全文获取类型
收费全文 | 11560篇 |
免费 | 385篇 |
国内免费 | 17篇 |
专业分类
电工技术 | 154篇 |
综合类 | 2篇 |
化学工业 | 2120篇 |
金属工艺 | 212篇 |
机械仪表 | 242篇 |
建筑科学 | 305篇 |
矿业工程 | 29篇 |
能源动力 | 250篇 |
轻工业 | 1541篇 |
水利工程 | 131篇 |
石油天然气 | 38篇 |
无线电 | 980篇 |
一般工业技术 | 1686篇 |
冶金工业 | 2853篇 |
原子能技术 | 101篇 |
自动化技术 | 1318篇 |
出版年
2023年 | 67篇 |
2022年 | 182篇 |
2021年 | 288篇 |
2020年 | 183篇 |
2019年 | 270篇 |
2018年 | 286篇 |
2017年 | 268篇 |
2016年 | 248篇 |
2015年 | 191篇 |
2014年 | 274篇 |
2013年 | 553篇 |
2012年 | 430篇 |
2011年 | 506篇 |
2010年 | 366篇 |
2009年 | 386篇 |
2008年 | 415篇 |
2007年 | 402篇 |
2006年 | 335篇 |
2005年 | 294篇 |
2004年 | 237篇 |
2003年 | 217篇 |
2002年 | 215篇 |
2001年 | 205篇 |
2000年 | 185篇 |
1999年 | 222篇 |
1998年 | 770篇 |
1997年 | 472篇 |
1996年 | 347篇 |
1995年 | 278篇 |
1994年 | 254篇 |
1993年 | 242篇 |
1992年 | 159篇 |
1991年 | 129篇 |
1990年 | 126篇 |
1989年 | 159篇 |
1988年 | 121篇 |
1987年 | 116篇 |
1986年 | 112篇 |
1985年 | 124篇 |
1984年 | 112篇 |
1983年 | 95篇 |
1982年 | 80篇 |
1981年 | 81篇 |
1980年 | 76篇 |
1979年 | 78篇 |
1978年 | 68篇 |
1977年 | 93篇 |
1976年 | 205篇 |
1975年 | 59篇 |
1974年 | 53篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Alfredo M. Gravagnuolo Eden Morales‐Narváez Charlene Regina Santos Matos Sara Longobardi Paola Giardina Arben Merkoçi 《Advanced functional materials》2015,25(38):6084-6092
Class I hydrophobin Vmh2, a peculiar surface active and versatile fungal protein, is known to self‐assemble into chemically stable amphiphilic films, to be able to change wettability of surfaces, and to strongly adsorb other proteins. Herein, a fast, highly homogeneous and efficient glass functionalization by spontaneous self‐assembling of Vmh2 at liquid–solid interfaces is achieved (in 2 min). The Vmh2‐coated glass slides are proven to immobilize not only proteins but also nanomaterials such as graphene oxide (GO) and quantum dots (QDs). As models, bovine serum albumin labeled with Alexa 555 fluorophore, anti‐immunoglobulin G antibodies, and cadmium telluride QDs are patterned in a microarray fashion in order to demonstrate functionality, reproducibility, and versatility of the proposed substrate. Additionally, a GO layer is effectively and homogeneously self‐assembled onto the studied functionalized surface. This approach offers a quick and simple alternative to immobilize nanomaterials and proteins, which is appealing for new bioanalytical and nanobioenabled applications. 相似文献
5.
6.
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
7.
8.
A theory is presented that explains how the visual system infers the lightness, opacity, and depth of surfaces from stereoscopic images. It is shown that the polarity and magnitude of image contrast play distinct roles in surface perception, which can be captured by 2 principles of perceptual inference. First, a contrast depth asymmetry principle articulates how the visual system computes the ordinal depth and lightness relationships from the polarity of local, binocularly matched image contrast. Second, a global transmittance anchoring principle expresses how variations in contrast magnitudes are used to infer the presence of transparent surfaces. It is argued that these principles provide a unified explanation of how the visual system computes the 3-D surface structure of opaque and transparent surfaces. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
Cypriano G da Trindade Neto Ana LP Fernandes Ana IB Santos Waldenice A Morais Marcos VM Navarro Tereza NC Dantas Mrcia R Pereira Jos LC Fonseca 《Polymer International》2005,54(4):659-666
Complexation of chitosan in aqueous solutions by low molecular weight electrolytes is one of the simplest methods for the preparation of aqueous chitosan dispersions. In this work, the influence of storage time, sulfate concentration, method of preparation and surfactant content on some properties of the resultant chitosan dispersions (turbidity, viscosity and zeta potential) was analyzed. Turbidimetry was adequate to monitor the formation of particles, while viscometry was suitable to monitor changes in the dispersing phase. An analysis of the properties of these systems, mainly in terms of particle–particle and macromolecule–macromolecule interactions was carried out. Copyright © 2004 Society of Chemical Industry 相似文献
10.
Arash Sarhangi Fard Navid M. Famili Patrick D. Anderson 《Computers & Chemical Engineering》2008,32(7):1471-1481
The main objective of the present work is to modify the traditional mapping method for the simulation of distributive mixing of multiphase flows in geometries involving moving parts such as, internal mixers or twin-screw extruders without a limitation on their geometrical periodicity. The periodicity condition, limits the results of traditional mapping method to tracking mapping mesh between specific discrete time intervals or distances for that geometry is repeated, hence, result is only for fixed orientation of rotors. Imaginary domain method is introduced to track mapping mesh from one state to the next free of geometrical periodicity limitations. In this work the method is introduced and its applicability and accuracy is discussed in details. A two-dimensional (2D) simulation of mixing of two Newtonian fluids with different viscosities in an intermeshing internal mixer is used as a test case study. In this example the key issues of ability to predict mixing state in details for all orientations of rotors is presented. To reduce diffusion errors of mapping method in the boundaries of the rotors, mapping mesh refinement technique that relies upon one single reference mesh is also presented. 相似文献