全文获取类型
收费全文 | 7253篇 |
免费 | 453篇 |
国内免费 | 15篇 |
专业分类
电工技术 | 222篇 |
综合类 | 34篇 |
化学工业 | 1680篇 |
金属工艺 | 225篇 |
机械仪表 | 209篇 |
建筑科学 | 230篇 |
矿业工程 | 35篇 |
能源动力 | 270篇 |
轻工业 | 1026篇 |
水利工程 | 61篇 |
石油天然气 | 38篇 |
武器工业 | 1篇 |
无线电 | 457篇 |
一般工业技术 | 1674篇 |
冶金工业 | 227篇 |
原子能技术 | 96篇 |
自动化技术 | 1236篇 |
出版年
2023年 | 57篇 |
2022年 | 54篇 |
2021年 | 178篇 |
2020年 | 148篇 |
2019年 | 172篇 |
2018年 | 286篇 |
2017年 | 272篇 |
2016年 | 305篇 |
2015年 | 240篇 |
2014年 | 365篇 |
2013年 | 725篇 |
2012年 | 481篇 |
2011年 | 592篇 |
2010年 | 464篇 |
2009年 | 372篇 |
2008年 | 295篇 |
2007年 | 266篇 |
2006年 | 176篇 |
2005年 | 183篇 |
2004年 | 116篇 |
2003年 | 129篇 |
2002年 | 150篇 |
2001年 | 117篇 |
2000年 | 98篇 |
1999年 | 73篇 |
1998年 | 97篇 |
1997年 | 80篇 |
1996年 | 72篇 |
1995年 | 59篇 |
1994年 | 58篇 |
1993年 | 58篇 |
1992年 | 49篇 |
1991年 | 38篇 |
1990年 | 39篇 |
1989年 | 40篇 |
1988年 | 27篇 |
1986年 | 24篇 |
1985年 | 52篇 |
1984年 | 63篇 |
1983年 | 53篇 |
1982年 | 48篇 |
1981年 | 70篇 |
1980年 | 59篇 |
1979年 | 51篇 |
1978年 | 43篇 |
1977年 | 37篇 |
1976年 | 52篇 |
1975年 | 35篇 |
1974年 | 25篇 |
1973年 | 38篇 |
排序方式: 共有7721条查询结果,搜索用时 218 毫秒
11.
12.
The fission yeast Schizosaccharomyces pombe is an important model organism for the study of fundamental questions in eukaryotic cell and molecular biology. A plethora of cellular processes are membrane associated and/or dependent on the proper functioning of cellular membranes. Phospholipids are not only the basic building blocks of cellular membranes; they also serve as precursors to numerous signaling molecules. In this review, we describe the biosynthetic pathways leading to major S. pombe phospholipids, how these pathways are regulated, and what is known about degradation and turnover of fission yeast phospholipids. This review also addresses the synthesis, regulation and the role of water-soluble phospholipid precursors. The last chapter of the review is devoted to the use of S. pombe for the biotechnological production of value-added lipid molecules. 相似文献
13.
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
14.
15.
The paper analyses the corrosion behaviour of naturally and artificially aged AA2024 alloy in NaCl solution and in the presence of an environment-friendly corrosion inhibitor, CeCl3. On the basis of the values of polarisation resistance and corrosion current density, the corrosion resistance of the protective inhibitor film is established as well as the general corrosion resistance of this aluminium alloy. Resistance to pit formation is determined based on the difference in pitting and corrosion potentials while resistance to pit growth is determined based on the amount of charge consumed during pit growth. A scanning electron microscope is used to examine the morphology of the pits formed during the pitting corrosion testing, as well as to determine the cerium content on intermetallic particles and the matrix AA2024 alloy. The corrosion behaviour of AA2024 alloy is investigated after different test periods in NaCl solution and in the same solution with the CeCl3 inhibitor. The corrosion resistance of both tempers of AA2024 alloy is more than one order of magnitude higher in the presence of CeCl3. An explanation of the observed differences in the corrosion behaviour of the naturally and artificially aged AA2024 alloy is proposed. Different corrosion behaviour of the alloy after different test periods is also explained. 相似文献
16.
I. Budić-Leto T. Lovrić J. Gajdoš Kljusurić I. Pezo U. Vrhovšek 《European Food Research and Technology》2006,222(3-4):397-402
Identification of anthocyanins in the wine made of the Croatian autochthonous grape variety of Babić (Vitis vinifera L.) was carried out and their profile was determined by means of high-performance liquid chromatography with diode array
and mass spectrometric detection. Dependence of anthocyanins content and profile on maceration treatment conditions was investigated.
Statistically significant differences of anthocyanins concentration in wines Babić produced by various maceration treatments
were confirmed by the use of multivariate analysis of variances. The investigation results indicated that the maceration temperature
exerts higher influence on anthocyanins concentration than the duration of maceration. In addition, on the basis of anthocyanin
composition and using different multivariate statistical analyses, differentiation of wines Babić according to maceration
treatments was procured. 相似文献
17.
Anna Hać 《Journal of Network and Systems Management》1994,2(1):49-62
This paper analyzes the performance of a switching architecture. The performance measures include the elapsed time of packet transfer and the waiting time to begin transfer. The architecture is partitioned depending on the type of network used and the expected traffic in the network. Every partition has a switch with a buffer that can absorb surges of bursty traffic within the network partition. The buffer size depends on the type of the network and incoming traffic. The partition size depends on the network bandwidth, network traffic, packet size and buffer size. Examples of different networks are used to show the applications of the model. The results show that the elapsed time of packet switch transfer depends exponentially on the number of partitions in the network. 相似文献
18.
Summary Both preferential adsorption coefficient λ and intrinsic viscosity [η] for poly (di-o-alkylphenyl methacrylates) /Tetrahydrofuran
(THF)/water have been determined. The results are discussed in relation to the steric effect of the ortho-substituent groups
on the aromatic ring. 相似文献
19.
20.
Ivan Fortelný Monika Lapčíková František Lednický Zdeněk Starý Zdeněk Kruliš 《Polymer Engineering and Science》2008,48(3):564-571
This article is focused on the phase structure development in immiscible polymer blends during melt mixing. Nonuniformity of the phase structure, i.e., the coexistence of areas containing particles with markedly different size distribution, was detected in quenched and compression molded samples of a number of various blends prepared by long and intensive mixing in the chamber of a Plasticorder. The same effect was found also for polystyrene/polyamide blends prepared in a twin‐screw extruder. It was shown that neglecting nonuniformity of the phase structure can lead to considerable error in evaluation of the effect of system parameters on the blend morphology. The reasons for the effect were discussed and it was found that inhomogeneous flow field in mixers is a plausible explanation of the nonuniform phase structure. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers 相似文献