全文获取类型
收费全文 | 7009篇 |
免费 | 479篇 |
国内免费 | 267篇 |
专业分类
电工技术 | 218篇 |
综合类 | 581篇 |
化学工业 | 875篇 |
金属工艺 | 440篇 |
机械仪表 | 1193篇 |
建筑科学 | 406篇 |
矿业工程 | 555篇 |
能源动力 | 99篇 |
轻工业 | 571篇 |
水利工程 | 85篇 |
石油天然气 | 1164篇 |
武器工业 | 45篇 |
无线电 | 195篇 |
一般工业技术 | 591篇 |
冶金工业 | 191篇 |
原子能技术 | 32篇 |
自动化技术 | 514篇 |
出版年
2024年 | 25篇 |
2023年 | 63篇 |
2022年 | 140篇 |
2021年 | 177篇 |
2020年 | 154篇 |
2019年 | 119篇 |
2018年 | 113篇 |
2017年 | 172篇 |
2016年 | 204篇 |
2015年 | 242篇 |
2014年 | 453篇 |
2013年 | 364篇 |
2012年 | 511篇 |
2011年 | 596篇 |
2010年 | 369篇 |
2009年 | 351篇 |
2008年 | 313篇 |
2007年 | 482篇 |
2006年 | 405篇 |
2005年 | 337篇 |
2004年 | 308篇 |
2003年 | 328篇 |
2002年 | 290篇 |
2001年 | 249篇 |
2000年 | 229篇 |
1999年 | 176篇 |
1998年 | 133篇 |
1997年 | 130篇 |
1996年 | 75篇 |
1995年 | 77篇 |
1994年 | 53篇 |
1993年 | 29篇 |
1992年 | 26篇 |
1991年 | 16篇 |
1990年 | 17篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1956年 | 1篇 |
排序方式: 共有7755条查询结果,搜索用时 15 毫秒
1.
2.
M. R. Thompson 《Drug development and industrial pharmacy》2015,41(8):1223-1231
Twin screw granulation (TSG) is a new process of interest to the pharmaceutical community that can continuously wet granulate powders, doing so at lower liquid concentrations and with better product consistency than found by a high shear batch mixer. A considerable body of research has evolved over the short time since this process was introduced but generally with little comparison of results. A certain degree of confidence has been developed through these studies related to how process variables and many attributes of machinery configuration will affect granulation but some major challenges still lay ahead related to scalability, variations in the processing regimes related to degree of channel fill and the impact of wetting and granulation of complex powder formulations. This review examines the current literature for wet granulation processes studied in twin screw extrusion machinery, summarizing the influences of operational and system parameters affecting granule properties as well as strives to provide some practical observations to newly interested users of the technique. 相似文献
3.
Andrés Mario Zervigón 《History of Photography》2019,43(2):130-143
For decades now, Douglas Crimp’s landmark 1980 essay ‘The Photographic Activity of Postmodernism’ has shaped our understanding of modernism’s aftermath, at least as it unfolded in North America and Western Europe. Less remembered, however, is the degree to which the procedures of disjunction, copying, appropriation, and outright theft that he highlighted were epitomised not just by contemporary photography, but by photomontage in particular. This article recovers the debates that led critics such as Crimp, Abigail Solomon-Godeau, Christopher Phillips, Benjamin Buchloh and others to turn to photomontage as one of their principal objects of concern in what became known as the postmodern critique of photography. Why was montage tasked to perform this critical function, particularly by people around the journal October who had not otherwise devoted the balance of their writing to photography’s history? The article suggests that these men and women, along with the contemporary artists they foregrounded, manifested what Mary Anne Doane has called a ‘desire for signification’, a reaction in the late 1970s against the mute theatricality of minimalist and conceptual art. Photomontage reintroduced representation to contemporary art and to the canon of art history. But unlike the reemerging illusionism in painting that also manifested this desire, montage guarded against an uncomplicated realism by highlighting and critiquing operations of representation in a manner that painting no longer could. 相似文献
4.
就经典分水岭图像分割算法中存在的过分割问题,提出一种结合位图切割和区域合并的彩色图像分割算法。对原始彩色图像通过空域梯度算子求其梯度图像,并利用位图切割重建梯度图像;对新梯度图像进行分水岭预分割;对预分割图像基于异质性最小原则进行区域合并,并获得最终分割结果。相比于现有的同类方法,该算法引入位图切割,抑制噪声对分割结果的影响,在边缘模糊处分割准确,得到符合人类视觉的较小分割区域数目,同时在运行效率上提高。 相似文献
5.
In order to protect bolts from corrosion, electroplating such as zinc plating is widely used. However, hydrogen can easily penetrate or diffuse into the vacancies and dislocations between the lattices of bolt steel during electroplating. As the diffused hydrogen defects inside the lattice are in gaseous form, small cracks can easily be produced due to high pressure from the hydrogen gas. In this research, in order to determine the root cause of the fracture in pole fastening screws resulting from hydrogen embrittlement in typical electric motors, additional factors that accelerate hydrogen embrittlement fracture were selectively applied, including a small fillet in the head–shank transition and excessive hardness, and parametric study was performed experimentally. 相似文献
6.
目前油田相当一部分产液井产液量相对较低,井下含水率高。这些特点给油井找水工作增加了很大难度,必然要求测试仪器具有适用于高含水率、低产液量的特点。取样式环空找水组合测井仪与常规过流式仪器相比,有着独特的优势,测量含水时不受井筒内流体的流速和抽油机冲程波动的影响。仪器含水测量精度可达到±5%以内,极大地提高了含水参数资料录取的准确性,对油田动态监测具有重要意义。 相似文献
7.
This article introduces a special section on the use of taxometrics to examine the categorical versus the dimensional structure of various forms of psychopathology. Paving the way into the special section, this introduction briefly describes 3 taxometric methods--mean above minus below a sliding cut (MAMBAC), maximum covariation (MAXCOV), and maximum eigenvalue (MAXEIG)--and discusses possible threats to statistical conclusion validity that often emerge when such techniques are applied in psychopathology research. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
利用系统分析方法进行单井措施优选 总被引:1,自引:0,他引:1
油井措施增油一直是油田控制产量递减、含水上升的主要做法,但是随着油田开采程度加深,地下油水分布十分复杂,选择油水井措施难度越来越大。为此,运用系统分析方法进行单井措施优选,通过对区块水驱油、水驱水、井间干扰以及油井的液、油、含水率间关系,综合判断出区块内滞留区、死油区和动用好的区域,指出今后挖潜方向。此方法均应用动态数据,客观性较强、准确性较高,克服了以往选择单井措施的盲目性和主观性。并将该方法在大庆油田杏八、九区基础井网提液试验过程中得到应用,效果较好。 相似文献
9.
针对壁体材料多样、结构复杂的高耸建筑物的爆破拆除,通过实验研究确定了爆破切口形式,运用力学理论推导了余留支撑体所对应的圆心角和爆破切口高度计算公式,并在工程实践中得到验证.对爆破拆除类似建筑物具有较大的实用价值. 相似文献
10.
李彩虹 《南京工业职业技术学院学报》2008,8(2):1-3
根据PET薄膜的特点和高分子熔融态流动理论,分析了挤出回收用螺杆的各段结构,及螺杆参数选择,设计出大长径比、深槽、双排气、高效专用螺杆。 相似文献