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   7242篇
  免费   11篇
  国内免费   1篇
电工技术   10篇
化学工业   102篇
金属工艺   19篇
机械仪表   9篇
建筑科学   23篇
能源动力   17篇
轻工业   81篇
水利工程   12篇
石油天然气   31篇
无线电   89篇
一般工业技术   100篇
冶金工业   6703篇
原子能技术   11篇
自动化技术   47篇
  2022年   8篇
  2021年   9篇
  2020年   9篇
  2019年   10篇
  2018年   9篇
  2017年   5篇
  2016年   12篇
  2015年   10篇
  2014年   9篇
  2013年   31篇
  2012年   15篇
  2011年   20篇
  2010年   6篇
  2009年   16篇
  2008年   13篇
  2007年   17篇
  2006年   26篇
  2005年   23篇
  2004年   19篇
  2003年   27篇
  2002年   10篇
  2001年   14篇
  2000年   8篇
  1999年   180篇
  1998年   1990篇
  1997年   1175篇
  1996年   787篇
  1995年   416篇
  1994年   378篇
  1993年   401篇
  1992年   70篇
  1991年   121篇
  1990年   119篇
  1989年   108篇
  1988年   114篇
  1987年   99篇
  1986年   84篇
  1985年   72篇
  1984年   7篇
  1983年   17篇
  1982年   39篇
  1981年   51篇
  1980年   62篇
  1979年   5篇
  1978年   27篇
  1977年   188篇
  1976年   363篇
  1975年   13篇
  1974年   8篇
  1973年   8篇
排序方式: 共有7254条查询结果,搜索用时 15 毫秒
1.
Assuming that the chemical reactions used to synthesize a combinatorial library member are successful, then knowledge of the specific reaction sequence is equivalent to knowing the member's chemical identity. Because the determination of chemical identity is typically not automatable and requires a substantial amount of material, schemes that encode a member's reaction history onto the reaction platform are of value. The primary benefits of encoding are relational nomenclature (all methods) and automated handling (some methods). Encoding methods evaluated to date are spatial, graphical, chemical, spectrometric, electronic, and physical.  相似文献   
2.
3.
OBJECTIVES: To assess that neuromuscular relaxation onset of the adductor pollicis (AP) is related to neuromuscular stimulation rate. To assess that train-of-four (TOF) at 0.05 Hz is a more accurate indicator of optimal tracheal intubation time and conditions, than TOF at 0.08 Hz. STUDY DESIGN: Prospective, comparative, randomized double-blind study. PATIENTS: Forty adults, physical class ASA 1 or 2, undergoing general anaesthesia with tracheal intubation were allocated to two groups (n = 20) according to the sequence of stimulation of the AP: either TOF at 0.05 Hz (test group) or TOF at 0.08 Hz (control group). METHODS: Induction of anaesthesia was achieved with thiopentone, fentanyl and vecuronium (0.1 mg.kg-1). Neuromuscular monitoring was obtained with force displacement transducers attached to each AP. Tracheal intubation was performed once AP muscular response obtained with TOF at 0.05 Hz for test group and TOF at 0.08 Hz for control group was abolished. Results are expressed as mean +/- SEM. Fisher exact test was used for intubation conditions comparison. Curarization time between groups was compared with unpaired Student's t test (P < 0.05 accepted). RESULTS: TOF with 0.05 Hz stimulation significantly increased curarization time: 217 +/- 7 versus 162 +/- 6 s (P < 0.001). Intubation conditions were excellent in 95% and good in 5% of patients in the study group, compared to 15 and 40% in the control group, respectively (P < 0.01) in 45% of the control group patients coughing at intubation occurred. CONCLUSION: Low stimulation rate (TOF at 0.05 Hz) of AP is a reliable technique to determine the appropriate intubation time for patients paralyzed with vecuronium.  相似文献   
4.
5.
We have grown cubic centimeter-size crystals of YBa2Cu3O x suitable for neutron studies, by a top-seeded melt-growth technique. Growth conditions were optimized with an eye toward maximizing phase purity. It was found that the addition of 2% Y2BaCuO5 and 0.5% Pt (by mass) were required to prevent melt loss and to obtain the highest crystallinity. A neutron diffraction study on a mosaic of six such crystals found that the final Y2BaCuO5 concentration was 5%, while other impurity phases comprised less than 1% by volume. The oxygen content was set to x = 6.5, the crystals were detwinned, and then carefully annealed to give the well-ordered ortho-II phase. The neutron study determined that 70% of the mosaic's volume was in the majority orthorhomic domain. The neutron (006) and (110) rocking curve widths were ~1° per crystal and ~2.2° for the mosaic, and the oxygen chain correlation lengths were >100 Å in the a- and b-directions and ~50 Å in the c-direction.  相似文献   
6.
7.
8.
9.
Morganella morganii postoperative endophthalmitis   总被引:1,自引:0,他引:1  
  相似文献   
10.
Replacement of the pyridinium ring of 6,11-ethanobenzo[b]quinolizinium cations with thiazolium (4a and 4b) and N-methylimidazolium (4c and 4d) resulted in equipotent compounds in the [3H]TCP binding assay. The corresponding N-methyl-1,2,4-triazolium analogs were less potent in this assay. The thiazolium derivative 4b, with a Ki = 2.9 nM, is being evaluated as a possible neuroprotective N-methyl-D-aspartic acid (NMDA) antagonist.  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