全文获取类型
收费全文 | 375篇 |
免费 | 24篇 |
出版年
2023年 | 2篇 |
2020年 | 10篇 |
2019年 | 11篇 |
2018年 | 6篇 |
2017年 | 10篇 |
2016年 | 6篇 |
2015年 | 10篇 |
2014年 | 21篇 |
2013年 | 19篇 |
2012年 | 28篇 |
2011年 | 18篇 |
2010年 | 15篇 |
2009年 | 15篇 |
2008年 | 28篇 |
2007年 | 25篇 |
2006年 | 13篇 |
2005年 | 11篇 |
2004年 | 16篇 |
2003年 | 12篇 |
2002年 | 12篇 |
2000年 | 3篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1993年 | 4篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1987年 | 2篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1975年 | 7篇 |
1974年 | 5篇 |
1973年 | 3篇 |
1969年 | 3篇 |
1958年 | 3篇 |
1957年 | 3篇 |
1956年 | 2篇 |
1939年 | 2篇 |
1938年 | 3篇 |
1936年 | 3篇 |
1931年 | 2篇 |
1913年 | 2篇 |
1911年 | 1篇 |
1910年 | 1篇 |
1875年 | 1篇 |
排序方式: 共有399条查询结果,搜索用时 975 毫秒
51.
Alois Teyber 《Plant Systematics and Evolution》1912,62(2-3):62-65
Ohne Zusammenfassung 相似文献
52.
Expression as inclusion bodies in Escherichia coli is a widely used method for the large-scale production of therapeutic proteins that do not require post-translational modifications. High expression yields and simple recovery steps of inclusion bodies from the host cells are attractive features industrially. However, the value of an inclusion body-based process is dominated by the solubilization and refolding technologies. Scale-invariant technologies that are economical and applicable for a wide range of proteins are requested by industry. The main challenge is to convert the denatured protein into its native conformation at high yields. Refolding competes with misfolding and aggregation. Thus, the yield of native monomer depends strongly on the initial protein concentrations in the refolding solution. Reasonable yields are attained at low concentrations (≤0.1 mg/mL). However, large buffer tanks and time-consuming concentration steps are required. We attempt to answer the question of the extent to which refolding of proteins is protected by patents. Low-molecular mass additives have been developed to improve refolding yields through the stabilization of the protein in solution and shielding hydrophobic patches. Progress has been made in the field of high-pressure renaturation and on-column refolding. Mixing times of the denatured protein in the refolding buffer have been reduced using newly developed devices and the introduction of specific mixers. Concepts of continuous refolding have been introduced to reduce tank sizes and increase yields. Some of the patents covering refolding of proteins will soon expire or have already expired. This gives more freedom to operate. 相似文献
53.
54.
Astrid Dürauer Dr. Sabrina Mayer Wolfgang Sprinzl Alois Jungbauer Rainer Hahn Dr. 《Biotechnology journal》2009,4(5):722-729
Efficient solubilization is a crucial step during inclusion body processing and dissolving conditions were usually empirically established. Here we describe a new methodology for rapid screening of solubilization conditions and evaluation of dissolution kinetics in microtiter plates. Increase of protein in solution over time was directly related to decrease of turbidity measured by absorbance at 600 nm. Dissolution kinetics of inclusion bodies were described by a first-order reaction kinetics, which was used for drug dissolution modeling. Reaction constants were in the range of 0.01–0.03 s–1 for buffer conditions providing sufficient solubilization power. This method is not limited to the screening of optimal buffer conditions for solubilization and can be applied for studying other parameters involved in the solubility of IBs, such as pI of the protein, influence of fermentation conditions, influence of initial protein concentration, and more. 相似文献
55.
We studied the opisthonephric (mesonephric) kidneys of adult male and female Xenopus laevis using scanning electron microscopy (SEM) of vascular corrosion casts and light microscopy of paraplast embedded tissue sections. Both techniques displayed glomeruli from ventral to mid-dorsal regions of the kidneys with single glomeruli located dorsally close beneath the renal capsule. Glomeruli in general were fed by a single afferent arteriole and drained via a single thinner efferent arteriole into peritubular vessels. Light microscopy and SEM of vascular corrosion casts revealed sphincters at the origins of afferent arterioles, which arose closely, spaced from their parent renal arteries. The second source of renal blood supply via renal portal veins varied interindividually in branching patterns with vessels showing up to five branching orders before they became peritubular vessels. Main trunks and their first- and second-order branches revealed clear longish endothelial cell nuclei imprint patterns oriented parallel to the vessels longitudinal axis, a pattern characteristic for arteries. Peritubular vessels had irregular contours and were never seen as clear cylindrical structures. They ran rather parallel, anastomosed with neighbors and changed into renal venules and veins, which finally emptied into the ventrally located posterior caval vein. A third source of blood supply of the peritubular vessels by straight terminal portions of renal arteries (vasa recta) was not found. 相似文献
56.
57.
Procházka L Turánek J Tesarík R Knotigová P Polásková P Andrysík Z Kozubík A Zák F Sova P Neuzil J Machala M 《Archives of biochemistry and biophysics》2007,462(1):54-61
A new hydrophobic platinum(IV) complex, LA-12, a very efficient anticancer drug lacking cross-resistance with cisplatin (CDDP), is now being tested in clinical trials. Here we investigated the apoptogenic activity of LA-12 and its effect on gap-junctional intercellular communication (GJIC) in the rat liver epithelial cell line WB-F344. LA-12 induced apoptosis much more efficiently than did CDDP due to a combination of rapid penetration into the cell and attack on DNA, leading to fast activation of p53 and caspase-3. Exposure of WB-F344 cells to LA-12 led to rapid induction of the time- and dose-dependent decrease in GJIC. On the molecular level, loss of GJIC induced by LA-12 was mediated by activation of extracellular signal-regulated kinase (ERK)-1 and ERK-2, as demonstrated by the use of inhibitors of ERK activation. Inhibition of GJIC was linked to rapid hyperphosphorylation of connexin-43 and disappearance of connexon clusters from membranes, which was not observed in the case of CDDP. 相似文献
58.
59.
Paula Agudelo Robert T. Robbins James McD. Stewart Alois Bell A. Forest Robinson 《Journal of nematology》2005,37(4):444-447
Observations on the development of reniform nematode (Rotylenchulus reniformis) on roots of Gossypium longicalyx, G. hirsutum, and two interspecific hybrids derived from them were made by light microscopy. Gossypium longicalyx is reported to be immune to reniform nematode, but the mechanism(s) for resistance are unknown. Penetration of G. longicalyx roots by female nematodes was confirmed, and incipient swelling of the females, indicating initiation of maturation of the reproductive system, was observed. Female maturation occurred up to the formation of a single embryo inside the female body but not beyond this point. In both hybrids, development was inhibited but progressed further than in the immune parent. Reactions ranged from highly compatible, with the formation of active syncytia and full development of females, to incompatible with little or no development of the female. Compatible plants showed characteristic hypertrophied cells, enlarged nuclei, dense cytoplasm, and partial dissolution of cell walls, whereas incompatible plant reactions included lignification of the cells adjacent to the nematode head, or the complete collapse and necrosis of the cells involved. The need to characterize reactions and to carefully select among the plants descended from the hybrids during the introgression process, as well as the importance of combining the results of reproduction tests with histological observation of the plant-nematode interactions, is discussed. 相似文献
60.
Ladislav Planka Petr Gal Helga Kecova Jiri Klima Jana Hlucilova Eva Filova Evzen Amler Petr Krupa Leos Kren Robert Srnec Lucie Urbanova Jana Lorenzova Alois Necas 《BMC biotechnology》2008,8(1):1-9