全文获取类型
收费全文 | 1605篇 |
免费 | 66篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 42篇 |
化学工业 | 451篇 |
金属工艺 | 16篇 |
机械仪表 | 34篇 |
建筑科学 | 44篇 |
矿业工程 | 3篇 |
能源动力 | 84篇 |
轻工业 | 208篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 120篇 |
一般工业技术 | 345篇 |
冶金工业 | 73篇 |
原子能技术 | 11篇 |
自动化技术 | 239篇 |
出版年
2024年 | 2篇 |
2023年 | 13篇 |
2022年 | 68篇 |
2021年 | 94篇 |
2020年 | 38篇 |
2019年 | 42篇 |
2018年 | 56篇 |
2017年 | 45篇 |
2016年 | 61篇 |
2015年 | 48篇 |
2014年 | 61篇 |
2013年 | 125篇 |
2012年 | 100篇 |
2011年 | 117篇 |
2010年 | 103篇 |
2009年 | 73篇 |
2008年 | 80篇 |
2007年 | 65篇 |
2006年 | 67篇 |
2005年 | 45篇 |
2004年 | 49篇 |
2003年 | 34篇 |
2002年 | 38篇 |
2001年 | 18篇 |
2000年 | 25篇 |
1999年 | 16篇 |
1998年 | 36篇 |
1997年 | 24篇 |
1996年 | 21篇 |
1995年 | 17篇 |
1994年 | 12篇 |
1993年 | 14篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1972年 | 3篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有1673条查询结果,搜索用时 10 毫秒
31.
Martina Casarin Tiago Moderno Fortunato Saima Imran Martina Todesco Deborah Sandrin Giulia Borile Ilaria Toniolo Massimo Marchesan Gino Gerosa Andrea Bagno Filippo Romanato Emanuele Luigi Carniel Alessandro Morlacco Fabrizio Dal Moro 《International journal of molecular sciences》2022,23(5)
Bladder cancer (BC) is among the most common malignancies in the world and a relevant cause of cancer mortality. BC is one of the most frequent causes for bladder removal through radical cystectomy, the gold-standard treatment for localized muscle-invasive and some cases of high-risk, non-muscle-invasive bladder cancer. In order to restore urinary functionality, an autologous intestinal segment has to be used to create a urinary diversion. However, several complications are associated with bowel-tract removal, affecting patients’ quality of life. The present study project aims to develop a bio-engineered material to simplify this surgical procedure, avoiding related surgical complications and improving patients’ quality of life. The main novelty of such a therapeutic approach is the decellularization of a porcine small intestinal submucosa (SIS) conduit to replace the autologous intestinal segment currently used as urinary diversion after radical cystectomy, while avoiding an immune rejection. Here, we performed a preliminary evaluation of this acellular product by developing a novel decellularization process based on an environmentally friendly, mild detergent, i.e., Tergitol, to replace the recently declared toxic Triton X-100. Treatment efficacy was evaluated through histology, DNA, hydroxyproline and elastin quantification, mechanical and insufflation tests, two-photon microscopy, FTIR analysis, and cytocompatibility tests. The optimized decellularization protocol is effective in removing cells, including DNA content, from the porcine SIS, while preserving the integrity of the extracellular matrix despite an increase in stiffness. An effective sterilization protocol was found, and cytocompatibility of treated SIS was demonstrated from day 1 to day 7, during which human fibroblasts were able to increase in number and strongly organize along tissue fibres. Taken together, this in vitro study suggests that SIS is a suitable candidate for use in urinary diversions in place of autologous intestinal segments, considering the optimal results of decellularization and cell proliferation. Further efforts should be undertaken in order to improve SIS conduit patency and impermeability to realize a future viable substitute. 相似文献
32.
Diana Valeria Rossetti Ilaria Inserra Alessia Nestic Federica Vincenzoni Federica Iavarone Irene Messana Massimo Castagnola Luca Massimi Gianpiero Tamburrini Massimo Caldarelli Claudia Desiderio 《International journal of molecular sciences》2022,23(6)
The present investigation aimed to explore the intact proteome of tissues of pediatric brain tumors of different WHO grades and localizations, including medulloblastoma, pilocytic astrocytoma, and glioblastoma, in comparison with the available data on ependymoma, to contribute to the understanding of the molecular mechanisms underlying the onset and progression of these pathologies. Tissues have been homogenized in acidic water–acetonitrile solutions containing proteases inhibitors and analyzed by LC–high resolution MS for proteomic characterization and label-free relative quantitation. Tandem MS spectra have been analyzed by either manual inspection or software elaboration, followed by experimental/theoretical MS fragmentation data comparison by bioinformatic tools. Statistically significant differences in protein/peptide levels between the different tumor histotypes have been evaluated by ANOVA test and Tukey’s post-hoc test, considering a p-value > 0.05 as significant. Together with intact protein and peptide chains, in the range of molecular mass of 1.3–22.8 kDa, several naturally occurring fragments from major proteins, peptides, and proteoforms have been also identified, some exhibiting proper biological activities. Protein and peptide sequencing allowed for the identification of different post-translational modifications, with acetylations, oxidations, citrullinations, deamidations, and C-terminal truncations being the most frequently characterized. C-terminal truncations, lacking from two to four amino acid residues, particularly characterizing the β-thymosin peptides and ubiquitin, showed a different modulation in the diverse tumors studied. With respect to the other tumors, medulloblastoma, the most frequent malignant brain tumor of the pediatric age, was characterized by higher levels of thymosin β4 and β10 peptides, the latter and its des-IS form particularly marking this histotype. The distribution pattern of the C-terminal truncated forms was also different in glioblastoma, particularly underlying gender differences, according to the definition of male and female glioblastoma as biologically distinct diseases. Glioblastoma was also distinguished for the peculiar identification of the truncated form of the α-hemoglobin chain, lacking the C-terminal arginine, and exhibiting oxygen-binding and vasoconstrictive properties different from the intact form. The proteomic characterization of the undigested proteome, following the top-down approach, was challenging to originally investigate the post-translational events that differently characterize pediatric brain tumors. This study provides a contribution to elucidate the molecular profiles of the solid tumors most frequently affecting the pediatric age, and which are characterized by different grades of aggressiveness and localization. 相似文献
33.
Isabel Pagani Pietro Demela Silvia Ghezzi Elisa Vicenzi Massimo Pizzato Guido Poli 《International journal of molecular sciences》2022,23(6)
In addition to CD4+ T lymphocytes, myeloid cells and, particularly, differentiated macrophages are targets of human immunodeficiency virus type-1 (HIV-1) infection via the interaction of gp120Env with CD4 and CCR5 or CXCR4. Both T cells and macrophages support virus replication, although with substantial differences. In contrast to activated CD4+ T lymphocytes, HIV-1 replication in macrophages occurs in nondividing cells and it is characterized by the virtual absence of cytopathicity both in vitro and in vivo. These general features should be considered in evaluating the role of cell-associated restriction factors aiming at preventing or curtailing virus replication in macrophages and T cells, particularly in the context of designing strategies to tackle the viral reservoir in infected individuals receiving combination antiretroviral therapy. In this regard, we will here also discuss a model of reversible HIV-1 latency in primary human macrophages and the role of host factors determining the restriction or reactivation of virus replication in these cells. 相似文献
34.
Laminar natural convection heat transfer inside fluid-filled, tilted square cavities cooled at one side and partially heated at the opposite side, is studied numerically. A computational code based on the SIMPLE-C algorithm is used for the solution of the system of mass, momentum, and energy transfer equations. Simulations are performed for a complete range of heater sizes and locations, Rayleigh numbers based on the side of the cavity from 103 to 107, Prandtl numbers from 0.7 to 700, and tilting angles of the enclosure from ?75° to +75°, where negative angles correspond to configurations with the heater facing downwards. It is found that the heat transfer rate increases with increasing the Rayleigh and Prandtl numbers, and the size of the heater. In addition, for negative inclinations of the enclosure the amount of heat exchanged decreases with increasing the tilting angle, while for positive inclinations the heat transfer rate either increases or decreases according as the heater is located toward the top or the bottom of the cavity. Finally, as far as the heater location is specifically concerned, the heat transfer performance has a peak for intermediate positions, the higher are the Rayleigh and Prandtl numbers, as well as the tilting angle for positive inclinations, the closer to the bottom of the cavity is the optimum heater location for maximum heat removal. 相似文献
35.
36.
Narizzano Massimo Pulina Luca Tacchella Armando Vuotto Simone 《Innovations in Systems and Software Engineering》2019,15(3-4):307-323
Innovations in Systems and Software Engineering - Property specification patterns (PSPs) have been proposed to ease the formalization of requirements, yet enable automated verification thereof. In... 相似文献
37.
Massimo Nespolo 《Crystallography Reviews》2017,23(4):302-303
Some statements in the review by Liu et al. [Liu Y, Liu Y, Drew GB. Comparison of calculations for interplanar distances in a crystal lattice. Cryst Rev. 2017] are corrected. The role of metric tensor to simplify calculations of interplanar spacings in crystal lattices is emphasized. 相似文献
38.
Massimo Venditti Davide Arcaniolo Marco De Sio Sergio Minucci 《International journal of molecular sciences》2021,22(15)
Herein, for the first time, the potential relationships between the cytoskeleton-associated proteins DAAM1 and PREP with different testicular disorders, such as classic seminoma (CS), Leydig cell tumor (LCT), and Sertoli cell-only syndrome (SOS), were evaluated. Six CS, two LCT, and two SOS tissue samples were obtained during inguinal exploration in patients with a suspect testis tumor based on clinical examination and ultrasonography. DAAM1 and PREP protein levels and immunofluorescent localization were analyzed. An increased DAAM1 protein level in CS and SOS as compared to non-pathological (NP) tissue was observed, while LCT showed no significant differences. Conversely, PREP protein level increased in LCT, while it decreased in CS and SOS compared to NP tissue. These results were strongly supported by the immunofluorescence staining, revealing an altered localization and signal intensity of DAAM1 and PREP in the analyzed samples, highlighting a perturbed cytoarchitecture. Interestingly, in LCT spermatogonia, a specific DAAM1 nuclear localization was found, probably due to an enhanced testosterone production, as confirmed by the increased protein levels of steroidogenic enzymes. Finally, although further studies are needed to verify the involvement of other formins and microtubule-associated proteins, this report raised the opportunity to indicate DAAM1 and PREP as new potential markers, supporting the cytoskeleton dynamics changes occurring during normal and/or pathological cell differentiation. 相似文献
39.
Alessandro Martucci Sabrina Sartori Alessandro Muffato Lidia Armelao Elisabetta Di Bartolomeo Enrico Traversa Massimo Guglielmi 《Journal of the American Ceramic Society》2003,86(11):1965-1968
Na2 O· x Al2 O3 ( x = 9, 11)films have been obtained by sol–gel method. Crystallization processes during heat treatments have been investigated by X–ray diffraction analysis. A metastable phase with the mullite structure, λ–Na2 O· x Al2 O3 , has been observed starting from 800°C. Films remained stable after a heat treatment at 1000°C for 250 h. Impedance spectroscopy measurements showed that the films of λ-Na2 O· x Al2 O3 possess a large three–dimensional ionic conductivity at 400°C. 相似文献
40.
Alessandro Martucci Mirko Pasquale Massimo Guglielmi Mike Post Jean Claude Pivin 《Journal of the American Ceramic Society》2003,86(9):1638-1640
Sol–gel derived silica (SiO2 ) films doped with nickel oxide (NiO) nanocrystals were fabricated. A bifunctional ligand was used, bearing amine groups capable of coordinating the nickel ions and hydrolysable siloxane groups for anchoring the metal complex moiety to the silicate matrix. Nickel oxide nanocrystals precipitated at 500°C while the film was still porous. The nanocomposite films showed a reversible change in the optical transmittance in the VIS-NIR range when exposed to carbon monoxide gas. The effects of residual porosity, testing temperature, and carbon monoxide gas concentration on optical transmittance were studied. 相似文献