全文获取类型
收费全文 | 2830篇 |
免费 | 172篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 60篇 |
综合类 | 1篇 |
化学工业 | 937篇 |
金属工艺 | 17篇 |
机械仪表 | 79篇 |
建筑科学 | 106篇 |
矿业工程 | 2篇 |
能源动力 | 83篇 |
轻工业 | 419篇 |
水利工程 | 27篇 |
石油天然气 | 5篇 |
无线电 | 229篇 |
一般工业技术 | 383篇 |
冶金工业 | 83篇 |
原子能技术 | 12篇 |
自动化技术 | 560篇 |
出版年
2023年 | 34篇 |
2022年 | 171篇 |
2021年 | 185篇 |
2020年 | 90篇 |
2019年 | 84篇 |
2018年 | 109篇 |
2017年 | 85篇 |
2016年 | 135篇 |
2015年 | 91篇 |
2014年 | 117篇 |
2013年 | 201篇 |
2012年 | 168篇 |
2011年 | 217篇 |
2010年 | 152篇 |
2009年 | 179篇 |
2008年 | 125篇 |
2007年 | 129篇 |
2006年 | 109篇 |
2005年 | 87篇 |
2004年 | 65篇 |
2003年 | 57篇 |
2002年 | 59篇 |
2001年 | 35篇 |
2000年 | 28篇 |
1999年 | 23篇 |
1998年 | 30篇 |
1997年 | 23篇 |
1996年 | 30篇 |
1995年 | 16篇 |
1994年 | 27篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 18篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 11篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1971年 | 2篇 |
1965年 | 2篇 |
1909年 | 2篇 |
排序方式: 共有3003条查询结果,搜索用时 0 毫秒
71.
ABSTRACT: Swordfish fillets, dry-salted and treated with liquid smoke, were sliced and packed in vacuum conditions and under modified atmosphere (MA) (5% O2 ,45% CO2 , 50% N2 ) and stored at chilled temperature (4°C) to determine the effect of different packaging on shelf-life. Sensory attributes, total volatile basic nitrogen (TVB-N), pH, lipid oxidation by thiobarbituric acid test, and microbiological counts were monitored during 45 d of storage. The TVB-N increased to levels recommended by European regulation at the time of sensory rejection, resulting as the most reliable parameter of quality decay. Lipid oxidation was low and microbial counts could not be correlated with quality decay. Sensory rejection (at least 50% of the assessors scoring =5 in a scale from 1 to 9) was sooner for MA-packed samples (12d) than for vacuum-packed ones (42d). 相似文献
72.
Giuseppe Palmiotti Massimo Salvatores Gerardo Aliberti H. Hiruta R. McKnight P. Oblozinsky W.S. Yang 《Annals of Nuclear Energy》2009
This paper presents a global approach to the validation of the parameters that enter into the neutronics simulation tools for advanced fast reactors with the objective to reduce the uncertainties associated to crucial design parameters. This global approach makes use of sensitivity/uncertainty methods; statistical data adjustments; integral experiment selection, analysis and “representativity” quantification with respect to a reference system; scientifically based cross-section covariance data and appropriate methods for their use in multigroup calculations. This global approach has been applied to the uncertainty reduction on the criticality of the Advanced Burner Reactor (both metal and oxide core versions) presently investigated in the frame of the GNEP initiative. The results obtained are very encouraging and allow to indicate some possible improvements of the ENDF/B-VII data file. 相似文献
73.
Asmaa M. Abu El-Soad Giuseppe Lazzara Mahmoud O. Abd El-Magied Giuseppe Cavallaro Jamelah S. Al-Otaibi M. I. Sayyed Elena G. Kovaleva 《International journal of molecular sciences》2022,23(4)
The modification of chitosan represents a challenging task in obtaining biopolymeric materials with enhanced removal capacity for heavy metals. In the present work, the adsorption characteristics of chitosan modified with carboxyl groups (CTS-CAA) towards copper (II) and zinc (II) ions have been tested. The efficacy of the synthesis of CTS-CAA has been evaluated by studying various properties of the modified chitosan. Specifically, the functionalized chitosan has been characterized by using several techniques, including thermal analyses (differential scanning calorimetry and thermogravimetry), spectroscopies (FT-IR, XRD), elemental analysis, and scanning electron microscopy. The kinetics and the adsorption isotherms of CTS-CAA towards both Cu (II) and Zn (II) have been determined in the aqueous solvent under variable pH. The obtained results have been analyzed by using different adsorption models. In addition, the experiments have been conducted at variable temperatures to explore the thermodynamics of the adsorption process. The regeneration of CTS-CAA has been investigated by studying the desorption process using different eluents. This paper reports an efficient protocol to synthesize chitosan-based material perspective as regenerative adsorbents for heavy metals. 相似文献
74.
Requirements analysis is an important phase in a software project. The analysis is often performed in an informal way by specialists who review documents looking for ambiguities, technical inconsistencies and incomplete parts. Automation is still far from being applied in requirements analyses, above all since natural languages are informal and thus difficult to treat automatically. There are only a few tools that can analyse texts. One of them, called QuARS, was developed by the Istituto di Scienza e Tecnologie dell'Informazione and can analyse texts in terms of ambiguity. This paper describes how QuARS was used in a formal empirical experiment to assess the impact in terms of effectiveness and efficacy of the automation in the requirements review process of a software company. 相似文献
75.
Michele Iuliani Sonia Simonetti Giulia Ribelli Andrea Napolitano Umile Giuseppe Longo Bruno Vincenzi Paolo Orsaria Vincenzo Denaro Giuseppe Tonini Daniele Santini Pantano Francesco 《International journal of molecular sciences》2022,23(5)
The CDK4/6 inhibitors (CDKi) palbociclib, ribociclib, and abemaciclib are currently approved in combination with anti-estrogen therapy for the treatment of advanced and/or metastatic hormone receptor-positive/HER2-neu-negative breast cancer patients. Given the high incidence of bone metastases in this population, we investigated and compared the potential effects of palbociclib, ribociclib, and abemaciclib on the breast cancer bone microenvironment. Primary osteoclasts (OCs) and osteoblasts (OBs) were obtained from human monocyte and mesenchymal stem cells, respectively. OC function was evaluated by tartrate-resistant acid phosphatase assay and real-time PCR; OB activity was assessed by an alizarin red assay. OB/breast cancer co-culture models were generated via the seeding of MCF-7 cells on a layer of OBs, and tumor cell proliferation was analyzed using flow cytometry. Here, we showed that ribociclib, palbociclib, and abemaciclib exerted similar inhibitory effects on the OC differentiation and expression of bone resorption markers without affecting OC viability. On the other hand, the three CDKi did not affect the ability of OB to produce bone matrix, even if the higher doses of palbociclib and abemaciclib reduced the OB viability. In OB/MCF-7 co-culture models, palbociclib demonstrated a lower anti-tumor effect than ribociclib and abemaciclib. Overall, our results revealed the direct effects of CDKi on the tumor bone microenvironment, highlighting differences potentially relevant for clinical practice. 相似文献
76.
Marialuisa Aragona Caterina Porcino Maria Cristina Guerrera Giuseppe Montalbano Rosaria Laur Marzio Cometa Maria Levanti Francesco Abbate Teresa Cobo Gabriel Capitelli Jos A. Vega Antonino German 《International journal of molecular sciences》2022,23(5)
The brain-derived neurotrophic factor (BDNF) was discovered in the last century, and identified as a member of the neurotrophin family. BDNF shares approximately 50% of its amino acid with other neurotrophins such as NGF, NT-3 and NT-4/5, and its linear amino acid sequences in zebrafish (Danio rerio) and human are 91% identical. BDNF functions can be mediated by two categories of receptors: p75NTR and Trk. Intriguingly, BDNF receptors were highly conserved in the process of evolution, as were the other NTs’ receptors. In this review, we update current knowledge about the distribution and functions of the BDNF-TrkB system in the sensory organs of zebrafish. In fish, particularly in zebrafish, the distribution and functions of BDNF and TrkB in the brain have been widely studied. Both components of the system, associated or segregated, are also present outside the central nervous system, especially in sensory organs including the inner ear, lateral line system, retina, taste buds and olfactory epithelium. 相似文献
77.
Giuseppe Floresta Chiara Zagni Davide Gentile Vincenzo Patamia Antonio Rescifina 《International journal of molecular sciences》2022,23(6)
The recent covid crisis has provided important lessons for academia and industry regarding digital reorganization. Among the fascinating lessons from these times is the huge potential of data analytics and artificial intelligence. The crisis exponentially accelerated the adoption of analytics and artificial intelligence, and this momentum is predicted to continue into the 2020s and beyond. Drug development is a costly and time-consuming business, and only a minority of approved drugs generate returns exceeding the research and development costs. As a result, there is a huge drive to make drug discovery cheaper and faster. With modern algorithms and hardware, it is not too surprising that the new technologies of artificial intelligence and other computational simulation tools can help drug developers. In only two years of covid research, many novel molecules have been designed/identified using artificial intelligence methods with astonishing results in terms of time and effectiveness. This paper reviews the most significant research on artificial intelligence in de novo drug design for COVID-19 pharmaceutical research. 相似文献
78.
Giuseppe Donato Mangano Malak Fouani Daniela DAmico Valentina Di Felice Rosario Barone 《International journal of molecular sciences》2022,23(6)
Cachexia is a multifactorial and multi-organ syndrome that is a major cause of morbidity and mortality in late-stage chronic diseases. The main clinical features of cancer-related cachexia are chronic inflammation, wasting of skeletal muscle and adipose tissue, insulin resistance, anorexia, and impaired myogenesis. A multimodal treatment has been suggested to approach the multifactorial genesis of cachexia. In this context, physical exercise has been found to have a general effect on maintaining homeostasis in a healthy life, involving multiple organs and their metabolism. The purpose of this review is to present the evidence for the relationship between inflammatory cytokines, skeletal muscle, and fat metabolism and the potential role of exercise training in breaking the vicious circle of this impaired tissue cross-talk. Due to the wide-ranging effects of exercise training, from the body to the behavior and cognition of the individual, it seems to be able to improve the quality of life in this syndrome. Therefore, studying the molecular effects of physical exercise could provide important information about the interactions between organs and the systemic mediators involved in the overall homeostasis of the body. 相似文献
79.
Lorenza Marinaccio Azzurra Stefanucci Giuseppe Scioli Alice Della Valle Gokhan Zengin Angelo Cichelli Adriano Mollica 《International journal of molecular sciences》2022,23(6)
Elastases are a broad group of enzymes involved in the lysis of elastin, the main component of elastic fibres. They are produced and released in the human body, mainly by neutrophils and the pancreas. The imbalance between elastase activity and its endogenous inhibitors can cause different illnesses due to their excessive activity. The main aim of this review is to provide an overview of the latest advancements on the identification, structures and mechanisms of action of peptide human neutrophil elastase inhibitors isolated from natural sources, such as plants, animals, fungi, bacteria and sponges. The discovery of new elastase inhibitors could have a great impact on the pharmaceutical development of novel drugs through the optimization of the natural lead compounds. Bacteria produce mainly cyclic peptides, while animals provide for long and linear amino acid sequences. Despite their diverse natural sources, these elastase inhibitors show remarkable IC50 values in a range from nM to μM values, thus representing an interesting starting point for the further development of potent bioactive compounds on human elastase enzymes. 相似文献
80.