全文获取类型
| 收费全文 | 1025篇 |
| 免费 | 25篇 |
专业分类
| 林业 | 22篇 |
| 农学 | 13篇 |
| 基础科学 | 9篇 |
| 76篇 | |
| 综合类 | 525篇 |
| 农作物 | 34篇 |
| 水产渔业 | 14篇 |
| 畜牧兽医 | 277篇 |
| 园艺 | 10篇 |
| 植物保护 | 70篇 |
出版年
| 2021年 | 5篇 |
| 2020年 | 6篇 |
| 2019年 | 6篇 |
| 2018年 | 7篇 |
| 2017年 | 10篇 |
| 2016年 | 9篇 |
| 2015年 | 8篇 |
| 2014年 | 6篇 |
| 2013年 | 29篇 |
| 2012年 | 17篇 |
| 2011年 | 28篇 |
| 2010年 | 14篇 |
| 2009年 | 13篇 |
| 2008年 | 19篇 |
| 2007年 | 23篇 |
| 2006年 | 29篇 |
| 2005年 | 23篇 |
| 2004年 | 25篇 |
| 2003年 | 18篇 |
| 2002年 | 29篇 |
| 2000年 | 7篇 |
| 1999年 | 10篇 |
| 1998年 | 10篇 |
| 1997年 | 6篇 |
| 1996年 | 10篇 |
| 1995年 | 6篇 |
| 1994年 | 5篇 |
| 1993年 | 11篇 |
| 1992年 | 11篇 |
| 1991年 | 16篇 |
| 1990年 | 17篇 |
| 1989年 | 43篇 |
| 1988年 | 44篇 |
| 1987年 | 58篇 |
| 1986年 | 51篇 |
| 1985年 | 62篇 |
| 1984年 | 57篇 |
| 1983年 | 84篇 |
| 1982年 | 62篇 |
| 1981年 | 58篇 |
| 1980年 | 7篇 |
| 1976年 | 6篇 |
| 1975年 | 9篇 |
| 1974年 | 10篇 |
| 1973年 | 10篇 |
| 1972年 | 4篇 |
| 1971年 | 4篇 |
| 1969年 | 4篇 |
| 1967年 | 7篇 |
| 1957年 | 4篇 |
排序方式： 共有1050条查询结果，搜索用时 15 毫秒
121.
A coalition of environmental groups headed by activist Jeremy Rifkin has filed lawsuits to halt experiments that would release genetically engineered organisms into the environment. One suit, filed against the National Institutes of Health on 14 September 1983, would block tests by researchers at the University of California, Berkeley. A second suit, filed 16 September 1983 against Cetus Madison and BioTechnica, seeks to halt field tests that had been approved by NIH's Recombinant DNA Advisory Committee. At issue are NIH's role in evaluating the risks of genetic experimentation, and the public's right of access to proprietary information. 相似文献
122.
123.
124.
125.
Nepalese porters routinely carry head-supported loads equal to 100 to 200% of their body weight (Mb) for many days up and down steep mountain footpaths at high altitudes. Previous studies have shown that African women carry head-supported loads of up to 60% of their Mb far more economically than army recruits carrying equivalent loads in backpacks. Here we show that Nepalese porters carry heavier loads even more economically than African women. Female Nepalese porters, for example, carry on average loads that are 10% of their Mb heavier than the maximum loads carried by the African women, yet do so at a 25% smaller metabolic cost. 相似文献
126.
127.
Norman C 《Science (New York, N.Y.)》1984,225(4663):701
128.
Norman C 《Science (New York, N.Y.)》1983,222(4619):35
The National Institutes of Health's Recombinant DNA Advisory Committee has given conditional approval to a proposal by the Cetus Madison Corporation to field test plants that have been genetically manipulated to resist some diseases. The committee made no recommendation, however, on another field test proposed by BioTechnica International Inc. Both proposals had been challenged by a coalition of environmental groups led by Jeremy Rifkin, who has now filed a freedom of information request to NIH asking for documents pertaining to their health and safety aspects. 相似文献
129.
Norman C 《Science (New York, N.Y.)》1982,218(4571):456
The President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research, scheduled to go out of business on 31 December 1982, requested a three-month extension of its life to complete several reports. This brief news item reports that the requested extension was added as an amendment to a budget bill by the Senate but then stripped from the bill by a House-Senate conference committee. 相似文献
130.