全文获取类型
收费全文 | 2319篇 |
免费 | 127篇 |
国内免费 | 3篇 |
出版年
2023年 | 11篇 |
2022年 | 10篇 |
2021年 | 18篇 |
2020年 | 22篇 |
2019年 | 10篇 |
2018年 | 34篇 |
2017年 | 27篇 |
2016年 | 52篇 |
2015年 | 74篇 |
2014年 | 106篇 |
2013年 | 144篇 |
2012年 | 146篇 |
2011年 | 156篇 |
2010年 | 123篇 |
2009年 | 87篇 |
2008年 | 133篇 |
2007年 | 149篇 |
2006年 | 133篇 |
2005年 | 115篇 |
2004年 | 109篇 |
2003年 | 114篇 |
2002年 | 126篇 |
2001年 | 28篇 |
2000年 | 25篇 |
1999年 | 35篇 |
1998年 | 30篇 |
1997年 | 23篇 |
1996年 | 26篇 |
1995年 | 25篇 |
1994年 | 22篇 |
1993年 | 19篇 |
1992年 | 18篇 |
1991年 | 11篇 |
1990年 | 17篇 |
1989年 | 13篇 |
1988年 | 17篇 |
1987年 | 22篇 |
1986年 | 11篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 16篇 |
1982年 | 18篇 |
1981年 | 10篇 |
1980年 | 14篇 |
1978年 | 12篇 |
1977年 | 9篇 |
1976年 | 12篇 |
1975年 | 9篇 |
1973年 | 11篇 |
1972年 | 12篇 |
排序方式: 共有2449条查询结果,搜索用时 203 毫秒
71.
Nevoigt E Pilger R Mast-Gerlach E Schmidt U Freihammer S Eschenbrenner M Garbe L Stahl U 《FEMS yeast research》2002,2(2):225-232
The GPD1 gene encoding the glycerol-3-phosphate dehydrogenase was overexpressed in an industrial lager brewing yeast (Saccharomyces cerevisiae ssp. carlsbergensis) to reduce the content of ethanol in beer. The amount of glycerol produced by the GPD1-overexpressing yeast in fermentation experiments simulating brewing conditions was increased 5.6 times and ethanol was decreased by 18% when compared to the wild-type. Overexpression of GPD1 does not affect the consumption of wort sugars. Only minor changes in the concentration of higher alcohols, esters and fatty acids could be observed in beer produced by the GPD1-overexpressing brewing yeast. However, the concentrations of several other by-products, particularly acetoin, diacetyl and acetaldehyde, were considerably increased. 相似文献
72.
John A. West Giuseppe C. Zuccarello Max Hommersand Ulf Karsten Solvig Görs 《Phycological Research》2006,54(1):1-14
Only two genera in the Rhodomelaceae share the morphological character of transverse division of periaxial cells into two or more tier cells in which the pit connection is retained between the lower cell and the axial cell: Bostrychia and Rhodolachne. One species, Rhodolachne radicosa Itono, has been reported from mangroves, a common habitat for Bostrychia. Many collections of an entity similar to Rhodolachne radicosa have been made from localities around the Indo‐Pacific. Culture observations show a Polysiphonia‐type sexual life history in Malaysia and New Caledonia isolates that produce self‐compatible bisexual gametophytes. The New Caledonia isolate also has unisexual gametophytes. An isolate from New South Wales (Australia) reproduces asexually through successive generations of tetrasporophytes. The Thailand isolate has successive generations of mixed‐phase tetrasporophytes. The tetrasporangial stichidia also bear male spermatangial sectors, but female structures are lacking. Western Australia and Madagascar isolates do not reproduce in culture. Molecular evidence, based on sequencing of the rbcL and the large subunit ribosomal RNA genes, shows that these isolates belong to the genus Bostrychia. Low molecular weight carbohydrate analysis reveals high levels of digeneaside in all isolates. The sugar hexitol sorbitol, an osmolyte characteristic of Bostrychia, occurs in all isolates, whereas the Madagascar and New Caledonia isolates have very low levels of dulcitol. Molecular, low molecular weight carbohydrate and morphological evidence show that Rhodolachne radicosa belongs within the genus Bostrychia. We transfer Rhodolachne radicosa to Bostrychia radicosa (Itono) West, Zuccarello and Hommersand. 相似文献
73.
Rafael Sobrano Fais Rafael Menezes da Costa Allan Carvalho Mendes Fabíola Mestriner Simon Gabriel ComermaSteffensen Rita C. Tostes Ulf Simonsen Fernando Silva Carneiro 《Journal of cellular and molecular medicine》2023,27(1):1
In the present study, we hypothesized that endothelin (ET) receptors (ETA and ETB) stimulation, through increased calcium and ROS formation, leads to Nucleotide Oligomerization Domain‐Like Receptor Family, Pyrin Domain Containing 3 (NLRP3) activation. Intracavernosal pressure (ICP/MAP) was measured in C57BL/6 (WT) mice. Functional and immunoblotting assays were performed in corpora cavernosa (CC) strips from WT, NLRP3−/− and caspase−/− mice in the presence of ET‐1 (100 nM) and vehicle, MCC950, tiron, BAPTA AM, BQ123, or BQ788. ET‐1 reduced the ICP/MAP in WT mice, and MCC950 prevented the ET‐1 effect. ET‐1 decreased CC ACh‐, sodium nitroprusside (SNP)‐induced relaxation, and increased caspase‐1 expression. BQ123 an ETA receptor antagonist reversed the effect. The ETB receptor antagonist BQ788 also reversed ET‐1 inhibition of ACh and SNP relaxation. Additionally, tiron, BAPTA AM, and NLRP3 genetic deletion prevented the ET‐1‐induced loss of ACh and SNP relaxation. Moreover, BQ123 diminished CC caspase‐1 expression, while BQ788 increased caspase‐1 and IL‐1β levels in a concentration‐dependent manner (100 nM–10 μM). Furthermore, tiron and BAPTA AM prevented ET‐1‐induced increase in caspase‐1. In addition, BAPTA AM blocked ET‐1‐induced ROS generation. In conclusion, ET‐1‐induced erectile dysfunction depends on ETA‐ and ETB‐mediated activation of NLRP3 in mouse CC via Ca2+‐dependent ROS generation. 相似文献
74.
Havard Attramadal Sushanta K. Banerjee Brahim Chaqour Gary Fisher Lester Lau Bernard Perbal Ulf Smith Herman Yeger 《Journal of cell communication and signaling》2023,17(1):7
In celebration of the twentieth anniversary of the inception of the CCN society, and of the first post-Covid-19 live meeting, the executive board of the ICCNS had chosen Nice as the venue for the 11th International workshop on the CCN family of genes. On this occasion participation in the meeting was extended to colleagues from other cell signaling fields who were invited to present both an overview of their work and the future directions of their laboratory. Also, for the first time, the members of the JCCS Editorial Board were invited to participate in a JCCS special session during which all aspects of the journal « life » were addressed and opened to free critical discussion. The scientific presentations and the discussions that followed showed once more that an expansion of the session topics was beneficial to the quality of the meeting and confirmed that the ARBIOCOM project discussed last April in Nice was now on track to be launched in 2023. The participants unanimously welcomed Professor Attramadal’s proposition to organize the 2024, 12th International CCN workshop in Oslo, Norway. 相似文献
75.
76.
Gesa P?hler Cornelia Panse Ulf Diederichsen Andreas Janshoff 《Biophysical journal》2012,103(11):2295-2303
Coiled-coil formation of four different oligopeptides was characterized in solution, on hydrogels, and on membranes by employing circular dichroism spectroscopy, surface plasmon resonance spectroscopy, attenuated total reflection infrared spectroscopy, and ellipsometry. Peptide sequences rich in either glutamic acid (E: E3Cys, i-E3Cys) or lysine (K: K3Cys, i-K3Cys) were used to represent minimal mimics of eukaryotic SNARE motifs. Half of the peptides were synthesized in reverse sequence, so that parallel and antiparallel heptad coiled-coil structures were formed. Either E-peptides or K-peptides were attached covalently to phospholipid anchors via maleimide chemistry, and served as receptors for the recognition of the corresponding binding partners added to solution. Attenuated total reflection infrared spectroscopy of single bilayers confirmed the formation of coiled-coil complexes at the membrane interface. Coiled-coil formation in solution, as compared with association at the membrane surface, displays considerably larger binding constants that are largely attributed to loss of translational entropy at the interface. Finally, the fusogenicity of the various coiled-coil motifs was explored, and the results provide clear evidence that hemifusion followed by full fusion requires a parallel orientation of α-helices, whereas antiparallel oriented coiled-coil motifs display only docking. 相似文献
77.
Ulf Karsten 《Journal of phycology》1996,32(4):501-506
The comparative growth and osmotic acclimation often culture strains of the marine benthic cyanobacterium Microcoleus chthonoplastes Thuret isolated from microbial mats in Germany, Spain, Egypt, the United States, Mexico, Chile, and Australia were investigated in salinities ranging from freshwater to twice seawater. All isolates showed a broad growth versus salinity response consistent with the dominance of this species in intertidal and hypersaline microbial communities. Growth optima, salinity preferences, and maximum growth rates differed for each isolate and could be related to the habitat from which they were isolated. This is most obvious when comparing strains from brackish habitats with those from a hypersaline lake. While the former isolates exhibited sharply pronounced growth optima under hyposaline conditions, cultures from the hypersaline environment grew best in salinity more than double seawater. The major low-molecular weight organic compounds present in all M. chthonoplastes strains were the carbohydrates glycosylglycerol and trehalose. This was proven by using 13C-nuclear magnetic resonance spectroscopy. Glycosylglycerol was synthesized and accumulated with increasing salinities, indicating its role as an osmolyte. In contrast, trehalose was present in relatively high concentrations under hyposaline conditions only. Differences in the patterns of growth versus salinity, as well as in those of osmotic acclimation among the M. chthonoplastes isolates, point to the development of different physiological ecotypes within the species. 相似文献
78.
79.
Patrick Jung Karen Baumann Lukas W. Lehnert Elena Samolov Sebastian Achilles Michael Schermer Luise M. Wraase Kai‐Uwe Eckhardt Maaike Y. Bader Peter Leinweber Ulf Karsten Jrg Bendix Burkhard Büdel 《Geobiology》2020,18(1):113-124
The Atacama Desert is the driest non‐polar desert on Earth, presenting precarious conditions for biological activity. In the arid coastal belt, life is restricted to areas with fog events that cause almost daily wet–dry cycles. In such an area, we discovered a hitherto unknown and unique ground covering biocenosis dominated by lichens, fungi, and algae attached to grit‐sized (~6 mm) quartz and granitoid stones. Comparable biocenosis forming a kind of a layer on top of soil and rock surfaces in general is summarized as cryptogamic ground covers (CGC) in literature. In contrast to known CGC from arid environments to which frequent cyclic wetting events are lethal, in the Atacama Desert every fog event is answered by photosynthetic activity of the soil community and thus considered as the desert's breath. Photosynthesis of the new CGC type is activated by the lowest amount of water known for such a community worldwide thus enabling the unique biocenosis to fulfill a variety of ecosystem services. In a considerable portion of the coastal Atacama Desert, it protects the soil from sporadically occurring splash erosion and contributes to the accumulation of soil carbon and nitrogen as well as soil formation through bio‐weathering. The structure and function of the new CGC type are discussed, and we suggest the name grit–crust. We conclude that this type of CGC can be expected in all non‐polar fog deserts of the world and may resemble the cryptogam communities that shaped ancient Earth. It may thus represent a relevant player in current and ancient biogeochemical cycling. 相似文献