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41.
Novel chiral amides (Ia-Ie, II) and azo compounds (III, IV) with a 1,3,4-thiadiazole unit in the rigid core were synthesized and their liquid crystalline properties investigated by polarizing optical microscopy and differential scanning calorimetry. The amides Ia-Ie contain a chiral alkoxy chain derived from (R)-2-octanol and an achiral chain varying from 6 to 10 carbon atoms at the end of the rigid core. In amide II one of the terminal group is a chiral alkoxy chain derived from (S)-isoleucine and the other terminal substituent is an achiral n-decyloxy chain. Azo compounds III and IV contain an achiral n-decyloxy chain and a chiral alkoxy chain derived from (R)-2-octanol and (S)-isoleucine, respectively, at the end of the rigid core. The first homologue in the series of amides (Ia) exhibits enantiotropic smectic X (SmX)-chiral nematic (N*) dimorphism and the homologues Ib-Ie display enantiotropic SmX-chiral smectic C (SmC*)-N* mesomorphism. Amide II displays an enantiotropic smectic A phase. The azo compounds III and IV do not show smectic order and only an enantiotropic N* phase was observed. Thus, the mesomorphic behaviour depends on the nature of the central linkage and on the nature of the chiral alkoxy chain. 相似文献
42.
R. P. Kokoulin A. G. Bogdanov D. M. Gromushkin G. Mannocchi A. A. Petrukhin O. Saavedra N. V. Tolkacheva G. Trinchero D. V. Chernov V. V. Shutenko I. I. Yashin 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(3):395-398
Characteristics of muon bundles detected with the DECOR detector are compared to predictions based on different hadron interaction models and various assumptions as to the spectrum and mass composition of primary cosmic rays. The intensity of primary cosmic rays derived from the muon bundle data is considerably higher than that measured by means of the fluorescence technique. Either changes in the hadron interaction characteristics at ultrahigh energies or a revision of the energy calibration in the fluorescence technique of measuring EAS energy is required to explain these results. 相似文献
43.
M. Aglietta G. Badino G. F. Bologna C. Castagnoli W. Fulgione P. Galeotti O. Saavedra G. Trinchero S. Vernetto V. L. Dadykin V. B. Kortchaguin P. V. Kortchaguin A. S. Malguin V. G. Ryassny O. G. Ryazhskaya V. P. Talochkin G. T. Zatsepin V. F. Yakushev 《Il Nuovo Cimento C》1986,9(2):185-195
Summary The Liquid Scintillation Detector (LSD experiment) is running since October 1984 in the Mont Blanc Laboratory, with 90 tons
of active mass. We discuss here some of the research aims of the experiment, and report the preliminary results on searching
for neutrino bursts from collapsing stars and on cosmic-ray muons.
Riassunto Nell'ottobre 1984 è entrato in misura l'esperimento LSD (Liquid Scintillation Detector) del Laboratorio del Monte Bianco, costituito di 90 tonnellate di rivelatore. In questo lavoro si discutono alcuni degli argomenti di ricerca dell'esperimento e si riportano i risultati preliminari sui burst di neutrini da collassi stellari e sui muoni della radiazione cosmica.
Резюме Зидкий сцинтилляционный детектор работает с октября 1984 года в лаборатории на Мон Блане. Детектор имеет 90 тонн активной массы. Мы обсуздаем некоторые цели этого эксперимента. Сообщаются предварительные результаты по поиску нейтринных вспышек от коллапсирующих звезд и мюонов в космических лучах.相似文献
44.
G. Battistoni C. Bloise P. Campana A. Ciocio E. Iarocci V. Chiarella G. P. Murtas G. Nicoletti L. Satta G. Bologna C. Castagnoli A. Castellina B. D'Ettorre Piazzoli P. Galeotti G. Mannocchi P. Picchi O. Saavedra S. Vernetto E. Bellotti E. Fiorini C. Liguori P. Negri A. Pullia S. Ragazzi M. Rollier L. Zanotti D. C. Cundy M. Price 《Il Nuovo Cimento C》1986,9(2):551-558
Summary A trigger dedicated to the search of superheavy monopoles operates since about two years in the NUSEX apparatus, installed
in the Mont Blanc tunnel. Monopoles are identified by time of flight and visualization of the pulses involved in a trigger.
The present upper limit on monopole flux is 2.3·10−13 cm−2 s−1 sr−1 (90% c.l.).
Riassunto Da circa due anni è operativo sull'apparato NUSEX, installato nel tunnel del Monte Bianco, un trigger dedicato alla ricerca dei monopoli previsti dalle teorie di grande unificazione. L'identificazione dei monopoli è basata sul tempo di volo e sulla localizzazione nello spazio degli impulsi coinvolti nel trigger. Il limite superiore fino ad oggi raggiunto per il flusso di monopoli è 2.3·10−13 cm−2s−1 sr−1 (90% c.l.).
Резюме Триггерная схема, предназначенная для поиска сверхтяжелых монополей, действует в течение почти двух лет в установке NUSEX, расположенной в туннеле под Мон Бланом. Идентификация монополей основана на времени пролета, а локализация в пространстве осуществляется с помощью импульсов в триггерной схеме. Настоящий верхний предел на поток монополей составляет 2.3· ·10−13 см−2 с−1 ср−1 (к 90% вероятностью).相似文献
45.
Serguei Shimorin 《Journal of Functional Analysis》2005,224(1):134-159
A general version of the commutant lifting theorem for operators between different spaces is proved. It includes as special cases the lifting theorems of Ball-Trent-Vinnikov and Volberg-Treil. A multivariable variant of the Volberg-Treil theorem is obtained as a corollary. A certain factorization property of reproducing kernels is shown to be a sufficient condition for the lifting. Another factorization property is shown to be a necessary condition. 相似文献
46.
Frédéric Barbeu Vaclav Sobolik Serguei Martemianov Laurent Gbahoue 《Comptes Rendus Mecanique》2002,330(6):433-436
The present paper demonstrates how the directional characteristics of an actual three-segment electrodiffusional sensor can be calculated from the probe image. It was shown that utilization of ‘ideal’ directional characteristics lead to an important (up to 15°) error in flow angle determination. The directional characteristics calculated from the probe image improve significantly (up to 50%) the accuracy of the flow angle measurements. To cite this article: F. Barbeu et al., C. R. Mecanique 330 (2002) 433–436. 相似文献
47.
Mario A. Bianchet Ying H. Pan Leighanne A. Brammer Basta Harry Saavedra Evan P. Lloyd Pankaj Kumar Rohini Mattoo Craig A. Townsend Gyanu Lamichhane 《BMC biochemistry》2017,18(1):8
Background
The carbapenem subclass of β-lactams is among the most potent antibiotics available today. Emerging evidence shows that, unlike other subclasses of β-lactams, carbapenems bind to and inhibit non-classical transpeptidases (L,D-transpeptidases) that generate 3 → 3 linkages in bacterial peptidoglycan. The carbapenems biapenem and tebipenem exhibit therapeutically valuable potencies against Mycobacterium tuberculosis (Mtb).Results
Here, we report the X-ray crystal structures of Mtb L,D-transpeptidase-2 (LdtMt2) complexed with biapenem or tebipenem. Despite significant variations in carbapenem sulfur side chains, biapenem and tebipenem ultimately form an identical adduct that docks to the outer cavity of LdtMt2. We propose that this common adduct is an enzyme catalyzed decomposition of the carbapenem adduct by a mechanism similar to S-conjugate elimination by β-lyases.Conclusion
The results presented here demonstrate biapenem and tebipenem bind to the outer cavity of LdtMt2, covalently inactivate the enzyme, and subsequently degrade via an S-conjugate elimination mechanism. We discuss structure based drug design based on the findings and propose that the S-conjugate elimination can be leveraged to design novel agents to deliver and locally release antimicrobial factors to act synergistically with the carbapenem carrier.48.
Adriana DoyleAlvaro Saavedra Maria Luiza B. TristãoMárcio Nele Ricardo Q. Aucélio 《Spectrochimica Acta Part B: Atomic Spectroscopy》2011,66(5):368-372
Official guidelines to perform chlorine determination in crude oil are (i) American Society for Testing and Materials (ASTM) D6470, which is based on the extraction of water from the oil and subsequent determination of the chloride by potentiometry, (ii) ASTM D3230, that measures the conductivity of a solution of crude oil in a mixture of organic solvents and (iii) US Environmental Protection Agency (EPA) 9075 that uses energy dispersive X-ray fluorescence spectrometry to quantify chlorine and it is applicable for the range from 200 μg g− 1 to percent levels of the analyte. The goal of this work is to propose method to quantify lower amounts of chlorine in crude oil using energy dispersive X-ray fluorescence spectrometry using a simple calibration strategy. Sample homogenization procedure was carefully studied in order to enable accurate results. The calibration curve was made with standards prepared by diluting aqueous NaCl standard in glycerin. The method presented a linear response that covers the range from 8 to at least 100 μg g− 1 of chlorine. Chlorine in crude oil samples from Campos Basin - Brazil were quantified by the proposed method and by potentiometry after extraction of chlorine from the oil. Results achieved using both methods were statistically the same at 95% confidence level. 相似文献
49.
Let S(r) denote a circle of circumference r. The circular consecutive choosability chcc(G) of a graph G is the least real number t such that for any r≥χc(G), if each vertex v is assigned a closed interval L(v) of length t on S(r), then there is a circular r‐coloring f of G such that f(v)∈L(v). We investigate, for a graph, the relations between its circular consecutive choosability and choosability. It is proved that for any positive integer k, if a graph G is k‐choosable, then chcc(G)?k + 1 ? 1/k; moreover, the bound is sharp for k≥3. For k = 2, it is proved that if G is 2‐choosable then chcc(G)?2, while the equality holds if and only if G contains a cycle. In addition, we prove that there exist circular consecutive 2‐choosable graphs which are not 2‐choosable. In particular, it is shown that chcc(G) = 2 holds for all cycles and for K2, n with n≥2. On the other hand, we prove that chcc(G)>2 holds for many generalized theta graphs. © 2011 Wiley Periodicals, Inc. J Graph Theory 67: 178‐197, 2011 相似文献
50.
Anne Boutet de Monvel Jan Janas Serguei Naboko 《Integral Equations and Operator Theory》2011,69(2):151-170
We give explicit examples of unbounded Jacobi operators with a few gaps in their essential spectrum. More precisely a class of Jacobi matrices whose absolutely continuous spectrum fills any finite number of bounded intervals is considered. Their point spectrum accumulates to +?? and ???. The asymptotics of large eigenvalues is also found. 相似文献