全文获取类型
收费全文 | 1227篇 |
免费 | 379篇 |
国内免费 | 35篇 |
专业分类
电工技术 | 10篇 |
技术理论 | 2篇 |
综合类 | 33篇 |
化学工业 | 542篇 |
金属工艺 | 49篇 |
机械仪表 | 19篇 |
建筑科学 | 15篇 |
矿业工程 | 11篇 |
能源动力 | 42篇 |
轻工业 | 62篇 |
水利工程 | 6篇 |
石油天然气 | 9篇 |
武器工业 | 4篇 |
无线电 | 175篇 |
一般工业技术 | 621篇 |
冶金工业 | 16篇 |
原子能技术 | 6篇 |
自动化技术 | 19篇 |
出版年
2024年 | 6篇 |
2023年 | 84篇 |
2022年 | 56篇 |
2021年 | 108篇 |
2020年 | 157篇 |
2019年 | 118篇 |
2018年 | 86篇 |
2017年 | 109篇 |
2016年 | 102篇 |
2015年 | 91篇 |
2014年 | 90篇 |
2013年 | 98篇 |
2012年 | 65篇 |
2011年 | 59篇 |
2010年 | 63篇 |
2009年 | 65篇 |
2008年 | 47篇 |
2007年 | 51篇 |
2006年 | 34篇 |
2005年 | 37篇 |
2004年 | 28篇 |
2003年 | 27篇 |
2002年 | 19篇 |
2001年 | 17篇 |
2000年 | 10篇 |
1980年 | 1篇 |
1951年 | 13篇 |
排序方式: 共有1641条查询结果,搜索用时 15 毫秒
1.
2.
Andoni Rodriguez‐Abetxuko Pablo Muumer Mitsuhiro Okuda Javier Calvo Mato Knez Ana Beloqui 《Advanced functional materials》2020,30(35)
Herein, the design, synthesis, and characterization of bifunctional hybrid nanoreactors used for concurrent one‐pot chemoenzymatic reactions are shown. In the design, the enzyme, glucose oxidase, is wrapped with a peroxidase‐mimetic catalytic polymer. Hemin, the organic catalyst, is linked to the flexible polymeric scaffold through coordination to the imidazole groups that hang out the network. This spatial arrangement, which works as a metabolic channel, is optimized for cooperative chemoenzymatic reactions in which the enzyme catalyzes first. A deep characterization of the integrated nanoreactors demonstrates that the confinement of two distinct catalytic sites in the nanospace is very effective in one‐pot reactions. Moreover, besides its role as scaffold material, the polymeric mantel protects both the biocatalyst and the chemical catalyst from degradation and inactivation in the presence of organic solvents. Furthermore, the polymeric environment of the nanoreactors can be tailored in order to trigger the assembly of those into highly active heterogeneous hybrid catalysts. Finally, the new nanoreactors are applied to the efficient degradation of organic aromatic compounds using glucose as the only fuel. 相似文献
3.
磁性纳米材料具有较强的化学稳定性、可再生回收、良好的吸附性能和易于分离等优点,在去除水溶液中的铀酰离子方面有广泛的应用前景。然而,磁性纳米材料也存在易团聚、易氧化等不足,通过表面修饰或改性等方法可改善其不足,提高其对废水中铀酰离子的去除能力,改善其吸附效果。本文通过总结近年来的相关研究资料,概括了磁性纳米材料的种类,归纳总结并比较了不同种类磁性纳米材料对含铀废水的去除能力及优势与不足,探讨了磁性纳米材料在含铀废水处理中的应用并对其机理进行了分析,阐述了磁性纳米材料去除溶液中铀酰离子的影响因素,简述了目前磁性纳米材料在处理含铀废水中有待解决的问题,并对其在分离放射性元素方面的应用前景进行了展望。 相似文献
4.
Vanish Kumar Deepak Kukkar Beshare Hashemi Ki‐Hyun Kim Akash Deep 《Advanced functional materials》2019,29(16)
Cancer is the second most common cause of death in the world. The principal limitations thus far encountered in the clinical practice of probing cancer are diverse and include low sensitivity, time consumption, bulkiness, and cost. In this respect, nanomaterial (NM)‐based sensing techniques are recognized as a superior alternative to efficiently resolve such limitations. A better understanding of NM‐based sensing platforms is thus important so that these novel avenues can easily be explored for clinical applications. These platforms have the merits of high sensitivity, high specificity, rapid response, and easy‐to‐read signals. This review offers a comprehensive survey of NM‐based advanced cancer‐sensing techniques and will help the scientific community establish optimum sensing strategies based on an accurate assessment of the interactions between cancer biomarkers and NM‐based platforms. 相似文献
5.
6.
Laura-Jayne. A. Ellis Stephen Kissane Iseult Lynch 《International journal of molecular sciences》2021,22(1)
There is increasing recognition that environmental nano-biological interactions in model species, and the resulting effects on progeny, are of paramount importance for nanomaterial (NM) risk assessment. In this work, Daphnia magna F0 mothers were exposed to a range of silver and titanium dioxide NMs. The key biological life history traits (survival, growth and reproduction) of the F1 intergenerations, at the first (F1B1), third (F1B3) and fifth (F1B5) broods, were investigated. Furthermore, the F1 germlines of each of the three broods were investigated over 3 more generations (up to 25 days each) in continuous or removed-from NM exposure, to identify how the length of maternal exposure affects the resulting clonal broods. Our results show how daphnids respond to NM-induced stress, and how the maternal effects show trade-offs between growth, reproduction and survivorship. The F1B1 (and following germline) had the shortest F0 maternal exposure times to the NMs, and thus were the most sensitive showing reduced size and reproductive output. The F1B3 generation had a sub-chronic maternal exposure, whereas the F1B5 generation suffered chronic maternal exposure where (in most cases) the most compensatory adaptive effects were displayed in response to the prolonged NM exposure, including enhanced neonate output and reduced gene expression. Transgenerational responses of multiple germlines showed a direct link with maternal exposure time to ‘sub-lethal’ effect concentrations of NMs (identified from standard OECDs acute toxicity tests which chronically presented as lethal) including increased survival and production of males in the F1B3 and G1B5 germlines. This information may help to fine-tune environmental risk assessments of NMs and prediction of their impacts on environmental ecology. 相似文献
7.
Nancy Soliman Gilles Gasser Christophe M. Thomas 《Advanced materials (Deerfield Beach, Fla.)》2020,32(47):2003294
Ru(II) polypyridyl complexes are compounds of great interest in cancer therapy due to their unique photophysical, photochemical, and biological properties. For effective treatment, they must be able to penetrate tumor cells effectively and selectively. The development of nanoscale carriers capable of delivering Ru(II) polypyridyl complexes has the potential to passively or selectively enhance their cellular uptake in tumor cells. Many different strategies have been explored to incorporate Ru(II) polypyridyl complexes into a variety of nanosized constructs, ranging from organic to inorganic materials. Herein, recent developments in nanomaterials loaded with Ru(II) polypyridyl complexes are highlighted. Their rational design, preparation, and physicochemical properties are described, and their potential applications in cancer therapy are eventually discussed. 相似文献
8.
分别以尿素和氨水为沉淀剂,采用热溶剂法制备了多孔的花状NiMn2O4和颗粒状NiMn2O4纳米电极材料,采用 X射线衍射仪、扫描电镜、透射电镜和N2 吸附-脱附等手段对NiMn2O4材料的物相、形貌结构和孔径分布进行了表征,并通过循环伏安、恒电流充放电、交流阻抗等方法测试了所制备材料的电化学性能。研究了沉淀剂对NiMn2O4材料形貌、微观结构及电化学性能的影响。结果表明:以尿素为沉淀剂的NiMn2O4是由纳米片组成的花状结构,纳米片厚度为50~60nm,比表面积为104m2/g。在 1A/g 电流密度下比电容为1614F/g,在5A/g电流密度下,尿素为沉淀剂的花状NiMn2O4材料经1000次恒电流充放电后其比电容可达初始值的89%。以氨水为沉淀剂的多孔NiMn2O4为直径约30nm的纳米颗粒结构,颗粒间团聚严重,比表面积为91m2/g。在1A/g电流密度下比电容为1147F/g,在5A/g电流密度下,氨水为沉淀剂的颗粒状NiMn2O4材料经1000次恒电流充放电后其比电容可达初始值的80%。尿素为沉淀剂的花状NiMn2O4具有优越的超级电容性能。 相似文献
9.
Dr. Eita Sasaki Ryan M. Dragoman Dr. Shiksha Mantri Dr. Dmitry N. Dirin Prof. Dr. Maksym V. Kovalenko Prof. Dr. Donald Hilvert 《Chembiochem : a European journal of chemical biology》2020,21(1-2):74-79
The enzyme lumazine synthase (LS) has been engineered to self-assemble into hollow-shell structures that encapsulate unnatural cargo proteins through complementary electrostatic interactions. Herein, we show that a negatively supercharged LS variant can also form organic–inorganic hybrids with gold nanomaterials. Simple mixing of LS pentamers with positively charged gold nanocrystals in aqueous buffer spontaneously affords protein-shelled gold cores. The procedure works well with differently sized and shaped gold nanocrystals, and the resulting shelled complexes exhibit dramatically enhanced colloidal stability over a wide range of pH (4.0–10.0) and at high ionic strength (up to 1 m NaCl). They are even stable over days upon dilution in buffer. Self-assembly of engineered LS shells in this way offers an easy and attractive alternative to commonly used ligand-exchange methods for stabilizing inorganic nanomaterials. 相似文献
10.
Annegret Potthoff Mirco Weil Tobias Mei?ner Dana Kühnel 《Science and Technology of Advanced Materials》2015,16(6)
During the last decade, nanomaterials (NM) were extensively tested for potential harmful effects towards humans and environmental organisms. However, a sound hazard assessment was so far hampered by uncertainties and a low comparability of test results. The reason for the low comparability is a high variation in the (1) type of NM tested with regard to raw material, size and shape and (2) procedures before and during the toxicity testing. This calls for tailored, nanomaterial-specific protocols. Here, a structured approach is proposed, intended to lead to test protocols not only tailored to specific types of nanomaterials, but also to respective test system for toxicity testing. There are existing standards on single procedures involving nanomaterials, however, not all relevant procedures are covered by standards. Hence, our approach offers a detailed way of weighting several plausible alternatives for e.g. sample preparation, in order to decide on the procedure most meaningful for a specific nanomaterial and toxicity test. A framework of several decision trees (DT) and flow charts to support testing of NM is proposed as a basis for further refinement and in-depth elaboration. DT and flow charts were drafted for (1) general procedure—physicochemical characterisation, (2) choice of test media, (3) decision on test scenario and application of NM to liquid media, (4) application of NM to the gas phase, (5) application of NM to soil and sediments, (6) dose metrics, (S1) definition of a nanomaterial, and (S2) dissolution. The applicability of the proposed approach was surveyed by using experimental data retrieved from studies on nanoscale CuO. This survey demonstrated the DT and flow charts to be a convenient tool to systematically decide upon test procedures and processes, and hence pose an important step towards harmonisation of NM testing. 相似文献