全文获取类型
收费全文 | 308916篇 |
免费 | 4438篇 |
国内免费 | 934篇 |
专业分类
电工技术 | 5432篇 |
综合类 | 391篇 |
化学工业 | 49054篇 |
金属工艺 | 12516篇 |
机械仪表 | 9104篇 |
建筑科学 | 7452篇 |
矿业工程 | 1945篇 |
能源动力 | 7094篇 |
轻工业 | 28709篇 |
水利工程 | 3347篇 |
石油天然气 | 7200篇 |
武器工业 | 26篇 |
无线电 | 32653篇 |
一般工业技术 | 60840篇 |
冶金工业 | 56614篇 |
原子能技术 | 7647篇 |
自动化技术 | 24264篇 |
出版年
2021年 | 2583篇 |
2019年 | 2292篇 |
2018年 | 4374篇 |
2017年 | 4220篇 |
2016年 | 4572篇 |
2015年 | 3089篇 |
2014年 | 4945篇 |
2013年 | 13326篇 |
2012年 | 7842篇 |
2011年 | 10242篇 |
2010年 | 8434篇 |
2009年 | 9492篇 |
2008年 | 9886篇 |
2007年 | 9703篇 |
2006年 | 8490篇 |
2005年 | 7823篇 |
2004年 | 7176篇 |
2003年 | 6889篇 |
2002年 | 6930篇 |
2001年 | 6756篇 |
2000年 | 6412篇 |
1999年 | 6558篇 |
1998年 | 16360篇 |
1997年 | 12022篇 |
1996年 | 9234篇 |
1995年 | 6945篇 |
1994年 | 6261篇 |
1993年 | 6108篇 |
1992年 | 4600篇 |
1991年 | 4554篇 |
1990年 | 4385篇 |
1989年 | 4413篇 |
1988年 | 4355篇 |
1987年 | 3703篇 |
1986年 | 3701篇 |
1985年 | 4317篇 |
1984年 | 4103篇 |
1983年 | 3746篇 |
1982年 | 3522篇 |
1981年 | 3692篇 |
1980年 | 3550篇 |
1979年 | 3463篇 |
1978年 | 3521篇 |
1977年 | 4094篇 |
1976年 | 5386篇 |
1975年 | 3219篇 |
1974年 | 3066篇 |
1973年 | 3104篇 |
1972年 | 2681篇 |
1971年 | 2503篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Byakova O. V. Stepanov G. V. Vlasov A. O. Danylyuk V. E. Semenov N. V. Berezovs’kyi O. M. Gnyloskurenko S. V. 《Strength of Materials》2019,51(5):726-734
Strength of Materials - The paper addresses the investigation of high-strain rate compressive behavior of Al foams subjected to impact at the intermediate striking velocity ranged from 40 to... 相似文献
92.
93.
Bram H. Frohock Jessica M. Gilbertie Dr. Jennifer C. Daiker Dr. Lauren V. Schnabel Dr. Joshua G. Pierce 《Chembiochem : a European journal of chemical biology》2020,21(7):933-937
The failure of frontline antibiotics in the clinic is one of the most serious threats to human health and requires a multitude of novel therapeutics and innovative approaches to treatment so as to curtail the growing crisis. In addition to traditional resistance mechanisms resulting in the lack of efficacy of many antibiotics, most chronic and recurring infections are further made tolerant to antibiotic action by the presence of biofilms. Herein, we report an expanded set of 5-benzylidene-4-oxazolidinones that are able to inhibit the formation of Staphylococcus aureus biofilms, disperse preformed biofilms, and, in combination with common antibiotics, are able to significantly reduce the bacterial load in a robust collagen-matrix model of biofilm infection. 相似文献
94.
E. G. Kulapina N. M. Makarova O. I. Kulapina I. A. Utc V. V. Baraguzina 《Petroleum Chemistry》2015,55(10):892-900
Potentiometric sensors with plasticized poly(vinyl chloride) membranes based on β-lactam–tetraalkylammonium ion associates sensitive to penicillin antibiotics are proposed. The physicochemical characteristics (solubility product constants and dissociation constants) of active membrane components and the electrode, transport, and selective properties of the membranes of liquidand solid-contact sensors have been studied. The quantitative characteristics of membrane transport (penetrability, ion flux, and transport rate) have been evaluated. The main charge carriers in the membranes and at the membrane/solution interface have been determined from the membrane transport characteristics. The potentiometric sensors are shown to be applicable to the determination of penicillin antibiotics in biological fluids (blood serum and oral fluid) from patients with urinary tract infection. 相似文献
95.
Bican Osman Bayça Salih Uğur Kuleyin Hamdi Gümrük Recep 《Metal Science and Heat Treatment》2021,63(3-4):156-162
Metal Science and Heat Treatment - The effect of solid boronizing at 950°C for 2 and 4 h on the phase composition, microstructure, hardness and abrasive wear of steel AISI 304L is studied... 相似文献
96.
97.
Huseyin Avci Esra Akkulak Hazal Gergeroglu Hamed Ghorbanpoor Onur Uysal Ayla Eker Sariboyaci Bahar Demir Merve Nur Soykan Suat Pat Reza Mohammadigharehbagh Ceren Özel Ahmet Cabuk Fatma Doğan Güzel 《应用聚合物科学杂志》2020,137(26):49184
Among the thermoplastic elastomers that play important roles in the polymer industry due to their superior properties, styrene-based species and polyurethane block copolymers are of great interest. Poly(styrene-ethylene-butadiene-styrene) (SEBS) as a triblock copolymer seems to have the potential to meet many demands in different applications due to various industrial requirements where durability, biocompatibility, breaking elongation, and interfacial adhesion are important. In this study, the SEBS triblock copolymer was functionalized with natural (Satureja hortensis, SH) and synthetic (nanopowder, TiO2) agents to obtain composite nanofibers by electrospinning and electrospraying methods for use in biomedical and water filtration applications. The results were compared with thermoplastic polyurethane (TPU) composite nanofibers, which are commonly used in these fields. Here, functionalized SEBS nanofibers exhibited antibacterial effect while at the same time improving cell viability. In addition, because of successful water filtration by using the SEBS composite nanofibers, the material may have a good potential to be used comparably to TPU for the application. 相似文献
98.
Dr. Blijke S. Kroezen Gabriele Conti Benedetta Girardi Dr. Jonathan Cramer Dr. Xiaohua Jiang Dr. Said Rabbani Jennifer Müller Maja Kokot Enrico Luisoni Prof. Daniel Ricklin Dr. Oliver Schwardt Prof. Beat Ernst 《ChemMedChem》2020,15(18):1706-1719
Siglecs are members of the immunoglobulin gene family containing sialic acid binding N-terminal domains. Among them, Siglec-8 is expressed on various cell types of the immune system such as eosinophils, mast cells and weakly on basophils. Cross-linking of Siglec-8 with monoclonal antibodies triggers apoptosis in eosinophils and inhibits degranulation of mast cells, making Siglec-8 a promising target for the treatment of eosinophil- and mast cell-associated diseases such as asthma. The tetrasaccharide 6’-sulfo-sialyl Lewisx has been identified as a specific Siglec-8 ligand in glycan array screening. Here, we describe an extended study enlightening the pharmacophores of 6’-sulfo-sialyl Lewisx and the successful development of a high-affinity mimetic. Retaining the neuraminic acid core, the introduction of a carbocyclic mimetic of the Gal moiety and a sulfonamide substituent in the 9-position gave a 20-fold improved binding affinity. Finally, the residence time, which usually is the Achilles tendon of carbohydrate/lectin interactions, could be improved. 相似文献
99.
Chitosan microspheres containing bromocresol green, cresol red, and phenolphthalein for corrosion detection, through pH change, are synthesized in order to be used in protective coatings for aluminium alloys. Microspheres containing corrosion detection species are characterized morphologically (SEM) and physico‐chemically (FTIR, TGA). Release studies (UV–vis) are performed in corrosion‐promoting conditions (pH, NaCl), and detection studies by immersion in media associated with corrosion activity while microspheres' sensing activity is evaluated visually. Electrochemical characterization of AA2024 substrates in the presence of chitosan spheres is performed to understand material performance, and a color change is observed as a result of local pH increase in cathodic areas when corrosion takes place. These findings can be correlated with the results from release studies and seem a promising approach for corrosion sensing purposes, not only because pH increase is possible to detect due to corrosion, but also because chitosan is considered an environmentally friendly material. 相似文献
100.
Arif Karademir Cem Aydemir Semiha Yenidogan Emine Arman Kandırmaz Rukiye G. Kıter 《Color research and application》2020,45(6):1170-1178
Alkyd resins are generally used in the production of printing inks. All industries look for alternative raw materials in the production of ink with the growing inclination toward using natural products. Resins forming the vehicle of the ink to be obtained from natural resources will provide benefits for the environment, nature, and living creatures. The aim of the study was to promote the use of natural resin in the ink system. Natural Pinus pinaster resin was added into vegetable and mineral oil-based solvents in pure form with alkyd resin in different amounts and ink varnishes of different combinations were prepared. Then, printing inks were produced from these varnishes in pure and hybrid form. Following the assessment of the rheological properties of the inks prepared, printing tests were conducted to assess the printing quality parameters. Ideal mixing ratios of the natural resins in the ink were determined for printability. The environmental importance and advantages of the use of natural resins were discussed. Recommendations were given in line with the results to encourage widespread use of natural resins in near future. 相似文献