全文获取类型
收费全文 | 658篇 |
免费 | 22篇 |
国内免费 | 3篇 |
专业分类
化学 | 528篇 |
晶体学 | 2篇 |
力学 | 3篇 |
数学 | 63篇 |
物理学 | 87篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 12篇 |
2019年 | 8篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 15篇 |
2015年 | 8篇 |
2014年 | 20篇 |
2013年 | 25篇 |
2012年 | 36篇 |
2011年 | 45篇 |
2010年 | 30篇 |
2009年 | 24篇 |
2008年 | 43篇 |
2007年 | 40篇 |
2006年 | 44篇 |
2005年 | 33篇 |
2004年 | 26篇 |
2003年 | 28篇 |
2002年 | 28篇 |
2001年 | 13篇 |
2000年 | 15篇 |
1999年 | 11篇 |
1998年 | 12篇 |
1997年 | 10篇 |
1996年 | 14篇 |
1995年 | 9篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 11篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 2篇 |
1981年 | 9篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有683条查询结果,搜索用时 15 毫秒
661.
Marini RD Groom C Doucet FR Hawari J Bitar Y Holzgrabe U Gotti R Schappler J Rudaz S Veuthey JL Mol R Somsen GW de Jong GJ Ha PT Zhang J Van Schepdael A Hoogmartens J Briône W Ceccato A Boulanger B Mangelings D Vander Heyden Y Van Ael W Jimidar I Pedrini M Servais AC Fillet M Crommen J Rozet E Hubert P 《Electrophoresis》2006,27(12):2386-2399
662.
663.
Raubenheimer HG Esterhuysen MW Frenking G Timoshkin AY Esterhuysen C Horvath UE 《Dalton transactions (Cambridge, England : 2003)》2006,(38):4580-4589
Deprotonated Fischer-type aminocarbene complexes, (CO)5M=C(NR2)CH3 (M = Cr or W; R = Me or propyl), react with Ph3PAu+ by metal group substitution - (CO)5M for Ph3PAu+--and attachment of the extricated M(CO)5 to the deprotonated methyl group. (The products may also be seen as aminovinylgold compounds coordinated to M(CO)5 moieties.) DFT calculations at the B3LYP level of theory using model compounds indicate a clear preference of the gold unit for central C to terminal coordination in the ligand [NMe2CCH2]-, whereas the Cr(CO)5 has a 7 kcal mol(-1) preference for C(vinyl) coordination compared to N-coordination. In related thiocarbenes, the sulfur donor atom should be the preferred point of attachment for the metal carbonyl unit. The latter prediction is borne out in practice, and in the three products isolated, including Ph3PAu{C(=CH2)SPh}Cr(CO)5 in a mixed crystal with [Ph3PAuSPh]Cr(CO)5, precisely this coordination mode is present. The latter component of the mixed crystal has also been prepared independently of the vinyl one. 相似文献
664.
Khan AS Mujer CV Alefantis TG Connolly JP Mayr UB Walcher P Lubitz W Delvecchio VG 《Journal of chemical information and modeling》2006,46(1):111-115
The potential devastation resulting from an intentional outbreak caused by biological warfare agents such as Brucella abortus and Bacillus anthracis underscores the need for next generation vaccines. Proteomics, genomics, and systems biology approaches coupled with the bacterial ghost (BG) vaccine delivery strategy offer an ideal approach for developing safer, cost-effective, and efficacious vaccines for human use in a relatively rapid time frame. Critical to any subunit vaccine development strategy is the identification of a pathogen's proteins with the greatest potential of eliciting a protective immune response. These proteins are collectively referred to as the pathogen's immunome. Proteomics provides high-resolution identification of these immunogenic proteins using standard proteomic technologies, Western blots probed with antisera from infected patients, and the pathogen's sequenced and annotated genome. Selected immunoreactive proteins can be then cloned and expressed in nonpathogenic Gram-negative bacteria. Subsequently, a temperature shift or chemical induction process is initiated to induce expression of the PhiX174 E-lysis gene, whose protein product forms an E tunnel between the inner and outer membrane of the bacteria, expelling all intracellular contents. The BG vaccine system is a proven strategy developed for many different pathogens and tested in a complete array of animal models. The BG vaccine system also has great potential for producing multiagent vaccines for protection to multiple species in a single formulation. 相似文献
665.
Gross JH Nieth N Linden HB Blumbach U Richter FJ Tauchert ME Tompers R Hofmann P 《Analytical and bioanalytical chemistry》2006,386(1):52-58
Liquid injection field desorption/ionization (LIFDI) has been applied to identify transition metal complexes that are highly
reactive to air and moisture by mass spectrometry. The complexes of nickel and rhodium were supplied as dilute solutions (∼0.2 mg
ml−1) in toluene, tetrahydrofuran or acetonitrile, and were applied onto the field desorption emitter inside the vacuum of the
ion source under inert conditions by means of the injection capillary unique to the LIFDI set-up. LIFDI mass spectrometry
on a double-focusing magnetic sector instrument provided spectra exhibiting intense molecular ion peaks for the species investigated
or signals that could easily be related to the target compound by assuming neutral loss of the weakest-bound ligand. Eventually,
byproducts of the synthesis or other components resulting from incomplete reactions or some degree of decomposition were also
detected.
Dedicated to Prof. J. J. Veith on the occasion of his 65th birthday. 相似文献
666.
667.
Ehrlich G Hassfeld J Eggert U Kalesse M 《Journal of the American Chemical Society》2006,128(43):14038-14039
The first total synthesis of the (+)-tedanolide is described. Pivotal steps are the Felkin-selective aldol coupling between C12 and C13 and an efficient Mitsunobu macrolactonization. Selective protecting group transformations and subsequent oxidations generate the macrocyclic triketone. In the endgame of the synthesis, four TBS groups are removed in one reaction and a chemo- and stereoselective final step epoxidation generates (+)-tedanolide. 相似文献
668.
Pikul AP Stockert U Steppke A Cichorek T Hartmann S Caroca-Canales N Oeschler N Brando M Geibel C Steglich F 《Physical review letters》2012,108(6):066405
Thermodynamic and transport properties of the La-diluted Kondo lattice CeNi(2)Ge(2) were studied in a wide temperature range. The Ce-rich alloys Ce(1-x)La(x)Ni(2)Ge(2) were found to exhibit distinct features of the coherent heavy Fermi liquid. At intermediate compositions (0.7≤x≤0.9), non-Fermi liquid properties have been observed, followed by the local Fermi liquid behavior in the dilute limit. The 4f-electron contribution to the specific heat was found to follow the predictions of the Kondo-impurity model in both the local as well as the coherent regimes, with the characteristic Kondo temperature decreasing rapidly from about 30 K for the parent compound CeNi(2)Ge(2) to about 1 K in the most dilute samples. The specific heat does not show any evidence for the emergence of a new characteristic energy scale related to the formation of the coherent Kondo lattice. 相似文献
669.
Erick M. Larramendi Z-B Karla Gutiérrez Osvaldo de Melo Ulrike Woggon Detlef Schikora Klaus Lischka 《Journal of Crystal Growth》2010,312(11):1807-1812
The use of a selenium–tellurium (SeTe) mixed source in the isothermal close space sublimation growth of CdSe epilayers is considered. The epitaxial growth was performed in flowing helium by sequential exposures of the substrate to vapors of the mixed SeTe source and elemental cadmium at temperatures within 350–410 °C. In spite of the mixed source (proposed to decrease the partial pressure of Se), tellurium incorporation was small and CdSexTe(1−x) (x∼0.98) epilayers were obtained. X-ray diffraction reciprocal space mapping shows the existence of hexagonal inclusions mainly on the (1 1 1) facets of the cubic phase. Material deposition on areas of the graphite crucible exposed to the sources, contamination of the Cd source and large growth rates suggest the existence of a selenium transport process via graphite. This transport might be the result of the combination of selenium deposition on graphite with a subsequent activated desorption of selenium under cadmium exposure. It affects Cd source purity and growth kinetic bringing on a modification of the usual atomic layer deposition regimen; however, a reproducible growth rate of the epilayers was obtained. 相似文献
670.
Daniel Hemmeter Ulrike Paap Dr. Nicola Taccardi Dr. Julian Mehler Dr. Peter S. Schulz Prof. Dr. Peter Wasserscheid Dr. Florian Maier Prof. Dr. Hans-Peter Steinrück 《Chemphyschem》2023,24(2):e202200391
We studied the formation and surface behavior of Pt(II) and Pd(II) complexes with ligand systems derived from two nitrile-functionalized ionic liquids (ILs) in solution using angle-resolved X-ray photoelectron spectroscopy (ARXPS). These ligand systems enabled a high solubility of the metal complexes in IL solution. The complexes were prepared by simple ligand substitution under vacuum conditions in defined excess of the coordinating ILs, [C3CNC1Im][Tf2N] and [C1CNC1Pip][Tf2N], to immediately yield solutions of the final products. The ILs differ in the cationic head group and the chain length of the functionalized substituent. Our XPS measurements on the neat ILs gave insights in the electronic properties of the coordinating substituents revealing differences in donation capability and stability of the complexes. Investigations on the composition of the outermost surface layers using ARXPS revealed no surface affinity of the nitrile-functionalized chains in the neat ILs. Solutions of the formed complexes in the nitrile ILs showed homogeneous distribution of the solute at the surface with the heterocyclic moieties preferentially orientated towards the vacuum, while the metal centers are rather located further away from the IL/vacuum interface. 相似文献