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   66616篇
  免费   142085篇
  国内免费   29840篇
  2019年   2697篇
  2018年   2273篇
  2017年   2075篇
  2016年   2165篇
  2015年   2341篇
  2014年   2380篇
  2013年   2285篇
  2012年   2631篇
  2011年   3519篇
  2010年   4884篇
  2009年   9789篇
  2008年   3807篇
  2007年   3690篇
  2006年   2614篇
  2005年   2795篇
  2004年   2869篇
  2003年   2288篇
  2002年   2987篇
  2001年   4239篇
  1999年   6689篇
  1998年   8883篇
  1997年   9129篇
  1996年   8461篇
  1995年   8765篇
  1994年   8120篇
  1993年   7989篇
  1992年   7860篇
  1991年   7813篇
  1990年   8636篇
  1989年   7885篇
  1988年   7171篇
  1987年   6277篇
  1986年   5782篇
  1985年   5232篇
  1984年   4023篇
  1983年   3227篇
  1982年   3543篇
  1981年   3210篇
  1980年   3147篇
  1979年   3249篇
  1978年   2960篇
  1977年   2899篇
  1976年   2719篇
  1975年   2302篇
  1974年   2456篇
  1973年   2462篇
  1972年   2810篇
  1971年   2592篇
  1970年   2342篇
  1969年   2390篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Summary The frequency of large granular lymphocytes (LGL) in the peripheral blood of healthy persons (n=56) and breast cancer patients (31 cases with stage-I and -II disease and 42 cases with stage-III and -IV disease) was studied. The frequency of LGL in peripheral blood was significantly depressed in cancer patients, and particularly in patients with advanced breast cancer.  相似文献   
102.
The murine cytomegalovirus m02 gene family encodes putative type I membrane glycoproteins named m02 through m16. A subset of these genes were fused to an epitope tag and cloned into an expression vector. In transfected and murine cytomegalovirus-infected cells, m02, m04, m05, m06, m07, m09, m10, and m12 localized to cytoplasmic structures near the nucleus, whereas m08 and m13 localized to a filamentous structure surrounding the nucleus. Substitution mutants lacking the m02 gene (SMsubm02) or the entire m02 gene family (SMsubm02-16) grew like their wild-type parent in cultured cells. However, whereas SMsubm02 was as pathogenic as the wild-type virus, SMsubm02-16 was markedly less virulent. SMsubm02-16 produced less infectious virus in most organs compared to wild-type virus in BALB/c and C57BL/6J mice, but it replicated to wild-type levels in the organs of immunodeficient gamma(c)/Rag2 mice, lacking multiple cell types including natural killer cells, and in C57BL/6J mice depleted of natural killer cells. These results argue that one or more members of the m02 gene family antagonize natural killer cell-mediated immune surveillance.  相似文献   
103.
104.
Polypeptides released into the culture medium of herpesvirus sylvilagus-infected cells were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of extracellular fluid from [35S]methionine- and [3H]glucosamine-labeled cell cultures. Virus-induced glycoproteins 31, 32, and 33 (molecular weights of 62,000, 59,000, and 54,000, respectively) were the most abundant species and appeared predominantly in the culture medium. This observation, together with the known cell-associated nature of herpesvirus sylvilagus, suggested that virus-induced glycoproteins 31, 32, and 33 were specifically released. Immunization of rabbits with virus-induced glycoproteins 13 (molecular weight of 130,000) and 32 resulted in the production of antibodies that neutralized viral infectivity in vitro. Both antiserum to gp13 and antiserum to gp32 immunoprecipitated gp13, gp26, gp33a, gp45, and virus-induced polypeptide 39 (molecular weights of 130,000, 77,000, 49,000, 27,000, and 36,000, respectively) from [35S]methionine-labeled cell extracts as well as virus-induced glycoproteins 31, 32, and 33 from the culture medium. In addition, membrane immunofluorescence assays indicate that an antigen(s) reactive with anti-gp13/32 serum was located on the plasma membrane of infected cells.  相似文献   
105.
106.
107.
108.
109.
110.
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