全文获取类型
收费全文 | 670篇 |
免费 | 49篇 |
出版年
2022年 | 6篇 |
2021年 | 14篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 11篇 |
2017年 | 11篇 |
2016年 | 16篇 |
2015年 | 35篇 |
2014年 | 42篇 |
2013年 | 39篇 |
2012年 | 50篇 |
2011年 | 45篇 |
2010年 | 25篇 |
2009年 | 23篇 |
2008年 | 29篇 |
2007年 | 43篇 |
2006年 | 31篇 |
2005年 | 43篇 |
2004年 | 38篇 |
2003年 | 29篇 |
2002年 | 27篇 |
2001年 | 20篇 |
2000年 | 9篇 |
1999年 | 14篇 |
1998年 | 14篇 |
1997年 | 6篇 |
1996年 | 12篇 |
1995年 | 12篇 |
1994年 | 7篇 |
1993年 | 1篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 8篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 5篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有719条查询结果,搜索用时 15 毫秒
701.
Anton I.P.M. de Kroon Pieter J. Rijken Cedric H. De Smet 《Progress in lipid research》2013,52(4):374-394
Glycerophospholipids are the most abundant membrane lipid constituents in most eukaryotic cells. As a consequence, phospholipid class and acyl chain homeostasis are crucial for maintaining optimal physical properties of membranes that in turn are crucial for membrane function. The topic of this review is our current understanding of membrane phospholipid homeostasis in the reference eukaryote Saccharomyces cerevisiae. After introducing the physical parameters of the membrane that are kept in optimal range, the properties of the major membrane phospholipids and their contributions to membrane structure and dynamics are summarized. Phospholipid metabolism and known mechanisms of regulation are discussed, including potential sensors for monitoring membrane physical properties. Special attention is paid to processes that maintain the phospholipid class specific molecular species profiles, and to the interplay between phospholipid class and acyl chain composition when yeast membrane lipid homeostasis is challenged. Based on the reviewed studies, molecular species selectivity of the lipid metabolic enzymes, and mass action in acyl-CoA metabolism are put forward as important intrinsic contributors to membrane lipid homeostasis. 相似文献
702.
F. Mikkers S. Ringoir R. De Smet 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1979,162(3):341-350
Uremic blood samples were analyzed for ionogenic substances using analytical isotachophoresis. Multicomponent separations proved that the uremic state shows significant differences from the normal state, especially with regard to anionic low-molecular-weight substances. As a quantitative parameter the ratio of anionic higher-molecular-weight substances to anionic low-molecular-weight substances is proposed: the HL ratio. Separation patterns and HL ratios were studied during nine weeks for one patient on chronic hemodialysis. The patient showed a low HL ratio due to excess of low-molecular-weight substances. Separation patterns before and after hemodialysis showed clear differences and the HL ratio increased. The method of analysis is neither time- nor sample-consuming and sample preparation is not needed. Experimental procedures are easily standardized and results are reliable. 相似文献
703.
704.
705.
706.
Christa Van Ginneken Marcel De Smet Frans Van Meir André Weyns 《The Histochemical journal》1998,30(10):703-709
Encouraged by the knowledge that microwaves have a beneficial effect on immunohistochemical reactions, the present study aimed to find out whether microwaves could improve the Cuprolinic Blue staining of enteric neurons as well as the actual method that has been developed for gastrointestinal whole-mount preparations. In addition to incorporating a microwave application in the method described by Holst and Powley (1995), some other modifications were made: two incubations before incubation in the staining solution and free-floating incubations. In the whole-mount preparations, most, if not all, enteric neurons were stained by Cuprolinic Blue. These neurons appeared as blue–green cells with non-reacting nuclei and neuronal processes. At higher magnification, the cytoplasm was characterized by a fine blue– green granulation, and the nucleolus in the nucleus appeared as a blue iridescent structure. Non-specific staining occurred in fibrocy tes and epithelial cells but, because of their location and appearance, they could easily be distinguished from neurons. The modified incubations and the incorporation of a microwave application into the conventional Cuprolinic Blue staining method turn the method into an easy-to-use one that seems to visualize most, if not all, enteric neurons in whole-mount preparations of the pig jejunum. 相似文献
707.
708.
Statistical and numerical taxonomic methods reveal two groups of pollen populations in one plant of Eryngium maritimum L. growing at Noordwijk aan Zee (The Netherlands); one group includes the tertiary and primary lateral inflorescences which possess inhibited growth; the other group comprises the secondary lateral inflorescences showing normal growth. The effects of the physiological inhibition mechanism are complex and are shown by many pollen characters— the dimensions of P (polar axis) and E (equatorial diameter), the presence of a thickening of the exine in the intermediate zone, the shape of the internal contour of the endexine, etc. The differentiation of two types of pollen populations has not only taxonomic interest at the individual, locality, or species level, but also physiological significance. The shape of the internal contour of the endexine, which is a very important feature of “macroevolution” of pollen types in Umbelliferae (Cerceau-Larrival), is directly influenced by the inhibited growth. 相似文献
709.
Norbert H. Fraeyman Eric J. Van de Velde Frits H. De Smet re F. De Schaepdryver 《Journal of neurochemistry》1982,39(4):1179-1184
Abstract: The distribution of the enzymatic activity of dopamine β-hydroxylase (DBH) in linear sucrose gradients was studied for a soluble fraction of the C1300 mouse neuroblastoma tumor, for the serum of tumor-bearing A/J mice, and for adrenal tissue and serum of control mice. In controls (adrenal gland and serum of A/J mice), about 75% of the DBH activity was associated with a high-molecular-weight form, denoted as DBHAA , with an apparent sedimentation coefficient of 11.3 S. About 25% of the DBH activity was attributable to a slower-sedimenting species (7.1 S), denoted as DBHBB . In tumor supernatants and in the serum of tumor-bearing mice, about 55% of the DBH activity was present as the 7.1 S species (DBHRB ), while only 35% was recovered as the high-molecular-weight form (DBHAA ). Approximately 5% of the activity could be attributed to a separate form, with a sedimentation coefficient of about 4.5 S. This form is designated DBHC . The ratio DBHR/DBHA is significantly higher in tumor tissue and in serum of tumor-bearing mice than in controls. The three enzymically active forms of DBH in the C1300 tumor are considered to represent the tetrameric (DBHAC ), dimeric (DBHB ), and monomeric (DBHC ) forms of the enzyme. 相似文献
710.
Jeroen De Smet Jeroen Wagemans Hanne Hendrix Ines Staes Annegrete Visnapuu Benjamin Horemans Abram Aertsen Rob Lavigne 《Microbial biotechnology》2021,14(3):967-978
C-di-GMP is a key signalling molecule which impacts bacterial motility and biofilm formation and is formed by the condensation of two GTP molecules by a diguanylate cyclase. We here describe the identification and characterization of a family of bacteriophage-encoded peptides that directly impact c-di-GMP signalling in Pseudomonas aeruginosa. These phage proteins target Pseudomonas diguanylate cyclase YfiN by direct protein interaction (termed YIPs, YfiN Interacting Peptides). YIPs induce an increase of c-di-GMP production in the host cell, resulting in a decrease in motility and an increase in biofilm mass in P. aeruginosa. A dynamic analysis of the biofilm morphology indicates a denser biofilm structure after induction of the phage protein. This intracellular signalling interference strategy by a lytic phage constitutes an unexplored phage-based mechanism of metabolic regulation and could potentially serve as inspiration for the development of molecules that interfere with biofilm formation in P. aeruginosa and other pathogens. 相似文献