全文获取类型
收费全文 | 455篇 |
免费 | 50篇 |
出版年
2023年 | 1篇 |
2022年 | 6篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 8篇 |
2016年 | 18篇 |
2015年 | 21篇 |
2014年 | 13篇 |
2013年 | 21篇 |
2012年 | 34篇 |
2011年 | 41篇 |
2010年 | 23篇 |
2009年 | 11篇 |
2008年 | 24篇 |
2007年 | 21篇 |
2006年 | 17篇 |
2005年 | 22篇 |
2004年 | 25篇 |
2003年 | 16篇 |
2002年 | 18篇 |
2001年 | 24篇 |
2000年 | 16篇 |
1999年 | 11篇 |
1998年 | 11篇 |
1997年 | 10篇 |
1996年 | 6篇 |
1995年 | 5篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 5篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1969年 | 1篇 |
1968年 | 2篇 |
排序方式: 共有505条查询结果,搜索用时 421 毫秒
101.
Elain Gutierrez‐Carbonell Giuseppe Lattanzio Alfonso Albacete Juan José Rios Julia Kehr Anunciación Abadía Michael A. Grusak Javier Abadía Ana Flor López‐Millán 《Proteomics》2015,15(22):3835-3853
The aim of this work was to study the effect of Fe deficiency on the protein profile of phloem sap exudates from Brassica napus using 2DE (IEF‐SDS‐PAGE). The experiment was repeated thrice and two technical replicates per treatment were done. Phloem sap purity was assessed by measuring sugar concentrations. Two hundred sixty‐three spots were consistently detected and 15.6% (41) of them showed significant changes in relative abundance (22 decreasing and 19 increasing) as a result of Fe deficiency. Among them, 85% (35 spots), were unambiguously identified. Functional categories containing the largest number of protein species showing changes as a consequence of Fe deficiency were signaling and regulation (32%), and stress and redox homeostasis (17%). The Phloem sap showed a higher oxidative stress and significant changes in the hormonal profile as a result of Fe deficiency. Results indicate that Fe deficiency elicits major changes in signaling pathways involving Ca and hormones, which are generally associated with flowering and developmental processes, causes an alteration in ROS homeostasis processes, and induces decreases in the abundances of proteins involved in sieve element repair, suggesting that Fe‐deficient plants may have an impaired capacity to heal sieve elements upon injury. 相似文献
102.
We have investigated the conformation of gramicidin A reconstituted in different phospholipid environments, small unilamellar vesicles, extensive bilayers, and micelles, by exploiting a recently proposed experimental approach based on high-performance liquid chromatography [Ba?ó et al. (1988) J. Chromatogr. 458, 105; Ba?ó et al. (1989) FEBS Lett. 250, 67]. The method allows the separation of conformational species of the peptide, namely, antiparallel double-stranded (APDS) dimers and beta 6.3-helical monomers, and quantitation of their proportions in the lipid environment. Various experimental parameters (e.g., nature of organic solvent, time of incubation in organic solvent, lipid-to-peptide mole ratio, time of sonication, and temperature) commonly involved in sample preparation protocols have been analyzed independently. The results show how the peptide conformation in model membranes is exquisitely dictated by the particular nature of the reconstitution protocol. In addition, we have elucidated the nature of the slow conformational transition of gramicidin toward the channel configuration that takes place upon incubation of the model membranes. This transition has been characterized as a temperature-dependent conversion from APDS dimeric to beta 6.3-helical monomeric forms. Analysis of kinetic data permits an accurate calculation of the rate constant for this process at different temperatures in phospholipid vesicles and micelles. Finally, an explanation is proposed for the laboratory-to-laboratory variation in the observed spectral patterns of inserted gramicidin.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
103.
Volume 62, no. 5, p. 1811, column 2, line 2: Reference "(16)" should read "(15)." Page 1812, column 1, line 17: "Willcocks and Carter (15)" should read "Willcocks et al. (14)." [This corrects the article on p. 1811 in vol. 62.]. 相似文献
104.
105.
Albino Maggio Matilde Paino D'Urzo Laura R. Abad Satomi Takeda Paul M. Hasegawa Ray A. Bressan 《Plant Molecular Biology Reporter》1996,14(3):249-260
A procedure for the extraction of large quantities of PR-5 proteins that have been recalcitrant to microbial-based expression
systems is described. Targeting of the recombinant proteins to the extracellular matrix allowed efficient protein extraction
by a vacuum infiltration/centrifugation system. Approximately 1 kg of fresh leaves from transgenic tobacco plants overexpressing
either truncated osmotin (Liu et al., 1996) or A9 fromAtriplex nummularia L. (Casas et al., 1991) yielded between 3 and 5 mg of purified proteins that fully retained their antifungal activity. The
entire system of overexpression, extraction, and purification could be easily scaled up for the production of several grams
of protein. 相似文献
106.
Francesc Muñoz‐Muñoz Valeria Paula Carreira Neus Martínez‐Abadías Victoria Ortiz Rolando González‐José Ignacio M. Soto 《Evolution; international journal of organic evolution》2016,70(7):1530-1541
To predict the response of complex morphological structures to selection it is necessary to know how the covariation among its different parts is organized. Two key features of covariation are modularity and integration. The Drosophila wing is currently considered a fully integrated structure. Here, we study the patterns of integration of the Drosophila wing and test the hypothesis of the wing being divided into two modules along the proximo‐distal axis, as suggested by developmental, biomechanical, and evolutionary evidence. To achieve these goals we perform a multilevel analysis of covariation combining the techniques of geometric morphometrics and quantitative genetics. Our results indicate that the Drosophila wing is indeed organized into two main modules, the wing base and the wing blade. The patterns of integration and modularity were highly concordant at the phenotypic, genetic, environmental, and developmental levels. Besides, we found that modularity at the developmental level was considerably higher than modularity at other levels, suggesting that in the Drosophila wing direct developmental interactions are major contributors to total phenotypic shape variation. We propose that the precise time at which covariance‐generating developmental processes occur and/or the magnitude of variation that they produce favor proximo‐distal, rather than anterior‐posterior, modularity in the Drosophila wing. 相似文献
107.
Marie-Josee MF Lemoy Angela Colagross Schouten Don R Canfield 《Comparative medicine》2016,66(1):59-62
Bioabsorbable hemostatic agents such as oxidized regenerated cellulose are widely used to control intraoperative diffuse capillary bleeding. Compared with electrocautery or ligation, oxidized regenerated cellulose has the advantage of controlling bleeding without occluding the vessel lumen or causing thermal injuries to adjacent tissue. Although the manufacturer recommends removal of the material once hemostasis is achieved, oxidized regenerated cellulose is a bioabsorbable hemostatic agent and is often left in the surgical bed to prevent subsequent bleeding after surgical closure. However, noninvasive imaging techniques have revealed granulomatous foreign-body reactions that mimic infection or tumor recurrence. We present a case report of sterile peritonitis and granuloma formation secondary to the presence of oxidized regenerated cellulose after intestinal resection to excise a colonic adenocarcinoma in an aged rhesus macaque.Bioabsorbable hemostatic agents such as oxidized regenerated cellulose (for example, Surgicel) are widely used to control intraoperative diffuse capillary bleeding. Compared with electrocautery or ligation, oxidized regenerated cellulose has the advantage of controlling bleeding without occluding the vessel lumen or causing thermal injuries to adjacent tissue.16Oxidized regenerated cellulose is formed by dissolving the α-cellulose of decomposed wood pulp in an alkaline solution and subsequently regenerating it as a continuous fiber. This fiber is then woven into a gauze and oxidized.17,22 Oxidized regenerated cellulose is supplied as a substrate that is flexible, malleable, and trimable.16The mechanism of hemostasis of oxidized regenerated cellulose is reportedly associated with its caustic activity.2 The oxidation of cellulose produces a low-pH organic acid that reacts with blood, thus forming an artificial clot and causing platelet aggregation.18Although the manufacturer recommends the removal of oxidized regenerated cellulose once hemostasis is achieved,8 the product, a bioabsorbable hemostatic agent, is often left in situ within the surgical bed to prevent bleeding after surgical procedures. The biodegradation and elimination of oxidized regenerated cellulose from the tissue occurs in 2 phases.14 Polyanhydroglucuronic acid, the major functional unit of oxidized regenerated cellulose, is readily soluble. This acid is degraded extracellulary and systematically cleared from the system approximately 18 h after implantation.13,14 The remaining fibrous residue, however, requires macrophage phagocytosis for clearance and can be observed within macrophages for at least 48 h after implantation.13 Unfortunately, these fibrous residues have a prolonged degradation, and their persistence for as long as 7 mo after surgery has been confirmed histologically.7Despite the biocompatibility of oxidized regenerated cellulose, granulomatous foreign-body reactions that imitate infection or tumor recurrence have been revealed by using noninvasive imaging techniques.1,11,12,15,17,18,22 Here we describe a case of peritonitis and granuloma formation secondary to the presence of oxidized regenerated cellulose after an intestinal resection to excise a colonic adenocarcinoma in an aged rhesus macaque. 相似文献
108.
109.
110.
Evolutionarily distant pathogens require the Arabidopsis phytosulfokine signalling pathway to establish disease 下载免费PDF全文