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   4084篇
  免费   179篇
  国内免费   8篇
化学   2727篇
晶体学   36篇
力学   78篇
数学   326篇
物理学   1104篇
  2023年   49篇
  2022年   48篇
  2021年   76篇
  2020年   116篇
  2019年   130篇
  2018年   85篇
  2017年   83篇
  2016年   163篇
  2015年   104篇
  2014年   163篇
  2013年   293篇
  2012年   277篇
  2011年   330篇
  2010年   196篇
  2009年   164篇
  2008年   259篇
  2007年   217篇
  2006年   199篇
  2005年   156篇
  2004年   127篇
  2003年   91篇
  2002年   68篇
  2001年   60篇
  2000年   61篇
  1999年   41篇
  1998年   30篇
  1997年   22篇
  1996年   37篇
  1995年   31篇
  1994年   39篇
  1993年   43篇
  1992年   29篇
  1991年   27篇
  1989年   19篇
  1988年   20篇
  1987年   26篇
  1986年   23篇
  1985年   18篇
  1984年   32篇
  1983年   21篇
  1982年   22篇
  1981年   30篇
  1980年   19篇
  1979年   27篇
  1978年   15篇
  1977年   18篇
  1976年   16篇
  1975年   15篇
  1973年   11篇
  1957年   13篇
排序方式: 共有4271条查询结果,搜索用时 46 毫秒
1.
Journal of Solid State Electrochemistry - Sodium-ion batteries have emerged as an exciting alternative to commercially dominant lithium-ion batteries for electric vehicles and other applications....  相似文献   
2.
Molecular Diversity - Practical synthesis and biological activities of quinazolinyl–triazinyl semicarbazides (10a–j) and quinazolinyl–triazinyl thiosemicarbazides (11a–j)...  相似文献   
3.
Structural Chemistry - A systematic investigation has been carried out to assess the performance of various exchange–correlation energy density functionals coupled with various basis sets to...  相似文献   
4.
Treatment of [Cp*RuCl2]2, 1 , [(COD)IrCl]2, 2 or [(p-cymene)RuCl2]2, 3 (Cp*=η5-C5Me5, COD= 1,5-cyclooctadiene and p-cymene=η6-iPrC6H4Me) with heterocyclic borate ligands [Na[(H3B)L], L1 and L2 ( L1 : L=amt, L2 : L=mp; amt=2-amino-5-mercapto-1,3,4-thiadiazole, mp=2-mercaptopyridine) led to the formation of borate complexes having uncommon coordination. For example, complexes 1 and 2 on reaction with L1 and L2 afforded dihydridoborate species [LAM(μ-H)2BHL] 4 – 6 ( 4 : LA=Cp*, M=Ru, L=amt; 5 : LA=Cp*, M=Ru, L=mp; 6 : LA=COD, M=Ir, L=mp). On the other hand, treatment of 3 with L2 yielded cis- and trans-bis(dihydridoborate) species, [Ru{(μ-H)2BH(mp)}2], cis- 7 and trans- 7 . The isolation and structural characterization of fac- and mer-[Ru{(μ-H)2BH(mp)}{(μ-H)BH(mp)2}], 8 from the same reaction offered an insight into the behaviour of these dihydridoborate species in solution. Fascinatingly, despite having reduced natural charges on Ru centres both at cis-and trans- 7 , they underwent hydroboration reaction with alkynes that yielded both Markovnikov and anti-Markovnikov addition products, 10 a – d .  相似文献   
5.
The photovoltaic performance of quantum-dot solar cells strongly depends on the charge-carrier relaxation and recombination processes, which need to be modulated in a favorable way to obtain maximum efficiency. Recently, significant efforts have been devoted to investigate the carrier dynamics of nanocrystal sensitizers, both in solution and deposited on TiO2 photoanodes, with the aim to correlate the excitonics with solar-energy conversion efficiency. This Minireview summarizes some proof of the concepts that efficiency can be directly correlated to the exciton dynamics of quantum-dot solar cells. The presented findings are based on CdSeS alloy, CdSe/CdS core/shell, Au/CdSe nanohybrids, and Mn-doped CdZnSSe nanocrystals, where the favourable excitonic processes are optimized to enhance the efficiency. Future prospects and limitations are addressed as well.  相似文献   
6.
7.
8.
Separation of xenon and krypton is of industrial and environmental concern; the existing technologies use cryogenic distillation. Thus, a cost‐effective, alternative technology for the separation of Xe and Kr and their capture from air is of significant importance. Herein, we report the selective Xe uptake in a crystalline porous organic oligomeric molecule, noria, and its structural analogue, PgC‐noria, under ambient conditions. The selectivity of noria towards Xe arises from its tailored pore size and small cavities, which allows a directed non‐bonding interaction of Xe atoms with a large number of carbon atoms of the noria molecular wheel in a confined space.  相似文献   
9.
JPC – Journal of Planar Chromatography – Modern TLC - Inula cappa (family Compositae) is used in the Ayurvedic medicinal system for the treatment of bronchitis, diabetes, fever,...  相似文献   
10.
The article describes synthesis and thermally triggered self‐assembly of a Poly (ethylene oxide)‐block‐poly (N‐insopropylacrylamide) (PEO‐b‐PNIPAm) in aqueous medium. At rt, the polymer remains as unimer, however, at lower critical solution temperature (LCST) of PNIPAm (32 °C), it forms a rather large undefined aggregate which at slightly elevated temperature (~40 °C) converges to well defined polymersome structure (Critical aggregation concentration = 0.45 mg/mL) with hydrodynamic diameter of 40–50 nm. By lowering the temperature, initial swelling of the compact vesicle followed by reversible disassembly to unimer was noticed. The polymersome exhibits encapsulation ability to a hydrophilic dye Calcein which can be spontaneously released by lowering the temperature below cloud point. Likewise a hydrophobic dye namely 8‐Anilino‐1‐naphthalenesulfonic acid (ANS) can also be encapsulated and released by thermal trigger. Detail photoluminescence studies reveal ANS dye can be used as a generalized probe molecule for detecting LCST of a thermoresponsive polymer by “fluorescence on” above LCST even by cursory observation. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2444–2451  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