全文获取类型
收费全文 | 512篇 |
免费 | 11篇 |
专业分类
电工技术 | 26篇 |
化学工业 | 104篇 |
金属工艺 | 12篇 |
机械仪表 | 16篇 |
建筑科学 | 5篇 |
能源动力 | 36篇 |
轻工业 | 44篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 75篇 |
一般工业技术 | 59篇 |
冶金工业 | 96篇 |
原子能技术 | 6篇 |
自动化技术 | 41篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 15篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 9篇 |
2017年 | 15篇 |
2016年 | 7篇 |
2015年 | 8篇 |
2014年 | 7篇 |
2013年 | 19篇 |
2012年 | 19篇 |
2011年 | 26篇 |
2010年 | 16篇 |
2009年 | 17篇 |
2008年 | 18篇 |
2007年 | 19篇 |
2006年 | 16篇 |
2005年 | 14篇 |
2004年 | 16篇 |
2003年 | 12篇 |
2002年 | 13篇 |
2001年 | 11篇 |
2000年 | 16篇 |
1999年 | 18篇 |
1998年 | 40篇 |
1997年 | 34篇 |
1996年 | 15篇 |
1995年 | 16篇 |
1994年 | 17篇 |
1993年 | 10篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1989年 | 1篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1972年 | 2篇 |
排序方式: 共有523条查询结果,搜索用时 0 毫秒
1.
Jasmin Kuhn Philipp M. Klein Nader Al Danaf Joel Z. Nordin Sren Reinhard Dominik M. Loy Miriam Hhn Samir El Andaloussi Don C. Lamb Ernst Wagner Yoshitsugu Aoki Taavi Lehto Ulrich Lchelt 《Advanced functional materials》2019,29(48)
Phosphorodiamidate morpholino oligomers (PMOs) are oligonucleotide analogs that can be used for therapeutic modulation of pre‐mRNA splicing. Similar to other classes of nucleic acid‐based therapeutics, PMOs require delivery systems for efficient transport to the intracellular target sites. Here, artificial peptides based on the oligo(ethylenamino) acid succinyl‐tetraethylenpentamine (Stp), hydrophobic modifications, and an azide group are presented, which are used for strain‐promoted azide‐alkyne cycloaddition conjugation with splice‐switching PMOs. By systematically varying the lead structure and formulation, it is determined that the type of contained fatty acid and supramolecular assembly have a critical impact on the delivery efficacy. A compound containing linolenic acid with three cis double bonds exhibits the highest splice‐switching activity and significantly increases functional protein expression in pLuc/705 reporter cells in vitro and after local administration in vivo. Structural and mechanistic studies reveal that the lipopeptide PMO conjugates form nanoparticles, which accelerate cellular uptake and that the content of unsaturated fatty acids enhances endosomal escape. In an in vitro Duchenne muscular dystrophy exon skipping model using H2K‐mdx52 dystrophic skeletal myotubes, the highly potent PMO conjugates mediate significant splice‐switching at very low nanomolar concentrations. The presented aminoethylene‐lipopeptides are thus a promising platform for the generation of PMO‐therapeutics with a favorable activity/toxicity profile. 相似文献
2.
The three-dimensional morphology of polyethylene single crystals grown from dilute solution has been examined by atomic force microscopy. Single crystals were deposited on a soft ground of aqueous solution of poly(vinyl alcohol) (PVA) to avoid the collapse of thin lamellar crystals with thickness of 10 nm. The observation of single crystals on dried PVA clarifies the morphology of a chair type crystal as well as well-known hollow pyramidal type. It has been confirmed that the screw dislocations in the chair type follow a selection rule of the handedness in a manner to relieve the distortion in the chair type. 相似文献
3.
Keizo Uematsu Masayori Miyashita Jin-Young Kim Zenji Kato Nozomu Uchida 《Journal of the American Ceramic Society》1991,74(9):2170-2174
Green bodies prepared by compaction of alumina granules were made transparent by an immersion liquid technique, and the internal structure was characterized with an optical microscope to study the effect of forming pressure on the internal structure. Clear images obtained by the technique provide more detailed information than other existing methods for structures ranging from one to tens of micrometers. Intergranular pores were present between unfractured granules. Their sizes and concentration tended to decrease with increasing forming pressure. However, pores were clearly present even in the green body prepared at 600 MPa. A rod- and needlelike feature was also found and was concluded to correspond to a high-density region. The significance of large pores and high-density regions on processing as well as the details of the technique is discussed. 相似文献
4.
A Shuaib MS Ijaz H Miyashita S Hussain R Kanthan 《Canadian Metallurgical Quarterly》1997,147(2):311-315
Repetitive cerebral ischemia produces more severe damage than a similar single duration insult. We have previously shown that, in gerbils, damage in the substantia nigra reticulata (SNr) is seen with repetitive insults rather than a single insult. We have also shown that there is a progressive decrease in the extracellular GABA in the striatum in the days preceding such damage, speculating that a loss of GABA may be in part responsible for this damage. This study evaluates the GABA levels in the SNr in animals exposed to repetitive ischemic insults. Each animal received a total of three ischemic insults of 3-min duration at hourly intervals. In vivo microdialysis was carried out to analyze the GABA and glutamate dialysate levels on Days 1, 3, 5, 7, and 14 following the ischemic insult. In the control and treated (ischemic) animals, there was a significant increase in the GABA levels with the introduction of nipecotic acid on Days 1, 3, 5, and 14. However, on Day 7 there was a significant attenuation in the GABA response to nipecotic acid in the treated animals in comparison to the controls. The glutamate levels in the treated animals were similar to the control animals on Days 1, 3, 5, and 7. However, on Day 14 the glutamate levels were significantly lower than on previous days. Our experiments for the first time measure extracellular glutamate and GABA responses in the SNr in animals exposed to repetitive ischemic insults. Our experiments show that there is a significant decrease in the GABA concentrations at a time when ischemic damage is developing in this region. This confirms our hypothesis that a decrease in GABA may be one factor contributing to neuronal damage during the period following repetitive ischemic insults. Further, the rebound increase in GABA levels on Day 14 with a concomitant fall in glutamate levels would indicate that reparative processes are still active in the 2 weeks following the insult. 相似文献
5.
The systematic relation between thin film transistors' (TFT's) characteristics and the deposition conditions of amorphous silicon nitride (a-SiN) films and hydrogenated amorphous silicon (a-Si:H) films is investigated. It is observed that field effect mobility μFE and threshold voltage Vth of the TFT's strongly depend on the deposition conditions of these films. The maximum μFE of 0.88 cm2/V·s is obtained for the TFT of which a-SiN film is deposited at a pressure of 85 Pa. This phenomenon is due to the variation of the interface states density between a-Si:H film and a-SiN film 相似文献
6.
Chaosuan Kanchanomai Yukio Miyashita Yoshiharu Mutoh 《Journal of Electronic Materials》2002,31(5):456-465
Low-cycle fatigue (LCF) tests on as-cast Sn-3.5Ag, Sn-3Ag-0.5Cu, Sn-3Ag-0.5Cu-1Bi, and Sn-3Ag-0.5Cu-3Bi solders was carried
out using a noncontact strain-controlled system at 20°C with a constant frequency of 0.1 Hz. The addition of Cu does not significantly
affect the fatigue life of eutectic Sn-Ag solder. However, the fatigue life was significantly reduced with the addition of
Bi. The LCF behavior of all solders followed the Coffin-Manson relationship. The fatigue life of the present solders is dominated
by the fracture ductility and can be described by the ductility-modified Coffin-Manson’s relationship. Steps at the boundaries
of dendrite phases were the initiation sites for microcracks for Sn-3.5Ag, Sn-3Ag-0.5Cu, and Sn-3Ag-0.5Cu-1Bi solders, while
for Sn-3Ag-0.5Cu-3Bi solder, cracks initiated along both the dendrite boundaries and subgrain boundaries in the dendrite phases.
The linking of these cracks and the propagation of cracks inside the specimen occurred both transgranularly through eutectic
phases and intergranularly along dendrite boundaries or subgrain boundaries. 相似文献
7.
Mio Yamaguchi Kiyoshi Takagi Koki Narita Yasuhiro Miki Yoshiaki Onodera Minoru Miyashita Hironobu Sasano Takashi Suzuki 《International journal of molecular sciences》2021,22(4)
Chemokines secreted from stromal cells have important roles for interactions with carcinoma cells and regulating tumor progression. C-C motif chemokine ligand (CCL) 5 is expressed in various types of stromal cells and associated with tumor progression, interacting with C-C chemokine receptor (CCR) 1, 3 and 5 expressed in tumor cells. However, the expression on CCL5 and its receptors have so far not been well-examined in human breast carcinoma tissues. We therefore immunolocalized CCL5, as well as CCR1, 3 and 5, in 111 human breast carcinoma tissues and correlated them with clinicopathological characteristics. Stromal CCL5 immunoreactivity was significantly correlated with the aggressive phenotype of breast carcinomas. Importantly, this tendency was observed especially in the CCR3-positive group. Furthermore, the risk of recurrence was significantly higher in the patients with breast carcinomas positive for CCL5 and CCR3 but negative for CCR1 and CCR5, as compared with other patients. In summary, the CCL5-CCR3 axis might contribute to a worse prognosis in breast cancer patients, and these findings will contribute to a better understanding of the significance of the CCL5/CCRs axis in breast carcinoma microenvironment. 相似文献
8.
The sorption and the permeation of iodine in water-swollen poly(vinyl alcohol) (PVA) membranes and the formation of PVA–iodine complexes were studied. The logarithms of the permeability and the diffusion coefficient decreased approximately linearly with the increase in polymer volume fraction. When the membrane was soaked in an aqueous I2–KI solution, it contracted and Young's modulus increased. These findings were explained in terms of the formation of extra junction points due to the PVA–iodine complexes. These changes were reversible and could be recovered by replacing the solution with water. The length of the polyiodine chain increased with the increase in the degree of hydration of the membrane. At a fixed degree of hydration, Young's modulus of an iodine-sorbed membrane was much greater than that of a membrane soaked in pure water. This finding was explained on the basis of a double-network structure. The extension of the membrane promoted the complex formation, and the complex disappeared when the tension was released. The critical strain necessary for the complex formation was independent of the degree of hydration. The length of polyiodine chain increased with strain and became constant at higher strains. 相似文献
9.
Keizo Uematsu Jin-Young Kim Masayori Miyashita Nozomu Uchida Katsuichi Saito 《Journal of the American Ceramic Society》1990,73(8):2555-2557
The internal structure of spray-dried alumina granules was characterized by optical microscopy by immersing them in a liquid having a refractive index close to that of alumina. This method provides a unique technique for the detailed analysis of the internal structure of spray-dried granules. 相似文献
10.
Shin'ichiro Asai Ueki Saruta Masayuki Tobita Minoru Takano Yasuo Miyashita 《应用聚合物科学杂志》1995,56(7):769-777
A thermoset type anisotropic conductive adhesive film (ACAF), which electrically connects an ITO glass and a flex circuit both having conducting pattersn of less than 100 μm in pitch, has been developed. In this development, bisphenol A and bisphenol F epoxy resins were tested to formulate an ACAF with easy-to-handle tackiness, flexibility, and strenght. A curing agent that gives fast cure and long shelf-life properties to the epoxy resin was also selected. The tensile stress–strain responses of obtained adhesive films were successfully used for determining the formulation. Good aftercure physical properties (electrical and mechanical) were obtained. Durability against high temperature and high humidity were also tested to confirm long-term stability of the conduction of this ACAF. © 1995 John Wiley & Sons, Inc. 相似文献