全文获取类型
收费全文 | 484篇 |
免费 | 30篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 207篇 |
金属工艺 | 1篇 |
机械仪表 | 13篇 |
建筑科学 | 21篇 |
矿业工程 | 1篇 |
能源动力 | 12篇 |
轻工业 | 118篇 |
水利工程 | 1篇 |
石油天然气 | 4篇 |
无线电 | 12篇 |
一般工业技术 | 58篇 |
冶金工业 | 18篇 |
自动化技术 | 48篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 48篇 |
2021年 | 45篇 |
2020年 | 21篇 |
2019年 | 10篇 |
2018年 | 16篇 |
2017年 | 15篇 |
2016年 | 19篇 |
2015年 | 11篇 |
2014年 | 19篇 |
2013年 | 35篇 |
2012年 | 41篇 |
2011年 | 38篇 |
2010年 | 20篇 |
2009年 | 25篇 |
2008年 | 24篇 |
2007年 | 16篇 |
2006年 | 15篇 |
2005年 | 10篇 |
2004年 | 7篇 |
2003年 | 11篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 8篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有516条查询结果,搜索用时 11 毫秒
491.
Frare E de Laureto PP Scaramella E Tonello F Marin O Deana R Fontana A 《Protein engineering, design & selection : PEDS》2005,18(10):487-495
Decorsin is a 39-residue polypeptide chain, crosslinked by three disulfide bridges, that strongly inhibits platelet aggregation. We report the chemical synthesis and characterization of analogs of decorsin with the aim of investigating the role of proline residues in protein structure, stability and biological activity. Decorsin analogs have been synthesized in which one (P23A and P24A decorsin) or two (P23,24A decorsin) proline residues have been substituted by alanine. The crude synthetic polypeptides were purified by reversed-phase HPLC in their reduced form and allowed to refold oxidatively to their disulfide-crosslinked species. The homogeneity of the synthetic mini-proteins, and also the correct pairing of the three disulfide bridges, were established by a number of analytical criteria, including fingerprinting analysis of the refolded synthetic analogs by using thermolysin and proteinase K as proteolytic enzymes. Replacement of proline by alanine results in a significant and cumulative decrease of the high thermal stability (Tm 74 degrees C) of native decorsin. The mono-substituted analogs display a Tm of 66-67 degrees C, while the double-substituted analog a Tm of 50 degrees C. On the other hand, the overall secondary and tertiary structures were not affected by the Pro-->Ala exchanges, as judged from circular dichroism measurements. Platelet aggregation assays established that the proline substitutions do not impair significantly the biological activity of decorsin. The results of this study clearly indicate that proline residues contribute significantly to the protein thermal stability. Our results are in line with the 'proline rule', previously advanced for explaining the unusual thermal stability of thermophilic enzymes, which usually show an enhanced content of proline residues with respect to their mesophilic counterparts. 相似文献
492.
F Locatelli G Beluffi G Giorgiani R Maccario P Fiori A Pession F Bonetti P Comoli V Calcaterra G Rondini F Severi 《Canadian Metallurgical Quarterly》1997,20(8):701-705
Allogeneic BMT has been reported to be the only curative therapy for children with juvenile autosomal recessive osteopetrosis. We report the case of a 14-month-old child in whom bone resorption was observed after cord blood transplantation (CBT). The patient was given CBT from an unrelated newborn matched for five of six HLA antigens. At the time of transplantation, the child presented with neurological symptoms, with feeding problems and visual impairment. A successful engraftment of donor hematopoiesis was demonstrated and the child experienced grade I acute GVHD. Progressive bone clearing was achieved and a bone marrow trephine demonstrated signs of osteoclast function. Despite full engraftment and bone resorption, neurologic deterioration did not improve. This experience documents that CBT can promote the correction of juvenile osteopetrosis. The shorter time needed both to identify an unrelated donor and to perform the transplant, as well as the lower incidence of GVHD make this procedure more appealing than BMT in children lacking an HLA-compatible relative. 相似文献
493.
Aribert B. Peters Christopher L. Salter Mario Polese Wallace F. Smith Dr. E. A. Brugger James W. Scott Pr. Marc Penouil Eric Sheppard John A. Schofield Thomas D. Georgianna Thomas A. Reiner Andrew Sussman Michael Whitbread Fred E. Case Patrizia Spinetti Ronald R. Boyce W. F. Lever W. Edwin Derrick M. Madden Jack E. Adams M. T. Daly Margot Garcia Reuben Weisz A. Subbakrishniah Gregory H. Wassail Alfred Nydegger John R. Ottensmann Vedia Dokmeci Arthur E. Kartman Rik G. Donckels Curtis C. Roseman Willem L. J. Doeve Robert G. Fletcher Zoltan Taganyi Vijay K. Mathur Daniel Todd Neil S. Grigg 《The Annals of Regional Science》1982,16(2):85-137
494.
Maddalena Grieco Maria Giovanna De Caris Elisa Maggi Federica Armeli Roberto Coccurello Tiziana Bisogno Maria DErme Mauro Maccarrone Patrizia Mancini Rita Businaro 《International journal of molecular sciences》2021,22(14)
The ability of endocannabinoid (eCB) to change functional microglial phenotype can be explored as a possible target for therapeutic intervention. Since the inhibition of fatty acid amide hydrolase (FAAH), the main catabolic enzyme of anandamide (AEA), may provide beneficial effects in mice model of Alzheimer’s disease (AD)-like pathology, we aimed at determining whether the FAAH inhibitor URB597 might target microglia polarization and alter the cytoskeleton reorganization induced by the amyloid-β peptide (Aβ). The morphological evaluation showed that Aβ treatment increased the surface area of BV-2 cells, which acquired a flat and polygonal morphology. URB597 treatment partially rescued the control phenotype of BV-2 cells when co-incubated with Aβ. Moreover, URB597 reduced both the increase of Rho protein activation in Aβ-treated BV-2 cells and the Aβ-induced migration of BV-2 cells, while an increase of Cdc42 protein activation was observed in all samples. URB597 also increased the number of BV-2 cells involved in phagocytosis. URB597 treatment induced the polarization of microglial cells towards an anti-inflammatory phenotype, as demonstrated by the decreased expression of iNOS and pro-inflammatory cytokines along with the parallel increase of Arg-1 and anti-inflammatory cytokines. Taken together, these data suggest that FAAH inhibition promotes cytoskeleton reorganization, regulates phagocytosis and cell migration processes, thus driving microglial polarization towards an anti-inflammatory phenotype. 相似文献
495.
D'Amico Rita; Vermigli Patrizia; Canetto Silvia Sara 《Canadian Metallurgical Quarterly》2011,4(3):175
In the United States, women tend to publish less than men do and to be overrepresented at the lower ranks of academia. This study examined the scientific productivity and career status of female and male psychology faculty in Italian universities. Psychology was selected as a discipline because for decades, it has had a female majority among its doctorates. Italy was the case study country because it has one of the highest representations of women among university faculty. This study's questions were: What is the representation of female psychology academics across faculty and high administration ranks? Is the publication productivity of female psychology academics different from that of their male peers? Finally, what institutional factors are associated with publication productivity among psychology academics? Our study focused on the 511 university psychology professors (250 women and 261 men) listed in 2004 in the Italian Ministry of Education University and Research website. We examined scientific productivity over 7 years, from 1998 to 2004, using PsycINFO. We found that women represented two thirds of assistant professors but only one third of full professors and department chairs. Overall, women published somewhat less (approximately one third less) than men, especially in international journals and as senior authors. However, consistent with prior evidence, when multiple predictors were considered together, both academic rank and institutional setting, but not sex-of-faculty, were associated with publication output. This study confirms prior observations that a strong female doctoral pipeline and scientific productivity are very slow at influencing the underrepresentation of women at the top ranks of academia. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
496.
Roda A Mirasoli M Dolci LS Buragina A Bonvicini F Simoni P Guardigli M 《Analytical chemistry》2011,83(8):3178-3185
A simple and versatile analytical device designed to perform, even simultaneously, different types of bioassays has been developed and optimized. A transparent microfluidics-based reaction chip, where analytes were quantitatively detected by means of biospecific reactions and chemiluminescence detection, was placed in contact with a thermoelectrically cooled CCD sensor through a fiber optic taper. Such a lensless contact imaging configuration combined adequate spatial resolution and high light collection efficiency within a small size portable device. The miniaturization of the reaction chamber ensured short analysis times (in the minutes range), while the use of chemiluminescence detection provided wide signal dynamic range and high detectability, down to attomole levels of protein and femtomole levels of nucleic acid analytes. A model hybrid panel test was realized by combining an enzyme assay for alkaline phosphatase activity, a nucleic acid hybridization assay for Parvovirus B19 DNA, and an immunoassay for horseradish peroxidase as a model antigen. The successful simultaneous quantification of the three targets demonstrated that a range of analytes, from enzymes to antigens, antibodies, and nucleic acids, can be measured in a single run, thus enabling the realization of a complete, personalized diagnostic panel test for early diagnosis of a given disease and patient follow-up. 相似文献
497.
Pesaresi I Cosottini M Belmonte G Maritato P Mascalchi M Puglioli M Sartucci F Bartolozzi C Murri L 《Magma (New York, N.Y.)》2011,24(5):285-296
Object
Simultaneous EEG-fMRI recordings allow the identification of haemodynamic changes induced by neuronal activity during ictal or interictal epileptiform events (IEDs). We evaluated the reproducibility of continuous EEG-fMRI (cEEG-fMRI) in patients with focal epilepsy. 相似文献498.
Lucia Cutuli Angela Pirillo Patrizia Uboldi Hartmut Kuehn Alberico L. Catapano 《Lipids》2014,49(4):317-326
Caveolae are cholesterol and glycosphingolipids-enriched microdomains of plasma membranes. Caveolin-1 represents the major structural protein of caveolae, that also contain receptors and molecules involved in signal transduction pathways. Caveolae are particularly abundant in endothelial cells, where they play important physiological and pathological roles in regulating endothelial cell functions. Several molecules with relevant functions in endothelial cells are localized in caveolae, including endothelial nitric oxide synthase (eNOS), which regulates the production of nitric oxide, and scavenger receptor class B type I (SR-BI), which plays a key role in the induction of eNOS activity mediated by high density lipoproteins (HDL). HDL have several atheroprotective functions, including a positive effect on endothelial cells, as it is a potent agonist of eNOS through the interaction with SR-BI. However, the oxidative modification of HDL may impair their protective role. In the present study we evaluated the effect of 15-lipoxygenase-mediated modification of HDL3 on the expression and/or activity of some proteins localized in endothelial caveolae and involved in the nitric oxide generation pathway. We found that after modification, HDL3 failed to activate eNOS and to induce NO production, due to both a reduced ability to interact with its own receptor SR-BI and to a reduced expression of SR-BI in cells exposed to modified HDL. These findings suggest that modification of HDL may reduce its endothelial-protective role also by interfering with vasodilatory function of HDL. 相似文献
499.
Alessandra Fortunata Perna Luigi Russo Vittoria DEsposito Pietro Formisano Dario Bruzzese Carmela Vigorito Annapaola Coppola Patrizia Lombari Domenico Russo Diego Ingrosso 《International journal of molecular sciences》2021,22(13)
Vascular calcification (VC) is a risk factor for cardiovascular events and mortality in chronic kidney disease (CKD). Several components influence the occurrence of VC, among which inflammation. A novel uremic toxin, lanthionine, was shown to increase intracellular calcium in endothelial cells and may have a role in VC. A group of CKD patients was selected and divided into patients with a glomerular filtration rate (GFR) of <45 mL/min/1.73 m2 and ≥45 mL/min/1.73 m2. Total Calcium Score (TCS), based on the Agatston score, was assessed as circulating lanthionine and a panel of different cytokines. A hemodialysis patient group was also considered. Lanthionine was elevated in CKD patients, and levels increased significantly in hemodialysis patients with respect to the two CKD groups; in addition, lanthionine increased along with the increase in TCS, starting from one up to three. Interleukin IL-6, IL-8, and Eotaxin were significantly increased in patients with GFR < 45 mL/min/1.73 m2 with respect to those with GFR ≥ 45 mL/min/1.73 m2. IL-1b, IL-7, IL-8, IL-12, Eotaxin, and VEGF increased in calcified patients with respect to the non-calcified. IL-8 and Eotaxin were elevated both in the low GFR group and in the calcified group. We propose that lanthionine, but also IL-8 and Eotaxin, in particular, are a key feature of VC of CKD, with possible marker significance. 相似文献
500.
Dr. Fanny Marlin Dr. Philippe Simon Dr. Stéphanie Bonneau Dr. Patrizia Alberti Céline Cordier Charlotte Boix Loïc Perrouault Aurélie Fossey Prof. Tula Saison‐Behmoaras Prof. Marc Fontecave Dr. Carine Giovannangeli 《Chembiochem : a European journal of chemical biology》2012,13(17):2593-2598
Oligonucleotides and their analogues, such as peptide nucleic acids (PNAs), can be used in chemical strategies to artificially control gene expression. Inefficient cellular uptake and inappropriate cellular localization still remain obstacles in biological applications, however, especially for PNAs. Here we demonstrate that conjugation of PNAs to flavin resulted in efficient internalization into cells through an endocytic pathway. The flavin–PNAs exhibited antisense activity in the sub‐micromolar range, in the context of a treatment facilitating endosomal escape. Increased endosomal release of flavin conjugates into the cytoplasm and/or nucleus was shown by chloroquine treatment and also—when the flavin–PNA was conjugated to rhodamine, a mild photosensitizer—upon light irradiation. In conclusion, an isoalloxazine moiety can be used as a carrier and attached to a cargo biomolecule, here a PNA, for internalization and functional cytoplasmic/nuclear delivery. Our findings could be useful for further design of PNAs and other oligonucleotide analogues as potent antisense agents. 相似文献