全文获取类型
收费全文 | 542篇 |
免费 | 69篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 12篇 |
综合类 | 8篇 |
化学工业 | 134篇 |
金属工艺 | 24篇 |
机械仪表 | 35篇 |
建筑科学 | 28篇 |
矿业工程 | 16篇 |
能源动力 | 12篇 |
轻工业 | 56篇 |
水利工程 | 7篇 |
石油天然气 | 16篇 |
武器工业 | 3篇 |
无线电 | 94篇 |
一般工业技术 | 112篇 |
冶金工业 | 29篇 |
原子能技术 | 2篇 |
自动化技术 | 31篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 21篇 |
2020年 | 10篇 |
2019年 | 17篇 |
2018年 | 22篇 |
2017年 | 20篇 |
2016年 | 21篇 |
2015年 | 28篇 |
2014年 | 30篇 |
2013年 | 45篇 |
2012年 | 39篇 |
2011年 | 46篇 |
2010年 | 32篇 |
2009年 | 41篇 |
2008年 | 28篇 |
2007年 | 29篇 |
2006年 | 22篇 |
2005年 | 15篇 |
2004年 | 15篇 |
2003年 | 14篇 |
2002年 | 16篇 |
2001年 | 10篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 13篇 |
1997年 | 10篇 |
1996年 | 4篇 |
1995年 | 11篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 5篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有619条查询结果,搜索用时 31 毫秒
611.
Highly Sensitive and Selective Field‐Effect‐Transistor NonEnzyme Dopamine Sensors Based on Pt/Conducting Polymer Hybrid Nanoparticles 下载免费PDF全文
Jun Seop Lee Jungkyun Oh Sung Gun Kim Jyongsik Jang 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(20):2399-2406
Dopamine (DA), as one of catecholamine family of neurotransmitters, is crucially important in humans owing to various critical effects on biometric system such as brine circuitry, neuronal plasticity, organization of stress responses, and control of cardiovascular and renal organizations. Abnormal level of dopamine in the central nervous system causes several neurological diseases, e.g., schizophrenia, Parkinson's disease, and attention deficit hybperactivity disorder (ADHD)/attention deficit disorder (ADD). In this report, we suggest the fabrication of nonenzyme field effect transistor (FET) sensor composed of immobilized Pt particle decorated conducting‐polymer (3‐carboxylate polypyrrole) nanoparticles (Pt_CPPy) to detect dopamine. The hybrid nanoparticles (NPs) are produced by means of facile chemical reduction of pristine CPPyNP‐contained Pt precursor (PtCl4) solution. The Pt_CPPys are then immobilized on an amine‐functionalized (–NH2) interdigitated‐array electrode substrate, through the formation of covalent bonds with amine groups (–CONH). The resulting Pt_CPPy‐based FET sensors exhibit high sensitivity and selectivity toward DA at unprecedentedly low concentrations (100 × 10?15m ) and among interfering biomolecules, respectively. Additionally, due to the covalent bonding involved in the immobilization process, a longer lifetime is expected for the FET sensor. 相似文献
612.
613.
614.
Kyu Hang Kyung Eduardo Medina Pradas Song Gun Kim Yong Jae Lee Kyong Ho Kim Jin Joo Choi Joo Hyong Cho Chang Ho Chung Rodolphe Barrangou Frederick Breidt 《Journal of food science》2015,80(5):M1031-M1038
The biochemistry and microbial ecology of 2 similar types of watery (mul) kimchi, containing sliced and unsliced radish and vegetables (nabak and dongchimi, respectively), were investigated. Samples from kimchi were fermented at 4, 10, and 20 °C were analyzed by plating on differential and selective media, high‐performance liquid chromatography, and high‐throughput DNA sequencing of 16S rDNA. Nabak kimchi showed similar trends as dongchimi, with increasing lactic and acetic acids and decreasing pH for each temperature, but differences in microbiota were apparent. Interestingly, bacteria from the Proteobacterium phylum, including Enterobacteriaceae, decreased more rapidly during fermentation at 4 °C in nabak cabbage fermentations compared with dongchimi. Although changes for Proteobacterium and Enterobacteriaceae populations were similar during fermentation at 10 and 20 °C, the homolactic stage of fermentation did not develop for the 4 and 10 °C samples of both nabak and dongchimi during the experiment. These data show the differences in biochemistry and microbial ecology that can result from preparation method and fermentation conditions of the kimchi, which may impact safety (Enterobacteriaceae populations may include pathogenic bacteria) and quality (homolactic fermentation can be undesirable, if too much acid is produced) of the product. In addition, the data also illustrate the need for improved methods for identifying and differentiating closely related lactic acid bacteria species using high‐throughput sequencing methods. 相似文献
615.
A High‐Performance Top‐Gated Graphene Field‐Effect Transistor with Excellent Flexibility Enabled by an iCVD Copolymer Gate Dielectric 下载免费PDF全文
Joong Gun Oh Kwanyong Pak Choong Sun Kim Jae Hoon Bong Wan Sik Hwang Sung Gap Im Byung Jin Cho 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(9)
A high‐performance top‐gated graphene field‐effect transistor (FET) with excellent mechanical flexibility is demonstrated by implementing a surface‐energy‐engineered copolymer gate dielectric via a solvent‐free process called initiated chemical vapor deposition. The ultrathin, flexible copolymer dielectric is synthesized from two monomers composed of 1,3,5‐trimethyl‐1,3,5‐trivinyl cyclotrisiloxane and 1‐vinylimidazole (VIDZ). The copolymer dielectric enables the graphene device to exhibit excellent dielectric performance and substantially enhanced mechanical flexibility. The p‐doping level of the graphene can be tuned by varying the polar VIDZ fraction in the copolymer dielectric, and the Dirac voltage (VDirac) of the graphene FET can thus be systematically controlled. In particular, the VDirac approaches neutrality with higher VIDZ concentrations in the copolymer dielectric, which minimizes the carrier scattering and thereby improves the charge transport of the graphene device. As a result, the graphene FET with 20 nm thick copolymer dielectrics exhibits field‐effect hole and electron mobility values of over 7200 and 3800 cm2 V?1 s?1, respectively, at room temperature. These electrical characteristics remain unchanged even at the 1 mm bending radius, corresponding to a tensile strain of 1.28%. The formed gate stack with the copolymer gate dielectric is further investigated for high‐frequency flexible device applications. 相似文献
616.
Tianyu Wang Min Zhang Kefan Zhou Helin Wang Ahu Shao Liuyan Hou Zhiqiao Wang Xiaoyu Tang Miao Bai Shaowen Li Yue Ma 《Advanced functional materials》2023,33(22):2215117
The practical use of polyethylene oxide polymer electrolyte in the solid-state sodium metallic batteries (SSMBs) suffers from the retard Na+ diffusion at the room temperature, mechanical fragility as well as the oxidation tendency at high voltages. Herein, a hetero-layered composite polymeric electrolyte (CPE) is proposed to enable the simultaneous interfacial stability with the high voltage cathodes (till 4.2 V) and Na metallic anode. Being incorporated within the polymer matrix, the sand-milled Na3Zr2Si2PO12 nanofillers and nanocellulose scaffold collectively endow the thin-layer (25 µm), ultralightweight (1.65 mg cm−2) CPE formation with an order of magnitude enhancement of the mechanical strength (13.84 MPa) and ionic conductivity (1.62 × 10−4 S cm−1) as compared to the pristine polymer electrolyte, more importantly, the improved dimension stability up to 180 °C. Upon the integration of the hetero-layered CPE with the iron hexacyanoferrate FeHCF cathode (1 mAh cm−2) and the Na foil, the cell model can achieve the room-temperature cycling stability (93.73% capacity retention for 200 cycles) as well as the high temperature tolerance till 80 °C, which inspires a quantum leap toward the surface-wetting-agent-free, energy-dense, wide-temperature-range SSMB prototyping. 相似文献
617.
Pramod B. Shinde Hong‐Se Oh Hyemin Choi Kris Rathwell Yeon Hee Ban Eun Ji Kim Inho Yang Dong Gun Lee David H. Sherman Han‐Young Kang Yeo Joon Yoon 《Advanced Synthesis \u0026amp; Catalysis》2015,357(12):2697-2711
YC‐17 is a 12‐membered ring macrolide antibiotic produced from Streptomyces venezuelae ATCC 15439 and is composed of the polyketide macrolactone 10‐deoxymethynolide appended with D ‐desosamine. In order to develop structurally diverse macrolactam analogues of YC‐17 with improved therapeutic potential, a combined approach involving chemical synthesis and engineered cell‐based biotransformation was employed. Eight new antibacterial macrolactam analogues of YC‐17 were generated by supplying a novel chemically synthesized macrolactam aglycone to S. venezuelae mutants harboring plasmids capable of synthesizing several unnatural sugars for subsequent glycosylation. Some YC‐17 macrolactam analogues were active against erythromycin‐resistant bacterial pathogens and displayed improved metabolic stability in vitro. The enhanced therapeutic potential demonstrated by these glycosylated macrolactam analogues reveals the unique potential of chemoenzymatic synthesis in antibiotic drug discovery and development.
618.
Tadeusz Balcerowski Burak Ozbek Ozge Akbulut Ahu Gümrah Dumanli 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(8):2205506
Structural color—a widespread phenomenon observed throughout nature is caused by light interference from ordered phases of matter. While state-of-the-art nanofabrication techniques can produce structural organization in small areas, cost-effective and scalable techniques are still lacking to generate tunable color at sub-micron length scales. In this work, structurally colored hydroxypropyl cellulose filaments are produced with a suppressed angular color response by 3D printing. The systematic study of the morphology of the filaments reveals the key stages in the induction of a two-degree hierarchical order through 3D printing. The first degree of order originated from the changing of the cholesteric pitch at a few hundred nm scale via chemical modification and tuning of the solid content of the lyotropic phase. Upon 3D printing, the secondary hierarchical order of periodic wrinkling is introduced through the Helfrich–Hurault deformation of the shear-aligned cholesteric phases. In single-layered filaments, four morphological zones with varying orders of wrinkles are identified. Detailed morphological characterization is carried out using SEM to shed light on the mechanism of the wrinkling behavior. Through this work, the possibility of modifying the wrinkling behavior is demonstrated and thus the angle dependence of the color response by changing the printing conditions. 相似文献
619.
Xiaoyu Tang Xiaosa Xu Miao Bai Min Zhang Heling Wang Zhiqiao Wang Ahu Shao Hongqiang Wang Yue Ma 《Advanced functional materials》2023,33(5):2210465
Poly(ethylene oxide) (PEO)-based solid polymer electrolyte promises interfacial compatibility with the high-capacity metallic anodes in all-solid-state batteries (ASSBs). However, the prototype construction is severely hindered by the parasitic ohmic resistance at the electrode-electrolyte interface, insufficient ionic pathway of the high loading cathode, as well as the PEO oxidation tendency at the high voltage. Herein, a laser-assisted strategy is presented toward ultra-efficient cathode modification (completes within 240 s) by constructing continuous, multi-scale artificial cathode/electrolyte interface (CEI). The tailorable, yet localized temperature gradient induced by the pulsed laser beam can customize the CEI species from the target precursor salts for the on-demand protection purpose. Derived from the tris(trimethylsilyl)phosphate, the proof-of-concept model achieves phosphorus-rich, ion-diffusion network across the high-mass-loading LiNi0.8Co0.1Mn0.1O2 cathode, which enables the high-rate operation of the ASSBs prototype as well as the extended shelf life at the oxidized idling state. Transmission-mode operando X-ray phase tracking unravels the electrochemical stability origin at the cathode/PEO interface due to the insulation of electron shuttling, where the layered to spinel phase transition and the lattice oxygen release are alleviated. This generic, readily tailorable, highly-efficient laser processing strategy thus provides unprecedented opportunities to secure the varieties of energy-dense, polymer-based ASSBs. 相似文献