全文获取类型
收费全文 | 2355篇 |
免费 | 201篇 |
国内免费 | 109篇 |
专业分类
电工技术 | 113篇 |
综合类 | 128篇 |
化学工业 | 818篇 |
金属工艺 | 115篇 |
机械仪表 | 134篇 |
建筑科学 | 162篇 |
矿业工程 | 19篇 |
能源动力 | 16篇 |
轻工业 | 203篇 |
水利工程 | 19篇 |
石油天然气 | 34篇 |
武器工业 | 19篇 |
无线电 | 269篇 |
一般工业技术 | 298篇 |
冶金工业 | 38篇 |
原子能技术 | 20篇 |
自动化技术 | 260篇 |
出版年
2024年 | 8篇 |
2023年 | 38篇 |
2022年 | 185篇 |
2021年 | 189篇 |
2020年 | 93篇 |
2019年 | 61篇 |
2018年 | 49篇 |
2017年 | 70篇 |
2016年 | 68篇 |
2015年 | 78篇 |
2014年 | 132篇 |
2013年 | 132篇 |
2012年 | 141篇 |
2011年 | 150篇 |
2010年 | 134篇 |
2009年 | 118篇 |
2008年 | 108篇 |
2007年 | 135篇 |
2006年 | 118篇 |
2005年 | 106篇 |
2004年 | 87篇 |
2003年 | 73篇 |
2002年 | 68篇 |
2001年 | 69篇 |
2000年 | 45篇 |
1999年 | 35篇 |
1998年 | 15篇 |
1997年 | 18篇 |
1996年 | 30篇 |
1995年 | 25篇 |
1994年 | 20篇 |
1993年 | 6篇 |
1992年 | 10篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有2665条查询结果,搜索用时 28 毫秒
151.
Nadine Jaeckels Stefan Tenzer Susanne Rosfa Hansjoerg Schild Heinz Decker Petra Wigand 《Food chemistry》2013
Lipid transfer proteins (LTP) play a major role in plant defence and are of particular interest due to their known ability to cause allergic reactions. These proteins are expressed in grapes and also remain detectable after vinification, especially in red wine. However, it remains unknown whether the protein undergoes any changes during the vinification process. Here, we present a purification method for LTPs from Dornfelder grapes and wine. By liquid-chromatography–mass spectroscopy (LC–MS/MS) we identified LTPs from two different species (Vitis vinifera and Vitis aestivalis). Additionally, the purified LTPs were characterised using spectrometric methods, confirming their high purity and structural stability during vinification. We conclude that LTPs are resistant to the alcohol content (13.5 vol%), acidic milieu of wine and other ingredients present during the vinification process, indicating that the allergenic potential of grape LTP is not diminished by the vinification process. 相似文献
152.
In this letter, we propose a data randomization scheme for endurance and interference mitigation of deeply‐scaled multilevel flash memory. We address the relationships between data patterns and the raw bit error rate. An on‐chip pseudorandom generator composed of an address‐based seed location decoder is developed and evaluated with respect to uniformity. Experiments performed with 2x‐nm and 4x‐nm NAND flash memory devices illustrate the effectiveness of our scheme. The results show that the error rate is reduced up to 86% compared to that of a conventional cycling scheme. Accordingly, the endurance phenomenon can be mitigated through analysis of interference that causes tech shrinkage. 相似文献
153.
Chemotherapy is the mainstream treatment of anaplastic large cell lymphoma (ALCL). However, chemotherapy can cause severe adverse effects in patients because it is not ALCL‐specific. In this study, a multifunctional aptamer‐nanomedicine (Apt‐NMed) achieving targeted chemotherapy and gene therapy of ALCL is developed. Apt‐NMed is formulated by self‐assembly of synthetic oligonucleotides containing CD30‐specific aptamer and anaplastic lymphoma kinase (ALK)‐specific siRNA followed by self‐loading of the chemotherapeutic drug doxorubicin (DOX). Apt‐NMed exhibits a well‐defined nanostructure (diameter 59 mm) and stability in human serum. Under aptamer guidance, Apt‐NMed specifically binds and internalizes targeted ALCL cells. Intracellular delivery of Apt‐NMed triggers rapid DOX release for targeted ALCL chemotherapy and intracellular delivery of the ALK‐specific siRNA induced ALK oncogene silencing, resulting in combined therapeutic effects. Animal model studies reveal that upon systemic administration, Apt‐NMed specifically targets and selectively accumulates in ALCL tumor site, but does not react with off‐target tumors in the same xenograft mouse. Importantly, Apt‐NMed not only induces significantly higher inhibition in ALCL tumor growth, but also causes fewer or no side effects in treated mice compared to free DOX. Moreover, Apt‐NMed treatment markedly improves the survival rate of treated mice, opening a new avenue for precision treatment of ALCL. 相似文献
154.
《国际聚合物材料杂志》2012,61(10):786-792
Optical properties of a green fluorescent protein (GFP) are examined using optical absorption, circular dichroism (CD), and circular polarized luminescence (CPL) spectroscopies. The GFP has chiroptical activity and exhibits green circular polarized emission, although the g em-factor is small. Poly(vinyl alcohol) (PVA)/GFP composite films are prepared to attempt long-term preservation of the GFP emission activity. After five years, the transparent PVA/GFP composite film still exhibits stable fluorescence that appears similar to the emission from the Aequorea jellyfish. 相似文献
155.
156.
157.
Lapointe Nicolas P.; Ung Roth-Visal; Bergeron Maxime; Cote Martin; Guertin Pierre A. 《Canadian Metallurgical Quarterly》2006,120(4):826
Reorganization and plasticity after spinal cord injury have been recently shown to take place in sublesional neuronal networks, but the possibility of strain-dependent changes at that level has never been explored. The authors studied the spontaneous return of hindlimb movement in low-thoracic spinal cord transected (Tx) mice from 3 commonly used strains. Without intervention, most CD1, C57BL/6, and BALB/c mice displayed some hindlimb movement recovery after Tx. Although all assessment methods unanimously reported that CD1 displayed higher recovery levels than did the C57BL/6 and BALB/c, higher scores were generally found with the Antri-Orsal-Barthe (M. Antri, D. Orsal, & J. Y. Barthe, 2002) and the Average Combined Score (P. A. Guertin, 2005a) methods. Such spontaneous recovery in low-thoracic Tx mice is likely the result of neuronal plasticity at the lumbosacral spinal cord level, suggesting that these sublesional changes are strain dependent. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
158.
159.
介绍了大型卷板机主动辊断裂后修复的技术过程及经济性分析,疲劳裂纹形成的原因;辊子材料材质的化学分析;补焊材料材质的确定;焊接 材料的选择;合理的焊接工艺参数的确定;焊前预热及焊后热处理方法;焊后超声波检查及其它检验方法;焊接修复的经济性分析,修复后的卷板机已正常运行,经超声波检验复查,焊缝处无裂纹产生,此种焊接修复方法是可行的。 相似文献
160.
模块式CD镜像服务器的实现及性能评测 总被引:1,自引:0,他引:1
介绍了一种可扩展性强、性能和成本可控的模块式CD镜像服务器的实现原理,解决了基于Linux的服务器专有操作系统中中文支持不好的问题。通过网络访问的方式对模块式CD镜像服务器的性能进行了评测。评测结果显示,对该服务器的数据访问速度大大高于对共享光驱中数据的访问速度。尤其是在多客户访问的情况下,该服务器可提供远远高于普通共享光驱的数据访问带宽。 相似文献