全文获取类型
收费全文 | 10137篇 |
免费 | 164篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 119篇 |
综合类 | 7篇 |
化学工业 | 1453篇 |
金属工艺 | 176篇 |
机械仪表 | 147篇 |
建筑科学 | 435篇 |
矿业工程 | 72篇 |
能源动力 | 204篇 |
轻工业 | 874篇 |
水利工程 | 113篇 |
石油天然气 | 43篇 |
武器工业 | 1篇 |
无线电 | 889篇 |
一般工业技术 | 1392篇 |
冶金工业 | 3159篇 |
原子能技术 | 74篇 |
自动化技术 | 1148篇 |
出版年
2022年 | 56篇 |
2021年 | 92篇 |
2020年 | 64篇 |
2019年 | 109篇 |
2018年 | 121篇 |
2017年 | 88篇 |
2016年 | 102篇 |
2015年 | 66篇 |
2014年 | 140篇 |
2013年 | 482篇 |
2012年 | 258篇 |
2011年 | 395篇 |
2010年 | 306篇 |
2009年 | 267篇 |
2008年 | 395篇 |
2007年 | 374篇 |
2006年 | 369篇 |
2005年 | 350篇 |
2004年 | 288篇 |
2003年 | 244篇 |
2002年 | 220篇 |
2001年 | 200篇 |
2000年 | 184篇 |
1999年 | 228篇 |
1998年 | 620篇 |
1997年 | 413篇 |
1996年 | 305篇 |
1995年 | 262篇 |
1994年 | 258篇 |
1993年 | 242篇 |
1992年 | 166篇 |
1991年 | 122篇 |
1990年 | 170篇 |
1989年 | 171篇 |
1988年 | 131篇 |
1987年 | 135篇 |
1986年 | 123篇 |
1985年 | 144篇 |
1984年 | 155篇 |
1983年 | 110篇 |
1982年 | 122篇 |
1981年 | 112篇 |
1980年 | 101篇 |
1979年 | 105篇 |
1978年 | 88篇 |
1977年 | 110篇 |
1976年 | 188篇 |
1975年 | 78篇 |
1974年 | 65篇 |
1973年 | 64篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Moustapha Moussa Amudhan Ponrajan Osvaldo H. Campanella Martin R. Okos Mario M. Martinez Bruce R. Hamaker 《International Journal of Food Science & Technology》2022,57(7):4594-4601
Traditional West African pearl millet couscous products are popular; however, their preparation is laborious, time-consuming and energy-demanding, involving agglomeration, steaming, drying and sieving steps. In this study, a process was developed to produce millet couscous using a high pressure, high temperature and low-cost single-screw extruder. The innovation was to directly process the cooked low-moisture extrudate to a couscous product by drying and milling to the appropriate particle size (ranging between 1 and 2 mm). Throughput for the traditional process as prepared for commercial sale is 50 kg per day, but with the same amount of labour, the extrusion process yields ~350 kg per day. A consumer sensory study held in Niamey (Niger) showed that the extruded millet couscous was comparable to traditional couscous, though this was dependent on selection of the proper millet variety. This novel extrusion process could stimulate small- to medium-scale manufacturing of couscous and couscous-type products in West Africa. 相似文献
2.
3.
Ricardo Cambraia Parreira Diana Paola Gmez‐Mendoza Itamar Couto Guedes de Jesus Rafael Pereira Lemos Anderson Kennedy Santos Cristiana Perdigo Rezende Henrique Csar Pereira Figueiredo Mauro Cunha Xavier Pinto Frank Kjeldsen Silvia Guatimosim Rodrigo Ribeiro Resende Thiago Verano‐Braga 《Proteomics. Clinical applications》2020,14(4)
4.
5.
HSDPA的度理论上最高达4.4M bit/s,但额的流量对无线接网络和空载传输容量要求有巨大影响。“3G的势头已经成为一个始终如一的主题。不过,正如我们所指出的,对3G手机的深刻领会并不总是伴随着对3G服务的持续理解。看上去高速下行包接入(HSDPA)技术可能是一个例外。它在欧洲发布,并且已经引起了人们浓厚的兴趣。看看它在亚洲的发展,我们不禁要问:它就是最终真正的3G吗?回首2002~2003年,HSDPA的部署看上去是一条漫长的道路,并且3GPP方面没有什么紧迫感,它的成员忙于应付WCDMA部署方面的复杂性。两件事的发生加速了HSDPA的部署:… 相似文献
6.
7.
Vivien Walsh Robin Roy Margaret Bruce Stephen Potter 《Creativity & Innovation Management》1993,2(2):78-86
A series of studies of top European and other firms has revealed patterns of design management associated with commercial success. Firms that invest resources and professional expertise in product and industrial design in traditional and new industries have been commercially more successful than firms that pay less attention to these aspects of design. As an industry matures there is a shift in emphasis from design associated with technological innovation, to designs supporting technical improvements, and then to supporting user needs, fashion and product variants. These issues are illustrated through the history of the evolution of the bicycle. 相似文献
8.
Antisense oligonucleotide inhibition of hepatitis C virus gene expression in transformed hepatocytes
R Hanecak V Brown-Driver MC Fox RF Azad S Furusako C Nozaki C Ford H Sasmor KP Anderson 《Canadian Metallurgical Quarterly》1996,70(8):5203-5212
Genetic and biochemical studies have provided convincing evidence that the 5' noncoding region (5' NCR) of hepatitis C virus (HCV) is highly conserved among viral isolates worldwide and that translation of HCV is directed by an internal ribosome entry site (IRES) located within the 5' NCR. We have investigated inhibition of HCV gene expression using antisense oligonucleotides complementary to the 5' NCR, translation initiation codon, and core protein coding sequences. Oligonucleotides were evaluated for activity after treatment of a human hepatocyte cell line expressing the HCV 5' NCR, core protein coding sequences, and the majority of the envelope gene (E1). More than 50 oligonucleotides were evaluated for inhibition of HCV RNA and protein expression. Two oligonucleotides, ISIS 6095, targeted to a stem-loop structure within the 5' NCR known to be important for IRES function, and ISIS 6547, targeted to sequences spanning the AUG used for initiation of HCV polyprotein translation, were found to be the most effective at inhibiting HCV gene expression. ISIS 6095 and 6547 caused concentration-dependent reductions in HCV RNA and protein levels, with 50% inhibitory concentrations of 0.1 to 0.2 microM. Reduction of RNA levels, and subsequently protein levels, by these phosphorothioate oligonucleotides was consistent with RNase H cleavage of RNA at the site of oligonucleotide hybridization. Chemically modified HCV antisense phosphodiester oligonucleotides were designed and evaluated for inhibition of core protein expression to identify oligonucleotides and HCV target sequences that do not require RNase H activity to inhibit expression. A uniformly modified 2'-methoxyethoxy phosphodiester antisense oligonucleotide complementary to the initiator AUG reduced HCV core protein levels as effectively as phosphorothioate oligonucleotide ISIS 6095 but without reducing HCV RNA levels. Results of our studies show that HCV gene expression is reduced by antisense oligonucleotides and demonstrate that it is feasible to design antisense oligonucleotide inhibitors of translation that do not require RNase H activation. The data demonstrate that chemically modified antisense oligonucleotides can be used as tools to identify important regulatory sequences and/or structures important for efficient translation of HCV. 相似文献
9.
In this paper we analyse issues associated with overloads in tandem switching systems in Common Channel Signalling (CCS) networks. In particular, we examine the need for, and effectiveness of, Automatic Congestion Control (ACC), a CCS mechanism which allows a congested switching system to inform adjacent CCS nodes of its level of overload, and subsequently controls the rate at which traffic is sent to the congested node. We demonstrate the critical need for end-offices and tandem switching systems to implement some form of ACC if network performance is to be maintained during congestion, especially in tandem exchanges. In addition, we find that the presently defined ACC should be expanded to allow more levels of congestion to be reported to adjacent nodes, so that a more effective, finer grained control is produced. 相似文献
10.
Valproate (VPA) has been shown to interact with all the major antiepileptic drugs (AEDs) through two mechanisms of action: displacement from albumin binding sites and inhibition of drug metabolism. More recently, evidence showed that VPA inhibits the elimination of drugs metabolized by glucuronide conjugation. Lorazepam (LZP), which is primarily eliminated by conjugation with glucuronic acid, is administered concurrently with VPA both in treatment of epilepsy and in patients treated with VPA for psychiatric disorders. Therefore, a significant drug interaction is likely. We investigated such interaction both in in vitro isolated perfused rat liver (IPRL) and in normal subjects. LZP [2 mg, intravenous (i.v.) bolus] was administered to 8 normal volunteers before and after chronic dosing with VPA. In 6 of 8 subjects, VPA significantly decreased LZP plasma clearance by an average of 40% (p < 0.05) and increased LZP concentrations by decreasing formation clearance of the LZP glucuronide. In the IPRL studies, VPA also significantly decreased formation of LZP glucuronide (from 0.72 +/- 0.14 to 0.22 +/- 0.15 ml/h/kg, p < 0.05), indicating that IPRL is a useful tool for evaluation of the effect of VPA on drugs eliminated by glucuronide conjugation. 相似文献