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71.
The effects of nitric oxide (NO) annealing on conventional thermal oxides are reported in this letter. The oxide thickness increase, resulting from NO annealing, is found to be only a few angstroms (<0.5 nm) and independent on the initial oxide thickness. Furthermore, both the electrical and physical characteristics are improved. This technique is expected to achieve sub-5 nm high quality ultrathin dielectric films for the applications in EEPROM's and ULSI 相似文献
72.
We describe a calculation ofT
c
(P, H) in a model of a disordered superconductor which is based on the de Gennes-Skal-Shklovskii (dGSS) picture of the large cluster in a percolation system. The calculation is done by carrying out successive decimations on the Landau-Ginzburg Hamiltonian describing the links in the model. We calculateT
c
(P, H) in the presence of longitudinal magnetic field by evaluating the renormalized Landau-Ginzburg coupling when the renormalized Landau-Ginzburg length equals the percolation link length in the dGSS picture and obtain the approximate analytic form ofT
c
(P, H).Work supported by China Natural Science Foundation 相似文献
73.
74.
TCDD的密度泛函理论研究 总被引:3,自引:0,他引:3
用B3LYP/6-311G~(**)方法全优经计算22个四氯二苯并对二(左口右恶)英( 简称TCDD)分子,得到几何构型、总能量、标准熵、标准焓和标准自由能。将2, 3,7,8-TCDD的计算构型与X射线衍射实验测定值进行了比较。计算结果表明,总 能量、标准焓和标准自由能与氯原子量换位置的相关性很高(r > 0.997).1,3,6, 8-TCDD的总能量处自由能最低,即最稳定,以此参照,得到异构体的总能量的相对 稳定性顺序和自由能的相对稳定性顺序。1,3,7,9-TCDD的稳定性次之,1,3,7,8- TCDD居第三,将这二个顺序与焚烧炉产生的TCDD异构体和合成的异构体对的生成面 分比进行了比较,说明焚烧炉中产生的TCDD和合成的TCDD对的分布主要受热力学控 制。 相似文献
75.
A simply fabricated microfluidic device using a green organic light emitting diode (OLED) and thin film interference filter as integrated excitation source is presented and applied to fluorescence detection of proteins. A layer-by-layer compact system consisting of glass/PDMS microchip, pinhole, excitation filter and OLED is designed and equipped with a coaxial optical fiber and for fluorescence detection a 300 microm thick excitation filter is employed for eliminating nearly 80% of the unwanted light emitted by OLEDs which has overlaped with the fluorescence spectrum of the dyes. The distance between OLED illuminant and microchannels is limited to approximately 1 mm for sensitive detection. The achieved fluorescence signal of 300 microM Rhodamine 6G is about 13 times as high as that without the excitation filter and 3.5 times the result of a perpendicular detection structure. This system has been used for fluorescence detection of Rhodamine 6G, Alexa 532 and BSA conjugates in 4% linear polyacrymide (LPA) buffer (in 1 x TBE, pH 8.3) and 1.4 fmol and 35 fmol mass detection limits at 0.7 nl injection volume for Alexa and Rhodamine dye have been obtained, respectively. 相似文献
76.
Bao Liu Ling Huang Juntao Liu Yao Zhong Xingshu Li Albert S.C. Chan 《Tetrahedron: Asymmetry》2007,18(24):2901-2904
Chiral tridentate N-tosylated aminoimine ligands were used in the Cu(II)-catalyzed enantioselective addition of phenylacetylene to N-aryl arylimines, affording products up to 92% ee. 相似文献
77.
78.
J. Hatta M. Okada S. Matuoka H. Yao 《Journal of Thermal Analysis and Calorimetry》1992,38(8):1775-1783
Using an ac calorimetric method, detailed behaviour of the heat capacity in dipalmitoyl-phosphatidylcholine-cholesterol system was studied in the cholesterol concentration less than 5 mol%. It was revealed that the heat capacity near the main transition was composed of at least four anomalies, i.e., multipeak took place in the heat capacity. This fact indicates that a simple theory explaining coexistence of two phases in two component systems does not work in the multipeak region. Then, relation between the multipeak heat capacity and the change of the ripple structure with the cholesterol concentration should be taken into account, when we consider thermodynamical behaviour of the systems.
Zusammenfassung Mittels AC-Kalorimetrie wurde bei Cholesterol-Konzentrationen von weniger als 5 mol% das Verhalten der Wärmekapazität im System Dipalmitoylphosphatidylcholin-Cholesterol untersucht. Es wurde gezeigt, daß sich die Wärmekapazität in der Nähe der Hauptumwandlung aus mindestens vier Anomalien zusammensetzt, d.h. bei der Wärmekapazität kann ein Multipeak beobachtet werden. Diese Tatsache zeigt, daß eine einfache Theorie, welche die Koexistenz zweier Phasen in einem Zweikomponenten-System erklärt, für die Multipeakregion nicht geeignet ist. Weiterhin sollte bei Überlegungen zum thermodynamischen Verhalten von Systemen eine Beziehung zwischen der Multipeak-Wärmekapazität bzw. der Welligkeitsstruktur und der Cholesterol-Konzentration berücksichtigt werden.相似文献
79.
Ning Li Chunhui Deng Ning Yao Xizhong Shen Xiangmin Zhang 《Analytica chimica acta》2005,540(2):317-323
In the study, we developed a simple, rapid, sensitive, and inexpensive method for determination of the disease biomarkers of acetone, hexanal and heptanal in human blood. For the first time, derivatization of carbonyls with O-2,3,4,5,6-(pentafluorobenzyl)hydroxylamine (PFBHA) was combined with headspace single-drop microextractin (HS-SDME) and gas chromatography-mass spectrometry (GC–MS) and applied to the analysis of acetone, hexanal, and heptanal in human blood. At first, acetone, hexanal and heptanal in blood were derivatized with PFBHA and formed oximes in several seconds. Sequentially, the oximes were headspace extracted and concentrated by a microdrop solvent. Finally, the extracted oximes were analyzed by GC–MS. HS-SDME conditions and method validations were studied. Due to needing of only 2 μl organic solvent, short extraction time of 8 min, and simple operation, derivatization-HS-SDME was shown to be a rapid, simple, and inexpensive technique for analysis of acetone, hexanal, and heptanal in human blood. Moreover, it had low detection limit values from 0.24 to 0.62 nM, and good reproducibility (R.S.D. less than 12%). 相似文献
80.
本文报导采用小角X射线散射方法(SAXS)对甲醇、乙醇和异丁醇分别与含水卵磷脂所形成的液晶相结构的研究. 它们与水-卵磷脂形成的液品结构有较大区别. 在水-卵磷脂体系中, 随着含水量增加, 双分子层层间距增大. 但当醇类加入水-卵磷脂体系中, 随着醇类含量增加, 层间距变小, 随着醇类中碳链的增长, 支链的引入, 层间距变小趋势强化。 相似文献