全文获取类型
收费全文 | 5200篇 |
免费 | 153篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 260篇 |
综合类 | 10篇 |
化学工业 | 1261篇 |
金属工艺 | 135篇 |
机械仪表 | 112篇 |
建筑科学 | 121篇 |
矿业工程 | 2篇 |
能源动力 | 201篇 |
轻工业 | 451篇 |
水利工程 | 9篇 |
石油天然气 | 8篇 |
武器工业 | 2篇 |
无线电 | 497篇 |
一般工业技术 | 820篇 |
冶金工业 | 928篇 |
原子能技术 | 99篇 |
自动化技术 | 446篇 |
出版年
2023年 | 24篇 |
2022年 | 44篇 |
2021年 | 117篇 |
2020年 | 47篇 |
2019年 | 49篇 |
2018年 | 73篇 |
2017年 | 69篇 |
2016年 | 99篇 |
2015年 | 70篇 |
2014年 | 149篇 |
2013年 | 257篇 |
2012年 | 223篇 |
2011年 | 249篇 |
2010年 | 200篇 |
2009年 | 227篇 |
2008年 | 234篇 |
2007年 | 210篇 |
2006年 | 168篇 |
2005年 | 181篇 |
2004年 | 129篇 |
2003年 | 138篇 |
2002年 | 132篇 |
2001年 | 111篇 |
2000年 | 108篇 |
1999年 | 109篇 |
1998年 | 407篇 |
1997年 | 236篇 |
1996年 | 174篇 |
1995年 | 122篇 |
1994年 | 117篇 |
1993年 | 109篇 |
1992年 | 58篇 |
1991年 | 57篇 |
1990年 | 46篇 |
1989年 | 67篇 |
1988年 | 42篇 |
1987年 | 33篇 |
1986年 | 47篇 |
1985年 | 42篇 |
1984年 | 43篇 |
1983年 | 37篇 |
1982年 | 27篇 |
1981年 | 36篇 |
1980年 | 29篇 |
1979年 | 31篇 |
1978年 | 28篇 |
1977年 | 41篇 |
1976年 | 49篇 |
1975年 | 13篇 |
1974年 | 16篇 |
排序方式: 共有5362条查询结果,搜索用时 296 毫秒
1.
Makoto Yamaguchi 《应用聚合物科学杂志》2021,138(14):50172
Perfluorosulfonic acid ionomer membranes have been widely used as proton conducting membranes in various electrochemical processes such as polymer electrolyte fuel cells and water electrolysis. While their thermal stability has been studied by thermogravimetry and analysis of low molecular weight products, their decomposition mechanism is little understood. In this study a newly developed methodology of thermal desorption and pyrolysis in combination with direct analysis in real time mass spectrometry is applied for Nafion membrane. An ambient ionization source and a high-resolution time-of-flight mass spectrometer enabled unambiguous assignment of gaseous products. Thermal decomposition is initiated by side chain detachment above 350°C, which leaves carbonyls on the main chain at the locations of the side chains. Perfluoroalkanes are released above 400°C by main chain scission and their further decomposition products dominate above 500 °C. DFT calculation of reaction energies and barrier heights of model compounds support proposed decomposition reactions. 相似文献
2.
Abidur Rahman Makoto Kobayashi Kotaro Sugimoto Yuta Endo Manabu Kojima Shigenori Furukawa Takafumi Watanabe Shu Soeda Yuko Hashimoto Keiya Fujimori Hideki Chiba 《International journal of molecular sciences》2021,22(7)
Background: Within the claudin (CLDN) family, CLDN12 mRNA expression is altered in various types of cancer, but its clinicopathological relevance has yet to be established due to the absence of specific antibodies (Abs) with broad applications. Methods: We generated a monoclonal Ab (mAb) against human/mouse CLDN12 and verified its specificity. By performing immunohistochemical staining and semiquantification, we evaluated the relationship between CLDN12 expression and clinicopathological parameters in tissues from 138 cases of cervical cancer. Results: Western blot and immunohistochemical analyses revealed that the established mAb selectively recognized the CLDN12 protein. Twenty six of the 138 cases (18.8%) showed low CLDN12 expression, and the disease-specific survival (DSS) and recurrence-free survival rates were significantly decreased compared with those in the high CLDN12 expression group. We also demonstrated, via univariable and multivariable analyses, that the low CLDN12 expression represents a significant prognostic factor for the DSS of cervical cancer patients (HR 3.412, p = 0.002 and HR 2.615, p = 0.029, respectively). Conclusions: It can be concluded that a reduced CLDN12 expression predicts a poor outcome for cervical cancer. The novel anti-CLDN12 mAb could be a valuable tool to evaluate the biological relevance of the CLDN12 expression in diverse cancer types and other diseases. 相似文献
3.
Aniruddha Nag Mohammed Asif Ali Jiabei Zhou Makoto Ogawa Tatsuo Kaneko 《大分子材料与工程》2021,306(11):2100459
Aromatic and functional polymers with processibility derived from biobased starting materials are prerequisite considering sustainable society. Poly(2,5-benzimidazole)s are rigid-rod polymers to show ultrahigh thermal stability such as flame retardance, while usually suffer from poor solubility. Here, poly(benzimidazole-co-amide)s are synthesized from two biobased monomers, 3,4-diaminobenzoic acid and a semirigid comonomer, 4-aminohydrocinnamic acid. The copolymers with an amide composition of 80 mol% and higher are soluble in widely used polar solvents to fabricate the films keeping high flame retardance, which is comparable with popular high-performance polymers such as aromatic polyimides, polyetheretherketone, polyphenylene sulfide, etc. 相似文献
4.
Lili Hao Jiaxiang Li Peng Wang Zongliang Wang Zhenxu Wu Yu Wang Zixue Jiao Min Guo Tongfei Shi Qigang Wang Yoshihiro Ito Yen Wei Peibiao Zhang 《Advanced functional materials》2021,31(15):2009661
The degradation behavior of implants is significantly important for bone repair. However, it is still unprocurable to spatiotemporally regulate the degradation of the implants to match bone ingrowth. In this paper, a magneto-controlled biodegradation model is established to explore the degradation behavior of magnetic scaffolds in a magnetothermal microenvironment generated by an alternating magnetic field (AMF). The results demonstrate that the scaffolds can be heated by magnetic nanoparticles (NPs) under AMF, which dramatically accelerated scaffold degradation. Especially, magnetic NPs modified by oleic acid with a better interface compatibility exhibit a greater heating efficiency to further facilitate the degradation. Furthermore, the molecular dynamics simulations reveal that the enhanced motion correlation between magnetic NPs and polymer matrix can accelerate the energy transfer. As a proof-of-concept, the feasibility of magneto-controlled degradation for implants is demonstrated, and an optimizing strategy for better heating efficiency of nanomaterials is provided, which may have great instructive significance for clinical medicine. 相似文献
5.
6.
7.
Ohsaki Makoto Fujiwara Jun Takeda Fumiyoshi 《International Journal of Mechanics and Materials in Design》2020,16(4):883-896
International Journal of Mechanics and Materials in Design - A simple iterative method is presented for cutting pattern optimization of frame-supported and pneumatic membrane structures for... 相似文献
8.
9.
A Oyane M Kasahara N Ichinose Y Yokoyama M Uchida A Ito 《武汉理工大学学报(材料科学英文版)》2005,20(B12):220-222
A synthetic polymer with a laminin-apatite composite layer on its surface would be useful as a percutaneous device. The preparation of such a composite was attempted in the present study using poly( ethylene terephthalate ) (PET) and polyethylene (PE) as the synthetic polymer. PET and PE plates and those pretreated with an oxygen plasma were alternately dipped in calcium and phosphate ion solutions, and then immersed in a metastable calcium phosphate solution supplemented with laminin ( LCP solution ). The PET and PE plates pretreated with an oxygen plasma formed a uniform and continuous layer of a laminin-apatite composite on their surfaces. In contrast, the PET and PE plates that had not been pretreated with an oxygen plasma did not form a continuous layer of a laminin-apatite composite on their surfaces. The hydrophilic functional groups on the PET and PE surfaces introduced by the plasma treatment were responsible for the successful laminin-apatite coruposite coating. 相似文献
10.
We present simulation results of the vortex dynamics in a trapped Bose-Einstein condensate in the presence of a rotating optical
lattice. Changing the potential amplitude and the relative rotation frequency between the condensate and the optical lattice,
we find a rich variety of dynamical phases of vortices. In particular, when the optical lattice rotates faster than the condensate,
the competition between the pinning force and the interactions by nucleated interstitial vortices leads to the melting of
vortex lattice, yielding a vortex liquid phase. 相似文献