全文获取类型
收费全文 | 1803篇 |
免费 | 167篇 |
国内免费 | 2篇 |
出版年
2023年 | 7篇 |
2022年 | 11篇 |
2021年 | 26篇 |
2020年 | 17篇 |
2019年 | 22篇 |
2018年 | 23篇 |
2017年 | 31篇 |
2016年 | 51篇 |
2015年 | 87篇 |
2014年 | 92篇 |
2013年 | 118篇 |
2012年 | 124篇 |
2011年 | 115篇 |
2010年 | 88篇 |
2009年 | 76篇 |
2008年 | 91篇 |
2007年 | 104篇 |
2006年 | 101篇 |
2005年 | 70篇 |
2004年 | 75篇 |
2003年 | 72篇 |
2002年 | 63篇 |
2001年 | 39篇 |
2000年 | 24篇 |
1999年 | 33篇 |
1998年 | 18篇 |
1997年 | 30篇 |
1996年 | 28篇 |
1995年 | 22篇 |
1994年 | 26篇 |
1993年 | 24篇 |
1992年 | 31篇 |
1991年 | 21篇 |
1990年 | 17篇 |
1989年 | 27篇 |
1988年 | 17篇 |
1987年 | 11篇 |
1986年 | 13篇 |
1985年 | 10篇 |
1984年 | 13篇 |
1982年 | 15篇 |
1981年 | 8篇 |
1980年 | 10篇 |
1978年 | 10篇 |
1974年 | 4篇 |
1973年 | 6篇 |
1972年 | 4篇 |
1971年 | 6篇 |
1970年 | 5篇 |
1960年 | 4篇 |
排序方式: 共有1972条查询结果,搜索用时 218 毫秒
61.
Effects of added germination agents on loss of optical density in electron-irradiated spores.
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)
Spores of Bacillus megaterium ATCC 14581, subjected to partial-cell iradiation, were exposed to either lysozyme, H2O2, or glucose in an attempt to reduce or eliminate the nonmonotonic behavior in curves of percentage of germination versus energy, obtained when such spores were resuspended in phosphate buffer alone. Except at the lower doses. H2O2 effectively eliminated this anomalous dip in these curves, whereas lysozyme amplified it greatly. Glucose was generally ineffective. Coinciding with the increases in optical density when lysozyme was present was the formation of an occluding product. 相似文献
62.
63.
Summary Cell recycle studies have been carried out with a strain of Zymomonas mobilis selected for its improved ethanol tolerance and faster rates of glucose uptake and ethanol production. As part of the investigation a capilliary cross-flow microfiltration unit with polyamide membranes has been evaluated in view of its potential advantages (low cost and ability to withstand repeated cleaning with caustic soda). The results demonstrate that ethanol concentrations of 60–65g/l can be sustained at productivities ranging from 120–200g/l/h. 相似文献
64.
65.
66.
Temmink Ralph J. M. Dorenbosch Martijn Lamers Leon P. M. Smolders Alfons J. P. Rip Winnie Lengkeek Wouter Didderen Karin Fivash Gregory S. Bouma Tjeerd J. van der Heide Tjisse 《Hydrobiologia》2021,848(17):3987-3999
Hydrobiologia - Aquatic ecosystems provide vital services, and macrophytes play a critical role in their functioning. Conceptual models indicate that in shallow lakes, plants with different growth... 相似文献
67.
Tan Laura X. L. van Dongen Wouter F. D. Sherman Craig D. H. Ekanayake Kasun B. Dann Peter Sutherland Duncan R. Weston Michael A. 《Biological invasions》2021,23(8):2485-2487
Biological Invasions - A correction to this paper has been published: https://doi.org/10.1007/s10530-021-02548-x 相似文献
68.
The length of Chlamydomonas flagella is tightly regulated. Mutations in four genes—LF1, LF2, LF3, and LF4—cause cells to assemble flagella up to three times wild-type length. LF2 and LF4 encode protein kinases. Here we describe a new gene, LF5, in which null mutations cause cells to assemble flagella of excess length. The LF5 gene encodes a protein kinase very similar in sequence to the protein kinase CDKL5. In humans, mutations in this kinase cause a severe form of juvenile epilepsy. The LF5 protein localizes to a unique location: the proximal 1 μm of the flagella. The proximal localization of the LF5 protein is lost when genes that make up the proteins in the cytoplasmic length regulatory complex (LRC)—LF1, LF2, and LF3—are mutated. In these mutants LF5p becomes localized either at the distal tip of the flagella or along the flagellar length, indicating that length regulation involves, at least in part, control of LF5p localization by the LRC. 相似文献
69.
Wouter de Munter Arjen B Blom Monique M Helsen Birgitte Walgreen Peter M van der Kraan Leo AB Joosten Wim B van den Berg Peter LEM van Lent 《Arthritis research & therapy》2013,15(6):R178
Introduction
Osteoarthritis (OA) is associated with the metabolic syndrome, however the underlying mechanisms remain unclear. We investigated whether low density lipoprotein (LDL) accumulation leads to increased LDL uptake by synovial macrophages and affects synovial activation, cartilage destruction and enthesophyte/osteophyte formation during experimental OA in mice.Methods
LDL receptor deficient (LDLr−/−) mice and wild type (WT) controls received a cholesterol-rich or control diet for 120 days. Experimental OA was induced by intra-articular injection of collagenase twelve weeks after start of the diet. OA knee joints and synovial wash-outs were analyzed for OA-related changes. Murine bone marrow derived macrophages were stimulated with oxidized LDL (oxLDL), whereupon growth factor presence and gene expression were analyzed.Results
A cholesterol-rich diet increased apolipoprotein B (ApoB) accumulation in synovial macrophages. Although increased LDL levels did not enhance thickening of the synovial lining, S100A8 expression within macrophages was increased in WT mice after receiving a cholesterol-rich diet, reflecting an elevated activation status. Both a cholesterol-rich diet and LDLr deficiency had no effect on cartilage damage; in contrast, ectopic bone formation was increased within joint ligaments (fold increase 6.7 and 6.1, respectively). Moreover, increased osteophyte size was found at the margins of the tibial plateau (4.4 fold increase after a cholesterol-rich diet and 5.3 fold increase in LDLr−/− mice). Synovial wash-outs of LDLr−/− mice and supernatants of macrophages stimulated with oxLDL led to increased transforming growth factor-beta (TGF-β) signaling compared to controls.Conclusions
LDL accumulation within synovial lining cells leads to increased activation of synovium and osteophyte formation in experimental OA. OxLDL uptake by macrophages activates growth factors of the TGF-superfamily. 相似文献70.
Anti-HIV Pronucleotides: SATE Versus Phenyl as a Protecting Group of AZT Phosphoramidate Derivatives
T. Beltran D. Egron I. Lefebvre C. Périgaud A. Pompon G. Gosselin 《Nucleosides, nucleotides & nucleic acids》2013,32(4-5):973-975
Abstract We comparatively studied the decomposition pathways in CEM cell extract of several PHENYL phosphoramidate diesters of AZT. A correlation between anti-HIV activities in TK? cell lines and pharmacokinetic data has been observed. This study would help to design corresponding SATE phosphoramidate diesters which revealed potent anti-HIV properties. 相似文献