全文获取类型
收费全文 | 574篇 |
免费 | 41篇 |
国内免费 | 1篇 |
学科分类
工业技术 | 616篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 34篇 |
2020年 | 18篇 |
2019年 | 10篇 |
2018年 | 24篇 |
2017年 | 17篇 |
2016年 | 17篇 |
2015年 | 11篇 |
2014年 | 32篇 |
2013年 | 44篇 |
2012年 | 49篇 |
2011年 | 53篇 |
2010年 | 34篇 |
2009年 | 34篇 |
2008年 | 29篇 |
2007年 | 29篇 |
2006年 | 20篇 |
2005年 | 26篇 |
2004年 | 15篇 |
2003年 | 14篇 |
2002年 | 16篇 |
2001年 | 9篇 |
2000年 | 4篇 |
1999年 | 9篇 |
1998年 | 11篇 |
1997年 | 8篇 |
1996年 | 8篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有616条查询结果,搜索用时 20 毫秒
1.
2.
3.
4.
5.
Kunkel Mark A.; Hector Mark A.; Góngora Coronado Elías; Castillo Vales Victor 《Canadian Metallurgical Quarterly》1989,36(3):322
Conducted a study of client expectations of psychological services in Yucatán, Mexico, under the sponsorship of a grant from the Organization of American States. The Expectations about Counseling–Brief form (EAC-B) questionnaire was translated and administered to 488 subjects across age, sex, and experience with psychological services. Subsequent analyses supported the reliability and robustness of the Spanish EAC-B, with factor structure similar to the EAC-B in English. Some relation was found among age, sex, prior counseling experience, and expectations about counseling. Implications of these data for future research and comparison with U.S. subjects are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
Maykel Cruz-Monteagudo Cristian Robert Munteanu Fernanda Borges Eugenio Uriarte Humberto González-Díaz 《Polymer》2008,49(25):5575-5587
The Quantitative Structure-Property Relationships (QSPRs) based on Graph or Network Theory are important for predicting the properties of polymeric systems. In the three previous papers of this series (Polymer 45 (2004) 3845-3853; Polymer 46 (2005) 2791-2798; and Polymer 46 (2005) 6461-6473) we focused on the uses of molecular graph parameters called topological indices (TIs) to link the structure of polymers with their biological properties. However, there has been little effort to extend these TIs to the study of complex mixtures of artificial polymers or biopolymers such as nucleic acids and proteins. In this sense, Blood Proteome (BP) is one of the most important and complex mixtures containing protein polymers. For instance, outcomes obtained by Mass Spectrometry (MS) analysis of BP are very useful for the early detection of diseases and drug-induced toxicities. Here, we use two Spiral and Star Network representations of the MS outcomes and defined a new type of TIs. The new TIs introduced here are the spectral moments (πk) of the stochastic matrix associated to the Spiral graph and describe non-linear relationships between the different regions of the MS characteristic of BP. We used the MARCH-INSIDE approach to calculate the πk(SN) of different BP samples and S2SNet to determine several Star graph TIs. In the second step, we develop the corresponding Quantitative Proteome-Property Relationship (QPPR) models using the Linear Discriminant Analysis (LDA). QPPRs are the analogues of QSPRs in the case of complex biopolymer mixtures. Specifically, the new QPPRs derived here may be used to detect drug-induced cardiac toxicities from BP samples. Different Machine Learning classification algorithms were used to fit the QPPRs based on πk(SN), showing J48 decision tree classifier to have the best performance. These results suggest that the present approach captures important features of the complex biopolymers mixtures and opens new opportunities to the application of the idea supporting classic QSPRs in polymer sciences. 相似文献
7.
H.J. Bolink E. Coronado D. Repetto M. Sessolo E.M. Barea J. Bisquert G. Garcia‐Belmonte J. Prochazka L. Kavan 《Advanced functional materials》2008,18(1):145-150
A new type of bottom‐emission electroluminescent device is described in which a metal oxide is used as the electron‐injecting contact. The preparation of such a device is simple. It consists of the deposition of a thin layer of a metal oxide on top of an indium tin oxide covered glass substrate, followed by the solution processing of the light‐emitting layer and subsequently the deposition of a high‐workfunction (air‐stable) metal anode. This architecture allows for a low‐cost electroluminescent device because no rigorous encapsulation is required. Electroluminescence with a high brightness reaching 5700 cd m–2 is observed at voltages as low as 8 V, demonstrating the potential of this new approach to organic light‐emitting diode (OLED) devices. Unfortunately the device efficiency is rather low because of the high current density flowing through the device. We show that the device only operates after the insertion of an additional hole‐injection layer in between the light‐emitting polymer (LEP) and the metal anode. A simple model that explains the experimental results and provides avenues for further optimization of these devices is described. It is based on the idea that the barrier for electron injection is lowered by the formation of a space–charge field over the metal‐oxide–LEP interface due to the build up of holes in the LEP layer close to this interface. 相似文献
8.
9.
10.
Alex H. Barbat Miguel Cervera Alex Hanganu Cruz Cirauqui Eugenio Oñate 《Nuclear Engineering and Design》1998,180(3):251-270
The evaluation of the failure pressure of the containment building of a large dry PWR-W three loops nuclear power plant, based on computer numerical simulation, is described in this paper. The proposed method considers fully three-dimensional finite element models in order to take into account the effect of the most significant structural characteristics (presence of three buttresses, penetrations, additional reinforcement around the penetrations, etc.), the lack of symmetry of the forces generated by the prestressing system, as well as the nonlinear behaviour of the materials and the sensitivity of the results to uncertainties associated with several parameters. The computational model is completely described, including the constitutive equations for the concrete, the reinforcing steel and prestressing tendons, the spatial discretization—isoparametric elements including the reinforcement are used. The structural models and the analyses performed for their calibration are also described. The influence on the failure pressure of incorporating the foundation slab in the structural model, and the influence of the thermal effects, are discussed. One of the conclusions of the numerical study is that the failure process can be appropriately simulated by means of a structural model which does not include either the foundation slab or the thermal effects. Finally, results of a probabilistic simulation of the failure pressure are given. 相似文献