全文获取类型
收费全文 | 855篇 |
免费 | 131篇 |
出版年
2022年 | 6篇 |
2021年 | 17篇 |
2019年 | 6篇 |
2018年 | 7篇 |
2016年 | 9篇 |
2015年 | 24篇 |
2014年 | 33篇 |
2013年 | 36篇 |
2012年 | 41篇 |
2011年 | 34篇 |
2010年 | 35篇 |
2009年 | 26篇 |
2008年 | 46篇 |
2007年 | 38篇 |
2006年 | 31篇 |
2005年 | 27篇 |
2004年 | 40篇 |
2003年 | 29篇 |
2002年 | 41篇 |
2001年 | 13篇 |
2000年 | 22篇 |
1999年 | 23篇 |
1998年 | 12篇 |
1997年 | 7篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 22篇 |
1991年 | 23篇 |
1990年 | 20篇 |
1989年 | 28篇 |
1988年 | 25篇 |
1987年 | 28篇 |
1986年 | 26篇 |
1985年 | 18篇 |
1984年 | 17篇 |
1983年 | 14篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 12篇 |
1978年 | 8篇 |
1977年 | 12篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1974年 | 9篇 |
1973年 | 7篇 |
1972年 | 6篇 |
1971年 | 10篇 |
1970年 | 7篇 |
排序方式: 共有986条查询结果,搜索用时 187 毫秒
981.
The gyrogen with tubes has been the object of repeated trials carried out over a period of some years. The aim of these trials was essentially to multiply BHK cells in monolayer and to reproduce the FMD virus in one operation. At the laboratory stage, the gyrogen represented three roller flasks; at the pilot stage, 100 roller flasks; and at the industrial stage, 500 flasks. Culturing cells on a glass support, is not in itself new, but the difficulty appeared when replicating the virus in order to obtain the high parameters necessary for vaccine production. Everything was accomplished so that finally the cell culture and viral multiplication could be carried out in situ in the same apparatus. 相似文献
982.
Conodonts are an extinct group of organisms, known from the Upper Cambrian to the Triassic. They have no extant representatives, and tooth-like buccal elements are usually the only remains of the animal found in the sediments. Therefore, most of their taxonomy rests on these elements that are good stratigraphic tools for these ancient periods, due to their rapid morphological evolution. Conodont species are usually described species that are based on either clusters of elements corresponding to an entire apparatus (natural assemblages), or on the most frequently preserved element. These described species are acceptable stratigraphic tools, but hardly consider the dimension of the variation that a biological species can encompass through time and space. In order to tackle temporal, environmental and biogeographical changes, recent studies have shown that morphological variation should be taken into account by quantitative analyses, aiming at getting at the closest of what the former species might have been. 相似文献
983.
Enhanced Nitrogen Fixation in a Rhizobium etli ntrC Mutant That Overproduces the Bradyrhizobium japonicum Symbiotic Terminal Oxidase cbb3 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Applied microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
984.
985.
The use of the 15 channels blood grouping autoanalyzer with automated recording and interpretation proved its fiability through more than 30 000 tests for ABO, Rh and Kell determinations. Misreactions come mostly from the carry-over phenomenom. However no discrepancy was noticed for ABO determination. Only few ones occured for Rhesus and Kell, leading to false positive interpretations which were always corrected by checking the event recorder track. New improvements are expected from the automatic phasing using a microprocessor and further extents are setting up with the connection to a computer. 相似文献
986.
N Niel E Rechencq A Muller J P Vidal R Escale T Durand J P Girard J C Rossi C Bonne 《Prostaglandins》1992,43(1):45-54
Seven new pseudopeptido and thioaromatic leukotriene analogues were synthesized and their agonist-antagonist and binding activities investigated. The synthesis led to the pleasing observation that the analogue in which the cysteinyl-glycine moiety was replaced by a 6-mercapto-3-(E)-hexenoic acid, not only exhibited potent affinity (guinea-pig lung parenchyma, IC50: 5 x 10(-9) M) but also showed 30% of the LTD4 agonist activity (guinea-pig ileum, ED 50: 2.7 x 10(-9)) giving very important key information on LTD4 geometry to the receptor. This compound was the first stable new pseudopeptido-leukotriene with such agonist activity and should contribute to the understanding of the metabolism of leukotriene D4. In addition, inversion of chirality at C5 and C6 carbon atoms of the leukotriene chain or replacement of the cysteinyl-glycine moiety by a thioaromatic acid led to new weak antagonists of the LTD4. 相似文献