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   3283篇
  免费   227篇
  国内免费   1篇
  3511篇
  2023年   20篇
  2022年   28篇
  2021年   78篇
  2020年   28篇
  2019年   53篇
  2018年   40篇
  2017年   46篇
  2016年   67篇
  2015年   155篇
  2014年   168篇
  2013年   215篇
  2012年   240篇
  2011年   249篇
  2010年   167篇
  2009年   140篇
  2008年   196篇
  2007年   237篇
  2006年   208篇
  2005年   178篇
  2004年   188篇
  2003年   156篇
  2002年   138篇
  2001年   28篇
  2000年   29篇
  1999年   24篇
  1998年   23篇
  1997年   31篇
  1996年   16篇
  1995年   22篇
  1994年   18篇
  1993年   14篇
  1992年   27篇
  1991年   18篇
  1990年   19篇
  1989年   11篇
  1988年   14篇
  1987年   14篇
  1986年   10篇
  1985年   13篇
  1984年   17篇
  1983年   11篇
  1982年   25篇
  1981年   19篇
  1980年   18篇
  1979年   13篇
  1978年   8篇
  1977年   7篇
  1975年   7篇
  1970年   5篇
  1965年   6篇
排序方式: 共有3511条查询结果,搜索用时 15 毫秒
81.
Single-cell multi-omics assays offer unprecedented opportunities to explore epigenetic regulation at cellular level. However, high levels of technical noise and data sparsity frequently lead to a lack of statistical power in correlative analyses, identifying very few, if any, significant associations between different molecular layers. Here we propose SCRaPL, a novel computational tool that increases power by carefully modelling noise in the experimental systems. We show on real and simulated multi-omics single-cell data sets that SCRaPL achieves higher sensitivity and better robustness in identifying correlations, while maintaining a similar level of false positives as standard analyses based on Pearson and Spearman correlation.  相似文献   
82.
Mounted paraffin sections, 2-4μ thick, ˙were stained, dehydrated, allowed to air dry, and given a thin coating of 1 % Plexi-glas solution in chloroform. The chloroform was allowed to evaporate completely in a dry atmosphere. An emulsion whose dried thickness was 100-150μ, was prepared from Ilford G5 type in gel form and glued to the section by means of a 15% solution of shellac in absolute alcohol. The surface of the emulsion was then cleaned with absolute ethyl alcohol, to remove the impermeable shellac layer. The exposure for radiation reaction was made at about 2°C and required, in the conditions of our experiment, about 24 hrs. The emulsions were processed by the “temperature-development method.” With the described procedure, autoradiographs have been obtained of various organs of albino rats, labeled with P32, S35 and other radioisotopes, and very precise localizations of the origin of electron tracks was attempted. This technic has allowed the fixing and staining of the tissues by means of all the reagents commonly employed in histology, without any damage to the emulsion and the obtaining of good adhesion and minimum separation between specimen and emulsion, thus permitting reliable extrapolations of electron tracks. Due to the fact that the emulsion is fully sensitized when placed in contact with the preparation the limits of the exposure times were well defined. The uniform development at all depths of the emulsion achieved by the temperature-development method facilitated the work with fast electron tracks.  相似文献   
83.
84.
85.
The development of drugs able to target BTK, PI3k‐delta and BCL2 has dramatically improved chronic lymphocytic leukaemia (CLL) therapies. However, drug resistance to these therapies has already been reported due to non‐recurrent changes in oncogenic pathways and genes expression signatures. In this study, we investigated the cooperative role of the BCL2 inhibitor venetoclax and the BRD4 inhibitor JQ1. In particular, we found that JQ1 shows additional activity with venetoclax, in CLL cell lines and in ex vivo isolated primary CD19+ lymphocytes, arguing in favour of combination strategies. Lastly, JQ1 is also effective in venetoclax‐resistant CLL cell lines. Together, our findings indicated that the BET inhibitor JQ1 could be a promising therapy in CLL, both as first‐line therapy in combination with venetoclax and as second‐line therapy, after the emergence of venetoclax‐resistant clones.  相似文献   
86.
Low electron/proton conductivities of electrochemical catalysts, especially earth‐abundant nonprecious metal catalysts, severely limit their ability to satisfy the triple‐phase boundary (TPB) theory, resulting in extremely low catalyst utilization and insufficient efficiency in energy devices. Here, an innovative electrode design strategy is proposed to build electron/proton transport nanohighways to ensure that the whole electrode meets the TPB, therefore significantly promoting enhance oxygen evolution reactions and catalyst utilizations. It is discovered that easily accessible/tunable mesoporous Au nanolayers (AuNLs) not only increase the electrode conductivity by more than 4000 times but also enable the proton transport through straight mesopores within the Debye length. The catalyst layer design with AuNLs and ultralow catalyst loading (≈0.1 mg cm?2) augments reaction sites from 1D to 2D, resulting in an 18‐fold improvement in mass activities. Furthermore, using microscale visualization and unique coplanar‐electrode electrolyzers, the relationship between the conductivity and the reaction site is revealed, allowing for the discovery of the conductivity‐determining and Debye‐length‐determining regions for water splitting. These findings and strategies provide a novel electrode design (catalyst layer + functional sublayer + ion exchange membrane) with a sufficient electron/proton transport path for high‐efficiency electrochemical energy conversion devices.  相似文献   
87.
88.
89.
The International Journal of Life Cycle Assessment - Scientific Life Cycle Assessment (LCA) literature provides some examples of LCA teaching in higher education, but not a structured overview of...  相似文献   
90.
The International Journal of Life Cycle Assessment - How to apply allocation in an life cycle assessment (LCA) is a long-running and controversial debate. Consensus seems to exist on the fact that...  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