全文获取类型
收费全文 | 445篇 |
免费 | 46篇 |
国内免费 | 115篇 |
专业分类
606篇 |
出版年
2024年 | 3篇 |
2023年 | 12篇 |
2022年 | 18篇 |
2021年 | 16篇 |
2020年 | 18篇 |
2019年 | 21篇 |
2018年 | 13篇 |
2017年 | 15篇 |
2016年 | 14篇 |
2015年 | 11篇 |
2014年 | 10篇 |
2013年 | 26篇 |
2012年 | 12篇 |
2011年 | 20篇 |
2010年 | 24篇 |
2009年 | 39篇 |
2008年 | 34篇 |
2007年 | 33篇 |
2006年 | 36篇 |
2005年 | 25篇 |
2004年 | 20篇 |
2003年 | 23篇 |
2002年 | 19篇 |
2001年 | 20篇 |
2000年 | 13篇 |
1999年 | 22篇 |
1998年 | 12篇 |
1997年 | 5篇 |
1996年 | 12篇 |
1995年 | 10篇 |
1994年 | 2篇 |
1993年 | 5篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有606条查询结果,搜索用时 0 毫秒
601.
602.
Eric T. Thacker Dale R. Gardner Terry A. Messmer Michael R. Guttery Dave K. Dahlgren 《The Journal of wildlife management》2012,76(3):588-592
Sagebrush (Artemisia spp.) constitutes the majority (>99%) of sage-grouse (Centrocercus spp.) winter diets. Thus, identification and protection of important winter habitats is a conservation priority. However, not all sagebrush may be alike. More information is needed regarding sage-grouse sagebrush winter dietary preferences for application to management. The objective of our research was to determine if chemical analysis of fecal pellets could be used to characterize winter sage-grouse diets as a substitute for more invasive methods. We collected and analyzed fecal pellets and sagebrush samples from 29 different sage-grouse flock locations in northwestern and southcentral Utah. Using gas chromatography, we were able to identify crude terpene profiles that were unique to Wyoming sagebrush (A. tridentata wyomingensis) and black sagebrush (A. nova). We subsequently used the profiles to determine sagebrush composition of sage-grouse fecal pellets, thus reflecting sage-grouse winter diets. This technique provides managers with a tool to determine which species or subspecies of sagebrush may be important in the winter diets of sage-grouse populations. © 2011 The Wildlife Society. 相似文献
603.
604.
C. S. Buer M. J. Correll T. C. Smith M. J. Towler P. J. Weathers M. Nadler J. Seaman D. Walcerz 《In vitro cellular & developmental biology. Plant》1996,32(4):299-304
Summary A nutrient-mist bioreactor was designed that separates the nutrient medium from the electronic components via an acoustic
window. This eliminates compromising culture sterility when repairing mechanical failures common with commercially available
mist reactors. The experimental mist bioreactor is low cost and can be assembled in any laboratory. Toxicity tests of several
potential acoustically transparent materials are included. Details of the construction procedures include methods for casting
the window. Growth data using the newly designed nutrient mist bioreactor are compared to data from a commercial mist reactor,
shake flasks, and Gelrite cultures.Artemisia annua hairy roots andNephrolepis exaltata shoot cultures showed growth comparable to the conventional tissue culture methods. 相似文献
605.
Anna Maria Pirttilä Merja Hirsikorpi Terttu Kämäräinen Laura Jaakola Anja Hohtola 《Plant Molecular Biology Reporter》2001,19(3):273-273
Several protocols described for plant DNA isolation fail to produce good quality DNA from medicinal herbs and aromatic plants.
These plants contain exceptionally high amounts of secondary metabolites that interfere with DNA isolation. To address this
problem, we developed 2 DNA isolation methods for sundew and tarragon that produce DNA suitable for molecular biological applications.
One of the methods also is applicable for milfoil and Siberian ginseng. 相似文献
606.