全文获取类型
收费全文 | 384篇 |
免费 | 14篇 |
国内免费 | 4篇 |
专业分类
化学 | 258篇 |
晶体学 | 5篇 |
力学 | 2篇 |
数学 | 36篇 |
物理学 | 101篇 |
出版年
2021年 | 3篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 7篇 |
2014年 | 13篇 |
2013年 | 17篇 |
2012年 | 10篇 |
2011年 | 9篇 |
2010年 | 21篇 |
2009年 | 14篇 |
2008年 | 19篇 |
2007年 | 15篇 |
2006年 | 17篇 |
2005年 | 18篇 |
2004年 | 34篇 |
2003年 | 16篇 |
2002年 | 16篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1973年 | 6篇 |
1969年 | 2篇 |
1968年 | 6篇 |
1967年 | 3篇 |
1966年 | 2篇 |
排序方式: 共有402条查询结果,搜索用时 985 毫秒
31.
Dr. Yuki Kishimoto Dr. Osamu Nakagawa Akane Fujii Dr. Kotaro Yoshioka Dr. Tetsuya Nagata Prof. Dr. Takanori Yokota Prof. Dr. Yoshiyuki Hari Prof. Dr. Satoshi Obika 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(7):2427-2438
Artificial nucleic acids are widely used in various technologies, such as nucleic acid therapeutics and DNA nanotechnologies requiring excellent duplex-forming abilities and enhanced nuclease resistance. 2′-O,4′-C-Methylene-bridged nucleic acid/locked nucleic acid (2′,4′-BNA/LNA) with 1,3-diaza-2-oxophenoxazine (BNAP ( BH )) was previously reported. Herein, a novel BH analogue, 2′,4′-BNA/LNA with 9-(2-aminoethoxy)-1,3-diaza-2-oxophenoxazine (G-clamp), named BNAP-AEO ( BAEO ), was designed. The BAEO nucleoside was successfully synthesized and incorporated into oligodeoxynucleotides (ODNs). ODNs containing BAEO possessed up to 104-, 152-, and 11-fold higher binding affinities for complementary (c) RNA than those of ODNs containing 2′-deoxycytidine ( C ), 2′,4′-BNA/LNA with 5-methylcytosine ( L ), or 2′-deoxyribonucleoside with G-clamp ( PAEO ), respectively. Moreover, duplexes formed by ODN bearing BAEO with cDNA and cRNA were thermally stable, even under molecular crowding conditions induced by the addition of polyethylene glycol. Furthermore, ODN bearing BAEO was more resistant to 3′-exonuclease than ODNs with phosphorothioate linkages. 相似文献
32.
33.
Chilling resistances of isolates of Pythium ultimum var. ultimum from the Arctic and Temperate Zones
Hoshino T Tojo M Kanda H Herrero ML Tronsmo AM Kiriaki M Yokota Y Yumoto I 《Cryo letters》2002,23(3):151-156
Chilling resistances in moss pathogenic fungi, Pythium ultimum var. ultimum, from Longyearbyen, Svalbard (78 degree N, 15 degree E), located in the Arctic Zone and in the same isolates from Temperate Zone, were determined. Both strains had similar optimum growth temperatures. However, the strains from Svalbard could grow and survive at 0 - 5 degrees C. In addition, chilling treatment induced irregular mycelial morphology in the Arctic isolates. On the other hand, the isolates from Japan did not grow at temperatures below 5C and were destroyed after chilling stress (0 degree C for 3 days or at 4 degrees C for 1 week). The results suggested that isolates from Svalbard highly adapted to the severe spring condition in Polar environments. 相似文献
34.
35.
36.
Shibata T Fujimoto T Yokota K Takagi K 《Journal of the American Chemical Society》2004,126(27):8382-8383
An asymmetric [2+2+2] cycloaddition of an alpha,omega-diyne, possessing ortho-substituted aryl groups on its terminus, and a monoalkyne with oxygen functionalities gave various axially chiral teraryl compounds. The coupling proceeded with extremely high enantio- (>99.5% ee) and diastereoselectivities (dl/meso = >95/5) when catalyzed by an iridium-chiral phosphine complex. As the products were readily transformed into diol compounds by deprotection without racemization, the present procedure provides access to a new chiral pool of diol compounds with C2 symmetry. 相似文献
37.
Yao G Fang X Yokota H Yanagida T Tan W 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(22):5686-5692
We have monitored the reaction dynamics of the DNA hybridization process on a liquid/solid interface at the single-molecule level by using a hairpin-type molecular beacon DNA probe. Fluorescence images of single DNA probes were recorded by using total internal reflection fluorescence microscopy. The fluorescence signal of single DNA probes during the hybridization to individual complementary DNA probes was monitored over time. Among 400 molecular beacon DNA probes that we tracked, 349 molecular beacons (87.5 %) were hybridized quickly and showed an abrupt fluorescence increase, while 51 probes (12.5 %) reacted slowly, resulting in a gradual fluorescence increase. This ratio stayed about the same when varying the concentrations of cDNA in MB hybridization on the liquid/surface interface. Statistical data of the 51 single-molecule hybridization images showed that there was a multistep hybridization process. Our results also showed that photostability for the dye molecules associated with the double-stranded hybrids was better than that for those with the single-stranded molecular beacon DNA probes. Our results demonstrate the ability to obtain a better understanding of DNA hybridization processes using single-molecule techniques, which will improve biosensor and biochip development where surface-immobilized molecular beacon DNA probes provide unique advantages in signal transduction. 相似文献
38.
Thermo-responsive cellulosic nanolayers were prepared from methylcellulose (MC), which is known to have a unique lower critical solution temperature. Thiosemicarbazide (TSC) was selectively introduced into the MC reducing end groups, and the corresponding MC-TSC derivative was spontaneously chemisorbed on an Au substrate at 4 °C to give MC self-assembled monolayers (SAMs). Linear MC chains were stably fixed onto the Au substrate, yielding an MC-SAM of thickness ca. 15 nm with a root mean square value less than 1 nm. The MC-SAM surface exhibited thermally responsive wetting characteristics; the water contact angle was found to rise and fall around 70 °C, possibly due to the solid-state phase transition of the MC nanolayers resulting from the inherent gelation of MC molecules in water. Such wetting behavior was shown to be reversible following repeated heating and cooling. The MC-SAM immersed in salt solution revealed lower phase transition temperatures, and an increase in sodium chloride concentration ranging from 0.0 to 1.0 M brought about a dramatic decrease in the apparent phase transition temperature from ca. 70 to 30 °C. For the purposely designed MC nanolayers, such controllable wetting properties are expected to prompt growing interest in the applications of cellulosic biopolymer interfaces. 相似文献
39.
Takumi Yokota 《Geometriae Dedicata》2008,133(1):169-179
In this paper, we consider the behavior of the total absolute and the total curvature under the Ricci flow on complete surfaces
with bounded curvature. It is shown that they are monotone non-increasing and constant in time, respectively, if they exist
and are finite at the initial time. As a related result, we prove that the asymptotic volume ratio is constant under the Ricci
flow with non-negative Ricci curvature, at the end of the paper.
相似文献
40.
Dave Witte Akihiko Yukie Roger Zierau 《Transactions of the American Mathematical Society》2000,352(4):1687-1708
We apply M. Ratner's theorem on closures of unipotent orbits to the study of three families of prehomogeneous vector spaces. As a result, we prove analogues of the Oppenheim Conjecture for simultaneous approximation by values of certain alternating bilinear forms in an even number of variables and certain alternating trilinear forms in six and seven variables.