全文获取类型
收费全文 | 1253篇 |
免费 | 64篇 |
国内免费 | 6篇 |
专业分类
化学 | 835篇 |
晶体学 | 10篇 |
力学 | 12篇 |
数学 | 139篇 |
物理学 | 327篇 |
出版年
2023年 | 3篇 |
2022年 | 18篇 |
2021年 | 22篇 |
2020年 | 14篇 |
2019年 | 17篇 |
2018年 | 10篇 |
2017年 | 12篇 |
2016年 | 31篇 |
2015年 | 39篇 |
2014年 | 29篇 |
2013年 | 86篇 |
2012年 | 82篇 |
2011年 | 78篇 |
2010年 | 61篇 |
2009年 | 63篇 |
2008年 | 86篇 |
2007年 | 79篇 |
2006年 | 77篇 |
2005年 | 74篇 |
2004年 | 48篇 |
2003年 | 39篇 |
2002年 | 46篇 |
2001年 | 34篇 |
2000年 | 36篇 |
1999年 | 23篇 |
1998年 | 16篇 |
1997年 | 17篇 |
1996年 | 12篇 |
1995年 | 16篇 |
1994年 | 16篇 |
1993年 | 10篇 |
1992年 | 12篇 |
1991年 | 11篇 |
1990年 | 13篇 |
1989年 | 12篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 16篇 |
1984年 | 13篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 8篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1971年 | 2篇 |
1957年 | 1篇 |
排序方式: 共有1323条查询结果,搜索用时 15 毫秒
121.
A. M. Stefanini Jincheng Xu L. Corradi G. Montagnoli H. Moreno Y. Nagashima L. Mueller M. Narayanasamy D. R. Napoli P. Spolaore S. Beghini F. Scarlassara G. F. Segato F. Soramel C. Signorini H. Esbensen S. Landowne G. Pollarolo 《Physics letters. [Part B]》1990,240(3-4):306-310
Elastic scattering angular distributions have been measured for 58Ni+64Ni at three energies around the Coulomb barrier employing a new kinematic coincidence technique. The data are compared with the results of coupled-channels calculations including inelastic excitations as well as one-and two-neutron transfer reactions. The agreement is good and the calculations also agree well with the available transfer and fusion reaction data. 相似文献
122.
Effectiveness of Photodynamic Therapy in Elimination of HPV‐16 and HPV‐18 Associated with CIN I in Mexican Women 下载免费PDF全文
Elizabeth Maldonado Alvarado Martha Olivia Osorio Peralta Alejandra Moreno Vázquez Lydia Alejandra Martínez Guzmán Maria Eugenia Melo Petrone Zulma Iveth Enriquez Mar Dora Estela Jovel Galdamez Bárbara Carrión Solana Guadalupe Balderas Martínez Eduarda Parra Rossana Inés Castellanos Oliveros Rosa Linda Bello Leiva Araceli Espinosa Montesinos Citlalli Barrera Mendoza Selma Eugenia Medina García Eva Ramón Gallegos 《Photochemistry and photobiology》2017,93(5):1269-1275
This study aimed to determine the effectiveness of photodynamic therapy (PDT), using δ‐aminolevulinic acid (5‐ALA), in the elimination of premalignant cervical lesions in Mexican patients with human papillomavirus (HPV) infection and/or cervical intraepithelial neoplasia (CIN). Thirty women diagnosed with CIN I and/or positive for HPV participated in the study. Topical 6% 5‐ALA in gel form was applied to the uterine cervix; after 4 h, the lesion area was irradiated with a light dose of 200 J cm?2 at 635 nm. This procedure was performed three times at 48‐h intervals. Clinical follow‐up was performed at 3, 6, and 12 months after the initial PDT administration, by colposcopy, cervical cytology, histopathological analysis, polymerase chain reaction, and hybrid capture. Of HPV‐infected patients without evidence of CIN I, 80% cleared the infection, while HPV associated with CIN I was eliminated in 83% of patients (P < 0.05). At 12 months, CIN I had regressed in 57% of patients, although this response was not statistically significant. PDT using 6% 5‐ALA is concluded to be effective in eliminating HPV infection associated or not with CIN I. 相似文献
123.
124.
This Article reveals a rare synthesis of pure Pr(2)O(2)CO(3) (POC) nanopowder by thermolysis (700 °C) of a single chemical precursor in an autogenic reaction. The autogenic thermolysis of praseodymium acetate is a solvent-free, efficient, and straightforward approach yielding luminescent POC nanoparticles. The as-prepared POC nanopowder converted to PrO(1.833) (PO) powder via combustion. Methodical morphological, structural, and compositional characterizations of POC and PO powders are carried out, supported by mechanistic elucidation and the photoluminescent properties. 相似文献
125.
Fernando de la Peña Moreno Gracia Patricia BlanchGema Flores Maria Luisa Ruiz del Castillo 《Journal of chromatography. A》2010,1217(7):1083-1088
A method based on the use of the through oven transfer adsorption–desorption (TOTAD) interface in on-line coupling between reversed phase liquid chromatography and gas chromatography (RPLC–GC) for the determination of chiral volatile compounds was developed. In particular, the method was applied to the study of the influence of methyl jasmonate (MJ) treatment on the production and enantiomeric composition of selected aroma compounds in strawberry. The compounds studied were ethyl 2-methylbutanoate, linalool and 4-hydroxy-2,5-dimethyl-3(2H)-furanone (i.e. furaneol), which were examined on days 3, 6 and 9 after treatment. The method developed resulted in relative standard deviations (RSDs) of 21.6%, 8.1% and 9.8% and limits of detection (LD) of 0.04, 0.07 and 0.02 mg/l for ethyl 2-methylbutanoate, linalool and furaneol, respectively. The application of the RPLC–TOTAD–GC method allowed higher levels of ethyl 2-methylbutanoate, linalool and furaneol to be detected, particularly after 9 days of treatment. Besides, MJ demonstrated to affect the enantiomeric distribution of ethyl 2-methylbutanoate. On the contrary, the enantiomeric composition of linalool and furaneol kept constant in both control and MJ-treated strawberries throughout the study. These results are discussed. 相似文献
126.
Moreno KX Harrison C Sherry AD Malloy CR Merritt ME 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,213(1):187-191
Nuclei with long T1s are optimal targets for dynamic nuclear polarization (DNP). Therefore, most of the agents used in metabolic imaging and spectroscopy studies are based on carboxylic acid moieties that lack protons, a strong source of dipolar relaxation. Metabolic flux information encoded into spectra of small molecule metabolites in the form of the 13C isotopomer data cannot be accessed using standard 13C hyperpolarization methods because protonated carbons relax too quickly through T1 dipolar relaxation. It is shown here that the longitudinal mixing sequence FLOPSY-8 can be used to transfer polarization from a long T1 storage nucleus to adjacent protonated carbons so that they may be detected with high sensitivity. We demonstrate that FLOPSY-8 allows a direct readout of isotopomer populations in butyrate and glutamate in vitro. 相似文献
127.
Since the first studies made by Kerker in the 1970s stating the conditions for null light scattering in certain directions by particles, such conditions have remained unquestioned. The increasing interest in scattering directionality by tuning the optical properties of materials demands a new analysis of this problem. In addition, as has been shown recently, one of Kerker's statements does not comply with the optical theorem. We propose corrected expressions for the null-scattering conditions that satisfy the optical theorem. 相似文献
128.
Israel Quiros Ricardo García-Salcedo Tonatiuh Matos Claudia Moreno 《Physics letters. [Part B]》2009,670(4-5):259-265
We apply the dynamical systems tools to study the linear dynamics of a self-interacting scalar field trapped on a DGP brane. The simplest kinds of self-interaction potentials are investigated: (a) constant potential, and (b) exponential potential. It is shown that the dynamics of DGP models can be very rich and complex. One of the most interesting results of this study shows that dynamical screening of the scalar field self-interaction potential, occurring within the Minkowski cosmological phase of the DGP model and that mimics 4D phantom behaviour, is an attractor solution for a constant self-interaction potential but not for the exponential one. In the latter case gravitational screening is not even a critical point of the corresponding autonomous system of ordinary differential equations. 相似文献
129.
Preface – New Trends in Calorimetry and its Applications. First Italian–Russian Calorimetry Workshop
Journal of Thermal Analysis and Calorimetry - 相似文献
130.
F. Gonzlez G. Videen P. J. Valle J. M. Saiz J. L. de la Pea F. Moreno 《Journal of Quantitative Spectroscopy & Radiative Transfer》2001,70(4-6):383-393
Four theoretical and computational methods to describe the scattering from simple particles on substrates are presented and discussed. These methods are based on the extinction theorem, image theory, the double-interaction model, and geometrical optics (ray-tracing). We compare the four methods with measurements of scattered light from gold metallic cylinders resting on a gold metallic substrate. In particular, we analyze the co-polarized (s and p polarization) full-scan and back-scattering intensities in the far field within the plane of incidence. Advantages and disadvantages of each method as a computational and reliable tool are discussed. 相似文献