全文获取类型
收费全文 | 178篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
184篇 |
出版年
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 6篇 |
2011年 | 5篇 |
2010年 | 5篇 |
2009年 | 7篇 |
2008年 | 3篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1990年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1972年 | 3篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1966年 | 3篇 |
1958年 | 2篇 |
1957年 | 6篇 |
1956年 | 3篇 |
1955年 | 3篇 |
1954年 | 2篇 |
1952年 | 2篇 |
1951年 | 4篇 |
1950年 | 3篇 |
1949年 | 2篇 |
1948年 | 2篇 |
1936年 | 2篇 |
1934年 | 2篇 |
1930年 | 2篇 |
1929年 | 1篇 |
1928年 | 2篇 |
1926年 | 2篇 |
1925年 | 3篇 |
1924年 | 1篇 |
1923年 | 3篇 |
排序方式: 共有184条查询结果,搜索用时 0 毫秒
181.
182.
M. TIEN KUO M. E. RIED G. F. SAUNDERS 《Differentiation; research in biological diversity》1976,5(2-3):175-178
The messenger RNA populations in two haematopoietic tissues were compared with respect to number of different sequences present and their relative abundancies. This was accomplished by hybridising complementary DNA to the cytoplasmic polyadenylated RNA from which it was transcribed and to heterologous polyadenylated RNA. The hybridisation kinetics were essentially the same in the homologous hybridisation. However, in heterologous hybridisation some differences were observed in the high abundancy messengers. 相似文献
183.
Segments of Avena mesocotyl were placed in buffered solutionsof phenoxyacetic acid (POA) or 2,4-dichlorophebnoxyacetic acid(2,4-D), containing carbon-14 in the carboxyl group, and thequantities of radioactivity taken up by the tissues measured.With freshly cut segments in solutions of 2,4-D there is accumulationof carbon-14, but the course of uptake is interrupted by a temporaryphase when some of the accumulated 2,4-D is released to theexternal solution. If after cutting the segments are first pretreatedby placing them for about 15 h in buffer, and then transferredto 2,4-D, there is progressive accumulation with no phase ofnet loss. Pretreated segments absorb greater quantities of either 2,4-Dor POA than freshly excised tissues. Following pretreatmentin buffer the course of uptake of POA is linear but for 2,4-Dthe course is curvilinear. However, after pretreatment withnon-radioactive 2,4-D the subsequent rate of uptake of radioactive2,4-D is constant over long periods. The uptake of radioactive2,4-D is largely independent of the concentration of non-radioactive2,4-D given during pretreatment. When segments which have absorbed 2,4-D-1-14C are transferredto buffer, a relatively small proportion of the carbon-14, themobile fraction, is released. The amount releasedfollowing different periods of uptake is constant whereas thelevel of non-mobile carbon-14, the residual fraction,rises progressively in step with accumulation. The uptake of POA and 2,4-D is accompained by the formationwithin the tissues of other radioactive substances. It is concludedthat the residual fraction is composed, at least in part, ofthese metabolic products and that accumulation and metabolicconversion are inter-connected. Dinitrophenol (DNP) slowly and progressively depresses the uptakeof POA whereas the uptake of 2,4-D is very rapidly arrested.However, after about 2 h, in the continued presence of DNP,uptake of 2,4-D restarts but the rate never attains that ofthe control. These divergent effects of DNP indicate that POAand 2,4-D are accumulated by different pathways. 相似文献
184.
RICHARD M. K. SAUNDERS 《Botanical journal of the Linnean Society. Linnean Society of London》2003,142(3):321-339
The species of Goniothalamus (Annonaceae) occurring in Peninsular Malaysia and Singapore are revised, updating the previous taxonomic treatment by James Sinclair, published in 1955. A total of 18 species is recognized, including a new species, G. tomentosus . Collections referrable to G. tomentosus were previously determined as ' G. marcanii '; examination of the types of G. marcanii reveals that the two taxa are not conspecific, however, and a new name is accordingly validated here. Goniothalamus tomentosus has closest affinities with the Javan/Sumatran species G. costulatus . Other important nomenclatural changes include the reduction of G. umbrosus to synonymy with G. tapis . © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 142 , 321−339. 相似文献