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排序方式: 共有549条查询结果,搜索用时 15 毫秒
151.
Dr. Raul Pereira Dr. Thibault Gendron Chandan Sanghera Hannah E. Greenwood Joseph Newcombe Dr. Patrick N. McCormick Dr. Kerstin Sander Prof. Dr. Maya Topf Prof. Dr. Erik Årstad Dr. Timothy H. Witney 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(9):2345-2351
Aldehyde dehydrogenases (ALDHs) catalyze the oxidation of aldehydes to carboxylic acids. Elevated ALDH expression in human cancers is linked to metastases and poor overall survival. Despite ALDH being a poor prognostic factor, the non-invasive assessment of ALDH activity in vivo has not been possible due to a lack of sensitive and translational imaging agents. Presented in this report are the synthesis and biological evaluation of ALDH1A1-selective chemical probes composed of an aromatic aldehyde derived from N,N-diethylamino benzaldehyde (DEAB) linked to a fluorinated pyridine ring either via an amide or amine linkage. Of the focused library of compounds evaluated, N-ethyl-6-(fluoro)-N-(4-formylbenzyl)nicotinamide 4 b was found to have excellent affinity and isozyme selectivity for ALDH1A1 in vitro. Following 18F-fluorination, [18F] 4 b was taken up by colorectal tumor cells and trapped through the conversion to its 18F-labeled carboxylate product under the action of ALDH. In vivo positron emission tomography revealed high uptake of [18F] 4 b in the lungs and liver, with radioactivity cleared through the urinary tract. Oxidation of [18F] 4 b , however, was observed in vivo, which may limit the tissue penetration of this first-in-class radiotracer. 相似文献
152.
David Schaffert Christina Troiber Eveline E. Salcher Thomas Frhlich Irene Martin Naresh Badgujar Christian Dohmen Daniel Edinger Raphaela Klger Gelja Maiwald Katarina Farkasova Silke Seeber Kerstin Jahn‐Hofmann Philipp Hadwiger Ernst Wagner 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2011,123(38):9149-9152
153.
The increasing global adoption of genetically modified (GM) plant derivatives in animal feed has provoked a strong demand for an appropriate detection method to evaluate the existence of transgenic protein in animal tissues and animal by-products derived from GM plant fed animals. A highly specific and sensitive sandwich enzyme immunoassay for the surveillance of transgenic Cry1Ab protein from Bt-maize in the blood plasma of cows fed on Bt-maize was developed and validated according to the criteria of EU-Decision 2002/657/EC. The sandwich assay is based on immuno-affinity purified polyclonal antibody raised against Cry1Ab protein in rabbits. Native and biotinylated forms of this antibody served as capture antibody and detection antibody for the ELISA, respectively. Streptavidin-horseradish peroxidase conjugate and TMB substrate provided the means for enzymatic colour development.The immunoassay allowed Cry1Ab protein determination in bovine blood plasma in an analytical range of 0.4-100 ng mL−1 with a decision limit (CCα) of 1.5 ng mL−1 and detection capability (CCβ) of 2.3 ng mL−1. Recoveries ranged from 89 to 106% (mean value of 98%) in spiked plasma.In total, 20 plasma samples from cows (n = 7) fed non-transgenic maize and 24 samples from cows (n = 8) fed transgenic maize (collected before and, after 1 and 2 months of feeding) were investigated for the presence of the Cry1Ab protein. There was no difference amongst both groups (all the samples were below 1.5 ng mL−1; CCα). No plasma sample was positive for the presence of the Cry1Ab protein at CCα and CCβ of the assay. 相似文献
154.
Surface acoustic wave biosensors: a review 总被引:2,自引:0,他引:2
This review presents an overview of 20 years of worldwide development in the field of biosensors based on special types of
surface acoustic wave (SAW) devices that permit the highly sensitive detection of biorelevant molecules in liquid media (such
as water or aqueous buffer solutions). 1987 saw the first approaches, which used either horizontally polarized shear waves
(HPSW) in a delay line configuration on lithium tantalate (LiTaO3) substrates or SAW resonator structures on quartz or LiTaO3 with periodic mass gratings. The latter are termed “surface transverse waves” (STW), and they have comparatively low attenuation
values when operated in liquids. Later Love wave devices were developed, which used a film resonance effect to significantly
reduce attenuation. All of these sensor approaches were accompanied by the development of appropriate sensing films. First
attempts used simple layers of adsorbed antibodies. Later approaches used various types of covalently bound layers, for example
those utilizing intermediate hydrogel layers. Recent approaches involve SAW biosensor devices inserted into compact systems
with integrated fluidics for sample handling. To achieve this, the SAW biosensors can be embedded into micromachined polymer
housings. Combining these two features will extend the system to create versatile biosensor arrays for generic lab use or
for diagnostic purposes.
SAW based biosensor immersed in a sample flow. Analyte molecules binding to the immobilized antibodies on the sensor surface
will influence the velocity of the SAW and hence the output signal generated by the driving electronics. 相似文献
155.
156.
Bollermann T Cadenbach T Gemel C Freitag K Molon M Gwildies V Fischer RA 《Inorganic chemistry》2011,50(12):5808-5814
The reactions of molybdenum(0) and rhodium(I) olefin containing starting materials with the carbenoid group 13 metal ligator ligand GaR (R = Cp*, DDP; Cp* = pentamethylcyclopentadienyl, DDP = HC(CMeNC(6)H(3)-2,6-(i)Pr(2))(2)) were investigated and compared. Treatment of [Mo(η(4)-butadiene)(3)] with GaCp* under hydrogen atmosphere at 100 °C yields the homoleptic, hexa coordinated, and sterically crowded complex [Mo(GaCp*)(6)] (1) in good yields ≥50%. Compound 1 exhibits an unusual and high coordinated octahedral [MoGa(6)] core. Similarly, [Rh(GaCp*)(5)][CF(3)SO(3)] (2) and [Rh(GaCp*)(5)][BAr(F)] (3) (BAr(F) = B{C(6)H(3)(CF(3))(2)}(4)) are prepared by the reaction of GaCp* with the rhodium(I) compound [Rh(coe)(2)(CF(3)SO(3))](2) (coe = cyclooctene) and subsequent anion exchange in case of 3. Compound 2 features a trigonal bipyramidal [RhGa(5)] unit. In contrast, reaction of excess Ga(DDP) with [Rh(coe)(2)(CF(3)SO(3))](2) does not result in a high coordinated homoleptic complex but instead yields [(coe)(toluene)Rh{Ga(DDP)}(CF(3)SO(3))] (4). The common feature of 2 and 4 in the solid state structure is the presence of short CF(3)SO(2)O···Ga contacts involving the GaCp* or rather the Ga(DDP) ligand. Compounds 1, 2, and 4 have been fully characterized by single crystal X-ray diffraction, variable temperature (1)H and (13)C NMR spectroscopy, IR spectroscopy, mass spectrometry, as well as elemental analysis. 相似文献
157.
Kerstin Kunz Michael Bolte Matthias Wagner Hans‐Wolfram Lerner Dr. 《无机化学与普通化学杂志》2009,635(11):1580-1584
The lithium tetrakis(methimazolyl)borate, Li[Bmt4], is accessible from the reaction of Li[BH4] with four equivalents of methimazole. The crystal structure of Li[Bmt4] supported by four water molecules is described. Reaction of Li[Bmt4] with [Ru(p‐cymene)Cl2]2 and subsequent treatment with NH4PF6 in CH3CN results in the formation of the complex [Ru(p‐cymene)(Bmt4)][PF6]. In addition, we report the result of the X‐ray structure analysis of the chiral Ru complex [Ru(p‐cymene)(Bmt4)][PF6]. 相似文献
158.
159.
160.
Kerstin Strupat Viatcheslav Kovtoun Huy Bui Rosa Viner George Stafford Stevan Horning 《Journal of the American Society for Mass Spectrometry》2009,20(8):1451-1463
A MALDI source is interfaced to a modified LTQ Orbitrap XL instrument. This work gives insight into the MALDI source design
and shows results obtained with the MALDI source coupled to an accurate mass, high-resolution hybrid mass spectrometer. MALDI-produced
ions and fragment ions thereof produced in the mass spectrometer may be analyzed and detected by the Orbitrap analyzer at
a maximum mass resolution of 100,000 (FWHM) at m/z 400 with high mass accuracy. An accuracy of ≤2 ppm is achieved by internal mass calibration using lock mass functionality;
using external mass calibration, an accuracy of ≤3 ppm is routinely obtained. External mass calibration of the hybrid mass
spectrometer is performed using a standard calibration mixture of different peptides and matrix components. The instrumental
capabilities are demonstrated for analytical methodologies such as Protein ID using Peptide Mass Fingerprint (PMF) and MS/MS
analyses of small molecule samples. Stability of mass accuracy and signal-to-noise ratio for low samples loads (on plates)
are demonstrated as well as the experimental dynamic range using α-cyano-4-hydroxy cinnamic acid (CHCA) matrix. 相似文献