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   277382篇
  免费   3797篇
  国内免费   293篇
电工技术   4236篇
综合类   107篇
化学工业   46131篇
金属工艺   15661篇
机械仪表   10700篇
建筑科学   4977篇
矿业工程   3828篇
能源动力   4360篇
轻工业   14530篇
水利工程   4363篇
石油天然气   13094篇
武器工业   33篇
无线电   21244篇
一般工业技术   67528篇
冶金工业   38977篇
原子能技术   11233篇
自动化技术   20470篇
  2021年   3429篇
  2019年   3410篇
  2018年   6609篇
  2017年   6883篇
  2016年   7241篇
  2015年   3978篇
  2014年   6392篇
  2013年   12365篇
  2012年   9012篇
  2011年   10448篇
  2010年   8578篇
  2009年   9232篇
  2008年   9257篇
  2007年   8897篇
  2006年   7045篇
  2005年   6150篇
  2004年   6037篇
  2003年   5808篇
  2002年   5605篇
  2001年   5290篇
  2000年   5261篇
  1999年   4629篇
  1998年   9237篇
  1997年   7191篇
  1996年   5299篇
  1995年   4191篇
  1994年   3836篇
  1993年   4092篇
  1992年   3381篇
  1991年   3537篇
  1990年   3608篇
  1989年   3499篇
  1988年   3410篇
  1987年   3379篇
  1986年   3260篇
  1985年   3435篇
  1984年   3358篇
  1983年   3235篇
  1982年   3107篇
  1981年   3166篇
  1980年   3200篇
  1979年   3315篇
  1978年   3553篇
  1977年   3677篇
  1976年   4415篇
  1975年   3248篇
  1974年   3331篇
  1973年   3398篇
  1972年   3005篇
  1971年   2788篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
Context: The administration of pharmabiotics is a promising alternative to antimicrobial drugs for the treatment and/or prevention of female urogenital infections.

Objective: To design pharmabiotic formulations including bioactive ingredients of microbial origin combined with non-microbial substances and then to evaluate the stability of the combinations during freeze-drying and storage.

Materials and methods: Different formulations including Lactobacillus gasseri CRL 1263, Lactobacillus salivarius CRL 1328, salivaricin CRL 1328 (a bacteriocin) and non-microbial compounds (lactose, inulin and ascorbic acid) were assayed, and the ingredients were freeze-dried together or separately. The formulations were stored in gelatin capsules at 4?°C for 360?d.

Results: The viability of lactobacilli was affected to different extents depending on the strains and on the formulations assayed. L. salivarius and ascorbic acid were successfully combined only after the freeze-drying process. Salivaricin activity was not detected in formulations containing L. gasseri. However, when combined with ascorbic acid, lactose, inulin or L. salivarius, the bacteriocin maintained its activity for 360?d. The selected microorganisms proved to be compatible for their inclusion in multi-strain formulations together with lactose, inulin and ascorbic acid. Salivaricin could be included only in a L. salivarius CRL 1328 single-strain formulation together with non-microbial substances.

Conclusions: This study provides new insights into the design of urogenital pharmabiotics combining beneficial lactobacilli, salivaricin CRL 1328 and compounds with different functionalities.  相似文献   
122.
123.
Powder Metallurgy and Metal Ceramics - The theoretical strength of LaB6 and MeB2 borides and a eutectic LaB6–TiB2 system is calculated with quasiharmonic approximation for uniaxial strain in...  相似文献   
124.
125.
126.
127.
High Temperature - The temperature dependences of the viscosity of liquid Fe90B x Si(10 − x) alloys are studied in the mode of heating and subsequent cooling. The temperature dependences of...  相似文献   
128.
An automated system for integrated electrophysical and optical studies of semiconductor nanoheterostructures, which operates in a wide temperature range from 15 to 475 K, is designed. The setup is intended to measure the temperature and frequency admittance and electroluminescence spectra of light-emitting diode and laser chips formed on substrates of diameter up to 50.2 mm, and the distribution of parameters over the wafer. The setup includes the closed-cycle helium cryogenic station, LCR meter, and temperature controller. The characterization results of nanoheterostructures with InGaN/GaN multiple quantum wells, which are used for creating highly efficient white and blue light-emitting diodes, are presented.  相似文献   
129.
The influence of the thermal cycling conditions on the thermal-cycling creep of a TN-1 alloy and the related irreversible deformations is studied. The conditions under which an anomalous increase in the irreversible deformations begins are determined. The structural mechanism of the irreversible deformations of an equiatomic alloy is shown to be analogous to the structural mechanism of metal creep at high temperatures: it predominantly has a dislocation character. It is proposed to use the effect of anomalous increase in the deformation of materials with reversible martensitic transformations for forming parts made of these materials at low temperatures.  相似文献   
130.
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