全文获取类型
收费全文 | 3614篇 |
免费 | 130篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 42篇 |
综合类 | 14篇 |
化学工业 | 1099篇 |
金属工艺 | 75篇 |
机械仪表 | 48篇 |
建筑科学 | 206篇 |
矿业工程 | 6篇 |
能源动力 | 56篇 |
轻工业 | 379篇 |
水利工程 | 40篇 |
石油天然气 | 2篇 |
无线电 | 189篇 |
一般工业技术 | 712篇 |
冶金工业 | 394篇 |
原子能技术 | 26篇 |
自动化技术 | 458篇 |
出版年
2023年 | 41篇 |
2022年 | 60篇 |
2021年 | 76篇 |
2020年 | 45篇 |
2019年 | 68篇 |
2018年 | 56篇 |
2017年 | 55篇 |
2016年 | 92篇 |
2015年 | 92篇 |
2014年 | 105篇 |
2013年 | 182篇 |
2012年 | 188篇 |
2011年 | 223篇 |
2010年 | 164篇 |
2009年 | 180篇 |
2008年 | 177篇 |
2007年 | 164篇 |
2006年 | 148篇 |
2005年 | 142篇 |
2004年 | 111篇 |
2003年 | 80篇 |
2002年 | 78篇 |
2001年 | 68篇 |
2000年 | 68篇 |
1999年 | 80篇 |
1998年 | 93篇 |
1997年 | 78篇 |
1996年 | 53篇 |
1995年 | 57篇 |
1994年 | 56篇 |
1993年 | 41篇 |
1992年 | 44篇 |
1991年 | 47篇 |
1990年 | 29篇 |
1989年 | 34篇 |
1988年 | 37篇 |
1987年 | 34篇 |
1986年 | 29篇 |
1985年 | 26篇 |
1984年 | 36篇 |
1983年 | 24篇 |
1982年 | 15篇 |
1981年 | 26篇 |
1980年 | 20篇 |
1979年 | 23篇 |
1978年 | 21篇 |
1977年 | 21篇 |
1976年 | 30篇 |
1975年 | 22篇 |
1974年 | 19篇 |
排序方式: 共有3746条查询结果,搜索用时 0 毫秒
31.
Scherer HU Wang J Toes RE van der Woude D Koeleman CA de Boer AR Huizinga TW Deelder AM Wuhrer M 《Proteomics. Clinical applications》2009,3(1):106-115
In several autoimmune disorders, including rheumatoid arthritis (RA), autoantibodies are thought to be the driving force of pathogenicity. Glycosylation of the Fc-part of human Igs is known to modulate biological activity. Hitherto, glycosylation of human IgG-Fc has been analyzed predominantly at the level of total serum IgG, revealing reduced galactosylation in RA. Given the pathogenic relevance of autoantibodies in RA, we wished, in the present study, to address the question whether distinct Fc-glycosylation features are observable at the level of antigen-specific IgG subpopulations. For this purpose, we have developed a method for the microscale purification and Fc-glycosylation analysis of anti-citrullinated peptide antibodies (ACPA). ACPA represent a group of autoantibodies that occur with unique specificity in RA patients. Their presence is associated with increased inflammatory disease activity and rapid joint destruction. Results indicate that ACPA of the IgG1 subclass vary considerably from total serum IgG1 with respect to Fc-galactosylation, with galactosylation being higher on ACPA than on serum IgG1 for some patients, while other patients show higher galactosylation on serum IgG1 than on ACPA. Using this method, studies can be performed on the biological and clinical relevance of ACPA glycosylation within RA patient cohorts. 相似文献
32.
33.
Optimized Photoinitiator for Fast Two‐Photon Absorption Polymerization of Polyester‐Macromers for Tissue Engineering 下载免费PDF全文
34.
R. Strauss G. Angloher A. Bento C. Bucci L. Canonica X. Defay A. Erb F. v. Feilitzsch N. Ferreiro Iachellini P. Gorla A. Gütlein D. Hauff J. Jochum M. Kiefer H. Kluck H. Kraus J. C. Lanfranchi J. Loebell A. Münster C. Pagliarone F. Petricca W. Potzel F. Pröbst F. Reindl K. Schäffner J. Schieck S. Schönert W. Seidel L. Stodolsky C. Strandhagen A. Tanzke H. H. Trinh Thi C. Türkoglu M. Uffinger A. Ulrich I. Usherov S. Wawoczny M. Willers M. Wüstrich A. Zöller 《Journal of Low Temperature Physics》2016,184(3-4):866-872
35.
Frida U. Ermawati Suminar Pratapa S. Suasmoro Thomas Hübert Ulrich Banach 《Journal of Materials Science: Materials in Electronics》2016,27(7):6637-6645
A series of Mg1?x Zn x TiO3, x = 0–0.5 (MZT0–MZT0.5) ceramics was synthesised and characterised. The dielectric properties of the samples in the frequency range of 1 Hz–7.7 GHz were explored using three different methods: a contacting electrode method, a parallel-plate method and a perturbed resonator method. The electrical properties in the space charge and dipolar polarisation frequency ranges are discussed in relation to the phase composition and microstructure data. Differences in the zinc substitution divided the dielectrics into two groups, namely MZT0–MZT0.2 and MZT0.3–MZT0.5, each with different amount of a main Mg1?x Zn x TiO3 solid solution phase and a secondary solid solution phase. Zinc substitution promoted the density of the ceramics, improved the purity of the main phase and increased the permittivity for frequencies up to 108 Hz, but reduced the permittivity in the microwave range. In the MZT0.3–MZT0.5 samples, for frequencies less than 1 MHz the quality (Q × f) factors were lower and log σ a.c, the AC conductivity, was higher than for the MZT0–MZT0.2 samples. Above 10 MHz, the (Q × f) factors and log σ a.c of the two groups were similar. 相似文献
36.
S Ewig A Glasmacher B Ulrich K Wilhelm H Sch?fer KH Nachtsheim 《Canadian Metallurgical Quarterly》1998,114(2):444-451
STUDY OBJECTIVE: To determine predictors of mortality from pulmonary infiltrates in neutropenic patients with acute leukemia during chemotherapy, and the significance of those factors related to the underlying malignancy and its therapy as well as of those related to the severity of the illness associated with pulmonary infiltrates. DESIGN: A historical cohort study. SETTING: A university teaching hospital and tertiary referral center. PATIENTS AND METHODS: Overall, 53 patients with neutropenia during chemotherapy and with first episodes of pulmonary infiltrates during a 4-year period were studied. Prognostic analysis included 38 variables. Multivariate analyses were performed by logistic regression. RESULTS: The survival rate from pneumonia was 57% (30/53). The following eight parameters were significantly associated with death in univariate analysis: comorbidity present; development of "late" pulmonary infiltrates (> or = 14 days after hospital admission); heart rate > or = 100 beats/min; a ratio heart rate/systolic blood pressure (HR/SBP) > or = 1.2; urea nitrogen > 7 mmol/L; radiographic score > or = 3; neutropenia < 1.0x10(9)/L at the treatment end point; and failed complete remission. In a multivariate model including only parameters available at diagnosis of pulmonary infiltrates, the presence of a ratio HR/SBP > or = 1.2 and of a radiographic score > or = 3 remained independently associated with death. In a second model also including the evolutionary parameter neutropenia < or = 1.0x10(9)/L at the treatment end point, both parameters remained significant together with neutropenia <1.0x 10(9)/L at the treatment end point. The presence of a ratio HR/SBP > or = 1.2 was a strong marker of early death. CONCLUSION: Both therapy- and malignancy-associated neutropenia as well as the severity of illness associated with pulmonary infiltrates are independent prognostic factors. Patients with a ratio HR/SBP > or = 1.2 at diagnosis of pulmonary infiltrates suffer from potentially reversible acute illness, are at risk for early death and, therefore, may be appropriate candidates for treatment in an ICU. 相似文献
37.
Ulrich Schmatz Catherine Dubourdieu Oleg Lebedev Gerard Delabouglise Francois Weiss Jean-Pierre Senateur 《Journal of Low Temperature Physics》1996,105(5-6):1301-1306
Thin and thick YBCO Films have been grown by Aerosol Assisted as well as by thermal MOCVD. The Aerosol Assisted MOCVD technique allows the growth of YBCO films from a single liquid source at deposition rates of up to 10m/h.Transport measurements (I-V) on etched microbridges using a single pulse technique have been performed. The angular magnetic field dependence Jc() of the critical current density from Tc down to 50 K has been measured. Transport properties are reported and discussed with respect to the microstructural features as determined by X-ray diffraction and electron microscopy. 相似文献
38.
A. A. Salem G. Stingeder M. Grasserbauer M. Shreiner K. H. Giessler F. Rauch 《Journal of Materials Science: Materials in Electronics》1996,7(6):373-379
The reliability of the relative sensitivity factor (RSF) approach for secondary ion mass spectrometry (SIMS) quantification of the leached layers on glass was investigated by measuring comparable samples of glass with SIMS and RBS (Rutherford backscattering spectrometry). The RSF factors were calculated using the nominal bulk compositions. Accurate results can be obtained only when the leached layer and the bulk glass have the same major elemental compositions (Si and O) and the matrix effect is inhibited. The concentrations of the different elements in the leached layer obtained from the comparable samples measured by SIMS and RBS are coincident within a factor of 2This paper is a part of a thesis submitted in partial fulfilment of the requirements for the PhD degree at the University of Technology of Vienna, 1991. The paper was orally presented in a symposium, Analysis of Working Materials, held in Vienna, 22–29 May 1991. 相似文献
39.
This paper presents a new method for three dimensional object tracking by fusing information from stereo vision and stereo audio. From the audio data, directional information about an object is extracted by the Generalized Cross Correlation (GCC) and the object’s position in the video data is detected using the Continuously Adaptive Mean shift (CAMshift) method. The obtained localization estimates combined with confidence measurements are then fused to track an object utilizing Particle Swarm Optimization (PSO). In our approach the particles move in the 3D space and iteratively evaluate their current position with regard to the localization estimates of the audio and video module and their confidences, which facilitates the direct determination of the object’s three dimensional position. This technique has low computational complexity and its tracking performance is independent of any kind of model, statistics, or assumptions, contrary to classical methods. The introduction of confidence measurements further increases the robustness and reliability of the entire tracking system and allows an adaptive and dynamical information fusion of heterogenous sensor information. 相似文献
40.
We present a new approach for an average-case analysis of algorithms and data structures that supports a non-uniform distribution of the inputs and is based on the maximum likelihood training of stochastic grammars. The approach is exemplified by an analysis of the expected size of binary tries as well as by three sorting algorithms and it is compared to the known results that were obtained by traditional techniques. Investigating traditional settings like the random permutation model, we rediscover well-known results formerly derived by pure analytic methods; changing to biased data yields original results. All but one step of our analysis can be automated on top of a computer-algebra system. Thus our new approach can reduce the effort required for an average-case analysis, allowing for the consideration of realistic input distributions with unknown distribution functions at the same time. As a by-product, our approach yields an easy way to generate random combinatorial objects according to various probability distributions. 相似文献