全文获取类型
收费全文 | 1355篇 |
免费 | 22篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 29篇 |
综合类 | 1篇 |
化学工业 | 278篇 |
金属工艺 | 51篇 |
机械仪表 | 37篇 |
建筑科学 | 20篇 |
能源动力 | 37篇 |
轻工业 | 128篇 |
水利工程 | 12篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 127篇 |
一般工业技术 | 205篇 |
冶金工业 | 359篇 |
原子能技术 | 23篇 |
自动化技术 | 72篇 |
出版年
2023年 | 3篇 |
2022年 | 18篇 |
2021年 | 17篇 |
2020年 | 6篇 |
2019年 | 11篇 |
2018年 | 15篇 |
2017年 | 6篇 |
2016年 | 19篇 |
2015年 | 11篇 |
2014年 | 22篇 |
2013年 | 55篇 |
2012年 | 51篇 |
2011年 | 70篇 |
2010年 | 48篇 |
2009年 | 50篇 |
2008年 | 60篇 |
2007年 | 49篇 |
2006年 | 34篇 |
2005年 | 41篇 |
2004年 | 28篇 |
2003年 | 41篇 |
2002年 | 42篇 |
2001年 | 31篇 |
2000年 | 31篇 |
1999年 | 32篇 |
1998年 | 123篇 |
1997年 | 87篇 |
1996年 | 59篇 |
1995年 | 38篇 |
1994年 | 25篇 |
1993年 | 37篇 |
1992年 | 20篇 |
1991年 | 23篇 |
1990年 | 13篇 |
1989年 | 23篇 |
1988年 | 15篇 |
1987年 | 13篇 |
1986年 | 14篇 |
1985年 | 18篇 |
1984年 | 14篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 8篇 |
1976年 | 11篇 |
1974年 | 5篇 |
1967年 | 2篇 |
排序方式: 共有1381条查询结果,搜索用时 15 毫秒
1.
M Furuta K Hayakawa S Katano Y Saito Y Nakayama T Takahashi R Imai T Ebara N Mitsuhashi H Niibe 《Canadian Metallurgical Quarterly》1996,26(2):95-98
Vaccination with peptides that induce a specific immune response is a potential prophylactic or therapeutic strategy against viral infections and tumors. Because of the extensive polymorphism of the HLA loci, synthetic peptide vaccines must consist of a cocktail of peptides that bind specifically to different HLA molecules. Such cocktails should be optimized for the target population as each population has its specific HLA gene frequencies. To achieve maximum population coverage with a minimum number of peptides, information is needed on the ranking of the most frequent HLA phenotypes. We introduce the minimal phenotype panel, which is the smallest combination of HLA antigens selected so that the proportion of individuals in a population that express at least one of the antigens in the panel exceeds a desired minimum value. We developed a method for assembling minimal phenotype panels based on known HLA class I gene frequencies. We give an example based on a set of 2446 well-defined HLA-typed, random, healthy, unrelated, Dutch Caucasoid individuals. In addition, we discuss the possibility of assembling minimal phenotype panels based on two-locus haplotypes, which enables the assembly of phenotype panels from the antigens of both loci. 相似文献
2.
K Ku K Nakayama Y Saitoh S Nosaka T Kitano T Hanada H Nagami K Yamada K Minami 《Canadian Metallurgical Quarterly》1997,64(2):399-403
Forty-eight Russell's viper bite patients (40 males, 8 females), age ranging from 16-76 years were studied. Out of 48 patients, 14 were found to have a prolonged whole blood clotting time test (WBCT) (i.e. incoagulable blood) (Group 1); 23 had a normal WBCT (i.e. clotted blood) (Group II); and 11 patients had a normal WBCT on admission which changed to non-clotting during the clinical course (Group III). Four patients from group I developed hypotension and 2 expired. The serum cortisol concentration (mean +/- SEM) on admission among groups I and II were 639 +/- 45.6 and 424 +/- 33.2 nmol/l respectively. The blood cortisol level in 35 subjects (controls) were 370.7 +/- 17.7 nmol/l (mean +/- SEM). There was a significant rise of blood cortisol in patients with incoagulable blood when compared to controls at the time of admission to the hospital (p < 0.05); but there was no significant difference among those patients with clotted blood. A much higher mean serum cortisol level was observed in 4 patients with hypotension as compared to 10 patients without shock. These patients with hypotension according to our study shown to have a favorable response to steroid therapy and eventually recovered. Whether higher doses of steroid in addition to antiserum confer extra benefit in suppressing nonspecific venom effects on the pituitary and/or adrenal is not known. 相似文献
3.
4.
Wakejima A. Matsunaga K. Okamoto Y. Ando Y. Nakayama T. Miyamoto H. 《Electronics letters》2005,41(25):1371-1372
A single-ended amplifier using small packaged GaN-FETs exhibits a record 2.14 GHz W-CDMA output power. The amplifier, composed of paralleled 48 mm gate periphery FET die, delivers a peak saturated output power of 371 W with a linear gain of 11.2 dB at a drain voltage of 45 V under 2.14 GHz 3GPP W-CDMA signal input. The output power density (output power/package size) of 1.1 W/mm/sup 2/ is twice as high as that of the existing over 300 W GaAs-FET amplifiers. A low 5 MHz offset ACLR of -36 dBc with a drain efficiency of 24% is also obtained at 8 dB power back off from the saturated output power. 相似文献
5.
K Nakayama K Takahashi LD Shultz K Miyakawa K Tomita 《Canadian Metallurgical Quarterly》1997,78(4):245-257
In mice homozygous for the 'viable motheaten' (mev) mutation, numbers of macrophage progenitor cells, particularly monocytes, were markedly increased in the bone marrow and spleen. Increased mobilization of these precursor cells to peripheral tissues and their differentiation to macrophages were evidenced by striking increases in macrophage numbers. Immunohistochemical double staining of tissue sections and flow cytometry analyses of single cell suspensions from these mice demonstrated CD5 (Ly-1)-positive macrophages in the peritoneal cavity, spleen and other tissues. Ly-1-positive macrophage precursor cells were demonstrated in the peritoneal cavity of the mev mice and developed in the omental milky spots. The development of marginal metallophilic and marginal zone macrophages was poor in the splenic white pulp and related macrophage populations were absent in the other lymphoid tissues. The numbers of epidermal Langerhans cells in the skin and T cell-associated dendritic cells in the thymic medulla, lymph nodes, and the other peripheral lymphoid tissues were decreased. However, increased numbers of dendritic cells accumulated in the lungs, liver, and kidneys. These abnormalities in development and differentiation of macrophages and dendritic cells may be ascribed to the deficiency in haematopoietic cell SHP-1 tyrosine phosphatase or may be a secondary consequence of abnormal microenvironments, (either constitutive or in response to inflammatory stimuli) in the haematopoietic and lymphopoietic organs and tissues of these mice. 相似文献
6.
S. Arimoto T. Nakayama 《Mechatronics, IEEE/ASME Transactions on》1996,1(2):168-180
Dynamics and control of nonlinear mechanical systems and advanced mechatronic systems can be investigated more vividly and efficiently by using corresponding nonlinear position-dependent circuits that describe Lagrange's equations of motions and interactions with objects or/and task environments. Such expressions of Lagrange's equations via nonlinear circuits are indebted to lumped-parameter discretization of mechanical systems as a set of rigid bodies through equations of motion due to Newton's second law. This observation is quite analogous to validity of electric circuits that can be derived as lumped parameter versions of Maxwell's equations of electromagnetic waves. Couplings of nonlinear mechanical circuits with electrical circuits through actuator dynamics are also discussed. In such electromechanical circuits the passivity should be a generalization of impedance concept in order to cope with general nonlinear position-dependent circuits and play a crucial role in their related motion control problems. In particular, it is shown that the passivity as an input-output property gives rise to a necessary and sufficient characterization of H/sub /spl infin//-tuning for disturbance attenuation of robotic systems, which can give another system theoretic interpretation of the energy conservation law. 相似文献
7.
T. Tanaka H. Nakayama K. Kimura 《Fatigue & Fracture of Engineering Materials & Structures》1985,8(1):13-22
The impact fatigue crack growth characteristics of a low carbon steel and an aluminium alloy were studied. An impact fatigue testing machine of the Hopkinson bar type was used in these experiments to conduct a series of crack growth tests under simple impact stresses. The following characteristics of impact fatigue crack growth behaviour were revealed: (1) crack growth rate is higher in impact fatigue than in non-impact fatigue; (2) crack opening ratio in impact fatigue takes a higher value than in non-impact fatigue; (3) crack tip plastic zone size is smaller in impact fatigue than in non-impact fatigue. 相似文献
8.
The roller drawing of ultrahigh molecular weight polyethylene (UHMW-PE) sheets were carried out in the roller temperature Tr range of 100–140°C. In addition to the roller drawing in the solid state (Tr = 100°C), we attempted to crystallize the molten UHMW-PE sheet under the roller-drawing process (Tr = 100–140°C). The tensile and dynamic viscoelastic properties, the molecular orientation, and the microstructure of the roller-drawn UHMW-PE sheets were investigated. The mechanical properties of UHMW-PE sheets were much improved by crystallization during the roller drawing process at Tr = 140°C. The sheets roller-drawn at Tr = 135 and 140°C exhibited c-axis orientation to the draw direction and (100) alignment in the sheet plane. However, at Tr = 100°C the elastic motion of the amorphous chains induces the twinnings of lattice, which enhances the transition to the (110) alignment in the sheet plane. The dynamic storage modulus below γ-dispersion temperature showed good correlation with crystallinity and orientation functions, while taut tie molecules and thick crystallites play an important role in the storage modulus above γ-dipersion temperature. 相似文献
9.
This paper analyzes the factors underpinning transboundary Environmental Impact Assessment (EIA) methodologies through an examination of the Navigation Channel Improvement Project of the Lancang-Mekong River from China-Myanmar Boundary Marker 243 to Ban Houei Sai of Laos. A comparison of the project's expected and reported transboundary impacts shows that the EIA failed to predict a number of adverse impacts, including social and economic impacts. The restricted scale and scope of the transboundary impact assessment (TIA) is probably due to certain fundamental restrictions on how the EIA was conducted. The case study highlights the importance of public involvement (including advance notification) and adequate regulatory frameworks or guidelines in the EIA and TIA processes. 相似文献
10.
Hitoshi Kurokawa Taku Nakayama Yasunori Kobayashi Ken Suzuki Mutsumi Takahashi Seiichi Takami Momoji Kubo Naotsugu Itoh Parasuraman Selvam Akira Miyamoto 《Catalysis Today》2003,82(1-4):233-240
A modified Monte Carlo (MC) simulation was performed to investigate the hydrogen absorption behavior in Pd and Pd–Ag alloys of the composition PdxAg1−x (x=0.7–0.8) under H2 pressure (0.1 MPa) at different temperatures. The present method employed can consider the dissociative adsorption of hydrogen molecule and the subsequent absorption of hydrogen atom by formalizing the relationship between the pressure of hydrogen molecule and hydrogen atom. The potential parameters were determined to reproduce the solution enthalpy of hydrogen in pure metals. The results are in good agreement with experimental findings as well as previous theoretical studies. We confirmed that our method is useful to simulate the absorption of hydrogen in metals and alloys. 相似文献