全文获取类型
收费全文 | 461篇 |
免费 | 33篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 10篇 |
2020年 | 4篇 |
2019年 | 10篇 |
2018年 | 18篇 |
2017年 | 17篇 |
2016年 | 27篇 |
2015年 | 18篇 |
2014年 | 30篇 |
2013年 | 46篇 |
2012年 | 21篇 |
2011年 | 18篇 |
2010年 | 16篇 |
2009年 | 11篇 |
2008年 | 14篇 |
2007年 | 8篇 |
2006年 | 18篇 |
2005年 | 6篇 |
2004年 | 9篇 |
2003年 | 7篇 |
2002年 | 9篇 |
2000年 | 12篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 3篇 |
1993年 | 9篇 |
1992年 | 11篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1980年 | 3篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1973年 | 3篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1968年 | 3篇 |
1967年 | 3篇 |
1924年 | 2篇 |
1917年 | 5篇 |
1913年 | 2篇 |
排序方式: 共有494条查询结果,搜索用时 15 毫秒
91.
Jar KŘíŽenecký 《Development genes and evolution》1913,37(4):629-634
Ohne Zusammenfassung 相似文献
92.
Jar KŘíŽenecký 《Development genes and evolution》1913,36(3):294-341
Ohne Zusammenfassung 相似文献
93.
Søren Lykke-Andersen Kristina Žumer Ewa Šmidová Molska Jérôme O. Rouvière Guifen Wu Carina Demel Björn Schwalb Manfred Schmid Patrick Cramer Torben Heick Jensen 《Molecular cell》2021,81(3):514-529.e6
- Download : Download high-res image (140KB)
- Download : Download full-size image
94.
Concentration of methanol in the medium strongly affected not only the physiology but also the cytology ofCandida boidinii strain 2 cells in a methanol-limited chemostat at a constant dilution rateD 0.1/h and at low pH 3.0. The formation of large cubic peroxisomes with high alcohol oxidase (AO) activity observed at low
methanol concentration (S
0 3 g/L) disappeared on increasing the methanol concentration in the inflow medium. The AO activity in the cells sharply decreased,
followed by accumulation of riboflavin phosphate and residual methanol in the medium. The activity of catalase was relatively
stable. At methanol concentrationS
0>K
I (K
1 equal to 12 g methanol per L), which included a substantial increase in methanol dissimilation, documented by higher formaldehyde
and formate dehydrogenase activities and by lower yield coefficient on methanol, the yeast cells contained large lobe-shaped
peroxisomes and a smaller number of larger mitochondria. The cells formed pseudomycelium with a thick septum between the mother
and daughter cells. 相似文献
95.
96.
97.
Peridinium cinctum is a common freshwater dinophyte with a long history of research. Erich Lindemann was the first to assess intraspecific variability in this species focusing on plate pattern variation. Since then, this issue has been neglected but with the application of DNA sequence diagnostics, a combination of morphological and molecular characters may enable taxonomic delimitations. Our aim was to identify distinct morphotypes using plate pattern as the main characteristic and then compare them to the geographic occurrence of particular ribotypes (as inferred from sequences of the Internal Transcribed Spacer: ITS) in samples from Central Europe. Approximately 200 observations were carried out under the inverse light microscope for each of a total of 15 strains. We observed two main variations from the abundant plate pattern in P. cinctum, namely an unusual position of the 2a plate and the irregular shape of the 1a plate. In 88 (predominantly clonal) strains, we identified five different ribotypes (submitted as 71 new GenBank entries) which had no clear correlation to the defined morphotypes and/or spatial occurrences. In four cases, we detected two distinct ribotypes at the same locality. However, samples collected south of the Danube River presented a different predominant morphotype from the rest of the samples, thus implying a potential biogeographic signal as inferred from morphology. In general, there is morphological and molecular variability in P. cinctum, which is under-studied and which may uncover geographic or ecological correlations or even the existence of cryptic species. 相似文献
98.
Understanding biological and ecological factors affecting seed germination of the multipurpose tree Anogeissus leiocarpa
下载免费PDF全文
![点击此处可从《Plant biology (Stuttgart, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
E. Mattana M. Sacande G. Bradamante P. Gomez‐Barreiro S. Sanogo T. Ulian 《Plant biology (Stuttgart, Germany)》2018,20(3):602-609
- Anogeissus leiocarpa (DC.) Guill. & Perr. (Combretaceae) has important economic and cultural value in West Africa as source of wood, dye and medicine. Although this tree is in high demand by local communities, its planting remains limited due to its very low propagation via seed.
- In this study, X‐rays were used to select filled fruits in order to characterise their morphology and seed germination responses to treatment with sulphuric acid and different incubation temperatures.
- Morphological observations highlighted a straight orthotropous seed structure. The increase in mass detected for both intact and scarified fruits through imbibition tests, as well as morphological observations of fruits soaked in methylene blue solution, confirmed that they are water‐permeable, although acid‐scarified fruits reached significantly higher mass increment values than intact ones. Acid scarification (10 min soaking in 98% H2SO4) positively affected seed germination rate but not final germination proportions. When intact fruits where incubated at a range of temperatures, no seeds germinated at 10 °C, while maximum seed germination (ca. 80%) was reached at 20 °C. T50 values ranged from a minimum of ca. 12 days at 25 °C to a maximum of ca. 34 days at 15 and 35 °C. A theoretical base temperature for germination (Tb) of ca. 10 °C and a thermal requirement for 50% germination (S) of ca. 195 °Cd were also identified for intact fruits.
- The results of this study revealed the seed germination characteristics driven by fruit and seed morphology of this species, which will help in its wider propagation in plantations.
99.
Five white-rot basidiomycetes were evaluated for their potential to improve ruminal degradation of wheat straw.Polyorus brumalis, Lyophyllum ulmarium III,Trametes gibbosa, Pleurotus ostreatus, and aPleurotus ostreatus mutant were incubated on wheat straw for 30 d at 28°C. Detergent fiber, crude protein andin vitro dry matter digestibility (IVDMD) were determined. The results showed increasing crude protein and ash contents in fungus-treated
straw. IVDMD values were increased in straws treated withP. ostreatus, P. ostreatus mutant andT. gibbosa only. Relative to untreated wheat straw the detergent fiber content—neutral detergent fiber (NDF), and acid detergent fiber
(ADF) was reduced in fungus-treated straw and out of three fractions—hemicellulose, cellulose and lignin, hemicellulose showed
the largest proportionate loss whereas lignin the smallest one in all 5 samples of fungus treated straw. 相似文献
100.
B. Cukrowska J. Šinkora Z. Řeháková I. Šplíchal L. Tučková R. Barot-Ciorbaru A. T. J. Bianchi R. Lodinová-Žádníková H. Tlaskalová-Hogenová 《Folia microbiologica》1995,40(4):421-430
Immunoglobulin (Ig) response to different polyclonal B-cell activators was measured by ELISA in cell culture media of thymocytes,
splenocytes and liver cells isolated from pig fetuses, 8-d-old germ-free piglets and conventionally reared pigs. Both in fetal
and in postnatal life polyclonally stimulated lymphocytes were found to produce predominantly the IgM isotype; the first IgM
formation was detected in 50-d-old fetal liver (gestation in pigs lasts 114 d). Surprisingly, 73-d-old fetal thymic cells
were shown to be induced to Ig synthesis and secretion. In contrast to splenocytes of the same age, which secreted exclusively
IgM, fetal thymocytes produced IgM, IgG and IgA. Polyclonally stimulated splenic cells as compared with thymic cells started
to produce IgA later in fetal ontogeny, whereas the IgG response was not detectable in splenic cell culture media during the
whole embryonal development and appeared only after birth. The earliest and the highest Ig stimulation was found after cultivation
of lymphocytes withNocardia delipidated cell mitogen. Interestingly, the moderate stimulatory effect of 65-kDa heat shock protein (Hsp-65) in polyclonal
IgM response of fetal splenocytes was observed. We showed that thymic B lymphocytes represent probably the first maturing
B cell population detectable in fetal life, which is able to differentiate after polyclonal stimulation into IgM as well as
IgA and IgG producing cells.
Dedicated to Professor J. Šterzl on the occasion of his 70th birthday 相似文献