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   1959篇
  免费   9篇
  国内免费   8篇
电工技术   15篇
综合类   1篇
化学工业   149篇
金属工艺   13篇
机械仪表   20篇
建筑科学   58篇
矿业工程   2篇
能源动力   14篇
轻工业   101篇
水利工程   6篇
石油天然气   2篇
无线电   50篇
一般工业技术   92篇
冶金工业   1394篇
原子能技术   13篇
自动化技术   46篇
  2021年   11篇
  2019年   10篇
  2018年   8篇
  2017年   7篇
  2016年   7篇
  2015年   7篇
  2014年   8篇
  2013年   33篇
  2012年   20篇
  2011年   14篇
  2010年   26篇
  2009年   26篇
  2008年   20篇
  2007年   26篇
  2006年   17篇
  2005年   18篇
  2004年   13篇
  2003年   18篇
  2002年   15篇
  2001年   14篇
  2000年   16篇
  1999年   60篇
  1998年   439篇
  1997年   243篇
  1996年   182篇
  1995年   84篇
  1994年   78篇
  1993年   86篇
  1992年   18篇
  1991年   20篇
  1990年   21篇
  1989年   22篇
  1988年   33篇
  1987年   23篇
  1986年   15篇
  1985年   22篇
  1984年   16篇
  1983年   24篇
  1982年   17篇
  1981年   12篇
  1980年   14篇
  1979年   10篇
  1978年   11篇
  1977年   35篇
  1976年   80篇
  1975年   16篇
  1974年   8篇
  1973年   9篇
  1971年   6篇
  1970年   5篇
排序方式: 共有1976条查询结果,搜索用时 15 毫秒
101.
102.
An infant with neonatal meningitis caused by Pseudomonas cepacia responded promptly to treatment with trimethoprim-sulfamethoxazole (Bactrim) after other abtibiotics had failed. Pseudomonas cepacia has proven to be resistant to most of the commonly used antibiotics.  相似文献   
103.
The unstable hemoglobin (Hb) Saint Etienne (alpha2beta295F8 His replaced by G1n) (betaSE) was found in the red blood cells of an 8-year-old boy. The composition of this hemoglobin was 26% Saint Etienne, 52% A, 3% A2 and 19% HbF. Studies of hemoglobin synthesis indicate: a) a balanced synthesis of alpha and non-alpha chains (alpha=betaA + betaSE + gamma), b) an increased pool of free alpha hemoglobin chains, and c) a rapid exchange of alpha chains between this pool and HbSE. The alpha chain pool resulted from the dissociation of HbSE and the greater instability of betaSE chains than alpha chains upon heating. Hemoglobin F is of the fetal type and is heterogeneously distributed among the red cells. Furthermore, two populations of red blood cells could be separated according to their i antigen content. Analysis of the hemoglobins revealed a heterogeneous distribution. Thus, F hemoglobin was preferentially associated with cells having low i antigen level, while Saint Etienne hemoglobin was increased in cells having a high i antigen level. HbF and HbSE were not present in the parents of the propositus. Study of the genetic markers confirmed the filiation. The parents were normal upon clinical and hematological examination; they exhibited a normal pattern and synthesis of hemoglobin. The Hb Saint Etienne case is compared with Hb Istanbul, which in spite of the same amino acid substitution is not associated with increased HbF level.  相似文献   
104.
Analytical values for 10 varieties of hops from the 1971 crop are presented in relation to the district of production. Where comparisons can be made it is seen that variation within growths is less than in previous seasons. It was found that for Whitbread Golding Variety a sampling rate of 1 in 10 would be acceptable for commercial purposes.  相似文献   
105.
  相似文献   
106.
Granulosa cells from small (less than 2mm) antral porcine follicles were grown in culture to study the effects of various hormones on growth, morphology and progesterone secretion. Culture medium 199D + 4% serum was found to be most suitable since it maintained a fairly constant cell population. Estradiol (1mug/ml) and human FSH stimulated cell growth. LH and FSH stimulated progesterone secretion and induced morphological changes associated with luteinization. Estradiol (0.1 mug/ml) inhibited progesterone secretion by granulosa cells.  相似文献   
107.
We report a new application of affinity capture-elution electrospray mass spectrometry (ACESI-MS) to assay the enzymes phosphomannomutase (PMM) and phosphomannose isomerase (PMI), which when deficient cause congenital disorders of glycosylation CDG-type Ia and type Ib, respectively. The novel feature of this mass-spectrometry-based assay is that it allows one to distinguish and quantify enzymatic products that are isomeric with their substrates that are present simultaneously in complex mixtures, such as cultured human cell homogenates. This is achieved by coupled assays in which the PMM and PMI primary products are in vitro subjected to another enzymatic reaction with yeast transketolase that changes the mass of the products to be detected by mass spectrometry. The affinity purification procedure is fully automated, and the mass spectrometric analysis is multiplexed in a fashion that is suitable for high-throughput applications.  相似文献   
108.
109.
110.
Stahl's ear is a congenital malformation of the auricle, which is uncommon in non-Oriental societies. A number of different treatment modalities have been suggested, many of which yield unpredictable results. We review current treatment modalities from the English literature and describe a novel, simple surgical method of repair. First, a helical rim incision is made to expose the abnormal third crus and upper pole of the ear. The third crus is excised as a narrow wedge of cartilage and posterior skin, and the defect is closed primarily. The free third crus cartilage is then grafted onto the scaphal cartilage in an anatomically correct position to form a superior crus. The anterior skin flap is redraped and bolstered over this graft. Only a very small scar on the helical rim remains visible anteriorly.  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