全文获取类型
收费全文 | 2147篇 |
免费 | 144篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 31篇 |
综合类 | 3篇 |
化学工业 | 604篇 |
金属工艺 | 29篇 |
机械仪表 | 32篇 |
建筑科学 | 53篇 |
能源动力 | 149篇 |
轻工业 | 235篇 |
水利工程 | 21篇 |
石油天然气 | 29篇 |
无线电 | 166篇 |
一般工业技术 | 302篇 |
冶金工业 | 145篇 |
原子能技术 | 5篇 |
自动化技术 | 494篇 |
出版年
2023年 | 35篇 |
2022年 | 89篇 |
2021年 | 141篇 |
2020年 | 76篇 |
2019年 | 77篇 |
2018年 | 112篇 |
2017年 | 87篇 |
2016年 | 110篇 |
2015年 | 76篇 |
2014年 | 123篇 |
2013年 | 145篇 |
2012年 | 120篇 |
2011年 | 154篇 |
2010年 | 73篇 |
2009年 | 96篇 |
2008年 | 91篇 |
2007年 | 69篇 |
2006年 | 59篇 |
2005年 | 65篇 |
2004年 | 45篇 |
2003年 | 25篇 |
2002年 | 31篇 |
2001年 | 26篇 |
2000年 | 13篇 |
1999年 | 22篇 |
1998年 | 26篇 |
1997年 | 23篇 |
1996年 | 21篇 |
1995年 | 18篇 |
1994年 | 15篇 |
1993年 | 25篇 |
1992年 | 22篇 |
1991年 | 22篇 |
1990年 | 20篇 |
1989年 | 17篇 |
1988年 | 22篇 |
1987年 | 10篇 |
1986年 | 11篇 |
1985年 | 4篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 14篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1978年 | 4篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1973年 | 4篇 |
1971年 | 4篇 |
排序方式: 共有2298条查询结果,搜索用时 312 毫秒
221.
Awad R. Mansour A.M. Hussein 《International Communications in Heat and Mass Transfer》1990,17(6):823-830
An analytical solution for diffusion with homogenous n the order nonlinear chemical reaction in laminar flow of a Newtonian fluid through tubular reactor with unknown boundary conditions is presented. The results of the new solution have been compared with previously published numerical solutions and shown to be accurate. 相似文献
222.
Mohd Zobir bin Hussein Asmah Hj Yahaya Zulkarnain Zainal Loo Hee Kian 《Science and Technology of Advanced Materials》2005,6(8):956-962
Controlled release formulation of an herbicide, 2,4-dichlorophenoxyacetate (24D) was developed by the virtue of the formation of organic–inorganic nanohybrid material and its ion exchange property. The inorganic Zn–Al layered double hydroxide (ZAL) was used as a matrix, hosting an active agent or a guest, 24D by self-assembly technique. The resulting material (ZAD) was subsequently used to study the release property of 24D into aqueous solutions containing chloride, carbonate as well as distilled water. The release of the guest 24D was found to be rapid initially followed by a more sustained release thereafter and this behavior was dependent on the type of anions and their concentrations in the release medium, the aqueous solution. The mechanism of release has been interpreted on the basis of the ion exchange process between the 24D anion intercalated into the interlamellae host and carbonate or chloride and/or hydroxyl anions in the aqueous solution. 相似文献
223.
A semi-empirical kinetic model that fits laboratory data and predicts pilot plant data was developed. The model is a modified version of a recently reported third-order kinetic equation for the reaction of nonstoichiometric amounts of hydroxyl and carboxylic groups. The model can be used to quantify the effects of reaction temperature and inert gas flow rate on the reaction rate. The Arrhenius temperature dependence of the rate constant permitted the calculation of the reaction activation energy (53.6 kJ/mol). The gas flow rate dependence is an empirical function of the molar ratio of reactants to inert gas. The same function is simultaneously used as the process scale-up rule. The mathematical model can be potentially used for commercial-sized reactors. 相似文献
224.
225.
This paper summarizes comprehensive experimental studies on scaled models of squat bridge columns repaired and retrofitted with advanced composite-material jackets. In the experimental program, a total of 14 half-scale squat circular and rectangular reinforced concrete columns were tested under fully reversed cyclic shear in a double bending configuration. In order to provide a basis for comparison, a total of three as-built columns were tested. Another 10 column samples were tested after being retrofitted with different composite jacket systems. One circular as-built column was repaired after failure. The repair process involved both crack injection as well as addition of carbon/epoxy composite jacket. The repaired column was then retested and evaluated. Experimental results showed that all as-built columns developed an unstable behavior and failed in brittle shear mode. The common failure mode for all retrofitted samples was due to flexure with significant improvement in the column ductility. The repaired column demonstrated ductility enhancement over the as-built sample. 相似文献
226.
227.
Stefano Sivolella Giulia Brunello Nadia Ferrarese Alessandro Della Puppa Domenico D’Avella Eriberto Bressan Barbara Zavan 《International journal of molecular sciences》2014,15(2):3088-3117
Injury to peripheral nerves can occur as a result of various surgical procedures, including oral and maxillofacial surgery. In the case of nerve transaction, the gold standard treatment is the end-to-end reconnection of the two nerve stumps. When it cannot be performed, the actual strategies consist of the positioning of a nerve graft between the two stumps. Guided nerve regeneration using nano-structured scaffolds is a promising strategy to promote axon regeneration. Biodegradable electrospun conduits composed of aligned nanofibers is a new class of devices used to improve neurite extension and axon outgrowth. Self assembled peptide nanofibrous scaffolds (SAPNSs) demonstrated promising results in animal models for central nervous system injuries, and, more recently, for peripheral nerve injury. Aims of this work are (1) to review electrospun and self-assembled nanofibrous scaffolds use in vitro and in vivo for peripheral nerve regeneration; and (2) its application in peripheral nerve injuries treatment. The review focused on nanofibrous scaffolds with a diameter of less than approximately 250 nm. The conjugation in a nano scale of a natural bioactive factor with a resorbable synthetic or natural material may represent the best compromise providing both biological and mechanical cues for guided nerve regeneration. Injured peripheral nerves, such as trigeminal and facial, may benefit from these treatments. 相似文献
228.
Farahnaz Barahuie Mohd Zobir Hussein Sharida Fakurazi Zulkarnain Zainal 《International journal of molecular sciences》2014,15(5):7750-7786
Layered hydroxides (LHs) have recently fascinated researchers due to their wide application in various fields. These inorganic nanoparticles, with excellent features as nanocarriers in drug delivery systems, have the potential to play an important role in healthcare. Owing to their outstanding ion-exchange capacity, many organic pharmaceutical drugs have been intercalated into the interlayer galleries of LHs and, consequently, novel nanodrugs or smart drugs may revolutionize in the treatment of diseases. Layered hydroxides, as green nanoreservoirs with sustained drug release and cell targeting properties hold great promise of improving health and prolonging life. 相似文献
229.
230.
Structure–Activity Relationship Study of Spider Polyamine Toxins as Inhibitors of Ionotropic Glutamate Receptors
下载免费PDF全文
![点击此处可从《ChemMedChem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Xiao‐Feng Xiong Dr. Mette H. Poulsen Rama A. Hussein Dr. Niels G. Nørager Prof. Kristian Strømgaard 《ChemMedChem》2014,9(12):2661-2670
The spider polyamine toxins Joro spider toxin‐3 (JSTX‐3) and Nephila polyamine toxins‐1 and ‐8 (NPTX‐1 and NPTX‐8) are isolated from the venom of the orb‐weaver spider Nephila clavata (Joro spider). They share a high degree of structural resemblance, their aromatic head groups being the only difference, and were recently found to be very potent open‐channel blockers of ionotropic glutamate (iGlu) receptors. In this study we designed and synthesized a collection of 24 analogues of these toxins using a recently developed solid‐phase synthetic methodology. Systematic variation in two regions of the toxins and subsequent evaluation of biological activity at AMPA and NMDA subtypes of iGlu receptors provided succinct information on structure–activity relationships. In particular, one set of analogues were found to display exquisite selectivity and potency for AMPA receptors relative to the natural products. Thus, this systematic SAR study has provided new pharmacological tools for studies of iGlu receptors. 相似文献