全文获取类型
收费全文 | 25714篇 |
免费 | 946篇 |
国内免费 | 33篇 |
专业分类
电工技术 | 334篇 |
综合类 | 38篇 |
化学工业 | 5854篇 |
金属工艺 | 450篇 |
机械仪表 | 494篇 |
建筑科学 | 1337篇 |
矿业工程 | 101篇 |
能源动力 | 661篇 |
轻工业 | 1970篇 |
水利工程 | 235篇 |
石油天然气 | 73篇 |
无线电 | 1892篇 |
一般工业技术 | 4657篇 |
冶金工业 | 4791篇 |
原子能技术 | 209篇 |
自动化技术 | 3597篇 |
出版年
2023年 | 219篇 |
2022年 | 361篇 |
2021年 | 576篇 |
2020年 | 350篇 |
2019年 | 444篇 |
2018年 | 550篇 |
2017年 | 477篇 |
2016年 | 657篇 |
2015年 | 566篇 |
2014年 | 768篇 |
2013年 | 1461篇 |
2012年 | 1197篇 |
2011年 | 1558篇 |
2010年 | 1106篇 |
2009年 | 1047篇 |
2008年 | 1195篇 |
2007年 | 1114篇 |
2006年 | 965篇 |
2005年 | 777篇 |
2004年 | 774篇 |
2003年 | 678篇 |
2002年 | 583篇 |
2001年 | 446篇 |
2000年 | 383篇 |
1999年 | 429篇 |
1998年 | 843篇 |
1997年 | 598篇 |
1996年 | 467篇 |
1995年 | 445篇 |
1994年 | 403篇 |
1993年 | 382篇 |
1992年 | 278篇 |
1991年 | 203篇 |
1990年 | 282篇 |
1989年 | 269篇 |
1988年 | 224篇 |
1987年 | 238篇 |
1986年 | 236篇 |
1985年 | 280篇 |
1984年 | 230篇 |
1983年 | 231篇 |
1982年 | 215篇 |
1981年 | 200篇 |
1980年 | 174篇 |
1979年 | 205篇 |
1978年 | 170篇 |
1977年 | 192篇 |
1976年 | 245篇 |
1975年 | 162篇 |
1974年 | 126篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Markus Steiner Franz J. Gassner Thomas Parigger Daniel Neureiter Alexander Egle Roland Geisberger Richard Greil Nadja Zaborsky 《International journal of molecular sciences》2021,22(17)
Chronic lymphocytic leukemia (CLL) is considered a clonal B cell malignancy. Sporadically, CLL cases with multiple productive heavy and light-chain rearrangements were detected, thus leading to a bi- or oligoclonal CLL disease with leukemic cells originating either from different B cells or otherwise descending from secondary immunoglobulin rearrangement events. This suggests a potential role of clonal hematopoiesis or germline predisposition in these cases. During the screening of 75 CLL cases for kappa and lambda light-chain rearrangements, we could detect a single case with CLL cells expressing two distinct kappa and lambda light chains paired with two separate immunoglobulin heavy-chain variable regions. Furthermore, this patient also developed a prostate carcinoma. Targeted genome sequencing of highly purified light-chain specific CLL clones from this patient and from the prostate carcinoma revealed the presence of a rare germline polymorphism in the POLE gene. Hence, our data suggest that the detected SNP may predispose for cancer, particularly for CLL. 相似文献
942.
To conduct a well‐planned plant shutdown, so as to reduce flare emissions for the sake of plant profitability and local environmental sustainability, one of the primary tasks is to perform comprehensive and precise accountings for flare emissions. Since the literature is still lacking systematic and quantitative studies, plant‐wide dynamic simulations are employed to simulate an ethylene plant shutdown and characterize its flare emission sources through which dynamic emission profiles of various emission species changing with respect to time are obtained. Plant shutdown emission inventories are enriched with details for point emission sources, and possible technical supports are provided to both industry and environmental agencies on evaluating and developing cost‐effective flare minimization strategies in the future. 相似文献
943.
Vanessa Reusche Prof. Dr. Franziska Thomas 《Chembiochem : a European journal of chemical biology》2021,22(10):1779-1783
A two-step synthesis for methionine-containing hydrophobic and/or aggregation-prone peptides is presented that takes advantage of the reversibility of methionine oxidation. The use of polar methionine sulfoxide as a building block in solid-phase peptide synthesis improves the synthesis quality and yields the crude peptide, with significantly improved solubility compared to the reduced species. This facilitates the otherwise often laborious peptide purification by high-performance liquid chromatography. The subsequent reduction proceeds quantitatively. This approach has been optimised with the methionine-rich Tar-DNA-binding protein 43 (307–347), but is also more generally applicable, as demonstrated by the syntheses of human calcitonin and two aggregation-prone peptides from the human prion protein. 相似文献
944.
945.
Iason Thomas Ioannis Panagoulias Ioanna Aggeletopoulou Anastasia Varvarigou Bessie E. Spiliotis Athanasia Mouzaki 《International journal of molecular sciences》2021,22(14)
To investigate the effect of leptin in childhood ITP, we measured plasma leptin in 39 children with acute ITP, after treatment and in remission, and in 33 healthy age/BMI-matched controls. We also cultured ITP and control peripheral blood mononuclear cells (PBMCs) with recombinant leptin to assess its direct effect on pro/anti-inflammatory cytokine gene expression. A significant increase in leptin was observed in children with active disease compared to controls. A significant inverse correlation of leptin with platelet count was also observed in children with acute ITP. Leptin remained high after treatment with IVIg, whereas steroid treatment lowered leptin below control levels. In remission, leptin was in the control range. Cytokine gene expression was significantly increased in children with acute ITP compared with controls, with highest expression for IFN-γ and IL-10. IVIg/steroid treatment significantly decreased IFN-γ and IL-10 expression. In remission, IFN-γ and IL-10 expression remained low. Addition of leptin to PBMCs isolated from patients in remission resulted in a significant increase in IL-10 gene expression compared to controls. Further experiments with purified T-cells and monocytes identified monocytes as the source of leptin-induced IL-10. We suggest that leptin acts as an active anti-inflammatory agent in childhood ITP by promoting IL-10 secretion by monocytes. 相似文献
946.
947.
Mladen Ladika Thomas H. Kalantar Hui Shao Stacey L. Dean J. Keith Harris Paul J. Sheskey Karen Coppens Karen M. Balwinski Debora L. Holbrook 《应用聚合物科学杂志》2014,131(7)
Polyampholyte latexes can exist within a certain pH range as low‐viscosity aqueous dispersions, while upon a pH shift to the vicinity of the isoelectric point they undergo ionic coacervation. Three classes of coacervation latexes were synthesized and evaluated for their suitability for use in tablet coating applications. Pharmaceutical tablet coatings are commonly based on hydroxypropyl methyl cellulose, poly(vinyl alcohol), and acrylic polymers. Because of the high viscosity of their aqueous solutions, and to the consequent required low concentrations of the tablet coating polymers in the coating solutions to enable sufficiently low viscosity for effective spray application, the current commercial pharmaceutical tablet coating technology requires the removal of large amounts of water during the manufacturing process. In this work, films prepared from high‐solids, low‐viscosity coacervated acrylic latexes showed good hardness, very low tackiness, an excellent combination of optical properties, and very low water vapor permeability. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40049. 相似文献
948.
949.
Mario Borlaf Albert Serra-Capdevila Carles Colominas Thomas Graule 《Journal of the European Ceramic Society》2019,39(13):3797-3803
Digital Light Processing (DLP) is a powerful technique for the preparation of ceramic parts with high resolution and complex shapes. In the last years, the development of photosensitive slurries for the production of ceramics with good mechanical properties has received much attention. In this work, ZrO2 UV-curable slurries were prepared in two steps for their application in DLP. Firstly, the surface modification of the ZrO2 particles was carried out using a dispersing agent and secondly, the modified powder was dispersed in an acrylate based mixture. Parts with different geometries were printed and a resolution experiment was also carried out in order to determine the limitations of the slurry. Finally, 30 bars were produced to study the mechanical properties of the sintered parts (ρ = 6.00 ± 0.01 g/mL) by 4-point bending tests and Weibull analysis, obtaining a flexural strength σ0 = 741 (718–765) MPa with a Weibull coefficient of 11.4. 相似文献
950.
Thomas Veltzke Lars Kiewidt Jorg Thöming 《American Institute of Chemical Engineers》2015,61(4):1404-1412
In many technical processes gas, multicomponent diffusion takes place in confinements that are rarely uniform in direction of their long axis (e.g., catalysts pores). Here, we show that in conical tubes multicomponent diffusion is hindered. This effect increases with ratio of inlet to outlet cone radius Λ, indifferent of the orientation of the tube. Based on the Maxwell–Stefan equations, predictive analytical solution for ideal multicomponent diffusion in slightly tapered ducts is developed. In two‐bulb diffusion experiments on a uniform tube, the results of Duncan and Toor (1962) were reproduced. Comparison of model and experiment shows that the solution presented here provides a reliable quantitative prediction of the temporal change of H2, N2, and CO2‐concentration for both tube geometries, uniform and slightly conical. In the demonstrated case (Λ = 3.16), mass diffusion is 68% delayed. Thus, for gaseous diffusion in “real,” typically tapered pores the transport limitation is more serious than considered so far. © 2014 American Institute of Chemical Engineers AIChE J, 61: 1404–1412, 2015 相似文献