全文获取类型
收费全文 | 16185篇 |
免费 | 2960篇 |
国内免费 | 2636篇 |
专业分类
化学 | 11986篇 |
晶体学 | 297篇 |
力学 | 1125篇 |
综合类 | 214篇 |
数学 | 1615篇 |
物理学 | 6544篇 |
出版年
2024年 | 46篇 |
2023年 | 304篇 |
2022年 | 578篇 |
2021年 | 637篇 |
2020年 | 724篇 |
2019年 | 670篇 |
2018年 | 589篇 |
2017年 | 629篇 |
2016年 | 825篇 |
2015年 | 892篇 |
2014年 | 1055篇 |
2013年 | 1302篇 |
2012年 | 1619篇 |
2011年 | 1654篇 |
2010年 | 1168篇 |
2009年 | 1179篇 |
2008年 | 1133篇 |
2007年 | 1004篇 |
2006年 | 955篇 |
2005年 | 837篇 |
2004年 | 639篇 |
2003年 | 471篇 |
2002年 | 496篇 |
2001年 | 449篇 |
2000年 | 324篇 |
1999年 | 290篇 |
1998年 | 246篇 |
1997年 | 181篇 |
1996年 | 170篇 |
1995年 | 125篇 |
1994年 | 127篇 |
1993年 | 93篇 |
1992年 | 80篇 |
1991年 | 73篇 |
1990年 | 50篇 |
1989年 | 28篇 |
1988年 | 28篇 |
1987年 | 14篇 |
1986年 | 21篇 |
1985年 | 19篇 |
1984年 | 13篇 |
1983年 | 8篇 |
1982年 | 12篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1975年 | 1篇 |
1971年 | 2篇 |
1959年 | 2篇 |
1957年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Potential Analysis - Using coupling by change of measure and an approximation technique, Wang’s Harnack inequalities are established for a class of functional SDEs driven by subordinate... 相似文献
12.
The highly stereoselective intramolecular metal carbenoid insertion reaction of sulfinimine-derived delta-amino alpha-diazoesters is used to prepare cis-5-tert-butylproline. A concerted or nearly concerted metal carbenoid N-H insertion reaction mechanism is proposed. 相似文献
13.
14.
银微电极微分电位溶出分析法研究 总被引:3,自引:1,他引:3
本文首次报道了银微电极微分电位溶出分析法。用化学刻蚀法方便地制作了银微电极,用于DPSA具有背景值低,分辨率好、精密度及灵敏度高,在不搅拌,仅需一定酸度而酸度而无其它介质的条件下就能测试等优点,对人工试样及自来水样分析,结果令人满意。 相似文献
15.
An etiobilirubin‐IIβ analog with the central C(10) CH2 group replaced by a diacetylene unit ( 1 ) was synthesized by base‐catalyzed condensation of bis‐[3‐methyl‐4‐ethyl‐5‐formylpyrrol‐2‐yl]‐diacetylene ( 3 ) with 3‐methyl‐4‐ethyl‐5‐p‐toluenesulfonyl‐2‐pyrrolinone ( 10 ). Diacetylenic rubin 1 is a dark red solid, giving orange solutions with uv‐visible absorption maxima near 460 nm. 相似文献
16.
The absorption spectra of 4f electron transitions of the complexes of neodymium and erbium with 8-hydroxyquinoline-5-sulphonic acid in the presence of diethylamine and ethanol have been measured by normal and third-derivative spectrophotometry. Their molar absorptivities are 70.7 l.mol~(-1).cm~(-1) for Nd and 62.5 l.mol~(-1).cm~(-1) for Er. They are 7.6 times and 14.9 times greater than those of corresponding chlorides, respectively. Use of the third-derivative spectra both eliminates the interference of Ce(Ⅳ) and increases the sensitivity for Nd and Er. Beer,s Law was obeyed from 0-10 ug/ml of Nd and Er. The method has been applied to the determination of neodymium and erbium in rare earth mixtures. 相似文献
17.
A novel method for the determination of proteins in aqueous solutions has been developed based on the enhancement of resonance light scattering (RLS) of Ag nanoparticles in the presence of proteins. Factors including acidity of the media, concentration of Ag hydrosol, reaction time, temperature, and interference of non-protein substances were investigated. Under the optimal conditions, with the enhanced RLS signals at 452nm, the linear ranges of calibration curves were 0–0.8µgmL–1 for bovine serum albumin (BSA), 0–1.2µgmL–1 for human serum albumin (HSA), and 0–2.5µgmL–1 for human -IgG (-IgG), respectively. The detection limits were 1.3ngmL–1 for BSA, 10ngmL–1 for HAS, and 5.7ngmL–1 for -IgG.This method has been applied to the analysis of synthetic samples and real human serum samples, and the results were in good agreement with those reported by the hospital, indicating that the method presented here is not only sensitive and simple, but also reliable and suitable for practical applications. 相似文献
18.
O. Reuter R. Langley Dr. Wan Manshol Bin W. Zn 《Radiation Physics and Chemistry》1998,52(1-6):429-432
This paper presents anew design concept for a gamma irradiation plant for the continuous processing of pumpable liquids. Typical applications of such a plant include
- • * the irradiation vulcanisation of natural latex rubber
- • * disinfection of municipal sewage sludge for agricultural use
- • * sterilisation of liquids in the pharmaceutical and cosmetics industries
- • * industrial processing of bulk liquids
The authors describe the design and operation of the latex irradiator now operating on a small production scale in Malaysia and proposed developments.
The design allows irradiation processing to be carried out under an inert or other gaseous environment.
State-of-the-art computer control system ensures the fully automatic processing operation needed by industrial computers. 相似文献
19.
Bin XIN Dan PU Shao Xiang XIONG* Guang Hui WANG Beijing Mass Spectrometry Center Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 《中国化学快报》2003,14(2)
Recently, capillary electrophoresis/electrospray ionization mass spectrometry (CE/ESI- MS) has been rapidly developed as a powerful analytical tool for charged species ranged from small molecules such as carboxylic acids1, phenolic compounds2, metal species3, tetramines4, herbicides5, drugs and drug metabolites6 to peptides and proteins7, 8. The ESI mode has proven to be sensitive, versatile and relatively easy to use in combination with CE. CE confers rapid analysis and efficient separ… 相似文献
20.
A two-tiered organizing scheme with multiple-length scales for construction of dandelion-like hollow CuO microspheres has been elucidated: (1) mesoscale formation of rhombic building units from smaller nanoribbons via oriented aggregation and (2) macroscopic organization of these units into the CuO microspheres. This self-assembly concept may also be applicable to other metal oxides by creating geometric constraints for constructional units. 相似文献