全文获取类型
收费全文 | 3113篇 |
免费 | 230篇 |
国内免费 | 1篇 |
出版年
2023年 | 34篇 |
2022年 | 33篇 |
2021年 | 73篇 |
2020年 | 50篇 |
2019年 | 59篇 |
2018年 | 123篇 |
2017年 | 90篇 |
2016年 | 167篇 |
2015年 | 134篇 |
2014年 | 174篇 |
2013年 | 271篇 |
2012年 | 150篇 |
2011年 | 134篇 |
2010年 | 137篇 |
2009年 | 85篇 |
2008年 | 100篇 |
2007年 | 47篇 |
2006年 | 102篇 |
2005年 | 61篇 |
2004年 | 50篇 |
2003年 | 54篇 |
2002年 | 36篇 |
2001年 | 53篇 |
2000年 | 50篇 |
1999年 | 50篇 |
1998年 | 57篇 |
1997年 | 33篇 |
1996年 | 42篇 |
1995年 | 40篇 |
1994年 | 48篇 |
1993年 | 51篇 |
1992年 | 28篇 |
1991年 | 28篇 |
1989年 | 23篇 |
1988年 | 32篇 |
1987年 | 27篇 |
1985年 | 28篇 |
1984年 | 22篇 |
1983年 | 21篇 |
1981年 | 26篇 |
1980年 | 33篇 |
1978年 | 24篇 |
1975年 | 21篇 |
1974年 | 34篇 |
1973年 | 26篇 |
1972年 | 22篇 |
1971年 | 23篇 |
1969年 | 22篇 |
1967年 | 20篇 |
1966年 | 23篇 |
排序方式: 共有3344条查询结果,搜索用时 15 毫秒
1.
A. Španová 《Folia microbiologica》1980,25(4):281-288
Temperature-sensitive (ts) mutations of the G101 phage were isolated after mutagenesis with hydroxylamine. A complementation analysis of 61ts mutants showed that these mutants may be divided into at least 12 complementation groups. Twots mutants probably originated in genes which control lytic functions of the G101 phage. It was shown by three factor crosses
that all of the 12ts mutations tested are localized on that side of the “c” region where the probablecI repressor gene is positioned. Sevents mutations is closely linked to thecI
26 clear marker, three exhibit a closer linkage and two do not exhibit any linkage withcI. All mutations isolated until now can be arrange linearly. According to the present knowledge the preliminary genetic map
of the G101 phage is linear. 相似文献
2.
3.
H. Štorchová 《Biologia Plantarum》1994,36(3):358-358
4.
5.
6.
7.
8.
Jan Batelka Jakub Prokop Hans Pohl Ming Bai Weiwei Zhang Rolf G. Beutel 《Systematic Entomology》2019,44(2):396-407
Extremely miniaturized longipedes insects (body length c. 0.3 mm) embedded in two pieces of Cretaceous amber from Myanmar are described and interpreted. Using inverted fluorescence and light microscopy for detailed analysis of microstructures, the inclusions were identified as primary larvae of the beetle family Ripiphoridae, subfamily Ripidiinae. While the structure of thoracic and abdominal segments including appendages corresponds well with the groundplan known in recent members of Ripidiinae, a curved prosternal ridge with prominent spines (each c. 5 μm), the reduced condition of stemmata and antennae and the lack of sharp mandibles are unique features within the entire family, apparently apomorphies of the longipedes larvae. A sinuate prosternal edge with a dense row of spines (prosternoctenidium) might be homologous with ‘head ctenidia’ in some previously described miniaturized conicocephalate larvae, but further investigation is needed. The morphological differences between the head of longipedes larvae and extant Ripidiinae are interpreted as adaptations to different groups of hosts and life strategies. Palaeoethology of the longipedes larvae is briefly discussed. In addition, the systematic placement of conicocephalate larvae from Canadian, Myanmar and Russian Cretaceous ambers, already interpreted by various authors as primary instars within Coleopterida (assigned to either Strepsiptera or to the coleopteran Tenebrionoidea: Ripiphoridae), is discussed. 相似文献
9.
S. H. Habib S.-E. Ooi Ond?ej Novák Danu?e Tarkowská Jakub Rol?ík Karel Dole?al S. S. R. Syed-Alwee C.-L. Ho P. Namasivayam 《Plant Growth Regulation》2012,68(2):313-317
Comparative mineral and hormonal analyses were made on tissue culture derived truncated leaf syndrome and wild type oil palm seedlings. Mineral analysis confirmed that Boron, Zinc and chlorophyll levels were significantly lower in truncated leaf syndrome leaves than those of wild type. Hormonal analysis also revealed various cytokinin derivatives such as trans-zeatin, trans-zeatin riboside, trans-zeatin O-glucoside and trans-zeatin riboside 5??mono phosphate were significantly higher in truncated leaf syndrome leaves compared to wild type leaves. Brassinolide level was also significantly higher in truncated leaf syndrome leaves than those of the wild type. These observations suggest that the truncated leaf syndrome abnormality could be associated to high cytokinin and brassinosteroid production which affects the uptake of Boron and Zinc. 相似文献
10.
F. Šrámek 《Biologia Plantarum》1999,42(4):582-582