全文获取类型
收费全文 | 2739篇 |
免费 | 166篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 12篇 |
综合类 | 3篇 |
化学工业 | 641篇 |
金属工艺 | 43篇 |
机械仪表 | 18篇 |
建筑科学 | 132篇 |
矿业工程 | 6篇 |
能源动力 | 46篇 |
轻工业 | 463篇 |
水利工程 | 29篇 |
石油天然气 | 16篇 |
武器工业 | 1篇 |
无线电 | 134篇 |
一般工业技术 | 495篇 |
冶金工业 | 505篇 |
原子能技术 | 17篇 |
自动化技术 | 347篇 |
出版年
2023年 | 13篇 |
2022年 | 17篇 |
2021年 | 104篇 |
2020年 | 60篇 |
2019年 | 48篇 |
2018年 | 59篇 |
2017年 | 91篇 |
2016年 | 87篇 |
2015年 | 86篇 |
2014年 | 109篇 |
2013年 | 158篇 |
2012年 | 167篇 |
2011年 | 201篇 |
2010年 | 157篇 |
2009年 | 132篇 |
2008年 | 167篇 |
2007年 | 160篇 |
2006年 | 146篇 |
2005年 | 105篇 |
2004年 | 87篇 |
2003年 | 87篇 |
2002年 | 71篇 |
2001年 | 54篇 |
2000年 | 25篇 |
1999年 | 38篇 |
1998年 | 38篇 |
1997年 | 39篇 |
1996年 | 37篇 |
1995年 | 25篇 |
1994年 | 33篇 |
1993年 | 34篇 |
1992年 | 26篇 |
1991年 | 18篇 |
1990年 | 27篇 |
1989年 | 22篇 |
1988年 | 20篇 |
1987年 | 21篇 |
1986年 | 17篇 |
1985年 | 21篇 |
1984年 | 8篇 |
1983年 | 16篇 |
1982年 | 9篇 |
1981年 | 4篇 |
1980年 | 14篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 10篇 |
1974年 | 7篇 |
1973年 | 4篇 |
1960年 | 5篇 |
排序方式: 共有2908条查询结果,搜索用时 250 毫秒
81.
82.
83.
Preparation and Reinforcement of Dual‐Porous Biocompatible Cellulose Scaffolds for Tissue Engineering 下载免费PDF全文
Nicole Pircher David Fischhuber Leticia Carbajal Christine Strauß Jean‐Marie Nedelec Cornelia Kasper Thomas Rosenau Falk Liebner 《大分子材料与工程》2015,300(9):911-924
Biocompatible cellulose‐based aerogels composed of nanoporous struts, which embed interconnected voids of controlled micron‐size, have been prepared employing temporary templates of fused porogens, reinforcement by interpenetrating PMMA networks and supercritical carbon dioxide drying. Different combinations of cellulose solvent (Ca(SCN)2/H2O/LiCl or [EMIm][OAc]/DMSO) and anti‐solvent (EtOH), porogen type (paraffin wax or PMMA spheres) and porogen size (various fractions in the range of 100–500 μm) as well as intensity of PMMA reinforcement have been investigated to tailor the materials for cell scaffolding applications. All aerogels exhibited an open and dual porosity (micronporosity >100 μm and nanoporosity extending to the low micrometer range). Mechanical properties of the dual‐porous aerogels under compressive stress were considerably improved by introduction of interpenetrating PMMA networks. The effect of the reinforcing polymer on attachment, spreading, and proliferation of NIH 3T3 fibroblast cells, cultivated on selected dual‐porous aerogels to pre‐evaluate their biocompatibility was similarly positive. 相似文献
84.
MA‐NOTMP: A Triazacyclononane Trimethylphosphinate Based Bifunctional Chelator for Gallium Radiolabelling of Biomolecules 下载免费PDF全文
Sophie Poty Dr. Pauline Désogère Dr. Jakub Šimeček Dr. Claire Bernhard Dr. Victor Goncalves Dr. Christine Goze Dr. Frédéric Boschetti Dr. Johannes Notni Prof. Dr. Hans J. Wester Prof. Dr. Franck Denat 《ChemMedChem》2015,10(9):1475-1479
In the past few years, gallium‐68 has demonstrated significant potential as a radioisotope for positron emission tomography (PET), and the optimization of chelators for gallium coordination is a major goal in the development of radiopharmaceuticals. Methylaminotriazacyclononane trimethylphosphinate (MA‐NOTMP), a new C‐functionalized triazacyclononane derivative with phosphinate pendant arms, presents excellent coordination properties for 68Ga (low ligand concentration, labelling at low pH even at room temperature). A “ready‐to‐be‐grafted” bifunctional chelating agent (p‐NCS‐Bz‐MA‐NOTMP) was prepared to allow 68Ga labelling of sensitive biological vectors. Conjugation to a bombesin(7–14) derivative was performed, and preliminary in vitro experiments demonstrated the potential of MA‐NOTMP in the development of radiopharmaceuticals. This new chelator is therefore of major interest for labelling sensitive biomolecules, and further in vivo experiments will soon be performed. 相似文献
85.
The physical and chemical property changes of chemical vapor deposited ultra low-κ (ULK) SiOCH dielectric films due to different post ash treatments were studied by Auger electron spectroscopy, ellipsometric porosimetry and surface free energy evaluation. Structural changes in the ULK layer with respect to the carbon content were analyzed. Using a downstream and a reactive ion etch process for photo resist removal a reduction of carbon was observed. For different plasma gas chemistries the pore size reduction depends first on the process condition (downstream or reactive ion etch) and then on the gas. Differences in the pore size then also influence the amount of carbon depletion besides the influence of the gases used for photo resist processes. The damage at the surfaces was characterized by contact angle measurements providing both the polar and dispersive part of the surface free energy. The wettability of different solvents and repair chemicals was classified calculating their surface free energies and comparing those energies with the surface free energies of modified ULK surface. It is shown that especially reducing gases provide a surface free energy with a higher dispersive part compared to oxidative plasma treatments. Furthermore it was found that the wettability of repair chemicals and solvents strongly changes for reductive based strip processes with plasma exposure time, since a high variation of the surface free energy occur. 相似文献
86.
Eoin Cunningham Nicholas Dunne Gavin Walker Christine Maggs Ruth Wilcox Fraser Buchanan 《Journal of materials science. Materials in medicine》2010,21(8):2255-2261
The application of synthetic cancellous bone has been shown to be highly successful when its architecture mimics that of the
naturally interconnected trabeculae bone it aims to replace. The following investigation demonstrates the potential use of
marine sponges as precursors in the production of ceramic based tissue engineered bone scaffolds. Three species of natural
sponge, Dalmata Fina (Spongia officinalis Linnaeus, Adriatic Sea), Fina Silk (Spongia zimocca, Mediterranean) and Elephant Ear (Spongia agaricina, Caribbean) were selected for replication. A high solid content (80 %wt), low viscosity (126 mPas) hydroxyapatite slurry
was developed, infiltrated into each sponge species and subsequently sintered, producing a scaffold structure that replicated
pore architecture and interconnectivity of the precursor sponge. The most promising of the ceramic tissue engineered bone
scaffolds developed, Spongia agaricina replicas, demonstrated an overall porosity of 56–61% with 83% of the pores ranging between 100 and 500 μm (average pore size
349 μm) and an interconnectivity of 99.92%. 相似文献
87.
88.
Christine C. Roberts Lorraine F. Francis 《Journal of Coatings Technology and Research》2013,10(4):441-451
The minimum film formation temperature (MFFT) is the minimum drying temperature needed for a latex coating to coalesce into an optically clear, dense crack-free film. To better understand the interplay of forces near this critical temperature, cryogenic scanning electron microscopy (cryoSEM) was used to track the latex particle deformation and water migration in coatings dried at temperatures just above and below the MFFT. Although the latex particles completely coalesced at both temperatures by the end of the drying process, it was discovered that particle deformation during the early drying stages was drastically different. Below the MFFT, cracks initiated just as menisci began to recede into the packing of consolidated particles, whereas above the MFFT, partial particle deformation occurred before menisci entered the coating and cracks were not observed. The spacing between cracks measured in coatings dried at varying temperatures decreased with decreasing drying temperature near the MFFT, whereas it was independent of temperature below a critical temperature. Finally, the addition of small amounts of silica aggregates was found to lessen the cracking of latex coatings near the MFFT without adversely affecting their optical clarity. 相似文献
89.
John F. Hall Christine A. Mecklenborg Dongmei Chen Siddharth B. Pratap 《Renewable Energy》2011,36(3):1075-1080
Variable-speed wind turbines are able to adapt to low wind speeds and therefore have greater efficiency than fixed-speed turbines during partial-load operation. Unfortunately, the high cost and low reliability of the electronics that enable variation in speed have discouraged this mode of operation for distributed wind turbines. Alternatively, a Variable-Ratio Gearbox (VRG) can be integrated into the fixed-speed wind turbine to facilitate operation with a discrete set of variable speeds that boost efficiency. The VRG concept is based upon mature technology taken from the automotive industry and is characterized by low cost and high reliability. In this paper, a model-based design methodology is introduced to study the performance gain of integrating a VRG into a fixed-speed stall-regulated wind turbine system. The results demonstrate how this device can improve the efficiency of the fixed-speed turbine in the partial-load region and the potential to use the VRG to limit power in the full-load region where pitch control is often used. 相似文献
90.
Lash Steven J.; Timko Christine; Curran Geoffery M.; McKay James R.; Burden Jennifer L. 《Canadian Metallurgical Quarterly》2011,25(2):238
Continuing care following initial substance use disorder treatment often is associated with improved treatment outcomes and evidence-based interventions (EBIs) have been developed in this area. However, rates of patient participation in continuing care treatment and mutual help groups (MHGs) are low and a large gap exists between the existing EBIs and actual clinical care. This paper uses the Consolidated Framework for Implementation Research (CFIR; Damschroder et al., 2009) to review the literature on continuing care treatment and monitoring, and mutual help-group promotion. Although existing research provides implications for implementing EBIs in continuing care, few direct implementation trials have been conducted. This literature indicates that EBIs in continuing care have been successfully modified for different settings, that they can be delivered using different modalities (e.g., individual, group, and telephone-based care), and that low cost options are available. Additionally, much is known about the differential effectiveness of continuing care with different populations that may guide treatment programs and providers in selecting the most effective interventions for their clients. One significant barrier to successful implementation of EBIs for continuing care is the lack of information about incentives for providing continuing care across what in the CFIR terminology is a program's outer setting (i.e., external economic, political, and social setting), and its inner setting (i.e., internal political, structural, and cultural contexts). Implications for implementation of EBIs in substance use disorder continuing care are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献