首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   172篇
  免费   18篇
  2023年   1篇
  2022年   1篇
  2021年   4篇
  2020年   3篇
  2019年   2篇
  2018年   5篇
  2017年   3篇
  2016年   6篇
  2015年   7篇
  2014年   8篇
  2013年   11篇
  2012年   7篇
  2011年   13篇
  2010年   7篇
  2009年   6篇
  2008年   6篇
  2007年   4篇
  2006年   3篇
  2005年   12篇
  2004年   9篇
  2003年   10篇
  2002年   10篇
  2001年   7篇
  2000年   11篇
  1999年   3篇
  1998年   2篇
  1996年   1篇
  1995年   4篇
  1993年   1篇
  1992年   3篇
  1990年   3篇
  1989年   1篇
  1987年   1篇
  1986年   2篇
  1984年   1篇
  1983年   1篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1973年   1篇
  1972年   1篇
  1969年   1篇
  1967年   1篇
  1964年   1篇
  1935年   1篇
排序方式: 共有190条查询结果,搜索用时 15 毫秒
181.
The zooxanthellate dendrophylliid coral, Turbinaria peltata (Scleractinia), exhibit various growth forms that increase the photoreception area through the development of coenosteum skeletons. Because it is difficult to make detailed observations of the internal structures, we visualized inner skeletal structures using nondestructive microfocus X‐ray computed tomography (CT) imaging. After removal of the coenosteum skeletons from the X‐ray CT images, three‐dimensional 3D‐models were reconstructed for individual corallites. Regular budding was observed from the 3D‐model and cross‐sectional images as follows: 1) lateral corallites occurred only near the two primary septa on one side, apart from a directive primary septum with distinct polarity; 2) the budding occurred upward at acute angles; and 3) these regular structures and polarity were repeated throughout growth with every generation. Even in zooxanthellate dendrophylliids, the same budding modes as observed in azooxanthellate equivalents control the colonial growth. These characteristics provide clues for understanding the mechanisms that regulate the shapes of modular marine organisms. J. Morphol. 276:1100–1108, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
182.
There are few legal marine protected areas in Japan rather than fishing-ban areas. Fishers did not seek legal fishing-ban areas but they did establish fishing-ban areas by autonomous bases. We briefly introduce the institutional history and features of Japanese coastal fishery management, including the past decade’s major legislative developments. Japan still has a decentralized co-management system involving fishers and the government, and ca. 98% of Japanese fishers are artisanal. There are several successful cases of coastal fisheries management in Japan. However, offshore industrial fisheries have problems in Japan. We compare coastal fisheries co-management between Japan and Chile. We finally discuss the possibility of improvement for Japanese fisheries.  相似文献   
183.
Measurement of the effects of drugs, mediators and infectious agents on various models of lung disease, as well as assessment of lung function in the intact mouse has the potential for significantly advancing our knowledge of lung disease. However, the small size of the mouse presents significant challenges for the assessment of lung function. Because of compromises made between precision and noninvasiveness, data obtained may have an uncertain bearing on the mechanical response of the lung. Nevertheless, considerable recent progress has been made in developing valid and useful measures of mouse lung function. These advances, resulting in our current ability to measure sophisticated indices of lung function in laboratory animals, are likely to lead to important insights into the mechanisms of lung disease.  相似文献   
184.
185.
Biotin-avidin immobilization has been routinely used as a tool to study peptide-receptor and peptide-antibody interactions. Biotinylated peptides can also be employed to localize cells that express the peptides' receptor, and to analyse ligand-receptor binding. Insulin-like peptide 3 (INSL3) is a peptide hormone which contains A- and B-chains connected by two disulphide bonds and plays a role in testicular descent during sexual development. In order to study the interaction of INSL3 with its receptor LGR8, a G protein-coupled receptor, we chemically synthesized Nalpha-mono-biotinylated human INSL3 (B-hINSL3) and compared it structurally and biologically with hINSL3. Both peptides exhibited similar, but high, receptor binding affinities on human foetal kidney fibroblast 293T cells transfected human LGR8 based on a competition radioreceptor assay with 33P-labelled relaxin H2 (B33). The modified B-hINSL3 showed full biological activity as determined by the stimulation of gubernacular cell proliferation. The labelled B-hINSL3 contains a higher alpha-helix content, and this increased helical structure is accompanied by an increase in ability to stimulate cAMP accumulation in 293T cells expressing LGR8. Our results suggest that the N-terminal region of the A-chain is not involved in the interaction of INSL3 with its receptor. However, the introduction of biotin onto the N-terminus of the A-chain promoted conformational stability which, in turn, permitted better receptor activation.  相似文献   
186.
187.
Cytochrome c-551 was isolated and purified from a photosyntheticbacterium Chromatium vinosum by ammonium sulfate fractionation,ion-exchange chromatography and gel filtration. The cytochromehad absorption maxima at 280, 407 and 523–524 nm in theoxidized form, and 416, 521 and 549.5 nm in the reduced form.The reduced-minusoxidized difference millimolar absorption coefficientwas 9.90 mM–1cm–1 for the wavelength pair, 550.5minus 540 nm. The molecular weight of the cytochrome was 16,000by gel filtration on Sephadex G-100 and 15,500 by sodium dodecylsulfate-polyacrylamidegel electrophoresis. The midpoint redox potential was +240 mVat pH 8.0. Cytochrome c-551 was released from bacterial cells when spheroplastswere produced but EDTA and lysozyme treatments. The releasedcytochrome had the same properties as those of the cytochromepreparation obtained by disruption of cells through a Frenchpressure cell. This confirms the earlier suggestion that cytochromec-551 is located in the periplasmic space of cells. (Received August 21, 1982; Accepted October 28, 1982)  相似文献   
188.
189.
190.
Ichthyological Research - Two new deepwater assfish species, Bassozetus trachibranchus and Bassozetus squamosus, are described from the 29 western Atlantic and four western Indian and western South...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号