全文获取类型
收费全文 | 446216篇 |
免费 | 7967篇 |
国内免费 | 1511篇 |
学科分类
工业技术 | 455694篇 |
出版年
2021年 | 5059篇 |
2020年 | 3885篇 |
2019年 | 4771篇 |
2018年 | 7747篇 |
2017年 | 7734篇 |
2016年 | 8477篇 |
2015年 | 5542篇 |
2014年 | 9044篇 |
2013年 | 23179篇 |
2012年 | 14334篇 |
2011年 | 18817篇 |
2010年 | 14823篇 |
2009年 | 16553篇 |
2008年 | 16582篇 |
2007年 | 15888篇 |
2006年 | 14256篇 |
2005年 | 12721篇 |
2004年 | 12002篇 |
2003年 | 11774篇 |
2002年 | 11173篇 |
2001年 | 10684篇 |
2000年 | 9356篇 |
1999年 | 9893篇 |
1998年 | 25566篇 |
1997年 | 17351篇 |
1996年 | 13253篇 |
1995年 | 10212篇 |
1994年 | 8874篇 |
1993年 | 8853篇 |
1992年 | 6366篇 |
1991年 | 6016篇 |
1990年 | 5935篇 |
1989年 | 5566篇 |
1988年 | 5216篇 |
1987年 | 4587篇 |
1986年 | 4452篇 |
1985年 | 4953篇 |
1984年 | 4537篇 |
1983年 | 4064篇 |
1982年 | 3729篇 |
1981年 | 3772篇 |
1980年 | 3500篇 |
1979年 | 3387篇 |
1978年 | 3376篇 |
1977年 | 3829篇 |
1976年 | 4968篇 |
1975年 | 2903篇 |
1974年 | 2701篇 |
1973年 | 2755篇 |
1972年 | 2302篇 |
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
41.
Theoretical Foundations of Chemical Engineering - The results of numerical modeling of the heat and mass transfer of drops during drying of a liquid under the conditions of... 相似文献
42.
Osipenko M. A. Kharitonov D. S. Makarova I. V. Romanovsky V. I. Kurilo I. I. 《Protection of Metals and Physical Chemistry of Surfaces》2021,57(3):550-558
Protection of Metals and Physical Chemistry of Surfaces - The dependences of the protective properties of the anodic oxide coatings on the AD31 aluminum alloy surface modified with nitrates of... 相似文献
43.
Semiconductors - In conductors with a very low defect density, electrons at low temperatures collide mainly with the sample edges; therefore, the ballistic transport of charge and heat is... 相似文献
44.
Maryam Oroujeni Sara S. Rinne Anzhelika Vorobyeva Annika Loftenius Joachim Feldwisch Per Jonasson Vladimir Chernov Anna Orlova Fredrik Y. Frejd Vladimir Tolmachev 《International journal of molecular sciences》2021,22(5)
Radionuclide imaging of HER2 expression in tumours may enable stratification of patients with breast, ovarian, and gastroesophageal cancers for HER2-targeting therapies. A first-generation HER2-binding affibody molecule [99mTc]Tc-ZHER2:V2 demonstrated favorable imaging properties in preclinical studies. Thereafter, the affibody scaffold has been extensively modified, which increased its melting point, improved storage stability, and increased hydrophilicity of the surface. In this study, a second-generation affibody molecule (designated ZHER2:41071) with a new improved scaffold has been prepared and characterized. HER2-binding, biodistribution, and tumour-targeting properties of [99mTc]Tc-labelled ZHER2:41071 were investigated. These properties were compared with properties of the first-generation affibody molecules, [99mTc]Tc-ZHER2:V2 and [99mTc]Tc-ZHER2:2395. [99mTc]Tc-ZHER2:41071 bound specifically to HER2 expressing cells with an affinity of 58 ± 2 pM. The renal uptake for [99mTc]Tc-ZHER2:41071 and [99mTc]Tc-ZHER2:V2 was 25–30 fold lower when compared with [99mTc]Tc-ZHER2:2395. The uptake in tumour and kidney for [99mTc]Tc-ZHER2:41071 and [99mTc]Tc-ZHER2:V2 in SKOV-3 xenografts was similar. In conclusion, an extensive re-engineering of the scaffold did not compromise imaging properties of the affibody molecule labelled with 99mTc using a GGGC chelator. The new probe, [99mTc]Tc-ZHER2:41071 provided the best tumour-to-blood ratio compared to HER2-imaging probes for single photon emission computed tomography (SPECT) described in the literature so far. [99mTc]Tc-ZHER2:41071 is a promising candidate for further clinical translation studies. 相似文献
45.
Golubev N. V. Ignat’eva E. S. Maurus A. A. Ziyatdinova M. Z. Lopatina E. V. Lorenzi R. Paleari A. Sigaev V. N. 《Glass and Ceramics》2021,77(11-12):415-418
Glass and Ceramics - The influence of Al2O3 as an additive and the heat-treatment regime on the luminescence spectra of gallate glass-ceramics was investigated. It is shown that its luminescence... 相似文献
46.
Mahantesh H. M. Nageswara Guptha M. Hema M. S. 《Wireless Personal Communications》2021,120(3):2349-2365
Wireless Personal Communications - 2In Software Defined Network based Internet of Things (SDN-IoT), the path selected for forwarding the packets as per rules, should be Quality of Service (QoS)... 相似文献
47.
Kruglikov S. S. Zagorskii D. L. Kolesnikov V. A. Doludenko I. M. Bedin S. A. 《Theoretical Foundations of Chemical Engineering》2021,55(5):942-951
Theoretical Foundations of Chemical Engineering - The effect of the electrolyte composition, mass-transfer conditions, pore diameter, interpore distance, and electric parameters on the formation of... 相似文献
48.
Minsu Kang Jooyong Lee Sangyoon Ko Dr. Sang-Hee Shim 《Chembiochem : a European journal of chemical biology》2021,22(8):1396-1399
Expansion microscopy combined with single-molecule localization microscopy (ExSMLM) has a potential for approaching molecular resolution. However, ExSMLM faces multiple challenges such as loss of fluorophores and proteins during polymerization, digestion or denaturation, and an increase in linkage error arising from the distance between the fluorophore and the target molecule. Here, we introduce a trifunctional streptavidin to link the target, fluorophore and gel matrix via a biotinylizable peptide tag. The resultant ExSMLM images of vimentin filaments demonstrated high labeling efficiency and a minimal linkage error of ∼5 nm. Our ExSMLM provides a simple and practical means for fluorescence imaging with molecular resolution. 相似文献
49.
Felipe A. Perdomo Siti H. Khalit Claire S. Adjiman Amparo Galindo George Jackson 《American Institute of Chemical Engineers》2021,67(3):e17194
The SAFT-γ Mie group-contribution equation of state is used to represent the fluid-phase behavior of aqueous solutions of a variety of linear, branched, and cyclic amines. New group interactions are developed in order to model the mixtures of interest, including the like and unlike interactions between alkyl primary, secondary, and tertiary amine groups (NH2, NH, N), cyclic secondary and tertiary amine groups (cNH, cN), and cyclic methine-amine groups (cCHNH, cCHN) with water (H2O). The group-interaction parameters are estimated from appropriate experimental thermodynamic data for pure amines and selected mixtures. By taking advantage of the group-contribution nature of the method, one can describe the fluid-phase behavior of mixtures of molecules comprising those groups over broad ranges of temperature, pressure, and composition. A number of aqueous solutions of amines are studied including linear, branched aliphatic, and cyclic amines. Liquid–liquid equilibria (LLE) bounded by lower critical solution temperatures (LCSTs) have been reported experimentally and are reproduced here with the SAFT-γ Mie approach. The main feature of the approach is the ability not only to represent accurately the experimental data employed in the parameter estimation, but also to predict the vapor–liquid, liquid–liquid, and vapor–liquid–liquid equilibria, and LCSTs with the same set of parameters. Pure compound and binary phase diagrams of diverse types of amines and their aqueous solutions are assessed in order to demonstrate the main features of the thermodynamic and fluid-phase behavior. 相似文献
50.
Young Been Kim Sung Hyeon Jung Dong Su Kim Nishad G. Deshpande Hee Won Suh Hak Hyeon Lee Ji Hoon Choi Ho Seong Lee Hyung Koun Cho 《Advanced functional materials》2021,31(38):2102439
Antimony triselenide (Sb2Se3) nanoflake-based nitrogen dioxide (NO2) sensors exhibit a progressive bifunctional gas-sensing performance, with a rapid alarm for hazardous highly concentrated gases, and an advanced memory-type function for low-concentration (<1 ppm) monitoring repeated under potentially fatal exposure. Rectangular and cuboid shaped Sb2Se3 nanoflakes, comprising van der Waals planes with large surface areas and covalent bond planes with small areas, can rapidly detect a wide range of NO2 gas concentrations from 0.1 to 100 ppm. These Sb2Se3 nanoflakes are found to be suitable for physisorption-based gas sensing owing to their anisotropic quasi-2D crystal structure with extremely enlarged van der Waals planes, where they are humidity-insensitive and consequently exhibit an extremely stable baseline current. The Sb2Se3 nanoflake sensor exhibits a room-temperature/low-voltage operation, which is noticeable owing to its low energy consumption and rapid response even under a NO2 gas flow of only 1 ppm. As a result, the Sb2Se3 nanoflake sensor is suitable for the development of a rapid alarm system. Furthermore, the persistent gas-sensing conductivity of the sensor with a slow decaying current can enable the development of a progressive memory-type sensor that retains the previous signal under irregular gas injection at low concentrations. 相似文献