全文获取类型
收费全文 | 975篇 |
免费 | 91篇 |
出版年
2022年 | 7篇 |
2021年 | 15篇 |
2020年 | 9篇 |
2018年 | 22篇 |
2017年 | 6篇 |
2016年 | 24篇 |
2015年 | 34篇 |
2014年 | 35篇 |
2013年 | 39篇 |
2012年 | 50篇 |
2011年 | 58篇 |
2010年 | 37篇 |
2009年 | 32篇 |
2008年 | 44篇 |
2007年 | 43篇 |
2006年 | 43篇 |
2005年 | 39篇 |
2004年 | 38篇 |
2003年 | 34篇 |
2002年 | 28篇 |
2001年 | 43篇 |
2000年 | 25篇 |
1999年 | 22篇 |
1998年 | 18篇 |
1997年 | 8篇 |
1995年 | 9篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 17篇 |
1991年 | 15篇 |
1990年 | 26篇 |
1989年 | 23篇 |
1988年 | 19篇 |
1987年 | 10篇 |
1986年 | 9篇 |
1985年 | 14篇 |
1984年 | 15篇 |
1983年 | 8篇 |
1982年 | 10篇 |
1980年 | 5篇 |
1979年 | 12篇 |
1978年 | 8篇 |
1977年 | 12篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1971年 | 7篇 |
1970年 | 8篇 |
1969年 | 4篇 |
1968年 | 7篇 |
1966年 | 4篇 |
排序方式: 共有1066条查询结果,搜索用时 312 毫秒
131.
132.
133.
134.
Fritz Bergmann 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1973,43(5):222-225
Summary Using techniques of starch gel zone electrophoresis, a considerable variation among esterase and leucine aminopeptidase isoenzyme patterns was found in the endosperm of dormant seeds of Norway spruce (Picea abies). Since the so-called primary endosperm of conifers is only a further developmental stage of the haploid female gametophyte, simple Mendelian segregations can be determined in seeds of individual open-pollinated trees. It was therefore possible to identify some esterase and leucine aminopeptidase loci only with regard to phenotypic frequency distributions without difficult crossing procedures.
Angenommen durch G. Melchers 相似文献
Angenommen durch G. Melchers 相似文献
135.
136.
137.
Optimization of Aqueous Extraction from Kalanchoe pinnata Leaves to Obtain the Highest Content of an Anti‐inflammatory Flavonoid using a Response Surface Model
下载免费PDF全文
![点击此处可从《Phytochemical analysis : PCA》网站下载免费的PDF全文](/ch/ext_images/free.gif)
138.
139.
Timothy D. Siferd Harold E. Welch Martin A. Bergmann Martin F. Curtis 《Polar Biology》1997,18(1):16-22
The seasonal distribution of sympagic amphipods was investigated in the Chesterfield Inlet area of northwestern Hudson Bay
(63°30′N). Amphipod abundance was measured by photographic samples and species composition was determined by sweep net samples.
Twelve species of amphipods were collected, the most common being Ischyrocerus anguipes, Pontogeneia inermis, Apherusa megalops and Weyprechtia pinguis. The major environmental variable affecting amphipod distribution was water depth. Amphipod abundance was highest near 20
m and near zero past 50 m. The maximum recorded abundance was 1367 m−2. A minor factor affecting the distribution of amphipods was snow depth, through its modifying effect on light and thereby
the growth of ice algae. Amphipods began to inhabit the sea ice shortly after its formation. From the beginning of March,
the number of amphipods on the ice increased steadily to about the 3rd week of April, after which numbers declined. This pattern
coincided with the seasonal ice algae abundance. Amphipods reduced ice algal biomass over 20-m depth by 63%. No evidence of
diurnal changes in abundance was observed.
Received: 15 May 1996 / Accepted: 4 November 1996 相似文献
140.
Enzymology of the oxidation of ammonia to nitrite by bacteria 总被引:23,自引:0,他引:23
Alan B. Hooper Todd Vannelli David J. Bergmann David M. Arciero 《Antonie van Leeuwenhoek》1997,71(1-2):59-67
The enzymes which catalyze the oxidation of ammonia to nitrite by autotrophic bacteria are reviewed. A comparison is made with enzymes which catalyze the same reactions in methylotrophs and organotrophic heterotrophic bacteria. 相似文献