全文获取类型
收费全文 | 1790篇 |
免费 | 88篇 |
国内免费 | 11篇 |
学科分类
工业技术 | 1889篇 |
出版年
2023年 | 37篇 |
2022年 | 53篇 |
2021年 | 66篇 |
2020年 | 71篇 |
2019年 | 58篇 |
2018年 | 98篇 |
2017年 | 57篇 |
2016年 | 78篇 |
2015年 | 51篇 |
2014年 | 75篇 |
2013年 | 175篇 |
2012年 | 105篇 |
2011年 | 126篇 |
2010年 | 73篇 |
2009年 | 104篇 |
2008年 | 75篇 |
2007年 | 65篇 |
2006年 | 47篇 |
2005年 | 42篇 |
2004年 | 40篇 |
2003年 | 28篇 |
2002年 | 19篇 |
2001年 | 10篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 17篇 |
1997年 | 14篇 |
1996年 | 12篇 |
1995年 | 20篇 |
1994年 | 18篇 |
1993年 | 17篇 |
1992年 | 16篇 |
1991年 | 21篇 |
1990年 | 5篇 |
1989年 | 16篇 |
1988年 | 10篇 |
1987年 | 8篇 |
1986年 | 13篇 |
1985年 | 21篇 |
1984年 | 25篇 |
1983年 | 23篇 |
1982年 | 14篇 |
1981年 | 15篇 |
1980年 | 12篇 |
1979年 | 11篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1971年 | 2篇 |
排序方式: 共有1889条查询结果,搜索用时 15 毫秒
1.
Mit Rita Goswami Prayas Singh Pankaj Chamoli Sumit Bhardwaj Kuldeep Kumar Raina Ravi Kumar Shukla 《应用聚合物科学杂志》2021,138(43):51260
ZnO rice like nonarchitects are grafted on the graphene carbon core via a rapid microwave synthesis route. The prepared grafted systems are characterized via XRD, SEM, RAMAN, and XPS to examined the structural and morphological parameters. Zinc oxide grafted graphene sheets (ZnO-G) are further doped in β-phase of polyvinylidene fluoride (PVDF) to prepare the polymer nanocomposites (PNCs) via mixed solvent approach (THF/DMF). β-phase confirmation of PVDF PNCs is done by FTIR studies. It is observed that ZnO-G filler enhances the β-phase content in the PNCs. Non-doped PVDF and PNCs are further studied for rheological behavior under the shear rate of 1–100 s−1. Doping of ZnO-G dopant to the PVDF matrix changes its discontinuous shear thickening (DST) behavior to continues shear thickening behavior (CST). Hydrocluster formation and their interaction with the dopant could be the reason for this striking DST to CST behavioral change. Strain amplitude sweep (10−3% -10%) oscillatory test reveals that the PNCs shows extended linear viscoelastic region with high elastic modulus and lower viscous modulus. Effective shear thickening behavior and strong elastic strength of these PNCs present their candidature for various fields including mechanical and soft body armor applications. 相似文献
2.
Singh Rajeev Kumar Tiwari Akhilesh Gupta Rajendra Kumar 《Multimedia Tools and Applications》2022,81(5):6051-6067
Multimedia Tools and Applications - Currently, Deep Learning is playing an influential role for Image analysis and object classification. Maize’s diseases reduce production that subsequently... 相似文献
3.
Rajender Prasad Tiwari Syed Zimad Husain Hashmi Raghav Sharma Saif Ahmad Khan Balaji Birajdar 《Journal of the American Ceramic Society》2019,102(8):4659-4669
Residual NiO phase is generally detected in 0.9(KNbO3)–0.1(BaNi1/2Nb1/2O3-δ) (KBNNO) synthesized using NiO as a nickel precursor by solid-state reaction. In this work, NiO phase is found to exist in the form of the residual NiO particles with a size of 100-200 nm using energy dispersive X-ray elemental mapping. These NiO residual particles are eliminated by using nickel acetate as a nickel precursor and a 100% perovskite phase KBNNO is successfully synthesized at as low as 600°C temperature. Furthermore, using the two-step sintering technique, 100% relative density is achieved in this material. The nickel acetate–based KBNNO shows a robust ferromagnetism with the saturation magnetization of 11.42 memu/g and the remanent magnetization of 3.89 memu/g which is 38 times higher than that of previously reported value in NiO-based KBNNO. Thus, a highly pure and fully dense KBNNO ceramic with superior magnetic properties is obtained using nickel acetate and by the two-step sintering method. This is a key step forward in the processing of KBNNO and is likely to have a significant impact on other physical properties of this newly invented and promising photovoltaic perovskite material. 相似文献
4.
5.
Karishma Tiwari Pulak Sarkar Solagna Modak Harwinder Singh Sumit Kumar Pramanik Santanu Karan Amitava Das 《Advanced materials (Deerfield Beach, Fla.)》2020,32(8):1905621
Separation membranes with higher molecular weight cut-offs are needed to separate ions and small molecules from a mixed feed. The molecular sieving phenomenon can be utilized to separate smaller species with well-defined dimensions from a mixture. Here, the formation of freestanding polyimine nanofilms with thicknesses down to ≈14 nm synthesized via self-assembly of pre-synthesized imine oligomers is reported. Nanofilms are fabricated at the water–xylene interface followed by reversible condensation of polymerization according to the Pieranski theory. Polyimine nanofilm composite membranes are made via transferring the freestanding nanofilm onto ultrafiltration supports. High water permeance of 49.5 L m-2 h−1 bar−1 is achieved with a complete rejection of brilliant blue-R (BBR; molecular weight = 825 g mol−1) and no more than 10% rejection of monovalent and divalent salts. However, for a mixed feed of BBR dye and monovalent salt, the salt rejection is increased to ≈18%. Membranes are also capable of separating small dyes (e.g., methyl orange; MO; molecular weight = 327 g mol−1) from a mixed feed of BBR and MO. Considering a thickness of ≈14 nm and its separation efficiency, the present membrane has significance in separation processes. 相似文献
6.
Purushottam B. Tiwari Prem P. Chapagain Ahmed Seddek Thirunavukkarasu Annamalai Aykut Üren Yuk-Ching Tse-Dinh 《ChemMedChem》2020,15(7):623-631
A topoisomerase-DNA transient covalent complex can be a druggable target for novel topoisomerase poison inhibitors that represent a new class of antibacterial or anticancer drugs. Herein, we have investigated molecular features of the functionally important Escherichia coli topoisomerase I (EctopoI)-DNA covalent complex (EctopoIcc) for molecular simulations, which is very useful in the development of new antibacterial drugs. To demonstrate the usefulness of our approach, we used a model small molecule (SM), NSC76027, obtained from virtual screening. We examined the direct binding of NSC76027 to EctopoI as well as inhibition of EctopoI relaxation activity of this SM via experimental techniques. We then performed molecular dynamics (MD) simulations to investigate the dynamics and stability of EctopoIcc and EctopoI-NSC76027-DNA ternary complex. Our simulation results show that NSC76027 forms a stable ternary complex with EctopoIcc. EctopoI investigated here also serves as a model system for investigating a complex of topoisomerase and DNA in which DNA is covalently attached to the protein. 相似文献
7.
Yashvir Singh Abhishek Sharma Nishant Singh Amneesh Singla Pankaj Mohan Rastogi 《国际自然能源杂志》2020,41(13):1534-1547
ABSTRACT Fossil fuel resource is on the draining stage which leads to an increment in the cost of the petroleum products. Nowadays, research is focused on the development of environmental friendly lubricants which are derivatives of renewable sources. Inedible plant oil-driven bio-lubricants are environmentally friendly because they are non-hazardous, biodegradable, as well as there is no emission of toxic gases. This study involves the characterisations, advantages, as well as utilisation of inedible plant oil-driven bio-lubricants as an alternative for tribological applications. This report presents the status about the global lubricant market as well as potential outlook. Inedible plant oil-driven bio-lubricants bear high viscosity, high lubricity, and high viscosity index which can enhance the equipment service life and has the ability to carry high load and results in minimum amount of metal traces during combustion. 相似文献
8.
9.
Chandel Narendra Singh Chakraborty Subir Kumar Rajwade Yogesh Anand Dubey Kumkum Tiwari Mukesh K. Jat Dilip 《Neural computing & applications》2021,33(10):5353-5367
Neural Computing and Applications - The identification of water stress is a major challenge for timely and effective irrigation to ensure global food security and sustainable agriculture. Several... 相似文献
10.
Sustainable and efficient food supply chain has become an essential component of one’s life. The model proposed in this paper is deeply linked to people's quality of life as a result of which there is a large incentive to fulfil customer demands through it. This proposed model can enhance food quality by making the best possible food quality accessible to customers, construct a sustainable logistics system considering its environmental impact and ensure the customer demand to be fulfilled as fast as possible. In this paper, an extended model is examined that builds a unified planning problem for efficient food logistics operations where four important objectives are viewed: minimising the total expense of the system, maximising the average food quality along with the minimisation of the amount of CO2 emissions in transportation along with production and total weighted delivery lead time minimisation. A four objective mixed integer linear programming model for intelligent food logistics system is developed in the paper. The optimisation of the formulated mathematical model is proposed using a modified multi-objective particle swarm optimisation algorithm with multiple social structures: MO-GLNPSO (Multi-Objective Global Local Near-Neighbour Particle Swarm Optimisation). Computational results of a case study on a given dataset as well as on multiple small, medium and large-scale datasets followed by sensitivity analysis show the potency and effectiveness of the introduced method. Lastly, there has been a scope for future study displayed which would lead to the further progress of these types of models. 相似文献