全文获取类型
收费全文 | 772篇 |
免费 | 25篇 |
国内免费 | 1篇 |
专业分类
化学 | 526篇 |
晶体学 | 17篇 |
力学 | 16篇 |
数学 | 44篇 |
物理学 | 195篇 |
出版年
2023年 | 3篇 |
2021年 | 7篇 |
2019年 | 12篇 |
2018年 | 12篇 |
2017年 | 7篇 |
2016年 | 11篇 |
2015年 | 16篇 |
2014年 | 15篇 |
2013年 | 28篇 |
2012年 | 36篇 |
2011年 | 42篇 |
2010年 | 19篇 |
2009年 | 18篇 |
2008年 | 51篇 |
2007年 | 39篇 |
2006年 | 23篇 |
2005年 | 30篇 |
2004年 | 34篇 |
2003年 | 27篇 |
2002年 | 31篇 |
2001年 | 19篇 |
2000年 | 21篇 |
1999年 | 15篇 |
1998年 | 14篇 |
1997年 | 7篇 |
1996年 | 11篇 |
1995年 | 16篇 |
1994年 | 14篇 |
1993年 | 10篇 |
1992年 | 18篇 |
1991年 | 12篇 |
1990年 | 13篇 |
1989年 | 15篇 |
1988年 | 13篇 |
1987年 | 12篇 |
1986年 | 14篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 5篇 |
1980年 | 8篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 4篇 |
1976年 | 9篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1973年 | 3篇 |
1967年 | 4篇 |
排序方式: 共有798条查询结果,搜索用时 15 毫秒
791.
792.
793.
Kazunobu Sugihara Sachiko Kaidzu Masahiro Sasaki Sho Ichioka Yuji Takayanagi Hiroshi Shimizu Ichiya Sano Katsunori Hara Masaki Tanito 《Photochemistry and photobiology》2023,99(3):967-974
Two krypton-chloride germicidal excimer lamp units (Care222 TRT-104C11-UI-U3, USHIO Inc.) were installed in the examination room of an ophthalmology department. The irradiation dose was set not to exceed the former (i.e., before 2022) threshold limit value (TLV) (22 mJ cm−2/8 h) recommended by the ACGIH. Section 1: The eyes and lids of the six ophthalmologists (5 wore glasses for myopic correction) who worked in the room for a mean stay of 6.7 h week−1 were prospectively observed for 12 months. Slitlamp examinations revealed neither acute adverse events such as corneal erosion, conjunctival hyperemia, and lid skin erythema nor chronic adverse events such as pterygium, cataract, or lid tumor. The visual acuity, refractive error, and corneal endothelial cell density remained unchanged during the study. Section 2: The irradiation of samples placed on the table or floor using the same fixtures in the room (5–7.5 mJ cm−2) was associated with >99% inhibition of φX174 phage and >90% inhibition of Staphylococcus aureus. In conclusion, no acute or chronic health effects in human participants was observed in a clinical setting of full-room ultraviolet germicidal irradiation by 222-nm lamp units, and high efficacy in deactivation of microorganisms was determined in the same setting. 相似文献
794.
795.
796.
797.
C.‐H. Ahn M. Tahara T. Uozumi J. Jin S. Tsubaki T. Sano K. Soga 《Macromolecular rapid communications》2000,21(7):385-389
The polymerization of 2‐butene and its copolymerization with ethylene have been investigated using four kinds of dichlorobis(β‐diketonato)titanium complexes, [ArN(CH2)3NAr]TiCl2 (Ar = 2,6‐iPr2C6H3) and typical metallocene catalysts. The obtained copolymers display lower melting points than those produced of homopolyethylene under the same polymerization conditions. 13C NMR analysis indicates that 9.3 mol‐% of 2‐butene units were incorporated into the polymer chains with Ti(BFA)2Cl2‐MAO as the catalyst system. With the trans‐2‐butene a higher copolymerization rate was observed than with cis‐2‐butene. A highly regioselective catalyst system for propene polymerization, [ArN(CH2)3NAr]TiCl2 complex using a mixture of triisobutylaluminium and Ph3CB(C6F5)4 as cocatalyst, was found to copolymerize a mixture of 1‐butene and trans‐2‐butene with ethylene up to 3.1 mol‐%. Monomer isomerization‐polymerization proceeds with typical metallocene catalysts to produce copolymers consisting of ethylene and 1‐butene. 相似文献
798.
Yuzo Kaneko Kiyotaka Sakai Akihiko Kikuchi Yasuhisa Sakurai Teruo Okano 《Macromolecular Symposia》1996,109(1):41-53
The synthesis and characterization of comb-type grafted thermo-sensitive hydrogels is presented. These hydrogels were synthesized by polymerization of N-isopropylacrylamide (IPAAm) with a PIPAAm macromonomer. This process leads to a crosslinked IPAAm backbone polymer, copolymerized with highly mobile comb-type PIPAAm chains. These new thermo-responsive copolymers displayed higher equilibrium swellings at lower temperatures and rapid deswelling kinetics at elevated temperatures. The swelling/deswelling for comb-type gels is dependent on the graft chain lengths, in contrast to normal PIPAAm gel lacking the graft chains. As the temperature is increased above the critical temperature, the dehydrated graft chains aggregated due to hydrophobic attraction. Rapid and reversible kinetics of the graft-type gel were observed in response to stepwise temperature changes within short time cycles: phenomena not observed in normal crosslinked thermo-sensitive gels. The influence of freely mobile graft chains on both the equilibrium and dynamic properties of comb-type PIPAAm gel is demonstrated. Possible application of graft-type gel is discussed for actuator systems. 相似文献