全文获取类型
收费全文 | 616篇 |
免费 | 26篇 |
国内免费 | 7篇 |
专业分类
化学 | 485篇 |
晶体学 | 3篇 |
力学 | 23篇 |
数学 | 77篇 |
物理学 | 61篇 |
出版年
2023年 | 3篇 |
2022年 | 10篇 |
2021年 | 13篇 |
2020年 | 16篇 |
2019年 | 17篇 |
2018年 | 6篇 |
2017年 | 12篇 |
2016年 | 25篇 |
2015年 | 20篇 |
2014年 | 16篇 |
2013年 | 35篇 |
2012年 | 28篇 |
2011年 | 54篇 |
2010年 | 29篇 |
2009年 | 35篇 |
2008年 | 47篇 |
2007年 | 39篇 |
2006年 | 35篇 |
2005年 | 18篇 |
2004年 | 25篇 |
2003年 | 23篇 |
2002年 | 12篇 |
2001年 | 7篇 |
2000年 | 9篇 |
1999年 | 9篇 |
1998年 | 6篇 |
1997年 | 12篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1975年 | 4篇 |
1971年 | 2篇 |
1969年 | 2篇 |
1967年 | 3篇 |
1943年 | 2篇 |
排序方式: 共有649条查询结果,搜索用时 291 毫秒
641.
642.
Jinbo Zhu Zhiqiang Yan Filip Bokovi Cally J. E. Haynes Marion Kieffer Jake L. Greenfield Jin Wang Jonathan R. Nitschke Ulrich F. Keyser 《Chemical science》2021,12(43):14564
Since the discovery of the G-quadruplex (G4) structure in telomeres in 1980s, studies have established the role it plays in various biological processes. Here we report binding between DNA G4 and a self-assembled tetrahedral metal-organic cage 1 and consequent formation of aggregates, whereby the cage protects the DNA G4 from cleavage by S1 nuclease. We monitor DNA–cage interaction using fluorescence spectroscopy, firstly by quenching of a fluorescent label appended to the 5′ end of G4. Secondly, we detect the decrease in fluorescence of the G4-selective dyes thioflavin-T and Zn-PPIX bound to various DNA G4 sequences following the addition of cage 1. Our results demonstrate that 1 interacts with a wide range of G4s. Moreover, gel electrophoresis, circular dichroism and dynamic light scattering measurements establish the binding of 1 to G4 and indicate the formation of aggregate structures. Finally, we find that DNA G4 contained in an aggregate of cage 1 is protected from cleavage by S1 nuclease.We find FeII4L4 binds to G-quadruplex and forms aggregates. G-quadruplex in the aggregates is protected from digestion by S1 nuclease. 相似文献
643.
644.
645.
Marion Pommet Andréas Redl Marie-Hélène Morel Sandra Domenek Stéphane Guilbert 《Macromolecular Symposia》2003,197(1):207-218
Proteins, as heteropolymers, offer a large range of possible interactions and chemical reactions. The thermoplastic behavior of proteins has been studied in order to produce bioplastics by thermal or thermomechanical processes such as mixing, extrusion or hot molding. The extrusion trials were performed by using a co-rotating twin-screw extruder, recording torque, temperature and die pressure. Batch mixing was done in a two blade counter-rotating mixer, with continuous recording of torque and product temperature. Proteins were alternatively extruded, mixed or hot molded under a large range of processing conditions. Protein aggregation during each process was estimated from the accumulation of SDS-insoluble protein fraction. Protein aggregation evidences a cross-linking reaction the activation energy of which was dependent on the thermoplastic process used. The increase in network density appears to be induced by the severity of the treatment: temperature and shear strongly affect the structural characteristics of the protein-based bioplastics. 相似文献
646.
Ralph J.S. van Mechelen Jarno E.J. Wolters Sebastian Fredrich Christian J.F. Bertens Marion J.J. Gijbels Albert P.H.J. Schenning Leonard Pinchuk Theo G.M.F. Gorgels Henny J.M. Beckers 《Macromolecular bioscience》2023,23(10):2300075
Fibrosis of the filtering bleb is one of the main causes of failure after bleb-forming glaucoma surgery. Intraoperative application of mitomycin C (MMC) is the current gold standard to reduce the fibrotic response. However, MMC is cytotoxic and one-time application is often insufficient. A sustained-release drug delivery system (DDS), loaded with MMC, may be less cytotoxic and equally or more effective. Two degradable (polycaprolactone (PCL) and polylactic-co-glycolic acid (PLGA)) MMC-loaded DDSs are developed. Release kinetics are first assessed in vitro followed by rabbit implants in conjunction with the PRESERFLO MicroShunt. As a control, the MicroShunt is implanted with adjunctive use of a MMC solution. Rabbits are euthanized at postoperative day (POD) 28 and 90. The PLGA and PCL DDSs release (on average) 99% and 75% of MMC, respectively. All groups show functioning blebs until POD 90. Rabbits implanted with a DDS show more inflammation with avascular thin-walled blebs when compared to the control. However, collagen is more loosely arranged. The PLGA DDS shows less inflammation, less foreign body response (FBR), and more complete degradation at POD 90 when compared to the PCL DDS. Further optimization with regard to dosage is required to reduce side effects to the conjunctiva. 相似文献
647.
Colorless lath-shaped single crystals of the title compound are obtained from a melt of Y2O3, YF3, and SiO2 (2:5:3 molar ratio) using CsCl as a flux (evacuated silica tube, 973 K, 9 d, 10 K/h cooling rate). 相似文献
648.
Marion Helou Olivier Miserque Jean‐Michel Brusson Jean‐Franois Carpentier Sophie M. Guillaume 《Macromolecular rapid communications》2009,30(24):2128-2135
α,ω‐Dihydroxy‐telechelic poly(trimethylenecarbonate), HO‐PTMC‐OH, is synthesized from the controlled “immortal” ring‐opening polymerization (ROP) of trimethylene carbonate under mild conditions (bulk, 60 °C), using ZnEt2 or, more efficiently, [(BDI)Zn(N(SiMe3)2)] (BDI = CH(CMeNC6H3‐2,6‐iPr2)2) as catalyst precursor, in the presence of a diol HO‐R‐OH (R = (CH2)2 or CH2C6H4CH2; 0.5–10 equiv. vs Zn) acting both as co‐initiator and chain transfer agent. Alternatively, HO‐PTMC‐OH is prepared upon hydrogenolysis of HO‐PTMC‐OCH2Ph, initially prepared from the ROP of TMC using the [(BDI)Zn(N(SiMe3)2)]/PhCH2OH system, under smooth operating conditions using Pd/charcoal. Well‐defined dihydroxy‐functionalized PTMCs of molar mass ranging from = 2 000 to 109 500 g · mol−1 were thus quantitatively obtained and fully characterized by NMR, MALDI‐TOF‐MS and SEC analyses. The versatility of this “immortal” ROP allows the preparation of alike α,ω‐functional polyester such as linear HO‐poly(lactide)‐OH, as well as star polymers such as the glycerol‐based PTM‐OH3.
649.