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951.
Given a fixed point free antianalytic involution k of a domain G in thecomplex plane, bounded by a finite number of analytic curves, k-invariant Greensfunctions are defined on G. The Lindelöfs principle is extended to k-invariantGreens functions. When G is the annulus, k-invariant Greens functions areobtained in the explicit form. Since the factorization of the annulus by the group kgenerated by k produces a Möbius strip, the respective result helped us to obtain explicitforms for Greens functions on the Möbius strip. 相似文献
952.
Florea Dumitraşcu Mino R. Caira Constantin Drăghici Miron Teodor Căproiu Andrei Bădoiu 《Journal of chemical crystallography》2004,34(9):577-583
Evidence for non-coplanarity of the pyridine and pyridinium rings in a series of 1-phenacyl-1,10-phenanthrolinium bromides was gleaned from 1H-NMR data recorded in DMSO-d
6 solution. The X-ray structure of 1-(4-chlorophenacyl)-1,10-phenanthrolinium bromide, as representative of this series, was determined in order to establish whether such a molecular distortion occurs in the solid state. The title compound crystallizes in the space group C2/c as a sesquihydrate of formula C20H14BrClN2O·1.5H2O with a = 35.7348(3) Å, b = 5.3468(1) Å, c = 21.7312(2) Å, = 116.4076(4)° and Z = 8. In the crystal, the helical chirality is manifested as a pronounced twist in the phenanthrolinium moiety, with the pyridine and pyridinium rings inclined at 6.8(2)°. This distortion is attributed to intramolecular hydrogen bonding of type C–H···N involving the methylene group and the uncharged nitrogen atom of the phenanthrolinium moiety. In the crystal, the cations surround an intricate array of water molecules and bromide ions held together by O–H···Br– hydrogen bonds and comprising infinite chains ···Br–···H–O–H···Br–···, cross-linked by water molecules. 相似文献
953.
Dc and ac measurements were performed on bulk samples of undoped and 15% Sb doped As2Se3 as a function of temperature (90–400 K) and frequency (103–106 Hz). The dc results show an activated conductivity dependence on temperature with an activation energy of 0.8 eV above room temperature. The ac results give a temperature dependent frequency exponent s. The temperature dependence of G
ac is discussed in terms of the mechanisms involved. Results are compared with the predictions of the Quantum Mechanical Tunnelling and Correlated Barrier Hopping models. It is found that doping increases the dc conductivity but has no effect on the ac conductivity. 相似文献
954.
E. Aktulga C. Zaim Çil G. Aktaş 《Applied Physics A: Materials Science & Processing》1989,48(6):517-520
One of the major problems of the method of phase shift analysis of modulated photocurrent for studying the density of states in the energy gap of amorphous semiconductors has been the determination of the energy scale corresponding to this DOS profile. This study presents a new way of dealing with this problem. This new method is especially useful in the case where the DOS profile lacks a characteristic peak. A computer analysis is used to confirm the validity of this method and to demonstrate how it can be used. 相似文献
955.
D. Ieşan 《Journal of Elasticity》1989,21(1):101-115
The equilibrium theory of linear piezoelectricity is considered. Saint-Venant's problem for a homogeneous and anisotropic piezoelectric cylinder is studied. 相似文献
956.
The electrophilic addition of bromine to dibromohomobenzonorbornadiene derivatives at -45 +/- 5 degrees C led to the formation of the rearranged and non-rearranged tetrabromides in a ratio of 6:4. However, high-temperature bromination of the same system in CCl4 at 77 degrees C produced only non-rearranged products. The formation mechanism of the isomers and the role of the substituent on the rearrangement is discussed. The structure elucidation of the isomeric tetrabromides was achieved from NMR spectral data. The agreement between the calculated dihedral angles and the measured coupling constants is especially excellent. The gamma-gauche effect is discussed. 相似文献
957.
Elvan Üstün Aykut Özgür Kübra A. Coşkun Serpil Demir İsmail Özdemir Yusuf Tutar 《Journal of Coordination Chemistry》2016,69(22):3384-3394
Carbon monoxide (CO) is an important signaling molecule which plays significant roles in the pathogenesis of cancer. CO is produced by enzymatic degradation of heme in mammals. Heme oxygenase 1 (HO-1) catalyzes the breakdown of heme into CO, ferrous iron, and biliverdin. CO induces HO-1 and inhibits cell proliferation. Cancer cells exposed to several stress factors (hypoxia, reactive oxygen species, cis-platin, and oxidative stress), and HO-1 displays cytoprotective role against oxidative stress and inhibits apoptosis, metastases, angiogenesis, and cell proliferation processes. Therefore, metal containing CO-releasing molecules (CORMs) have been designed as an effective cancer treatment strategy. CORMs are responsible for releasing controlled amounts of CO to cells and tissues. Thus, we synthesized [Mn(CO)3(bpy)L]X manganese containing CORMs [bpy = 2,2′-bipyridine, X = hexafluorophosphate (PF6), trifluoromethanesulfonate (OTf), L = imidazole, methylimidazole, benzimidazole, N-benzylbenzimidazole, N-(4-chlorobenzyl)benzimidazole] to release CO in human invasive ductal breast (MCF-7) cell line. In vitro experiments indicated that the compounds inhibited cell proliferation and exhibited cytotoxic effect on breast cancer cells. Moreover, side groups of the compounds enhanced the anticancer effects in MCF-7 cell line. These manganese containing CORMs gave promising results and may be used as a drug template for effective treatment of invasive ductal breast carcinoma. 相似文献
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