全文获取类型
收费全文 | 1194篇 |
免费 | 53篇 |
国内免费 | 1篇 |
专业分类
1248篇 |
出版年
2023年 | 20篇 |
2022年 | 41篇 |
2021年 | 52篇 |
2020年 | 26篇 |
2019年 | 38篇 |
2018年 | 56篇 |
2017年 | 44篇 |
2016年 | 53篇 |
2015年 | 69篇 |
2014年 | 72篇 |
2013年 | 103篇 |
2012年 | 114篇 |
2011年 | 83篇 |
2010年 | 43篇 |
2009年 | 40篇 |
2008年 | 49篇 |
2007年 | 43篇 |
2006年 | 31篇 |
2005年 | 23篇 |
2004年 | 19篇 |
2003年 | 25篇 |
2002年 | 23篇 |
2001年 | 20篇 |
2000年 | 12篇 |
1999年 | 7篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 8篇 |
1990年 | 16篇 |
1989年 | 11篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1965年 | 2篇 |
1958年 | 2篇 |
排序方式: 共有1248条查询结果,搜索用时 15 毫秒
101.
102.
Kumari Jyoti Haque Md. Intesaful Jha Rajesh K. Rathore Mangal S. 《Molecular biology reports》2022,49(5):3729-3743
Molecular Biology Reports - Plant establishment, growth, development and productivity are adversely affected by abiotic stresses that are dominant characteristics of environmentally... 相似文献
103.
104.
105.
106.
Uma Kumari Rishi K. Vishwakarma Neha Gupta Ruby M. V. Shirgurkar Bashir M. Khan 《Physiology and Molecular Biology of Plants》2015,21(2):261-267
Bacopa monniera is an important source of metabolites with pharmaceutical value. It has been regarded as a valuable medicinal plant and its entire commercial requirement is met from wild natural population. Recently, metabolic engineering has emerged as an important solution for sustained supply of assured and quality raw material for the production of active principles. Present report describes efficient in vitro multiplication and transformation method for genetic manipulation of this species. MS medium supplemented with 2 mgl−1 BA and 0.2 mgl−1 IAA was found optimum for maximum shoot regeneration (98.33 %) from in vitro leaves with 2–3 longitudinal cuts. Agrobacterium tumefaciens-mediated transformation method was used for generating transgenic B. monniera plants. Putative transformants were confirmed by GUS assay and PCR based confirmation of hptII gene. DNA blot analysis showed single copy insertion of transgene cassette. An average of 87.5 % of the regenerated shoots were found PCR positive for hptII gene and GUS activity was detected in leaves of transgenic shoots at a frequency of 82.5 % The efficient multiple shoots regeneration system described herein may help in mass production of B. monniera plant. Also, the high frequency transformation protocol described here can be used for genetic engineering of B. monniera for enhancement of its pharmaceutically important metabolites. 相似文献
107.
The cold‐water climate shield: delineating refugia for preserving salmonid fishes through the 21st century 下载免费PDF全文
Daniel J. Isaak Michael K. Young David E. Nagel Dona L. Horan Matthew C. Groce 《Global Change Biology》2015,21(7):2540-2553
The distribution and future fate of ectothermic organisms in a warming world will be dictated by thermalscapes across landscapes. That is particularly true for stream fishes and cold‐water species like trout, salmon, and char that are already constrained to high elevations and latitudes. The extreme climates in those environments also preclude invasions by most non‐native species, so identifying especially cold habitats capable of absorbing future climate change while still supporting native populations would highlight important refugia. By coupling crowd‐sourced biological datasets with high‐resolution stream temperature scenarios, we delineate network refugia across >250 000 stream km in the Northern Rocky Mountains for two native salmonids—bull trout (BT) and cutthroat trout (CT). Under both moderate and extreme climate change scenarios, refugia with high probabilities of trout population occupancy (>0.9) were predicted to exist (33–68 BT refugia; 917–1425 CT refugia). Most refugia are on public lands (>90%) where few currently have protected status in National Parks or Wilderness Areas (<15%). Forecasts of refuge locations could enable protection of key watersheds and provide a foundation for climate smart planning of conservation networks. Using cold water as a ‘climate shield’ is generalizable to other species and geographic areas because it has a strong physiological basis, relies on nationally available geospatial data, and mines existing biological datasets. Importantly, the approach creates a framework to integrate data contributed by many individuals and resource agencies, and a process that strengthens the collaborative and social networks needed to preserve many cold‐water fish populations through the 21st century. 相似文献
108.
109.
110.