全文获取类型
收费全文 | 542篇 |
免费 | 27篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 9篇 |
综合类 | 8篇 |
化学工业 | 128篇 |
金属工艺 | 9篇 |
机械仪表 | 37篇 |
建筑科学 | 11篇 |
能源动力 | 44篇 |
轻工业 | 35篇 |
水利工程 | 14篇 |
石油天然气 | 3篇 |
无线电 | 63篇 |
一般工业技术 | 102篇 |
冶金工业 | 35篇 |
原子能技术 | 3篇 |
自动化技术 | 72篇 |
出版年
2024年 | 3篇 |
2023年 | 18篇 |
2022年 | 34篇 |
2021年 | 35篇 |
2020年 | 30篇 |
2019年 | 29篇 |
2018年 | 38篇 |
2017年 | 26篇 |
2016年 | 24篇 |
2015年 | 21篇 |
2014年 | 28篇 |
2013年 | 46篇 |
2012年 | 28篇 |
2011年 | 34篇 |
2010年 | 16篇 |
2009年 | 18篇 |
2008年 | 15篇 |
2007年 | 18篇 |
2006年 | 10篇 |
2005年 | 12篇 |
2004年 | 8篇 |
2003年 | 11篇 |
2002年 | 8篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有573条查询结果,搜索用时 11 毫秒
41.
The crystallization behaviour of lithia calcia silicate system containing MgO, SrO, and Al2O3 has been investigated using DTA, XRD and SEM. The coefficient of thermal expansion and Vicker's microhardness of the obtained products were also evaluated. The main crystalline phases formed after different heat-treatments were lithium metasilicate, wollastonite, diopside, β-spodumene ss, pseudo-wollastonite, Sr2SiO4, Sr2Mg(Si2O7) and μ-(Ca,Sr)SiO3. The wollastonite structure can accept considerable amount of strontium to form wollastonite strontium solid solution, while there is no solid solution of strontium in pseudo-wollastonite. 相似文献
42.
43.
Umer Shafique Jamil Anwar Waheed uz-Zaman Rabia Rehman Muhammad Salman Amara Dar Nadia Jamil 《Journal of Hydro》2012,6(3):221-226
Migration of soluble and suspended materials by directional freezing of aqueous systems has been studied qualitatively. Slow freezing was employed vertically as well as horizontally through solutions and suspensions. In all cases, the impurities (soluble salts as well as suspended materials) were appreciably forced out by dynamic freezing front. The phenomenon worked for concentrating/separating inorganic ions, soluble organic compounds and dyes in synthetic solutions as well as in natural streams. Various analytical techniques were employed to monitor the migrating species through the freezing media. It was found that separation efficiency depends on different factors like rate of cooling, pH and concentration. Model experiments were designed and exercised successfully to employ the technique for treatment of dye-polluted water. 相似文献
44.
45.
A. Oral Salman 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(2):196-213
The millimeter wave radiation of a dielectric leaky-wave antenna (DLWA) coupled with a metallic diffraction grating with a
sinusoidal height profile is experimentally investigated. The interaction between dielectric and grating is contactless and
it is from the broad-face of the dielectric line. The measured field patterns are compared with the simulated HFSS patterns.
Antenna parameters such as polarization, HPBW, cross-polarization and side lobe levels are measured. The effects of the geometrical
parameters of the grating to the radiation are also investigated. Some results are compared with a DLWA which has another
diffraction grating profile shape (rectangular). The investigated antenna can be used as a frequency scanning antenna in mm-wave
radars because it has low cross and side lobe levels and narrow beam width. 相似文献
46.
King Eden B.; Dunleavy Dana G.; Dunleavy Eric M.; Jaffer Salman; Morgan Whitney Botsford; Elder Katie; Graebner Raluca 《Canadian Metallurgical Quarterly》2011,17(1):54
Although scholars agree that traditional forms of discrimination have generally been supplanted by subtler interpersonal manifestations of discrimination, it is yet unknown whether targets of these behaviors or the American judicial branch recognize such negative behaviors as violations of extant law. Extending research and theory, we propose that denigrating messages toward women and ethnic minorities (i.e., microaggressions) emerge in workplace interactions and are sometimes interpreted as discrimination. Specifically, this research explores the presence, severity, and frequency of microaggressions that appear in a random sample of race and gender discrimination cases in federal court dockets since the year 2000. The results suggest that microinsults, microinvalidations, and microassaults are reported in a variety of discrimination claims. However, only overt and intentional forms of microaggressions (microassaults) increased the likelihood that decisions favored plaintiffs. Thus, there may be a disconnect between forms of discrimination perceived by claimants and how those forms are evaluated by the legal system that protects victims of discrimination. This potential misalignment of science and practice is discussed, as are directions for future research. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
47.
Salman M. A. Salman 《国际水》2013,38(4):580-585
Abstract International rivers serve a number of purposes, the most obvious are the navigational and non-navigational uses. Less noticed is the fact that international rivers are also used to delimit boundaries between nations. The immediate question that would arise is: Where are such boundaries actually drawn across the river? Boundaries, however, are established by treaties and the answer to this question is often included in the interpretation of treaties delimiting such water boundaries, taking into account the special characteristics of the international river. Indeed, this has been the case regarding the boundaries across the Chobe river between Botswana and Namibia. Determining where such boundaries lie would result in deciding to whom a disputed Island, the Kasikili/Sedudu, belongs. In a praiseworthy step, the two countries agreed to take their dispute over the Island, after failure to resolve it through negotiations, to the International Court of Justice. This paper discusses the uses of international rivers as boundaries, and reviews the dispute between Botswana and Namibia, and the decision of the Court thereon. 相似文献
48.
Salman M.A. Salman 《国际水》2013,38(3):415-418
Abstract Of the voluminous resolutions issued by United Nations General Assembly, the Millennium Declaration, adopted in 2000, is one of the most significant. It specifies eight development goals and sets the year 2015 as the target date for achieving such goals. Although water is not explicitly mentioned as one of those eight principal goals, it is specified as a subset under one of those goals. Three years later, the United Nations General Assembly paid special attention to water by issuing a separate resolution declaring the period 2005 to 2015 as the “International Decade for Action, Water for Life.” This article reviews and discusses the Resolution and analyzes its added value. 相似文献
49.
50.
BH Güven? T Salman B Tokar E Sürmen T AltuG A Celik 《Canadian Metallurgical Quarterly》1997,12(5-6):367-369
Fetal tissue transplantation has gathered considerable interest among researchers dealing with organ transplantation. A large number of studies concerning fetal intestinal transplantation have been published in the past 2 decades, almost all of them aiming to determine the feasibility of a properly functioning fetal transplant in continuity with the host's own enteral system. This study was designed to determine the absorptive capacity of the neogut in vivo, without anastomosing the transplant to the host's intestine, and to evaluate its use as an accessory enteral segment. Intestinal segments taken from Wistar albino fetuses were transplanted subcutaneously into the abdominal wall of 20 Sprague-Dawley rats. Immunosuppression was maintained by daily cyclosporin A (Cy A) 10 mg/kg injections s.c. and evaluated by determination of serum Cy A level and T-helper/T-suppressor cell ratio. The neogut was converted into a Thiry-Vella loop 2 weeks after transplantation. A test solution composed of 20% glucose and Trophamine was perfused via the stomas; glucose and amino acid absorption gradients were calculated. The gamma-glutamyl transferase (GGT) activity and mitotic index of the neogut were determined. Results were compared to those obtained from the host. There was no significant difference (P > 0.05) in glucose absorption between the neogut and the host tissue. Amino acid absorption and specific GGT activity were significantly less (P < 0.01) in the neogut. There was no significant difference (P > 0.05) between neogut and host intestine in mitotic index. Our data support the idea of using a transplanted fetal intestinal segment as an accessory feeding route. 相似文献