全文获取类型
收费全文 | 13502篇 |
免费 | 1013篇 |
国内免费 | 745篇 |
出版年
2024年 | 13篇 |
2023年 | 148篇 |
2022年 | 372篇 |
2021年 | 758篇 |
2020年 | 428篇 |
2019年 | 535篇 |
2018年 | 491篇 |
2017年 | 363篇 |
2016年 | 547篇 |
2015年 | 885篇 |
2014年 | 1015篇 |
2013年 | 1020篇 |
2012年 | 1241篇 |
2011年 | 1041篇 |
2010年 | 643篇 |
2009年 | 584篇 |
2008年 | 670篇 |
2007年 | 640篇 |
2006年 | 530篇 |
2005年 | 502篇 |
2004年 | 419篇 |
2003年 | 370篇 |
2002年 | 269篇 |
2001年 | 226篇 |
2000年 | 162篇 |
1999年 | 180篇 |
1998年 | 122篇 |
1997年 | 127篇 |
1996年 | 119篇 |
1995年 | 118篇 |
1994年 | 127篇 |
1993年 | 87篇 |
1992年 | 76篇 |
1991年 | 96篇 |
1990年 | 62篇 |
1989年 | 52篇 |
1988年 | 29篇 |
1987年 | 24篇 |
1986年 | 15篇 |
1985年 | 34篇 |
1984年 | 21篇 |
1983年 | 25篇 |
1982年 | 14篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1974年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Plant Molecular Biology - 相似文献
2.
3.
Yunfan Sun Liang Wu Yu Zhong Kaiqian Zhou Yong Hou Zifei Wang Zefan Zhang Jiarui Xie Chunqing Wang Dandan Chen Yaling Huang Xiaochan Wei Yinghong Shi Zhikun Zhao Yuehua Li Ziwei Guo Qichao Yu Liqin Xu Jia Fan 《Cell》2021,184(2):404-421.e16
- Download : Download high-res image (233KB)
- Download : Download full-size image
4.
Danielle E. Haulsee Dewayne A. Fox Matthew W. Breece Tonya M. Clauss Matthew J. Oliver 《PloS one》2016,11(2)
We developed a long-term tagging method that can be used to understand species assemblages and social groupings associated with large marine fishes such as the Sand Tiger shark Carcharias taurus. We deployed internally implanted archival VEMCO Mobile Transceivers (VMTs; VEMCO Ltd. Nova Scotia, Canada) in 20 adult Sand Tigers, of which two tags were successfully recovered (10%). The recovered VMTs recorded 29,646 and 44,210 detections of telemetered animals respectively. To our knowledge, this is the first study to demonstrate a method for long-term (~ 1 year) archival acoustic transceiver tag implantation, retention, and recovery in a highly migratory marine fish. Results show low presumed mortality (n = 1, 5%), high VMT retention, and that non-lethal recovery after almost a year at liberty can be achieved for archival acoustic transceivers. This method can be applied to study the social interactions and behavioral ecology of large marine fishes. 相似文献
5.
6.
Flash spectroscopy data were obtained for purple membrane fragments at pH 5, 7, and 9 for seven temperatures from 5 degrees to 35 degrees C, at the magic angle for actinic versus measuring beam polarizations, at fifteen wavelengths from 380 to 700 nm, and for about five decades of time from 1 microsecond to completion of the photocycle. Signal-to-noise ratios are as high as 500. Systematic errors involving beam geometries, light scattering, absorption flattening, photoselection, temperature fluctuations, partial dark adaptation of the sample, unwanted actinic effects, and cooperativity were eliminated, compensated for, or are shown to be irrelevant for the conclusions. Using nonlinear least squares techniques, all data at one temperature and one pH were fitted to sums of exponential decays, which is the form required if the system obeys conventional first-order kinetics. The rate constants obtained have well behaved Arrhenius plots. Analysis of the residual errors of the fitting shows that seven exponentials are required to fit the data to the accuracy of the noise level. 相似文献
7.
8.
9.
10.
The objective of this investigation was to find a simple method for the production of phenolic-rich products and sugar derivatives via separation of liquefied lignocellulosic materials. After liquefaction, the liquefied products were separated by addition of a sufficient amount of water. It was found that those hydrophobic phenolics could be largely separated from aqueous solutions. Preparation of polyurethane foams using biopolyol and isocyanate was studied. Water was used as an environmentally friendly blowing agent. The factors influencing the cell structure of foams such as catalyst, dosage of blowing agent, and mass ratio of biopolyol to PEG were studied. The microstructure of synthesized foams was characterized by SEM. 相似文献