全文获取类型
收费全文 | 2227篇 |
免费 | 102篇 |
国内免费 | 5篇 |
专业分类
化学 | 1698篇 |
晶体学 | 24篇 |
力学 | 45篇 |
数学 | 104篇 |
物理学 | 463篇 |
出版年
2023年 | 14篇 |
2022年 | 23篇 |
2021年 | 15篇 |
2020年 | 38篇 |
2019年 | 39篇 |
2018年 | 21篇 |
2017年 | 20篇 |
2016年 | 59篇 |
2015年 | 42篇 |
2014年 | 56篇 |
2013年 | 91篇 |
2012年 | 125篇 |
2011年 | 176篇 |
2010年 | 77篇 |
2009年 | 67篇 |
2008年 | 153篇 |
2007年 | 123篇 |
2006年 | 135篇 |
2005年 | 137篇 |
2004年 | 135篇 |
2003年 | 101篇 |
2002年 | 85篇 |
2001年 | 57篇 |
2000年 | 38篇 |
1999年 | 34篇 |
1998年 | 20篇 |
1997年 | 26篇 |
1996年 | 30篇 |
1995年 | 25篇 |
1994年 | 33篇 |
1993年 | 17篇 |
1992年 | 19篇 |
1991年 | 13篇 |
1990年 | 16篇 |
1989年 | 16篇 |
1988年 | 15篇 |
1987年 | 14篇 |
1986年 | 10篇 |
1985年 | 20篇 |
1984年 | 20篇 |
1983年 | 17篇 |
1982年 | 12篇 |
1981年 | 13篇 |
1980年 | 18篇 |
1979年 | 19篇 |
1978年 | 16篇 |
1976年 | 14篇 |
1975年 | 11篇 |
1974年 | 10篇 |
1973年 | 9篇 |
排序方式: 共有2334条查询结果,搜索用时 0 毫秒
1.
Tsuyoshi Kitamura 《Tetrahedron》2004,60(43):9649-9657
Synthesis of (+)-anthramycin was examined. A pyrrolobenzodiazepine skeleton could be synthesized by reductive cyclization of pyrrolidine derivative, which was obtained by enyne metathesis. The conjugated enamide ester part of (+)-anthramycin derivative was constructed by cross-metathesis. 相似文献
2.
3.
Tsuyoshi Katayama 《Queueing Systems》1992,11(3):299-306
This paper derives a conservation law for mean waiting times in a single-server multi-class service queueing system (M
X/G/1 type queue) with setup times which may be dependent on multiple customer classes and its arrival batch size by using the work decomposition property in the queueing system with vacations. 相似文献
4.
We investigate low-temperature behaviors of a system with chirality-pair interaction on a one-dimensional lattice. In the course of the investigation, we evaluate asymptotic forms of the characteristic values of the integral equation satisfied by the Mathieu functions. It turns out that the low-temperature behavior of correlation length of the chirality-pair correlation function is different from the one for the Ising model of spin ±1 but akin to the one for the Ising model of infinite spin. 相似文献
5.
6.
7.
Katsunori Nishimura Rie Hidaka Fumitoshi Hirayama Hidetoshi Arima Kaneto Uekama 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(1-2):85-88
Geometries, electronic properties and NMR-shielding of cucurbit[5]uril, decamethylcucurbit[5]uril, cucurbit[6]uril, cucurbit[7]uril,
and cucurbit[8]uril are investigated with DFT calculations. All molecules are highly symmetrical with a distinct geometric
flexibility. In addition with a characteristic partial charge distribution these findings account for their chemical complex
building ability. 相似文献
8.
I Kitagawa A Matsuda T Nishimura S Hirai I Yoshioka 《Chemical & pharmaceutical bulletin》1967,15(9):1435-1437
9.
10.
Hanioka N Jinno H Nishimura T Ando M Ozawa S Sawada J 《Biomedical chromatography : BMC》2001,15(5):328-333
A simple and sensitive assay for glucuronidation activity of 7-ethyl-10-hydroxycamptothecin (SN-38), the active metabolite of irinotecan (CPT-11), in human liver microsomes by high-performance liquid chromatography (HPLC) with fluorescence detection is reported. The method was validated for the determination of SN-38 glucuronide (SN-38G) with respect to specificity, linearity, recovery, stability, precision, accuracy, and limits of detection and quantitation. There was no interference from matrix and non-enzymatic reactions. The calibration curve for SN-38G was linear from 5 to 500 nM. Average recoveries ranged from 98 to 100% in spiked human liver microsome samples, and the SN-38G was stable at 4 degrees C for at least 72 h. The newly developed method was found to be more sensitive and selective than previous methods using thin layer chromatography and HPLC. The limit of quantitation for SN-38G was 5 nM (2.5 pmol/assay). The intra- and inter-day precision and accuracy were less than 7 and 4%, respectively. The intra- and inter-day precision of enzyme assay for UDP-glucuronosyltransferase (UGT) activity toward SN-38 in human liver microsomes was less than 4%. With this improved sensitivity, the kinetics of SN-38 glucuronidation in human liver microsomes could be determined more precisely. Therefore, this method is applicable to in vitro study on the side effects and drug interactions of CPT-11 using small amounts of biological sample. 相似文献