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   729篇
  免费   52篇
  国内免费   2篇
  783篇
  2024年   1篇
  2023年   2篇
  2022年   13篇
  2021年   18篇
  2020年   11篇
  2019年   13篇
  2018年   27篇
  2017年   15篇
  2016年   28篇
  2015年   52篇
  2014年   66篇
  2013年   59篇
  2012年   75篇
  2011年   62篇
  2010年   49篇
  2009年   35篇
  2008年   31篇
  2007年   34篇
  2006年   29篇
  2005年   24篇
  2004年   23篇
  2003年   19篇
  2002年   21篇
  2001年   14篇
  2000年   12篇
  1999年   13篇
  1998年   4篇
  1997年   1篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1992年   2篇
  1991年   4篇
  1990年   3篇
  1989年   1篇
  1988年   3篇
  1986年   1篇
  1984年   3篇
  1983年   3篇
  1982年   1篇
  1981年   2篇
  1972年   5篇
排序方式: 共有783条查询结果,搜索用时 12 毫秒
771.
Alizarin glucosyl transferase activity was found in five mutant strains ofStreptomyces aureofaciens. The activity bears no direct relationship to the final products of tetracycline biosynthesis. Translated by K. Sigler  相似文献   
772.
773.
To investigate serum levels of calcitonin gene-related peptide (CGRP), we developed a sensitive radioimmunoassay (RIA). RIA for CGRP in serum can present some problems: the serum may degradate the tracer during incubation and suppress the antigen-antibody reaction. We avoided these problems by using aprotinin and CGRP-free serum instead of a buffer for the standard curve. We detected serum CGRP in all 39 healthy subjects when CGRP-free serum was not used for the standard curve, but 34 of these subjects had serum CGRP levels below the detection limit (less than 80 pmol/l) when CGRP-free serum was used for the standard curve. We defined the normal range for serum CGRP as below 100.8 pmol/l, which was the maximum level found in the healthy subjects. We studied serum levels of this peptide in patients with thyroid diseases, because the thyroid may be one origin of circulating CGRP. Four of 10 patients with medullary thyroid carcinoma had elevated serum levels of CGRP. Seven of 24 patients with subacute thyroiditis had elevated serum levels of CGRP, but at least one year after clinical recovery, CGRP was undetectable in all. Seven of the 37 patients with hypothyroidism had elevated serum levels of CGRP. None of the patients with hyperthyroidism, adenomatous goiter, thyroid adenoma, or thyroid carcinoma had elevated serum CGRP levels. It is necessary to use a standard curve obtained by the addition of aprotinin and CGRP-free serum to the assay standards to measure serum CGRP levels. Some patients with subacute thyroiditis, hypothyroidism, or medullary thyroid carcinoma had elevated serum CGRP levels.  相似文献   
774.
775.
During a survey of fungal diversity associated with insects, mud, soil, and freshwater niches in different areas in Korea, nine interesting fungal strains were isolated. Based on their morphological characteristics and molecular phylogeny analyses, using a combined data set of β-tubulin (BenA), calmodulin (CaM), and second largest subunit of RNA polymerase (RPB2) sequences, the strains CNUFC AM-44, CNUFC JCW3-4, CNUFC S708, CNUFC WT202, CNUFC AS1-29, CNUFC JCW3-5, CNUFC JDP37, and CNUFC JDP62 were identified as Aspergillus alabamensis, A. floridensis, A. subversicolor, Penicillium flavigenum, P. laevigatum, P. lenticrescens, Talaromyces adpressus, and T. beijingensis, respectively. The strain CNUFC JT1301 belongs to series Westlingiorum in section Citrina and is phylogenetically related to P. manginii. However, slow growth when cultivated on CYA, MEA, CREA is observed and the property can be used to easily distinguish the new species from these species. Additionally, P. manginii is known to produce sclerotia, while CNUFC JT1301 strain does not. Herein, the new fungal species is proposed as P. aquadulcis sp. nov. Eight species, A. alabamensis, A. floridensis, A. subversicolor, P. flavigenum, P. laevigatum, P. lenticrescens, T. adpressus, and T. beijingensis, have not been previously reported in Korea. The present study expands the known distribution of fungal species belonging to the families Aspergillaceae and Trichocomaceae in Korea.  相似文献   
776.
Chromatin-mediated regulation of flowering time in Arabidopsis   总被引:1,自引:0,他引:1  
  相似文献   
777.
778.
Periodic paralysis has been known to be associated with thyrotoxicosis in Japan. The incidence was 8.6% among male and 0.4% among female thyrotoxic patients according to a survey performed in the three major thyroid clinics in Japan in 1957. To determine the changes in the incidence during the intervening 34 years, the same type of survey was carried out again in 1991 at the same three major thyroid clinics previously involved. The incidence of paralysis in 1991 was 4.3% among male and 0.04% among female thyrotoxic patients, indicating more than a 40% decrease in the incidence. The possible cause of the decrease is related to the changes in food consumption, namely, to the fact that less carbohydrate and more potassium were taken in 1991 than in 1957.  相似文献   
779.
Estimation of lipase activity by the diffusion plate method   总被引:2,自引:0,他引:2  
A diffusion plate method for the assay of the activity of lipases in large series of samples was worked out. When using this method the maximum deviation was found to be ±3.8%.  相似文献   
780.
In addition to typical acetyl esters, acetic ester aoetyl-hydrolase fromMycobacterium phlei can degrade aliphatic acetylated amino acids under suitable conditions.  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