全文获取类型
收费全文 | 68267篇 |
免费 | 10188篇 |
国内免费 | 1551篇 |
专业分类
化学 | 60415篇 |
晶体学 | 540篇 |
力学 | 1035篇 |
综合类 | 4篇 |
数学 | 8670篇 |
物理学 | 9342篇 |
出版年
2023年 | 249篇 |
2022年 | 218篇 |
2021年 | 714篇 |
2020年 | 1779篇 |
2019年 | 3133篇 |
2018年 | 1702篇 |
2017年 | 1291篇 |
2016年 | 4474篇 |
2015年 | 4354篇 |
2014年 | 4351篇 |
2013年 | 6178篇 |
2012年 | 5106篇 |
2011年 | 4574篇 |
2010年 | 4268篇 |
2009年 | 4140篇 |
2008年 | 4514篇 |
2007年 | 3856篇 |
2006年 | 3375篇 |
2005年 | 3404篇 |
2004年 | 2943篇 |
2003年 | 2299篇 |
2002年 | 1711篇 |
2001年 | 1443篇 |
2000年 | 1121篇 |
1999年 | 571篇 |
1998年 | 425篇 |
1997年 | 434篇 |
1996年 | 506篇 |
1995年 | 401篇 |
1994年 | 421篇 |
1993年 | 379篇 |
1992年 | 372篇 |
1991年 | 337篇 |
1990年 | 316篇 |
1989年 | 254篇 |
1988年 | 249篇 |
1987年 | 252篇 |
1986年 | 244篇 |
1985年 | 322篇 |
1984年 | 333篇 |
1983年 | 216篇 |
1982年 | 238篇 |
1981年 | 239篇 |
1980年 | 236篇 |
1979年 | 166篇 |
1978年 | 161篇 |
1977年 | 164篇 |
1976年 | 146篇 |
1975年 | 130篇 |
1973年 | 133篇 |
排序方式: 共有10000条查询结果,搜索用时 123 毫秒
1.
Marija argonja Darko Mekterovi Paula
urga Jagoda Ravli‐Gulan Iva Bogdanovi Radovi Gordana
auhar 《X射线光谱测定》2021,50(1):68-79
During metal welding and cutting, large amounts of particulate matter (PM) are produced that might represent a significant health risk for the exposed workers. In the present pilot study, we performed an elemental analysis of fine PM collected in a metal workshop. Also, elemental analysis of the hair and nail samples collected from workers exposed to the workshop dust and control group was done. Concentrations of 15 elements in PM were measured with X‐Ray Fluorescence (XRF) and Particle Induced X‐ray Emission (PIXE), whereas inductively coupled plasma mass spectrometry (ICP‐MS) was used to determine 12 elements in hair and nail samples. Mean 8‐hr concentrations of PM2.5, Fe, and Mn in the vicinity of welders were up to 1803, 860, and 30 μg/m3, respectively, whereas in the nearby city, daily PM2.5 concentrations are on average 11 μg/m3. We found that several elements, especially Fe and Mn, had substantially higher concentrations in hair and nail samples of exposed workers than in the control group, which indicates the accumulation of metals in workers' tissues, although limit values were not exceeded. 相似文献
2.
Set-Valued and Variational Analysis - In a Hilbert framework ℌ, we study the convergence properties of a Newton-like inertial dynamical system governed by a general maximally monotone... 相似文献
3.
Archiv der Mathematik - In this note, we introduce a criterion to detect vanishing of essential algebras of a Green biset functor by means of morphisms. We introduce the inflation morphism and... 相似文献
4.
In this article a coupled version of the improved divergence‐free‐condition compensated method will be proposed to simulate time‐varying geometries by direct forcing immersed boundary method. The proposed method can be seen as a quasi‐multi‐moment framework due to the fact that the momentum equations are discretized by both cell‐centered and cell‐face velocity. For simulating time‐varying geometries, a semi‐implicit iterative method is proposed for calculating the direct forcing terms. Treatments for suppressing spurious force oscillations, calculating drag/lift forces, and evaluating velocity and pressure for freshly cells will also be addressed. In order to show the applicability and accuracy, analytical as well as benchmark problems will be investigated by the present framework and compared with other numerical and experimental results. 相似文献
5.
Set-Valued and Variational Analysis - The production correspondence associated with a technology maps every input vector into the set of output vectors that may be obtained by means of those... 相似文献
6.
Landgrave-Barbosa Fernando Marmolejo-Valencia Andrés F. Baray-Calderón Alejandro Hu Hailin Aguilar-Cordero Julio César Amador-Bedolla Carlos Ugalde-Saldivar Víctor M. 《Journal of Solid State Electrochemistry》2022,26(3):649-661
Journal of Solid State Electrochemistry - A study of poly(3-hexylthiophene) (P3HT) thin films by spin-coating process, deposited on conducting glass substrates of fluorine-doped tin oxide (FTO), is... 相似文献
7.
Bazarra Noelia Castejón Alberto Fernández José R. Quintanilla Ramón 《Meccanica》2021,56(12):3025-3037
Meccanica - In this work we study, from the numerical point of view, a one-dimensional thermoelastic problem where the thermal law is of type III. Quasi-static microvoids are also assumed within... 相似文献
8.
9.
Kavitha Telikepalli Király Tamás Matuschke Jannik Schlotter Ildikó Schmidt-Kraepelin Ulrike 《Mathematical Programming》2022,192(1-2):567-595
Mathematical Programming - Let G be a digraph where every node has preferences over its incoming edges. The preferences of a node extend naturally to preferences over branchings, i.e., directed... 相似文献
10.
Verdecho María-José Alarcón-Valero Faustino Pérez-Perales David Alfaro-Saiz Juan-José Rodríguez-Rodríguez Raúl 《Central European Journal of Operations Research》2021,29(4):1231-1251
Central European Journal of Operations Research - Sustainability practice within supply chains remains in an early development phase. Enterprises still need tools that support the integration of... 相似文献