全文获取类型
收费全文 | 2067篇 |
免费 | 50篇 |
国内免费 | 4篇 |
专业分类
化学 | 1259篇 |
晶体学 | 16篇 |
力学 | 44篇 |
数学 | 195篇 |
物理学 | 607篇 |
出版年
2024年 | 6篇 |
2023年 | 16篇 |
2022年 | 49篇 |
2021年 | 35篇 |
2020年 | 41篇 |
2019年 | 54篇 |
2018年 | 46篇 |
2017年 | 54篇 |
2016年 | 77篇 |
2015年 | 42篇 |
2014年 | 83篇 |
2013年 | 159篇 |
2012年 | 122篇 |
2011年 | 130篇 |
2010年 | 89篇 |
2009年 | 88篇 |
2008年 | 121篇 |
2007年 | 110篇 |
2006年 | 77篇 |
2005年 | 59篇 |
2004年 | 52篇 |
2003年 | 40篇 |
2002年 | 39篇 |
2001年 | 33篇 |
2000年 | 28篇 |
1999年 | 14篇 |
1998年 | 13篇 |
1997年 | 11篇 |
1996年 | 17篇 |
1995年 | 22篇 |
1994年 | 22篇 |
1993年 | 33篇 |
1992年 | 26篇 |
1991年 | 25篇 |
1990年 | 23篇 |
1989年 | 24篇 |
1988年 | 12篇 |
1987年 | 28篇 |
1986年 | 19篇 |
1985年 | 21篇 |
1984年 | 16篇 |
1983年 | 18篇 |
1982年 | 16篇 |
1981年 | 15篇 |
1980年 | 15篇 |
1979年 | 20篇 |
1978年 | 6篇 |
1974年 | 5篇 |
1973年 | 6篇 |
1965年 | 7篇 |
排序方式: 共有2121条查询结果,搜索用时 15 毫秒
11.
12.
13.
Devdutt Chaturvedi Nisha Mishra Virendra Mishra 《Monatshefte für Chemie / Chemical Monthly》2007,70(6):57-60
A novel Mitsunobu-based protocol was developed for the synthesis of carbamates from the corresponding alcohols using carbon dioxide and amines
in good to excellent yields. This protocol is mild, chemoselective, and efficient compared to other reported methods. 相似文献
14.
Raj Gandhi Kamales Kar S. Uma Sankar Abhijit Bandyopadhyay Rahul Basu Pijushpani Bhattacharjee Biswajoy Brahmachari Debrupa Chakraborti M. Chaudhury J. Chaudhury Sandhya Choubey E. J. Chun Atri Desmukhya Anindya Datta Gautam Dutta Sukanta Dutta Anjan Giri Sourendu Gupta Srubabati Goswami Namit Mahajan H. S. Mani A. Mukherjee Biswarup Mukhopadhyaya S. N. Nayak M. Randhawa Subhendu Rakshit Asim K. Ray Amitava Raychaudhuri D. P. Roy Probir Roy Suryadeep Roy Shiv Sethi G. Sigl Arunansu Sil N. Nimai Singh Mark Vagins Urjit Yagnik 《Pramana》2003,60(2):405-409
This is the report of neutrino and astroparticle physics working group at WHEPP-7. Discussions and work on CP violation in
long baseline neutrino experiments, ultra high energy neutrinos, supernova neutrinos and water Cerenkov detectors are discussed. 相似文献
15.
Traditional inventory models assume that a buyer places one order with a supplier in each order cycle. A large number of researchers have studied the benefits of dual sourcing such that an order quantity is split and placed simultaneously with two suppliers. We show that many of the benefits of dual sourcing are due to order splitting rather than using two suppliers. We investigate order splitting with one supplier such that the first part of the order is sent out immediately but the second part of the order is released later (scheduled-release). Through extensive computational results, we show that in many situations where dual sourcing or the use of a cheaper supplier would be cost effective, single sourcing with order splitting using scheduled-release orders is better. The paper provides a quantitative rationale to continue with one supplier. We also summarize the qualitative reasons to prefer single sourcing or multiple sourcing. 相似文献
16.
M K Parida Nita Sinha B Adhikary B Allanach A Alok K S Babu B Brahmachari D Choudhury E J Chun P K Das A Ghosal D Hitlin W S Hou S Kumar H N Li E Ma S K Majee G Majumdar B Mishra G Mohanty S Nandi H Pas M K Parida S D Rindani J P Saha N Sahu Y Sakai S Sen C Sharma C D Sharma S Shalgar N N Singh S Uma Sankar N Sinha R Sinha F Simonetto R Srikanth R Vaidya 《Pramana》2006,67(5):849-860
This is the report of flavor physics and model building working group at WHEPP-9. While activites in flavor physics have been
mainly focused on B-physics, those in model building have been primarily devoted to neutrino physics. We present summary of working group discussions
carried out during the workshop in the above fields, and also briefly review the progress made in some projects subsequently. 相似文献
17.
The adsorption of mercury(II) on potassium titanate has been studied in chloride media at different pH values, adsorbate concentrations and temperatures. Effect of different ligands and acid concentrations on the uptake was also investigated. Desoprtion studies were also done to check the reversibility of the process. Interestingly a more or less constant and high value of adsorption has been found at different temperatures, pH values and concentrations and a decrease in the uptake with an increase in the bulk acid concentration was observed. 相似文献
18.
19.
The heavy mesons of the charmonium and upsilon family are described in an alternative static potential model chosen in a combination of Hulthen and linear potential. We find that the quark-confining potential in the form of an equal admixture of vector and scalar parts successfully explains the fine-hyperfine structures of \(c\bar c\) and \(b\bar b\) systems in a flavour-independent manner. The leptonic decay widths of the vector mesons ofψ and γ families are calculated taking into account the Poggio-Schnitzer correction. We obtain some of the bound states of the yet-to-be observed \(t\bar t\) system for thet-quark mass ranging from 50 to 200 GeV. 相似文献
20.
Mishra SR Bachmann KT Bernstein RH Blair RE Foudas C Lefmann WC Leung WC Oltman E Quintas PZ Sciulli FJ Shaevitz MH Smith WH Merritt FS Oreglia MJ Schellman H Schumm BA Borcherding F Fisk HE Lamm MJ Marsh W Merritt KW Yovanovitch DD Bodek A Budd HS Sakumoto WK 《Physical review letters》1989,63(2):132-135