) insula, anterior cingulate and bilateral hippocampus/caudate areas. These results show, for the first time, that the neuromodulation induced by exposure to low-intensity low-frequency magnetic fields can be observed in humans using functional brain imaging and that the detection mechanism for these effects may be different from those used by animals for orientation and navigation. Magnetoreception may be more common than presently thought. 相似文献
99.
A Web-based remote interactive laboratory (RIL) developed to deliver Internetworking laboratory experience to geographically remote graduate students is presented in this paper. The onsite Internetworking program employs hands-on laboratories in a group setting that correlates with the constructivist and collaborative pedagogical approach. This paper discusses the pedagogical and technical considerations that influence the design and implementation of the remote laboratory environment given the constraints of the special hardware and learning outcomes of the program. For wide-ranging usability, the remote Internetworking (INWK) laboratory uses de facto networking standards and commercial and broad-band Internet connectivity to ensure real-time secure interaction with equipment. A four-tier role architecture consisting of faculty, local facilitators, remote facilitators, and students has been determined appropriate to maintain academic integrity and ensure good quality of interaction with the remote laboratory. A survey employing a five-point scale has been devised to measure the usability of the remote access INWK laboratory. 相似文献
100.
Manoj Shrestha Toralf Mildner Torsten Schlumm Scott Haile Robertson Harald Möller 《Magma (New York, N.Y.)》2016,29(6):799-810