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   627篇
  免费   0篇
化学工业   13篇
金属工艺   3篇
轻工业   1篇
石油天然气   1篇
一般工业技术   8篇
冶金工业   592篇
原子能技术   1篇
自动化技术   8篇
  2021年   1篇
  2020年   1篇
  2014年   2篇
  2013年   1篇
  2011年   2篇
  2010年   2篇
  2009年   1篇
  2008年   2篇
  2007年   4篇
  2006年   3篇
  2005年   1篇
  2003年   1篇
  2001年   2篇
  2000年   1篇
  1999年   11篇
  1998年   144篇
  1997年   97篇
  1996年   53篇
  1995年   44篇
  1994年   31篇
  1993年   41篇
  1992年   7篇
  1991年   12篇
  1990年   9篇
  1989年   8篇
  1988年   7篇
  1987年   7篇
  1986年   8篇
  1985年   10篇
  1984年   1篇
  1983年   1篇
  1982年   3篇
  1981年   6篇
  1980年   5篇
  1979年   1篇
  1978年   6篇
  1977年   18篇
  1976年   60篇
  1975年   3篇
  1973年   1篇
  1972年   1篇
  1971年   3篇
  1968年   2篇
  1965年   1篇
  1964年   1篇
  1955年   1篇
排序方式: 共有627条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
Discusses the new socioeconomic conditions in public health, which imply higher requirements to the use of resources and to their quality. Emphasizes that a physician of a general profile promotes the development of such tendencies, the realization of which, in turn, is conductive to other structural changes reflecting the changes in the population health and in changing need in medical care.  相似文献   
85.
Rural schoolchildren between the ages of 6 and 18 years were screened for residual paralysis following poliomyelitis; 503 (0.85%) out of a total of 58,592 were victims. Of these, only 16 (3.8%) had received poliomyelitis vaccine, while the remainder had not been immunised. The disease had occurred before the age of 4 years in nearly 90%, the lower limbs being affected (98%) more often than the upper (2%). In the lower limbs, the quadriceps, hip adductors and tibialis anterior were frequently affected. The muscles supplied by the L4 and L5 spinal segments were most commonly involved, while those supplied by L1 and S3 were least. Some order does exist in the apparently irregular distribution of paralysis after poliomyelitis.  相似文献   
86.
Definitive identification of detached hooklets, scolex and fragments of the spiral wall of Cysticercus cellulosae on fine needle aspiration smears was documented. A critical review of aspirates from 200 diagnosed and 98 suspected lesions of soft tissue and intramuscular cysticercosis was done. Characteristic fragments of bladder wall cytomorphologically corresponding to viable or partially necrotic lesions were seen in 203 cases. Identification of fragments of an invaginated larva (i.e., hooklets, scolex or spiral wall) established the diagnosis in 33 of the suspected lesions. Cytomorphologically all these cases were from either necrotic or calcified lesions. In necrotic lesions with eosinophils, a careful search for fragments of the invaginated portion of the larva should be made.  相似文献   
87.
LNA (Locked Nucleic Acids, 1, X = O, Y = O) is a novel oligonucleotide analogue capable of recognizing complementary DNA and RNA with unprecedented thermal affinities. Synthesis of the first chemically modified LNA analogues is reported. A 9-mer phosphorothioate-LNA containing three LNA thymine monomers (1, X = O, Y = S, Base = thymin-1-yl) and 9-mer LNAs containing one, three or five 2'-thio-LNA monomers (1, X = S, Y = O, Base = uracil-1-yl) were able to recognize both complementary DNA and RNA with thermal affinities comparable to those of parent LNA.  相似文献   
88.
89.
90.
We have used differential hybridization to isolate and characterize two novel cDNAs expressed in chondrocytes and some osteoblastic cells. A rat osteosarcoma ROS17/2.8 cDNA library was screened and cDNA clones hybridizing strongly to radiolabeled porcine calvaria cDNA but weakly to a control radiolabeled cDNA were isolated. Two clones were obtained--p.6.1 and p.10.15. A radiolabeled probe of p10.15 was shown to hybridize specifically to a 2.3 Kb message RNA from a chondrogenic clonal cell population from rat calvaria-RCJ 3.1C5.18, and the mRNA was downregulated by 1,25 (OH)2D3, which inhibits chondrogenesis in these cells. The other clone, p6.1, was found to hybridize to a 0.95 Kb message that is expressed in rat liver, kidney, lung, muscle, and brain, but not expressed in spleen and expressed only in low levels in thymus.  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