全文获取类型
收费全文 | 1763篇 |
免费 | 43篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 78篇 |
综合类 | 1篇 |
化学工业 | 416篇 |
金属工艺 | 48篇 |
机械仪表 | 36篇 |
建筑科学 | 28篇 |
能源动力 | 92篇 |
轻工业 | 109篇 |
水利工程 | 3篇 |
无线电 | 209篇 |
一般工业技术 | 355篇 |
冶金工业 | 216篇 |
原子能技术 | 69篇 |
自动化技术 | 150篇 |
出版年
2023年 | 9篇 |
2022年 | 16篇 |
2021年 | 36篇 |
2020年 | 16篇 |
2019年 | 19篇 |
2018年 | 16篇 |
2017年 | 22篇 |
2016年 | 31篇 |
2015年 | 27篇 |
2014年 | 38篇 |
2013年 | 124篇 |
2012年 | 62篇 |
2011年 | 95篇 |
2010年 | 65篇 |
2009年 | 84篇 |
2008年 | 103篇 |
2007年 | 98篇 |
2006年 | 59篇 |
2005年 | 57篇 |
2004年 | 50篇 |
2003年 | 75篇 |
2002年 | 47篇 |
2001年 | 33篇 |
2000年 | 42篇 |
1999年 | 31篇 |
1998年 | 80篇 |
1997年 | 75篇 |
1996年 | 53篇 |
1995年 | 29篇 |
1994年 | 25篇 |
1993年 | 28篇 |
1992年 | 29篇 |
1991年 | 21篇 |
1990年 | 19篇 |
1989年 | 15篇 |
1988年 | 16篇 |
1987年 | 17篇 |
1986年 | 27篇 |
1985年 | 19篇 |
1984年 | 20篇 |
1982年 | 10篇 |
1981年 | 13篇 |
1980年 | 12篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 9篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 3篇 |
排序方式: 共有1810条查询结果,搜索用时 15 毫秒
1.
Lili Chen Nanami Fujisawa Masato Takanohashi Mazaya Najmina Koichiro Uto Mitsuhiro Ebara 《International journal of molecular sciences》2021,22(5)
This study demonstrates the rational fabrication of a magnetic composite nanofiber mesh that can achieve mutual synergy of hyperthermia, chemotherapy, and thermo-molecularly targeted therapy for highly potent therapeutic effects. The nanofiber is composed of biodegradable poly(ε-caprolactone) with doxorubicin, magnetic nanoparticles, and 17-allylamino-17-demethoxygeldanamycin. The nanofiber exhibits distinct hyperthermia, owing to the presence of magnetic nanoparticles upon exposure of the mesh to an alternating magnetic field, which causes heat-induced cell killing as well as enhanced chemotherapeutic efficiency of doxorubicin. The effectiveness of hyperthermia is further enhanced through the inhibition of heat shock protein activity after hyperthermia by releasing the inhibitor 17-allylamino-17-demethoxygeldanamycin. These findings represent a smart nanofiber system for potent cancer therapy and may provide a new approach for the development of localized medication delivery. 相似文献
2.
Masahiro Sato Miyu Koriyama Satoshi Watanabe Masato Ohtsuka Takayuki Sakurai Emi Inada Issei Saitoh Shingo Nakamura Kazuchika Miyoshi 《International journal of molecular sciences》2015,16(8):17838-17856
Some reports demonstrated successful genome editing in pigs by one-step zygote microinjection of mRNA of CRISPR/Cas9-related components. Given the relatively long gestation periods and the high cost of housing, the establishment of a single blastocyst-based assay for rapid optimization of the above system is required. As a proof-of-concept, we attempted to disrupt a gene (GGTA1) encoding the α-1,3-galactosyltransferase that synthesizes the α-Gal epitope using parthenogenetically activated porcine oocytes. The lack of α-Gal epitope expression can be monitored by staining with fluorescently labeled isolectin BS-I-B4 (IB4), which binds specifically to the α-Gal epitope. When oocytes were injected with guide RNA specific to GGTA1 together with enhanced green fluorescent protein (EGFP) and human Cas9 mRNAs, 65% (24/37) of the developing blastocysts exhibited green fluorescence, although almost all (96%, 23/24) showed a mosaic fluorescent pattern. Staining with IB4 revealed that the green fluorescent area often had a reduced binding activity to IB4. Of the 16 samples tested, six (five fluorescent and one non-fluorescent blastocysts) had indel mutations, suggesting a correlation between EGFP expression and mutation induction. Furthermore, it is suggested that zygote microinjection of mRNAs might lead to the production of piglets with cells harboring various mutation types. 相似文献
3.
Masato Enomoto 《Metallurgical and Materials Transactions A》1991,22(6):1235-1245
A previously developed computer model was modified to simulate the growth of grain boundary precipitates which grow by the ledge mechanism. The ledges were assumed to be nucleated in the grain boundary region at constant, parabolically decreasing, and random rates and to grow under the control of volume diffusion of solute to or from the riser of ledges. At lower under coolings at which the motion of individual ledges is slow, late-nucleated ledges soon catch up with first-nucleated ones, and precipitates tend to extend along the grain boundary: the overall precipitate shape is essentially that of a grain boundary allotriomorph. At larger undercoolings, first-nucleated ledges move fast to form a protuberance similar to Widmanstätten sideplates, while late-nucleated ones stay near the grain boundary region. The transition of precipitate shape from one to the other occurs in a very narrow range of supersaturation. The results are compared with various characteristics of the growth of proeutectoid ferrite allotriomorphs and sideplates in Fe-C alloys documented in the literature. 相似文献
4.
5.
A novel optical circulator is reported which employs an yttrium-iron-garnet (YIG) sphere, PANDA-fibre polarisers and a fibre-optic polarising beam splitter. The splitting ratios of the fibre-optic polarising beam splitter were 1.0:99.0 for x-polarisation and 97.5:2.5 for y-polarisation, with an excess loss of 0.5 dB at 1.30 ?m wavelength. The backward isolation of the optical circulator was 30 dB with the total insertion loss of 4.5 dB. 相似文献
6.
Keita Ikeue Shingo Ando Tomohiro Mitsuyama Yusuke Ohta Keishi Arayama Akiko Tsutsumi Masato Machida 《Topics in Catalysis》2008,47(3-4):175-180
Lanthanide-based oxysulfides and sulfide, LnTaO3.5S0.5, Ln10OS14 (Ln = La, Pr, Nd, Sm) and La4In5S13, were successively synthesized by sulfurization in a flowing H2S. The sulfurization decreased the band-gap energies from >4 eV to <3eV, because of the formation of occupied S3p orbitals
on the top of valence band. In accordance with the small band gap, the H2 evolution from a 0.01 M Na2S and 0.01 M Na2SO3 solution system was observed under irradiation of light up to >500 nm. The rate of H2 evolution under light irradiation of >500 nm increased in the order of Ni/LaTaO3.5S0.5 < Ru/La10OS14 < Pt/La4In5S13. 相似文献
7.
Masato Tanaka 《加拿大化工杂志》1985,63(5):723-727
The local variation of droplet diameter in a stirred tank was measured in the vicinity of the impeller and at another region. The degree of difference in droplet diameter between regions increases with the impeller speed. A correlation equation between the local difference in droplet diameter and the frequencies of coalescence and circulation of the droplet was derived according to the circulation interaction model. The degree of local difference in droplet diameter was found to be controlled strongly by the ratio of coalescence to circulation frequency. 相似文献
8.
A temperature sensor using a fiber-optic Fabry-Perot interferometer is described. A pseudo-heterodyne detection scheme is adopted to read the light phase difference in the Fabry-Perot interference output. A higher harmonic components comparison method is used to stabilize the system and to increase detection linearity. This system realizes not only highly sensitive temperature sensing with good linearity and minimal adjusting error, but also application to the sensing of other physical quantities such as vibrations. Additionally, the signal-to-noise ratio and distortion of the detected signal are investigated as functions of fiber end reflectivity. These results will be useful in designing a high performance fiber-optic Fabry-Perot thermometer. 相似文献
9.
We report 34 cases of tsutsugamushi disease seen from 1989 to 1993 at Yagi Clinic, northern Osumi, Kagoshima Prefecture. Nineteen patients (55.9%) showed the highest antibody titers against the Kawasaki strain Orientia tsutsugamushi (Ot) and 13 (38.2%) against the Kuroki strain Ot. It is suggested that two antigenic types (Kawasaki and Kuroki) of Ot were distributed in Kagoshima Prefecture, and the Kawasaki type Ot more or less dominates Kuroki type Ot. There was no difference in clinical features between the two groups of patients. 相似文献
10.
Miao Wang Xinluo Zhao Masato Ohkohchi Yoshinori Ando 《Fullerenes, Nanotubes and Carbon Nanostructures》1996,4(5):1027-1039
Carbon nanotubes prepared by de arc discharge of graphite electrodes in He and CH4 gas took markedly different morphology. Thick nanotubes embellished with many carbon nanoparticles were obtained by evaporation under high CH4 gas pressure and high arc current. Thin and long carbon nanotubes were obtained under a CH4 gas pressure of 50Torr and an arc current of 20A for the anode with a diameter of 6mm. 相似文献