全文获取类型
收费全文 | 178968篇 |
免费 | 9007篇 |
国内免费 | 4515篇 |
专业分类
电工技术 | 6249篇 |
技术理论 | 6篇 |
综合类 | 8377篇 |
化学工业 | 26907篇 |
金属工艺 | 10711篇 |
机械仪表 | 9867篇 |
建筑科学 | 10105篇 |
矿业工程 | 3871篇 |
能源动力 | 3977篇 |
轻工业 | 9701篇 |
水利工程 | 2881篇 |
石油天然气 | 7556篇 |
武器工业 | 805篇 |
无线电 | 19530篇 |
一般工业技术 | 27131篇 |
冶金工业 | 7317篇 |
原子能技术 | 1247篇 |
自动化技术 | 36252篇 |
出版年
2024年 | 182篇 |
2023年 | 1635篇 |
2022年 | 2488篇 |
2021年 | 4006篇 |
2020年 | 3222篇 |
2019年 | 2609篇 |
2018年 | 16799篇 |
2017年 | 16178篇 |
2016年 | 12621篇 |
2015年 | 4666篇 |
2014年 | 5101篇 |
2013年 | 5983篇 |
2012年 | 9360篇 |
2011年 | 15910篇 |
2010年 | 13866篇 |
2009年 | 10899篇 |
2008年 | 12000篇 |
2007年 | 12728篇 |
2006年 | 5534篇 |
2005年 | 5939篇 |
2004年 | 4084篇 |
2003年 | 3975篇 |
2002年 | 3177篇 |
2001年 | 2493篇 |
2000年 | 2472篇 |
1999年 | 2646篇 |
1998年 | 2101篇 |
1997年 | 1734篇 |
1996年 | 1725篇 |
1995年 | 1406篇 |
1994年 | 1154篇 |
1993年 | 737篇 |
1992年 | 650篇 |
1991年 | 457篇 |
1990年 | 346篇 |
1989年 | 294篇 |
1988年 | 228篇 |
1987年 | 140篇 |
1986年 | 112篇 |
1985年 | 68篇 |
1984年 | 45篇 |
1983年 | 40篇 |
1982年 | 41篇 |
1968年 | 43篇 |
1966年 | 42篇 |
1965年 | 45篇 |
1959年 | 37篇 |
1958年 | 37篇 |
1955年 | 63篇 |
1954年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Ping Xiao Jue Wang Lei Fang Zitong Zhao Xiangshi Sun Xiaochen Liu Haiqiang Cao Pengcheng Zhang Dangge Wang Yaping Li 《Advanced functional materials》2021,31(36):2104068
Neoantigen vaccines and adoptive dendritic cell (DC) transfer are major clinical approaches to initiate personalized immunity in cancer patients. However, the immunization efficacy is largely limited by the in vivo trajectory including neoantigens’ access to resident DCs and DCs’ access to lymph nodes (LNs). Herein, an innovative strategy is proposed to improve personalized immunization through neoantigen-loaded nanovaccines synergized with adoptive DC transfer. It is found that it enables selective delivery of neoantigens to resident DCs and macrophages by coating cancer cell membranes onto neoantigen-loaded nanoparticles. In addition, the nanovaccines promote the secretion of chemokine C-C motif ligand 2 (CCL2), CCL3, and C-X-C motif ligand 10 from macrophages, thus potentiating the access of transferred DCs to LNs. This immunization strategy enables coordinated delivery of identified neoantigens and autologous tumor lysate-derived undefined antigens, leading to initiation of antitumor T cell immunity in a personalized manner. It significantly inhibits tumor growth in prophylactic and established mouse tumor models. The findings provide a new vision for potentiating adoptive cell transfer by nanovaccines, which may open the door to a transformative possibility for improving personalized immunization. 相似文献
42.
Catalysis Letters - In this paper, five recombinant strains: GS115-LacA, GS115-LacB, GS115-LacC, KM71H-Lcc1 and GS115-Lcc2 were selected to produce laccase isozymes with high activities, which... 相似文献
44.
慢性阻塞性肺疾病(chronic obstructive pulmonary diseases,COPD)是一类十分常见的临床慢性炎症相关性的呼吸系统疾病,且严重威胁老年人的身体健康。为了探究全自动凝血检测仪在COPD患者急性加重期血液中生化指标检测中的应用。本研究收集2019年12月至2020年12月于我院呼吸内科病房确诊为COPD急性加重期(n=83)及稳定期(n=25)的患者为研究对象,以同期正常体检的健康人群为对照(n=25)。分析各组患者上述指标水平之间的差异。结果显示,用于患者血浆各指标检测后,相较于健康对照组,急性加重COPD组及稳定期COPD组D-二聚体(D-D)、纤维蛋白原(FIB)水平显著升高(P<0.05),活化部分凝血活酶时间、凝血酶原时间及凝血酶时间显著减少(P<0.05)。其中COPD急性加重期患者各生化指标变化更为明显。D-D、FIB水平升高为COPD患者急性加重的独立危险因素(P<0.05)。ACL-TOP型全自动凝血检测仪的检测结果基本符合实验室诊断学的标准,可用于临床指标的检测。而D-D、FIB水平能够用于评估COPD特别是急性加重... 相似文献
45.
Hansung Kim Md. Towfiq Tofail Ciby John 《JOM Journal of the Minerals, Metals and Materials Society》2018,70(4):473-478
Among a variety of solar cell types, thin-film solar cells have been rigorously investigated as cost-effective and efficient solar cells. In many cases, flexible solar cells are also fabricated as thin films and undergo frequent stress due to the rolling and bending modes of applications. These frequent motions result in crack initiation and propagation (including delamination) in the thin-film solar cells, which cause degradation in efficiency. Reliability evaluation of solar cells is essential for developing a new type of solar cell. In this paper, we investigated the effect of layer delamination and grain boundary crack on 3D thin-film solar cells. We used finite element method simulation for modeling of both electrical performance and cracked structure of 3D solar cells. Through simulations, we quantitatively calculated the effect of delamination length on 3D copper indium gallium diselenide (CIGS) solar cell performance. Moreover, it was confirmed that the grain boundary of CIGS could improve the solar cell performance and that grain boundary cracks could decrease cell performance by altering the open circuit voltage. In this paper, the investigated material is a CIGS solar cell, but our method can be applied to general polycrystalline solar cells. 相似文献
46.
Joalet Dalene Steenkamp Wouter Gideon Bam Sello Peter Tsebe 《JOM Journal of the Minerals, Metals and Materials Society》2018,70(11):2422-2427
Benchmarking is a tool available to furnace operators to evaluate their tap-hole life-cycle management practices against those of their peers. It allows furnace operators to challenge their own practices in order to increase furnace utilization. To facilitate the benchmarking process, it is necessary to define the variables to be considered and how they relate to one another. This article develops, from the literature and industry interviews, a holistic conceptualization of the variables that form part of tap-hole lifecycle management and performance. Specifically, the article focuses on the variables related to coke-bed-based processes (FeCr, SiMn, and HCFeMn) applying SAF technology of circular design. 相似文献
47.
Andrew Artzer Michael Moats Jack Bender 《JOM Journal of the Minerals, Metals and Materials Society》2018,70(12):2856-2863
Antimony and bismuth recovery from copper electrorefining electrolyte could reduce the impacts of these problem elements and produce a new primary source for them. Two proprietary phosphonic acid ester extractants were examined (REX-1 and REX-2) for the removal of antimony and bismuth from copper electrorefining electrolytes. Experimentation included shakeout and break tests to determine the basic parameters for the extractants in terms of maximum loading, break times, and extraction and stripping efficiency. Five permutations of extractant mixtures (100 wt.% REX-1 and 25 wt.%, 50 wt.%, 75 wt.% and 100 wt.% REX-2) were studied. It was determined that REX-2 was able to extract Sb and Bi from the electrolyte, but required some mixture with REX-1 to better facilitate stripping with 400 g/L sulfuric acid. The laboratory electrorefining electrolyte containing glue had faster disengagement times than a synthetic solution without glue. 相似文献
48.
Thermal barrier coatings (TBCs) are used to protect the hot sections of gas turbine engines and airplane engines. A TBC system comprises a substrate, bond coat, and TBC topcoat. The development of an accurate method for determining the Young’s modulus and Poisson’s ratio of TBC using a multilayered specimen is of importance. In this study, we applied the bending theory of a laminated plate to a three-layered material and proposed models to determine the Young’s modulus and Poisson’s ratio of the TBC layer using the bending strain of the TBC system specimen. Three methods were developed by utilizing (i) the coating biaxial strain, (ii) substrate biaxial strain, or (iii) coating and substrate biaxial strains. Subsequently, we determined appropriate dimensions of the specimen and span by using three-dimensional finite element analysis, and numerically verified the usefulness of the three proposed methods. However, the Young’s modulus and Poisson’s ratio determined using the multilayered specimen with a substrate are sensitive to experimental errors. Therefore, we evaluated the sensitivity of the three proposed methods to experimental error, and we determined the most insensitive method among them. Finally, we experimentally demonstrated the usefulness of this method. 相似文献
49.
Mykola Moroz Fiseha Tesfaye Myroslava Prokhorenko Serhiy Prokhorenko Oleksandr Reshetnyak 《Journal of Phase Equilibria and Diffusion》2018,39(1):11-16
Triangulation of the Ag-Hg-Se-I system in the vicinity of quaternary phase Ag4HgSe2I2 was performed by differential thermal analysis, X-ray diffraction and electromotive force (EMF) methods. The spatial position of the phase region Ag4HgSe2I2-Se-HgI2 regarding the figurative point of silver was used to write the chemical reaction of formation of Ag4HgSe2I2. The EMF measurements were carried out by applying an electrochemical cell: (–) C|Ag|Ag2GeS3 glass|Ag4HgSe2I2, HgI2, Se|C (+), where C is graphite and Ag2GeS3 glass is the fast purely Ag+ ions conducting electrolyte. The linear dependence of the EMF of the electrochemical cell on temperature was used to determine the standard thermodynamic values of Ag4HgSe2I2 for the first time. 相似文献
50.
Ying Zeng Bin Jiang Ouling Shi Gaofen Quan Salih Al-Ezzi FuSheng Pan 《Metals and Materials International》2018,24(4):830-839
Some alloying elements (Al, Er, Gd, Li, Mn, Sn, Y, Zn) were proved recently by calculations or experiments to improve the formability of Mg alloys, but ignoring their site preference in Mg crystals during the calculated process. A crystallographic model was built via first principle calculations to predict the site preferences of these elements. Regularities between doping elements and site preferences were summarized. Meanwhile, in the basis of the crystallographic model, a series of formulas were deduced combining the diffraction law. It predicted that a crystal plane with abnormal XRD peak intensity of the Mg-based solid solutions, compared to that of the pure Mg, prefers to possess solute atoms. Thus, three single-phase solid solution alloys were then prepared through an original In-situ Solution Treatment, and their XRD patterns were compared. Finally, the experiment further described the site preferences of these solute atoms in Mg crystal, verifying the calculation results. 相似文献