全文获取类型
收费全文 | 1111篇 |
免费 | 30篇 |
国内免费 | 12篇 |
专业分类
电工技术 | 63篇 |
综合类 | 5篇 |
化学工业 | 332篇 |
金属工艺 | 30篇 |
机械仪表 | 41篇 |
建筑科学 | 18篇 |
能源动力 | 55篇 |
轻工业 | 116篇 |
水利工程 | 2篇 |
无线电 | 57篇 |
一般工业技术 | 230篇 |
冶金工业 | 115篇 |
原子能技术 | 39篇 |
自动化技术 | 50篇 |
出版年
2023年 | 3篇 |
2022年 | 8篇 |
2021年 | 17篇 |
2020年 | 8篇 |
2019年 | 16篇 |
2018年 | 5篇 |
2017年 | 17篇 |
2016年 | 19篇 |
2015年 | 13篇 |
2014年 | 27篇 |
2013年 | 60篇 |
2012年 | 35篇 |
2011年 | 70篇 |
2010年 | 58篇 |
2009年 | 65篇 |
2008年 | 55篇 |
2007年 | 49篇 |
2006年 | 49篇 |
2005年 | 39篇 |
2004年 | 52篇 |
2003年 | 41篇 |
2002年 | 44篇 |
2001年 | 30篇 |
2000年 | 28篇 |
1999年 | 29篇 |
1998年 | 52篇 |
1997年 | 34篇 |
1996年 | 26篇 |
1995年 | 21篇 |
1994年 | 21篇 |
1993年 | 10篇 |
1992年 | 13篇 |
1991年 | 18篇 |
1990年 | 11篇 |
1989年 | 13篇 |
1988年 | 12篇 |
1987年 | 4篇 |
1986年 | 12篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 10篇 |
1976年 | 5篇 |
1973年 | 3篇 |
1970年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有1153条查询结果,搜索用时 15 毫秒
131.
The effects of PAF antagonists, of substances which influence the arachidonic acid metabolism, and of dexamethasone and ketotifen were evaluated in an acute PAF-induced mortality model in female NMRI mice. We established a dependence of sensitivity to PAF on strain (AB mice showed no dose dependence) and on sex of the animals as well as on the PAF charges used in our experiments. PAF produced resistance in surviving animals against the PAF-induced death on repeated application. The PAF antagonists, WEB 2170 and WEB 2086, provided the best dose-dependent protection against PAF toxicity, followed by dexamethasone, by the COX/LOX synthetase inhibitor X 86 (a BW 755 C-analogue) and by the PAF receptor antagonist BN 52021. Particularly remarkable was the excellent prevention by aspirin. Aspirin may not only inhibit the cyclooxygenase pathway but also endogenous PAF synthesis. Other drugs, i.e. indomethacin, the thromboxane receptor antagonist, BM 13177, the thromboxane synthetase inhibitor, HOE 944, as well as the lipoxygenase inhibitors (NDGA, esculetin, SHAM and phenidone) exerted a dose-dependent protection only at high doses. 相似文献
132.
Minoru Furukawa Patrick B. Berbon Terence G. Langdon Zenji Horita Minoru Nemoto Nikolai K. Tsenev Ruslan Z. Valiev 《Metallurgical and Materials Transactions A》1998,29(1):169-177
Experiments were conducted to determine the age-hardening characteristics and the mechanical properties of an Al-5.5 pct Mg-2.2
pct Li-0.12 pct Zr alloy processed by equal-channel angular (ECA) pressing to give a very fine grain size of ∼1.2 μm. The results show that peak aging occurs more rapidly when the grain size is very fine, and this effect is interpreted in
terms of the higher volume of precipitate-free zones in the fine-grained material. Mechanical testing demonstrates that the
ECA-pressed material exhibits high strength and good ductility at room temperature compared to conventional Al alloys containing
Li. Elongations of up to ∼550 pct may be achieved at an elevated temperature of 603 K in the ECA-pressed condition, thereby
confirming that, in this condition, the alloy may be a suitable candidate material for use in superplastic forming operations. 相似文献
133.
When a flexible arm is rotated by a motor about an axis through the arm's fixed end, transverse vibration may occur. The motor torque should be controlled in such a way that the motor rotates by a specified angle, while simultaneously stabilizing vibration of the flexible arm so that it is arrested as soon as possible at the end of rotation. In this paper, we first derive a partial differential equation and a set of boundary conditions governing the vibration. Then, a feedback control system which incorporates a dynamic compensator is designed using sensor outputs. A set of experiments has been constructed to demonstrate control strategies for a flexible arm, where a strain gage was used as a vibration sensor and a microcomputer was equipped as a controller. Several satisfactory experimental results are shown. 相似文献
134.
Kazuhiro Yamanaka Yoshiyuki WatanabeKazunori Yoshimoto Yasutaka UdaMasato Nomura 《Food chemistry》2010
The bran collected at each of the five steps of milling yields (98–100%, 96–98%, 94–96%, 92–94% and 90–92%) was defatted. Defatted rice bran (DRB) was added to methyl linoleate (ML) under various conditions, and its suppressive effect on lipid oxidation was kinetically evaluated to investigate the effective use of surplus rice bran. The rate constant, k, empirically evaluated by the Weibull equation for the oxidation of ML with DRB, was lower than that without DRB and decreased with increasing the maximum milling yield of added DRB. The oxidation of ML strongly depended on the added amount of DRB, but the k value was almost constant for a specific amount of DBR added to ML. The dependency of the k value on relative humidity was weak, regardless of the addition of DRB. The difference between the k values for oxidation processes of ML, with and without DRB, increased with increasing temperature. 相似文献
135.
Fujiwara Y Kimura H Miyati T Kabasawa H Matsuda T Ishimori Y Yamaguchi I Adachi T 《Magma (New York, N.Y.)》2012,25(2):103-111
Object
To propose a new arterial spin labeling (ASL) perfusion-imaging method (alternate slab width inversion recovery ASL: AIRASL) that takes advantage of the qualities of 3.0 T. 相似文献136.
Aniwat Hasook Hiroki Muramatsu Shuichi Tanoue Yoshiyuki Iemoto Tsunemune Unryu 《Polymer Composites》2008,29(1):1-8
This study analyzes the effect of different screw rotating speeds on the clay dispersion and mechanical properties of nanocomposites prepared by melt compounding polylactic acid (PLA) with an organoclay in a co‐rotating twin screw extruder. Polyamide 12 (PA12) was used as an additive. Two different screw rotating speeds, 65 rpm and 150 rpm, were used in this study. According to the tensile strength data, the Young's modulus of the PLA/clay nanocomposites showed improvement at a screw rotating speed of 150 rpm. The Young's modulus improved with the addition of the organoclay to PLA matrix, but decreased when PA12 was added to the PLA matrix. The tensile strengths and elongations become small by adding organoclay to PLA matrix. The tensile strengths of the PLA/organoclay nanocomposites increased for the higher screw rotating speed (150 rpm). The d‐spacing of PLA/PA12/Clay nanocomposites was independent of the addition of PA12. The size of the clay aggregates in the PLA/PA12/Clay nanocomposites is smaller than that of PLA/Clay. Furthermore, the thermal stability of the PLA/Clay nanocomposite increases with addition of PA12, while on the whole, it had little influence on the tensile properties. POLYM. COMPOS., 29:1–8, 2008. © 2007 Society of Plastics Engineers 相似文献
137.
Che-Jui Yeh Chiao-Chu Ku Wei-Chen Lin Chiao-Yuan Fan Prof. Dr. Medel Manuel L. Zulueta Dr. Yoshiyuki Manabe Prof. Dr. Koichi Fukase Prof. Dr. Yaw-Kuen Li Prof. Dr. Shang-Cheng Hung 《Chembiochem : a European journal of chemical biology》2019,20(2):237-240
Many circulating cancer-related proteins, such as fibroblast growth factors (FGFs), associate with glycosaminoglycans—particularly heparan sulfate—at the cell surface. Disaccharide analogues of heparan sulfate had previously been identified as the shortest components out of the sugars that bind to FGF-1 and FGF-2. Taking note of the typical pose of l -iduronic acid, we conceived of per-O-sulfonated analogues of such disaccharides, and devised a single-step procedure for per-O-sulfonation of unprotected sugars with concomitant 1,6-anhydro bridge formation to achieve such compounds through direct use of SO3 ⋅ Et3N as sulfonation reagent and dimethylformamide as solvent. The synthesized sugars based on the oligomaltose backbone bound FGF-1 and FGF-2 mostly at the sub-micromolar level, although the tetrasaccharide analogue achieved low-nanomolar binding with FGF-2. 相似文献
138.
Daisuke Yamanaka Suzuka Kurita Yuka Hanayama Yoshiyuki Adachi 《International journal of molecular sciences》2021,22(4)
β-Glucan is widely distributed in various plants and microorganisms and is composed of β-1,3-linked d-glucose units. It may have a branched short or long side chain of glucose units with β-1,6- or β-1,4-linkage. Numerous studies have investigated different β-glucans and revealed their bioactivities. To understand the structure-function relationship of β-glucan, we constructed a split-luciferase complementation assay for the structural analysis of long-chain β-1,6-branched β-1,3-glucan. The N- and C-terminal fragments of luciferase from deep-sea shrimp were fused to insect-derived β-1,3-glucan recognition protein and fungal endo-β-1,6-glucanase (Neg1)-derived β-1,6-glucan recognition protein, respectively. In this approach, two β-glucan recognition proteins bound to β-glucan molecules come into close proximity, resulting in the assembly of the full-length reporter enzyme and induction of transient luciferase activity, indicative of the structure of β-glucan. To test the applicability of this assay, β-glucan and two β-glucan recognition proteins were mixed, resulting in an increase in the luminescence intensity in a β-1,3-glucan with a long polymer of β-1,6-glucan in a dose-dependent manner. This simple test also allows the monitoring of real-time changes in the side chain structure and serves as a convenient method to distinguish between β-1,3-glucan and long-chain β-1,6-branched β-1,3-glucan in various soluble and insoluble β-glucans. 相似文献
139.
Trans‐fatty acid promotes thrombus formation in mice by aggravating antithrombogenic endothelial functions via Toll‐like receptors
下载免费PDF全文
![点击此处可从《Molecular nutrition & food research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kensuke Kondo Tatsuro Ishida Tomoyuki Yasuda Hideto Nakajima Kenta Mori Nobuaki Tanaka Takeshige Mori Tomoko Monguchi Masakazu Shinohara Yasuhiro Irino Ryuji Toh Yoshiyuki Rikitake Kazunobu Kiyomizu Yoshiaki Tomiyama Junichiro Yamamoto Ken‐ichi Hirata 《Molecular nutrition & food research》2015,59(4):729-740
140.
Cristina Di Carluccio Enrique Crisman Prof. Yoshiyuki Manabe Rosa Ester Forgione Dr. Alessandra Lacetera Dr. Jussara Amato Dr. Bruno Pagano Prof. Antonio Randazzo Prof. Angela Zampella Prof. Rosa Lanzetta Prof. Koichi Fukase Prof. Antonio Molinaro Prof. Paul R. Crocker Prof. Sonsoles Martín-Santamaría Dr. Roberta Marchetti Prof. Alba Silipo 《Chembiochem : a European journal of chemical biology》2020,21(1-2):129-140
CD22 (Siglec-2) is a B-cell surface inhibitory protein capable of selectively recognising sialylated glycans, thus dampening autoimmune responses against self-antigens. Here we have characterised the dynamic recognition of complex-type N-glycans by human CD22 by means of orthogonal approaches including NMR spectroscopy, computational methods and biophysical assays. We provide new molecular insights into the binding mode of sialoglycans in complex with h-CD22, highlighting the role of the sialic acid galactose moieties in the recognition process, elucidating the conformational behaviour of complex-type N-glycans bound to Siglec-2 and dissecting the formation of CD22 homo-oligomers on the B-cell surface. Our results could enable the development of additional therapeutics capable of modulating the activity of h-CD22 in autoimmune diseases and malignancies derived from B-cells. 相似文献