全文获取类型
收费全文 | 1136篇 |
免费 | 93篇 |
出版年
2023年 | 5篇 |
2022年 | 10篇 |
2021年 | 22篇 |
2020年 | 12篇 |
2019年 | 16篇 |
2018年 | 29篇 |
2017年 | 14篇 |
2016年 | 33篇 |
2015年 | 64篇 |
2014年 | 67篇 |
2013年 | 70篇 |
2012年 | 94篇 |
2011年 | 76篇 |
2010年 | 49篇 |
2009年 | 47篇 |
2008年 | 63篇 |
2007年 | 70篇 |
2006年 | 58篇 |
2005年 | 66篇 |
2004年 | 43篇 |
2003年 | 45篇 |
2002年 | 57篇 |
2001年 | 6篇 |
2000年 | 8篇 |
1998年 | 10篇 |
1996年 | 19篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 11篇 |
1992年 | 13篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 9篇 |
1980年 | 4篇 |
1978年 | 7篇 |
1976年 | 7篇 |
1974年 | 5篇 |
1973年 | 8篇 |
1971年 | 5篇 |
1969年 | 4篇 |
1968年 | 6篇 |
1953年 | 2篇 |
排序方式: 共有1229条查询结果,搜索用时 15 毫秒
11.
An application of diagonal electrophoresis to the selective purification of serine phosphate peptides. Serine phosphate peptides from ovalbumin 总被引:5,自引:3,他引:2
下载免费PDF全文
![点击此处可从《The Biochemical journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Celia P. Milstein 《The Biochemical journal》1968,110(1):127-134
A diagonal-electrophoresis method for the selective purification of serine phosphate peptides was applied to tryptic, chymotryptic and peptic digests of oxidized ovalbumin. This method is based on the release of the phosphate group bound to serine by treatment with alkaline phosphatase on paper. The identified serine phosphate peptides were purified by paper electrophoresis at pH6.5 and 2.0, dephosphorylation with bacterial alkaline phosphatase, and paper electrophoresis at pH2.0 again, in that order. The presence of two groups of serine phosphate peptides was apparent from the amino acid composition. One group contained no lysine, cysteic acid, proline, leucine or isoleucine (sequence 1) and the other had all those amino acids (sequence 2). Further degradation with subtilisin of those peptides and ;dansyl'-Edman sequence analysis established their partial sequences. The proposed sequences are as follows (with ;SerP' representing serine phosphate): sequence 1, -Ala-Gly-Arg-Glu-Val-Val-Gly-SerP-Ala-Glu-Ala-Gly-Asp-Val-Ala-Ala-Ser-(Val,Glx(2),Ser,Phe)-Arg-; sequence 2, -Asp-Lys-Leu-Pro-Gly-Phe-Gly-Asp-SerP-Ile-Glx-Ala-Glx-CySO(3)H-Gly-(Thr,Ser,Val)-(Asp,His,Val)-. The partial sequence of one of the phosphopeptides, Asp-(Glu,Ile,SerP), reported by Flavin (1954) was used to establish the proposed sequence 2. 相似文献
12.
Isolation of Aulacomya paramyosin 总被引:1,自引:1,他引:0
Celia P. Milstein 《The Biochemical journal》1967,103(3):634-640
Tropomyosin A or paramyosin has been isolated from the adductor muscle of Aulacomya magellanica. It has in common with other tropomyosins A the method used for extracting it from adductor muscle, its solubility, facility of crystallization, ammonium sulphate range of precipitation, amino acid composition and behaviour when digested with trypsin. As a particular feature it exhibits an unusual low viscosity for this type of tropomyosin. Its molecular weight, determined by the Archibald approach-to-sedimentation-equilibrium method, is 258000+/-16000. 相似文献
13.
Zafar U. Khan Antonia Gutiérrez Celia P. Miralles Angel L. De Blas 《Neurochemical research》1996,21(2):147-159
Subunit-specific antibodies to all the γ subunit isoforms described in mammalian brain (γ1, γ2S, γL, and γ3) have been made. The proportion of GABAA receptors containing each γ subunit isoform in various brain regions has been determined by quantitative immunoprecipitation.
In all tested regions of the rat brain, the γ1, and γ3 subunits are present in considerable smaller proportion of GABAA receptor than the γ2 subunit. Immunocytochemistry shows that γ1 immunoreactivity concentrates in the stratum oriens and stratum radiatum of the CA1 region of the hippocampus. In the dentate
gyrus, γ1 immunoreactivity concentrates on the outer 2/3 of the molecular layer coinciding with the localization of the axospinous
synapses of the perforant pathway. In contrast, γ3 immunoreactivity concentrates on the basket cells and other GABAergic local circuit neurons of the hilus. These cells are
also rich in γ2S. In the cerebellu, γ1 immunolabeling was localized on the Bergmann glia. The γ2S and γ2L subunits are differentially expressed in various brain regions. Thus the γ2S is highly expressed in the olfactory bulb and hippocampus whereas the γ2L is very abundant in inferior colliculus and cerebellum, particularly in Purkinje cells, as immunocytochemistry, in situ hybridization
and immunoprecipitation techniques have revealed. The γ2S and γ2L coexist in some brain areas and cell types. Moreover, the γ2S and γ2L subunits can coexist in the same GABAA receptor pentamer. We have shown that this is the case in some GABAA receptors expressed in cerebellar granule cells. These GABAA receptors also have α and β subunits forming the pentamer. Immunoblots have shown that the rat γ1, γ2S, γ2L and γ3 subunits are peptides of 47, 45, 47 and 44 kDa respectively. Results also indicate that there are aging-related changes in
the expression of the γ2S and γ2L subunits in various brain regions which suggest the existence of aging-related changes in the subunit composition of the
GABAA receptors which in turn might lead to changes in receptor pharmacology. The results obtained with the various γ subunit isoforms
are discussed in terms of the high molecular and binding heterogeneity of the native GABAA receptors in brain.
Special issue dedicated to Dr. Kinya Kuriyama 相似文献
14.
Robert Gellman 《Andrologie》1995,5(1):76-81
The symptom of impotence is, in the vast majority of cases, extremely welldefined. However, therapeutic approaches incorporate various strategies, including: andrological, analytical and behavioural. A great advance in recent years was due to the development of “integrative models” such as the “American Model” by Helen Kaplan, the “Geneva Model” of Willy Pasini, and our proposed “Parisian Model”, which is founded on the principles of analytical sexotherapy, and comprises several clearly defined stages. The management of impotence must not be restricted only to pharmacological treatment. 相似文献
15.
This study examines the ability of a number of short-term measuresof algal food quality to predict longer term demographic parametersfor two species of freshwater calanoid copepods, Diaptomus minuiusand Epischura lacustris. Food quality of two species of algaethat are usually considered highly edible (Cryptomonas erosavar. reflexa and Chlamydomonas reinhardtii) are compared withrespect to: (i) the biochemical constituents of the algae (totalN, total C and protein); (ii) short-term foraging responsesby D.minutus to either algal species (e.g. clearance, ingestionand assimilation rates); (iii) longer term demographic responses(e.g. survivorship and reproduction) by both D.minutus and E.lacustrisfed a diet of either algal species. Demographic responses ofthe two copepod species indicate that C.erosa is a higher qualityfood. In fact, survival and reproduction of both copepod speciesfed C.reinhardtii were not different from starved treatments.Cryptomonas erosa treatments also had greater C, N and protein.However, D.minutus ingested five times more C.reinhardtii thanC.erosa, indicative of compensatory feeding inthe presence of poor-quality food. Based upon these higher ingestionrates, individuals fed C.reinhardai actually ingested greateramounts of C, N and protein. Hence, ingestion rates taken aloneor coupled with biochemical parameters are not reliable predictorsof consumer demographic response. Assimilation rate, which waspositive for C.erosa and zero for C.reinhardtii, was the singlebest short-term predictor of food quality. 相似文献
16.
Niraj Shrestha Pallavi Chaturvedi Xiaoyun Zhu Michael J. Dee Varghese George Christopher Janney Jack O. Egan Bai Liu Mark Foster Lynne Marsala Pamela Wong Celia C. Cubitt Jennifer A. Foltz Jennifer Tran Timothy Schappe Karin Hsiao Gilles M. Leclerc Lijing You Christian Echeverri Catherine Spanoudis Ana Carvalho Leah Kanakaraj Crystal Gilkes Nicole Encalada Lin Kong Meng Wang Byron Fang Zheng Wang Jin-an Jiao Gabriela J. Muniz Emily K. Jeng Nicole Valdivieso Liying Li Richard Deth Melissa M. Berrien-Elliott Todd A. Fehniger Peter R. Rhode Hing C. Wong 《Aging cell》2023,22(5):e13806
17.
Celia Roberts 《American anthropologist》2003,105(3):670-671
Contraception across Cultures: Technologies, Choices, Constraints. Andrew Russell. Elisa J. Sobo. and Mary S. Thompson. Oxford: Berg Publishers, 2000. 224 pp. 相似文献
18.
Jeffrey W. Peng Celia A. Schiffer Ping Xu Wilfred F. van Gunsteren Richard R. Ernst 《Journal of biomolecular NMR》1996,8(4):453-476
Summary The influence of water binding on the conformational dynamics of the cyclic decapeptide antamanide dissolved in the model lipophilic environment chloroform is investigated by NMR relaxation measurements. The water-peptide complex has a lifetime of 35 s at 250 K, which is longer than typical lifetimes of water-peptide complexes reported in aqueous solution. In addition, there is a rapid intracomplex mobility that probably involves librational motions of the bound water or water molecules hopping between different binding sites. Water binding restricts the flexibility of antamanide. The experimental findings are compared with GROMOS molecular dynamics simulations of antamanide with up to eight bound water molecules. Within the simulation time of 600 ps, no water molecule leaves the complex. Additionally, the simulations show a reduced flexibility for the complex in comparison with uncomplexed antamanide. Thus, there is a qualitative agreement between the experimental NMR results and the computer simulations. 相似文献
19.
Herv Celia James D. Jontes Michael Whittaker Ronald A. Milligan 《Journal of structural biology》1996,117(3):236-241
Brush border myosin-I (BBMI) is a single-headed unconventional myosin found in the microvilli of intestinal epithelial cells, where it links the core bundle of actin filaments to the plasma membrane. An association of BBMI with anionic phospholipids has been shown to be mediated by a carboxy-terminal domain which is rich in basic amino acids. We have exploited this natural affinity of BBMI for negatively charged lipids to form two-dimensional (2D) crystals of this protein which are suitable for structural analysis by electron crystallographic techniques. The 2D crystals which we have obtained belong to one of two space groups, p22121or p2. We present here projection maps calculated from images of negatively stained crystals for each of these crystal types to a resolution of 20 Å and show that the asymmetric unit is the same in both crystal types. 相似文献
20.
David E. Holm Gerald Godette Celia Bonaventura Joseph Bonaventura M. David Boatright Linda L. Pearce Jim Peterson 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》1996,114(4):345-352
Contrary to previous reports, the functional and spectral properties of “monomeric” shark cytochrome c oxidases are not entirely similar to those of the “dimeric” beef enzyme. Most significantly, unlike the behavior of beef oxidase, the fully oxidized shark enzyme is not reducible by carbon monoxide. Also, preparations of the shark enzyme, isolated at pH 7.8-8.0, lead to more than 60% of the sample always being obtained in a resting form, whereas similarly prepared beef oxidase is very often obtained, both by ourselves and others, exclusively in the pulsed form. Although the electronic absorption, magnetic circular dichroism and electron paramagnetic resonance (EPR) spectra of cytochrome c oxidase obtained from several shark species are similar to those of the beef enzyme, there are some significant differences. In particular, the Soret maximum is at 422 nm in the case of the fully oxidized resting shark oxidases at physiological pH and not 418 nm as commonly found for the beef enzyme. Moreover, the resting shark oxidases do not necessarily exhibit a “g = 12” signal in their EPR spectra. The turnover numbers of recent preparations of the shark enzyme are higher than previously reported and, interestingly, do not differ within experimental uncertainty from those documented for several beef isoenzymes assayed under comparable conditions. 相似文献