全文获取类型
收费全文 | 1066篇 |
免费 | 15篇 |
国内免费 | 4篇 |
专业分类
化学 | 476篇 |
晶体学 | 12篇 |
力学 | 14篇 |
数学 | 140篇 |
物理学 | 443篇 |
出版年
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2016年 | 12篇 |
2015年 | 13篇 |
2014年 | 12篇 |
2013年 | 43篇 |
2012年 | 36篇 |
2011年 | 44篇 |
2010年 | 22篇 |
2009年 | 22篇 |
2008年 | 45篇 |
2007年 | 45篇 |
2006年 | 45篇 |
2005年 | 40篇 |
2004年 | 26篇 |
2003年 | 28篇 |
2002年 | 37篇 |
2001年 | 21篇 |
2000年 | 16篇 |
1999年 | 16篇 |
1998年 | 12篇 |
1997年 | 20篇 |
1996年 | 24篇 |
1995年 | 21篇 |
1994年 | 27篇 |
1993年 | 26篇 |
1992年 | 36篇 |
1991年 | 16篇 |
1990年 | 19篇 |
1989年 | 17篇 |
1988年 | 16篇 |
1987年 | 7篇 |
1986年 | 19篇 |
1985年 | 18篇 |
1984年 | 17篇 |
1983年 | 18篇 |
1982年 | 14篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 21篇 |
1978年 | 15篇 |
1977年 | 14篇 |
1976年 | 10篇 |
1975年 | 11篇 |
1974年 | 14篇 |
1973年 | 20篇 |
1972年 | 12篇 |
1967年 | 8篇 |
排序方式: 共有1085条查询结果,搜索用时 15 毫秒
51.
Zeng W Wang AQ Fisher AL Musson DG 《Rapid communications in mass spectrometry : RCM》2003,17(22):2475-2482
A generic high-throughput liquid chromatography (HTLC) tandem mass spectrometry (MS/MS) assay for the determination of compound I in human urine and dialysate (hemodialysis) was developed and validated. By using the HTLC on-line extraction technique, sample pretreatment was not necessary. The sample was directly injected onto a narrow bore large particle size extraction column (50 x 1.0 mm, 60 microm) where the sample matrix was rapidly washed away using a high flow rate (5 mL/min) aqueous mobile phase while analytes were retained. The analytes were subsequently eluted from the extraction column onto an analytical column using an organic-enriched mobile phase prior to mass spectrometric detection. The analytes were then eluted from the analytical column to the mass spectrometer for the determination. The linear dynamic range was 2.0-6000 ng/mL for the urine assay and 0.1-300 ng/mL for the dialysate assay. Intraday accuracy and precision were evaluated by analyzing five replicates of calibration standards at all concentrations used to construct the standard curve. For the urine assay, the precision (RSD%, n=5) ranged from 1.9 to 8.0% and the accuracy ranged from 87.8 to 105.2% of nominal value. For the dialysate assay, the precision (RSD%, n=5) ranged from 1.1 to 10.0% and the accuracy from 94.5 to 105.2% of nominal value. In-source fragmentation of the acyl glucuronide metabolite (compound III) did not interfere with the determination of parent compound I. The developed HTLC/MS/MS methodology was specific for compound I in the presence of compound III. Column life-time is increased and sample analysis time is decreased over traditional reversed-phase methods when direct injection assays for urine and dialysate are coupled with the technology of HTLC. 相似文献
52.
Richard Gilardi Clifford George Jerome Karle Philip E. Eaton Allison M. Fisher 《Journal of heterocyclic chemistry》1993,30(5):1385-1388
Exploration of the reactions of the 9-azahomocubane system led to derivatives of two small-ring systems containing aza-bridging atoms, 5-azatetracyclo[4.2.0.03,8.04,7]octane and 9-azatetracyclo[4.3.0.02,5.04,7]nonane. The structures were characterized by X-ray diffraction analyses. There are no prior X-ray structural reports on these systems. 相似文献
53.
54.
55.
56.
57.
58.
59.
60.