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81.
Tanaka Y Hoshino W Shimizu S Youfu K Aratani N Maruyama N Fujita S Osuka A 《Journal of the American Chemical Society》2004,126(10):3046-3047
When heated, bis-Cu(II) octaphyrin(1.1.1.1.1.1.1.1) is quantitatively split into two Cu(II) porphyrins both in solution and film states, which is accompanied by large absorption spectral changes. 相似文献
82.
Effect of moisture on impact toughness of sugar-coated tablets manufactured by the dusting method 总被引:1,自引:0,他引:1
The purpose of this study was to clarify the effect of moisture on the impact toughness of sugar-coated tablets manufactured by the dusting method. We demonstrated that moisture plays an important role in the impact toughness of sugar-coated tablets. Moisturizing the sugar-coating layer resulted in enhancement of impact toughness of sugar-coated tablets, while reducing moisture in the sugar-coating layer resulted in weakening of the impact toughness. This was due to the characteristics of sucrose, the main ingredient of the sugar-coating layer, which is a soft and non-fragile material at high moisture levels, but hard and fragile at low moisture levels. We also demonstrated that friability as an indicator of impact toughness changed with time, and friability should be measured at 14 d after manufacture. This is due to moisture movement from outer sugar-coating layer into the inner sugar-coated tablets. Incorporating microcrystalline cellulose (MCC) in the subcoating layer resulted in sugar-coating layers with high resistance against impact even though moisture content of sugar-coated tablets was low. We confirmed the high impact toughness of the sugar-coated tablets with MCC whose moisture content was low from the results of both free fall and friability tests. We suggest that the dusting method using dusting powder containing MCC is a useful method for the production of sugar-coated tablets containing moisture sensitive drugs. 相似文献
83.
The interaction of HCl with the D(2)O-ice surface has been investigated in the temperature range 15-200 K by utilizing time-of-flight secondary ion mass spectroscopy, temperature-programmed desorption, and x-ray photoelectron spectroscopy. The intensities of sputtered H(+)(D(2)O) and Cl(-) ions (the H(+) ions) are increased (decreased) markedly above 40 K due to the hydrogen bond formation between the HCl and D(2)O molecules. The HCl molecules which form ionic hydrates undergo H/D exchange at 110-140 K and a considerable fraction of them dissolves into the bulk above 140 K. The neutral hydrates of HCl should coexist as evidenced by the desorption of HCl above 170 K. They are incorporated completely in the D(2)O layer up to 140 K. The HCl molecules embedded in the thick D(2)O layer dissolve into the bulk, and the ionic hydrate tends to segregate to the surface above 150 K. 相似文献
84.
Reliability of mean transit time obtained using perfusion-weighted MR imaging; comparison with positron emission tomography 总被引:2,自引:0,他引:2
Mihara F Kuwabara Y Tanaka A Yoshiura T Sasaki M Yoshida T Masuda K Matsushima T 《Magnetic resonance imaging》2003,21(1):33-39
The purpose of this project was to assess the reliability of the cerebral mean transit time (MTT) obtained using perfusion-weighted MR imaging by comparing it with the MTT obtained when performing positron emission tomography (PET). Ten patients with chronic occlusive cerebrovascular disease were investigated. They had either unilateral internal carotid artery occlusion or middle cerebral artery occlusion. The regions-of-interest were placed in non-infarcted areas within the territory of the middle cerebral artery on the affected side. Control regions-of-interest were placed in mirrored regions of the contralateral side. Linear regression analyses were performed using the parameters of the MTT obtained with perfusion-weighted MR imaging and the MTT, cerebral blood flow, vascular reactivity, and oxygen extraction fraction obtained with PET. The respective MTTs of the affected and non-affected sides obtained with perfusion-weighted MR imaging versus those with PET were 7.3 +/- 2.2 s and 6.0 +/- 1.2 s versus 8.2 +/- 3.0 s and 6.4 +/- 1.7 s. The MTT obtained using perfusion-weighted MR imaging and PET demonstrated statistically significant correlation (r = 0.87, p < 0.0001). The MTT obtained with perfusion-weighted MR imaging correlated statistically with cerebral blood flow (r = -0.74, p < 0.001), vascular reactivity (r = -0.73, p < 0.001) and oxygen extraction fraction (r = 0.61, p < 0.01). Similarly, the MTT obtained using PET statistically correlated with cerebral blood flow (r = -0.78, p < 0.0001), vascular reactivity (r = -0.51, p < 0.05) and oxygen extraction fraction (r = 0.68, p < 0.01). The reliability of the MTT obtained using perfusion-weighted MR imaging appears to be approximately equal to that obtained with positron emission tomography. 相似文献
85.
We have fabricated a cryogenic atomic force microscope that is designed for structural investigation of freeze-fractured biological specimens. The apparatus is operated in liquid nitrogen gas at atmospheric pressure. Freeze-fracturing, freeze-etching and subsequent imaging are carried out in the same chamber, so that the surface topography of a fractured plane is easily visualized without ice contamination. A controlled superficial sublimation of volatile molecules allows us to obtain three-dimensional views of ultrastructures of biological membranes. 相似文献
86.
Kikugawa Y Nagashima A Sakamoto T Miyazawa E Shiiya M 《The Journal of organic chemistry》2003,68(17):6739-6744
N-Phthalimido-N-acylnitrenium ions are generated from N-acylaminophthalimides, a new class of precursors, by treatment with hypervalent iodine compounds (PIFA and HTIB). In HFIP, the nitrenium ions undergo intramolecular electrophilic substitution reactions to afford N-aminonitrogen heterocycles in high yields. In TFEA, spirodienones bearing the 1-azaspiro[4.5]decane skeleton are obtained by treatment of N-phthalimido-3-(4-halogenophenyl)propanamides with HTIB as a result of ipso attack of the intermediate nitrenium ion. Similarly, using PIFA in TFEA, ipso cyclization of unactivated benzenoid compounds occurs to afford spirodiene derivatives. This involves loss of aromaticity despite the absence of other activating substituents on the phenyl group. 相似文献
87.
88.
89.
Yasuo Kanai 《Proceedings of the American Mathematical Society》1999,127(10):3073-3080
In this paper, we present some relations between generalized distributivity of quotient algebras and Mahlo operations, and show that the distributivity implies some variants of stationary relections.
90.
Experiments have been conducted to investigate an effect of inlet restriction on the thermal-hydraulic stability. A Test
facility used in this study was designed and constructed to have non-dimensional values that are nearly equal to those of
natural circulation BWR. Experimental results showed that driving force of the natural circulation at the stability boundary
was described as a function of heat flux and inlet subcooling independent of inlet restriction. In order to extend experimental
database regarding thermal-hydraulic stability to different inlet restriction, numerical analysis was carried out based on
the homogeneous flow model. Stability maps in reference to the core inlet subcooling and heat flux were presented for various
inlet restrictions using the above-mentioned function. Instability region during the inlet subcooling shifted to the higher
inlet subcooling with increasing inlet restriction and became larger with increasing heat flux.
Received on 17 January 2000 相似文献