全文获取类型
收费全文 | 2155篇 |
免费 | 86篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 25篇 |
综合类 | 2篇 |
化学工业 | 403篇 |
金属工艺 | 25篇 |
机械仪表 | 41篇 |
建筑科学 | 199篇 |
矿业工程 | 3篇 |
能源动力 | 53篇 |
轻工业 | 153篇 |
水利工程 | 18篇 |
石油天然气 | 3篇 |
无线电 | 114篇 |
一般工业技术 | 535篇 |
冶金工业 | 357篇 |
原子能技术 | 17篇 |
自动化技术 | 296篇 |
出版年
2023年 | 11篇 |
2022年 | 28篇 |
2021年 | 43篇 |
2020年 | 23篇 |
2019年 | 31篇 |
2018年 | 39篇 |
2017年 | 36篇 |
2016年 | 44篇 |
2015年 | 55篇 |
2014年 | 74篇 |
2013年 | 119篇 |
2012年 | 110篇 |
2011年 | 154篇 |
2010年 | 100篇 |
2009年 | 93篇 |
2008年 | 118篇 |
2007年 | 129篇 |
2006年 | 108篇 |
2005年 | 99篇 |
2004年 | 65篇 |
2003年 | 61篇 |
2002年 | 50篇 |
2001年 | 42篇 |
2000年 | 34篇 |
1999年 | 31篇 |
1998年 | 82篇 |
1997年 | 55篇 |
1996年 | 29篇 |
1995年 | 33篇 |
1994年 | 25篇 |
1993年 | 26篇 |
1992年 | 24篇 |
1991年 | 19篇 |
1990年 | 30篇 |
1989年 | 23篇 |
1988年 | 21篇 |
1987年 | 26篇 |
1986年 | 12篇 |
1985年 | 12篇 |
1984年 | 11篇 |
1983年 | 12篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1979年 | 4篇 |
1977年 | 6篇 |
1976年 | 13篇 |
1973年 | 4篇 |
1920年 | 3篇 |
1919年 | 3篇 |
排序方式: 共有2244条查询结果,搜索用时 0 毫秒
1.
2.
Barch Deanna M.; Mitropoulou Vivian; Harvey Philip D.; New Antonia S.; Silverman Jeremy M.; Siever Larry J. 《Canadian Metallurgical Quarterly》2004,113(4):556
Research suggests that schizotypal personality disorder (SPD) is a part of the spectrum of schizophrenia-related illnesses. This article hypothesizes that a deficit in the representation and maintenance of context is a core cognitive disturbance in schizophrenia and that SPD individuals should demonstrate context-processing deficits. To test this hypothesis, the authors administered 3 versions of their AX-CPT task, designed to assess context processing, to 35 healthy controls and 26 individuals with DSM-IV SPD. They also administered working memory and selective attention tasks. SPD individuals displayed context representation deficits similar to those found in schizophrenia but did not show the same additional deficits in context maintenance. Context processing was strongly associated with working memory and selective attention performance in the SPD individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
The global market for liquid mixed‐metal stabilizers is migrating toward heavy‐metal‐free products, Historically, these systems have not been performance and cost competitive. High efficiency calcium‐zinc stabilizers have the potential to replace heavy‐metal‐based products. The intrinsic value of non‐phenolic lubricating calcium intermediates and calcium‐zinc stabilizers is discussed. 相似文献
4.
5.
JD Haag LA Shepel BD Kolman DM Monson ME Benton KT Watts JL Waller CC Lopez-Guajardo DJ Samuelson MN Gould 《Canadian Metallurgical Quarterly》2003,63(18):5808-5812
It has previously been shown that the Copenhagen (COP) rat contains several genetic loci that contribute to its mammary tumor-resistant phenotype after 7,12-dimethylbenz(a)anthracene (DMBA) administration. One of these loci, mammary carcinoma susceptibility 1 (Mcs1), is located on the centromeric end of chromosome 2 and appears to act in a semidominant fashion. To confirm the existence and independent action of this locus and also aid in the identification of the physical location of the Mcs1 gene, congenic lines were generated by transferring the Mcs1 COP allele onto a Wistar Furth (WF) genetic background. Male carriers were genotyped using microsatellite markers spanning 20-30 cM of the Mcs1 locus. One of the congenic lines minimally retained the COP allele at D2Mit29 on the centromeric end of chromosome 2 and extended distally to D2Rat201. Heterozygous Mcs1 carrier rats were interbred, and the female offspring were treated with DMBA. The female rats from the Mcs1 congenic line that carried one or two COP alleles of the Mcs1 region had a significantly reduced (65 and 85%, respectively) tumor development (P < 0.001) compared with rats carrying zero COP alleles at this locus. A WF.COP-D2Mit29/D2Rat201 homozygous congenic strain derived at the N10 generation was treated with DMBA, and the COP homozygous rats developed 1.5 +/- 0.3 carcinomas/rat versus 6.3 +/- 0.5 in WF control rats (P < 0.0001). Fine mapping of this congenic interval using several recombinant lines identified three genetic loci within the Mcs1 congenic region that independently supported a tumor resistance phenotype. These genetic loci have been termed Mcs1a, Mcs1b, and Mcs1c. In rats for which each locus was homozygous for the COP allele, tumor development was reduced by approximately 60% compared with littermate controls. The identification of these independent loci within the Mcs1 COP allele provide a model of the genetic complexity of cancer. 相似文献
6.
JeremyCurtis 《今日电子》2003,(12):30-31
移动终端是一种采用先进通信协议栈的复杂系统,它需要具有与许多网络供应商设备的互操作性、支持先进而丰富的多媒体应用程序,而且,所有这些都必需在一个资源有限的嵌入式系统的约束条件下实现。提供一个满足上述要求的软件解决方案需要考虑许多方面的问题并经历诸多阶段。成功的要素是:平台质量、应用程序集成质量和产品质量。平台质量能让制造商用来生成多种设计方案的移动手机参考设计,必须提供一个用于制造高品质终端用户产品的优质平台。移动手机软件包括三个关键部分——协议栈、应用程序架构和应用程序。协议栈毫无疑问是最为复杂的… 相似文献
7.
Yan R.-H. Lee K.F. Jeon D.Y. Kim Y.O. Park B.G. Pinto M.R. Rafferty C.S. Tennant D.M. Westerwick E.H. Chin G.M. Morris M.D. Early K. Mulgrew P. Mansfield W.M. Watts R.K. Voshchenkov A.M. Bokor J. Swartz R.G. Ourmazd A. 《Electron Device Letters, IEEE》1992,13(5):256-258
The authors report the implementation of deep-submicrometer Si MOSFETs that at room temperature have a unity-current-gain cutoff frequency (f T) of 89 GHz, for a drain-to-source bias of 1.5 V, a gate-to-source bias of 1 V, a gate oxide thickness of 40 Å, and a channel length of 0.15 μm. The fabrication procedure is mostly conventional, except for the e-beam defined gates. The speed performance is achieved through an intrinsic transit time of only 1.8 ps across the active device region 相似文献
8.
The review examines the evidence that the supply of cholesterol available for incorporation into nascent lipoprotein particles exerts a regulatory influence on apolipoprotein (apo) B secretion by the liver. Support for this hypothesis comes both from in vitro experiments and from recent observations in normal subjects and patients with dyslipidemia associated with familial hypercholesterolemia, obesity, noninsulin dependent diabetes mellitus, growth hormone deficiency and cholesteryl ester storage disease. The findings do not negate a role for triglyceride synthesis in determining apoB secretion in very low density lipoprotein, but the inhibitory effects on the latter process of pharmacological blockade of cholesterol synthesis or esterification suggest that it is conditional upon an adequate supply of cholesteryl ester. 相似文献
9.
P Collins M Watts M Brocklesby B Gerritsen P Veys 《Canadian Metallurgical Quarterly》1997,96(3):644-646
Familial haemophagocytic lymphohistiocytosis (HLH) is a disease with a very poor prognosis unless patients receive a bone marrow transplant. It is often difficult to find an HLA-matched donor and haploidentical familial donors may be considered. The main complication of this type of transplant is graft rejection. We describe a patient with familial HLH who received a haploidentical transplant using both mobilized peripheral blood and bone marrow stem cells in an attempt to overcome graft rejection by increasing the stem cell dose. The peripheral blood stem cell inoculum was CD34 enriched using a Cellpro column and T-cell depleted by Campath-1M, the patient received conditioning for a matched sibling donor transplant with the addition of Campath 1G. There was rapid and full engraftment and the patient remains disease free at 5 months. This technique may be applicable for other fatal inborn errors in the absence of an HLA-matched donor. 相似文献
10.