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   448篇
  免费   42篇
  2022年   3篇
  2021年   3篇
  2018年   2篇
  2017年   7篇
  2016年   9篇
  2015年   12篇
  2014年   19篇
  2013年   10篇
  2012年   24篇
  2011年   15篇
  2010年   16篇
  2009年   18篇
  2008年   26篇
  2007年   15篇
  2006年   15篇
  2005年   19篇
  2004年   18篇
  2003年   18篇
  2002年   13篇
  2001年   9篇
  2000年   10篇
  1999年   17篇
  1998年   10篇
  1997年   5篇
  1996年   7篇
  1995年   8篇
  1994年   4篇
  1993年   7篇
  1992年   11篇
  1991年   12篇
  1990年   11篇
  1989年   8篇
  1988年   9篇
  1987年   9篇
  1986年   6篇
  1985年   10篇
  1984年   10篇
  1983年   7篇
  1982年   6篇
  1981年   6篇
  1980年   3篇
  1979年   2篇
  1978年   7篇
  1977年   4篇
  1973年   3篇
  1972年   3篇
  1970年   2篇
  1969年   4篇
  1967年   3篇
  1966年   3篇
排序方式: 共有490条查询结果,搜索用时 15 毫秒
81.
82.
83.
The Tomb of the Shroud is a first-century C.E. tomb discovered in Akeldama, Jerusalem, Israel that had been illegally entered and looted. The investigation of this tomb by an interdisciplinary team of researchers began in 2000. More than twenty stone ossuaries for collecting human bones were found, along with textiles from a burial shroud, hair and skeletal remains. The research presented here focuses on genetic analysis of the bioarchaeological remains from the tomb using mitochondrial DNA to examine familial relationships of the individuals within the tomb and molecular screening for the presence of disease. There are three mitochondrial haplotypes shared between a number of the remains analyzed suggesting a possible family tomb. There were two pathogens genetically detected within the collection of osteological samples, these were Mycobacterium tuberculosis and Mycobacterium leprae. The Tomb of the Shroud is one of very few examples of a preserved shrouded human burial and the only example of a plaster sealed loculus with remains genetically confirmed to have belonged to a shrouded male individual that suffered from tuberculosis and leprosy dating to the first-century C.E. This is the earliest case of leprosy with a confirmed date in which M. leprae DNA was detected.  相似文献   
84.
Eurytrema procyonis is reported from the pancreatic ducts of domestic cats from North Carolina and Virginia. There were extensive histopathological alterations to the pancreas, especially the pancreatic ducts. However, there was no clinical evidence of infections. The incorporation of a synanthropic host in the life history of E. procyonis allows for rapid distribution of this fluke over its potential geographical range.  相似文献   
85.
86.
87.
Anti-p53 antibodies were examined in the plasma of 112 lung cancer patients by ELISA in order to study the distributions in lung cancer patients and the determinants of these antibodies in relation to lung cancer. Twenty (17.9 %) lung cancer patients were found to have anti-p53 antibodies. The distribution of the antibodies by histological type was 7/48 (14.6 %) adenocarcinoma, 8/32 (25.0 %) squamous cell carcinoma, 3/7 (42.9 %) small cell lung cancer, 0/4 large cell carcinoma, 0/8 adenosquamous cell carcinoma and 2/13 (15.4 %) other types. By ethnicity, 8/44 (18.2 %) Caucasians, 4/20 (20.0 %) Hispanics and 8/48 (16.7 %) African-Americans were positive for anti-p53 antibodies, with no significant differences among the groups (p=0.5137). The antibody positivity rates were higher in lung cancer patients 55 years or older (21.2 %) than in the patients under 55 years (7.4 %). The positive rates of the antibodies were 14.3 % in non-smokers, 16.7 % in ex-smokers and 19.1 % in current smokers, with heavy smokers (41 pack-years) having the highest positive rate (28.6 %), but none of these differences were statistically significant (p > 0.05). Seven controls who had anti-p53 antibodies were all ex-smokers or current smokers and some had occupational exposures. No anti-p53 antibodies were found in 41 non-smoking controls. These results suggest that the development of anti-p53 antibodies in pulmonary carcinogenesis and its association with smoking and other carcinogenic exposures deserve further study.  相似文献   
88.

Background  

Multi-Locus Sequence Typing (MLST) has emerged as a leading molecular typing method owing to its high ability to discriminate among bacterial isolates, the relative ease with which data acquisition and analysis can be standardized, and the high portability of the resulting sequence data. While MLST has been successfully applied to the study of the population structure for a number of different bacterial species, it has also provided compelling evidence for high rates of recombination in some species. We have analyzed a set of Campylobacter jejuni strains using MLST and Comparative Genomic Hybridization (CGH) on a full-genome microarray in order to determine whether recombination and high levels of genomic mosaicism adversely affect the inference of strain relationships based on the analysis of a restricted number of genetic loci.  相似文献   
89.

Background  

High purity of tumour samples is a necessity for accurate genetic and expression analysis and is usually achieved by positive selection in chronic lymphocytic leukaemia (CLL).  相似文献   
90.
A novel technique for the removal of metal ions inhibiting DNA extraction and PCR of archaeological bone extracts is presented using size exclusion chromatography. Two case studies, involving copper inhibition, demonstrate the effective removal of metal ion inhibition. Light microscopy, SEM, elemental analysis, and genetic analysis were used to demonstrate the effective removal of metal ions from samples that previously exhibited molecular inhibition. This research identifies that copper can cause inhibition of DNA polymerase during DNA amplification. The use of size exclusion chromatography as an additional purification step before DNA amplification from degraded bone samples successfully removes metal ions and other inhibitors, for the analysis of archaeological bone. The biochemistry of inhibition is explored through chemical and enzymatic extraction methodology on archaeological material. We demonstrate a simple purification technique that provides a high yield of purified DNA (>95%) that can be used to address most types of inhibition commonly associated with the analysis of degraded archaeological and forensic samples. We present a new opportunity for the molecular analysis of archaeological samples preserved in the presence of metal ions, such as copper, which have previously yielded no DNA results. Am J Phys Anthropol, 2009. © 2009 Wiley‐Liss, Inc.  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