全文获取类型
收费全文 | 173篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学 | 73篇 |
力学 | 4篇 |
数学 | 47篇 |
物理学 | 53篇 |
出版年
2021年 | 2篇 |
2016年 | 6篇 |
2014年 | 6篇 |
2013年 | 10篇 |
2012年 | 9篇 |
2011年 | 8篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1998年 | 8篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1976年 | 5篇 |
1970年 | 3篇 |
1935年 | 1篇 |
1930年 | 2篇 |
1929年 | 1篇 |
1928年 | 1篇 |
1927年 | 1篇 |
1926年 | 4篇 |
1925年 | 2篇 |
1924年 | 1篇 |
1923年 | 1篇 |
1922年 | 1篇 |
1920年 | 1篇 |
1918年 | 1篇 |
1916年 | 1篇 |
1913年 | 1篇 |
1911年 | 2篇 |
1910年 | 1篇 |
1890年 | 1篇 |
排序方式: 共有177条查询结果,搜索用时 15 毫秒
71.
Konrad Knopp 《Mathematische Annalen》1926,95(1):409-426
Ohne Zusammenfassung 相似文献
72.
Konrad Knopp 《Mathematische Zeitschrift》1930,31(1):276-305
Ohne Zusammenfassung 相似文献
73.
H. -J. Simonis F. Hagelberg M. Knopp K. -H. Speidel W. Karle J. Gerber 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1987,7(3):233-237
Effective transient magnetic fields have been measured for S ions traversing thin ferromagnetic foils of Fe, Ni and Gd at mean velocities of 8.0v 0 (v 0 =c/137). The deduced polarizations attached to 1s electrons are discussed together with all data available for light ions considering spin exchange scattering as polarization mechanism. 相似文献
74.
Sázelová P Kasicka V Koval D Kilár F Knopp D Peltre G 《Journal of chromatography. A》2003,990(1-2):303-309
Application of capillary isotachophoresis (CITP) for the analysis of water extracts of the dust samples collected in different periods in air-filtration devices in Prague car traffic tunnels and in Parisian metro station is presented. The extracts were analyzed in cationic mode with a leading electrolyte (LE) of 10 mM KOH, 25 mM acetic acid, pH 4.4, and a terminating electrolyte (TE) of 10 mM β-alanine, adjusted to pH 4.4 with acetic acid, and in anionic mode with LE 10 mM HCl, 20 mM histidine, pH 5.8 and TE 10 mM 2-(N-morpholino)ethanesulphonic acid, pH 3.7. Extracted amounts of UV-absorbing substances, including pollen allergens and organic pollutants, the number of the found components and concentrations of some inorganic ions (e.g. Cl−, K+, Na+, Ca2+) in the dust samples were determined. It was found that the extracted amounts of anionic components and their number were much higher than those of cationic components. Significant differences have been found in the analyses of the extracts of different origin. Much more material and more components were present in the extracts of samples from the pollen-rich period than from the pollen-free period, especially in anionic CITP mode. 相似文献
75.
T. Knopp D. Schanz A. Schröder M. Dumitra C. Cierpka R. Hain C. J. Kähler 《Flow, Turbulence and Combustion》2014,92(1-2):451-471
We present an experimental investigation of a turbulent boundary layer flow at a significant adverse pressure gradient at Reynolds number Re θ ?=?10000 using large field PIV. The testcase is designed to start from a zero pressure gradient flow at Re θ ?=?8000 with a distinct log-law region following a slowly rising adverse pressure gradient. This allows to reveal a breakdown of the log-law under the effect of the adverse pressure gradient. The region described by the log-law is progressively reduced in terms of y ?+? and then joins into a modified log-law which gives a good fit to the data up to at least y/δ 99?≈?0.2. The scaling in the overlap region is demonstrated using the mean velocity slope diagnostic function, enabled due to the high quality of the PIV data. Locally, the velocity profile is measured down to the wall using long-range microscopic PIV with particle tracking velocimetry to determine the wall shear stress directly in the adverse pressure gradient region. 相似文献
76.
77.
K.-H. Speidel G.J. Kumbartzki W. Knauer M. Knopp V. Mertens P.N. Tandon J. Gerber R.M. Freeman 《Physics letters. [Part B]》1981,102(1):6-8
Transient field (TF) precessions of the first excited 2+ state in 24,26Mg have yielded g = +0.50 (13) for 26Mg. Contrary to an earlier measurement the present data is in good agreement with Hartree-Fock calculations. The large effective TF of 280 (30) T at Mg nuclei for νion ≈ 2.0 ν0 is attributed to K-shell polarization of the ions. 相似文献
78.
Jia G Takayama Y Flanigan DC Kaeding CC Zhou J Chaudhari A Clark D Sammet S Liang J Choi S Knopp MV 《Magnetic resonance imaging》2011,29(3):335-341
Purpose
To establish the feasibility of chemical exchange saturation transfer (proteinCEST) MRI in the differentiation of osteoarthritis (OA) knee joints from non-OA joints by detecting mobile protein and peptide levels in synovial fluid by determining their relative distribution.Materials and Methods
A total of 25 knees in 11 men and 12 women with knee injuries were imaged using whole knee joint proteinCEST MRI sequence at 3 T. The joint synovial fluid was segmented and the asymmetric magnetization transfer ratio at 3.5 ppm MTRasym (3.5 ppm) was calculated to assess protein content in the synovial fluid. The 85th percentile of synovial fluid MTRasym (3.5 ppm) distribution profile was compared using the independent Student's t test. The diagnostic performance of the 85th percentile of synovial fluid MTRasym (3.5 ppm) in differentiating OA and non-OA knee joints was evaluated.Results
The 85th percentile of synovial fluid MTRasym (3.5 ppm) in knee joints with OA was 8.6%±3.4% and significantly higher than that in the knee joints without OA (6.3%±1.4%, P<.05). A knee joint with an 85th percentile of synovial fluid MTRasym (3.5 ppm) greater than 7.7% was considered to be an OA knee joint. With the threshold, the sensitivity, specificity and overall accuracy for differentiating knee joints with OA from the joints without OA were 54% (7/13), 92% (11/12) and 72% (18/25), respectively.Conclusion
proteinCEST MRI appears feasible as a quantitative methodology to determine mobile protein levels in synovial fluid and identify patterns characteristic for OA disease. 相似文献79.
A sensitive electrochemical approach for the detection of thrombin was designed by using densely packed hierarchical dendritic gold microstructures (HDGMs) with secondary and tertiary branches as matrices, and thionine-functionalized mesoporous silica nanospheres as signal tags. To prepare the signal tags, the positively charged thionine (as an indicator) was initially adsorbed onto the mesoporous silica nanoparticles (MSNs). Then [AuCl4]− ions were in situ reduced on the thionine-modified MSNs by ascorbic acid to construct nanogold-decorated MSNs (GMSNs). The formed GMSNs were employed as label of the aminated aptamers. The assay was carried out in PBS, pH 7.4 with a sandwich-type assay mode by using the assembled thionine in the GMSNs as indicators. Compared with the pure silica nanoparticles, mesoporous silica could provide a larger surface for the immobilization of biomolecules and improve the sensitivity of the aptasensor. Under optimal conditions, the electrochemical aptasensors exhibited a wide linear range from 0.001 to 600 ng mL−1 (i.e. 0.03 pM to 0.018 μM thrombin) with a low detection limit (LOD) of 0.5 pg mL−1 (≈15 fM) thrombin at 3σ. No obvious non-specific adsorption was observed during a series of analyses to detect target analyte. The precision, selectivity and stability of the aptasensors were acceptable. Importantly, the methodology was evaluated with thrombin spiked samples in blank fetal calf serum, and the recoveries were 94.2–112%, indicating an exciting potential for thrombin detection. 相似文献
80.
Werner Korsatko Christian Knopp Alfred Fuchsgruber Prof. Dr. Gustav Zigeuner 《Monatshefte für Chemie / Chemical Monthly》1976,107(3):745-755
The structures of tetrahydro-4-phenylspiro([1]benzopyran-2,4(1H)-pyrimidin)-2(3H)-ones and-thiones4 a, b resp., are proved by synthesis. 3-(2-methoxy-3,5-dimethylphenyl)-3-phenylpropionic acid11 b is prepared from 3,4-dihydro-6,8-dimethyl-4-phenylcoumarin10. The lithium salt of11 b reacts with isobutenyl-lithium to 1-(2-methoxy-3,5-dimethylphenyl)-5-methyl-1-phenyl-4-hexen-3-on12 a. 12 a is transferred with urea in acid medium and NH4CNS resp. in a mixture of dihydro-6-[2-(2-methoxy-3,5-dimethylphenyl)-2-phenyläthyl]-4,4-dimethyl-2(1H)-pyrimidinone and-thione13 a, b and tetrahydro-6-[2-(2-methoxy-3,5-dimethylphenyl)-2-phenyläthyliden]-4,4-dimethyl-2(1H)-pyrimidinone and-thione14 a, b resp.14 b leads to13 a, b with H2O2. Heating of13 a, 14 a and14 b resp. with pyridin-HCl leads to the spiro compounds4 a, b. 相似文献