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221.
A unique flow injection chemiluminescence (CL) method for the determination of calcium dobesilate in pharmaceutical preparations and human urine is presented in this paper. The analytical reagents involved in the CL reaction, luminol and ferricyanide, were both immobilized on an anion-exchange column in an FI system. The CL signal produced by the reaction of luminol with ferricyanide (the reagents had been eluted from the column through sodium phosphate injection) decreased in the presence of dobesilate. The decreased CL intensity was linear to the dobesilate concentration in the range 0.2100.0ngmL–1. At a flow rate of 2.0mLmin–1, one analytical cycle can be completed in 1.5min, including sampling and washing, resulting in a throughput of 40 cycles per hour. The proposed method was applied successfully to the determination of dobesilate in pharmaceutical preparations and human urine without any pre-treatment. It was found that, after oral administration, the dobesilate concentration reached its maximum after three hours, and the dobesilate metabolism ratio in 24 hours was 57.1% in the bodies of volunteers.Received September 14, 2002; accepted March 11, 2003
Published online July 16, 2003 相似文献
222.
Summary Chlorobenzenes, triazine and phenylurea herbicides were separated by normal micellar electrokinetic chromatography (MEKC)
and by micellar electrokinetic chromatography with reversed flow (RF-MEKC) in running buffers containing organic solvents.
The relationship between the two techniques is similar to that between reversed-phase and normal-phase HPLC. Using RF-MEKC,
the separation of lipophilic compounds is often improved compared to normal MEKC.
The migration in MEKC and in RF-MEKC was characterised by lipophilic and polar indices. The experimental values of the lipophilic
indices of the compounds tested in the two techniques were close to the indices in reversed-phase HPLC (RP-HPLC). This enables
the use of the indices determined in RP-HPLC for predicting the effects of changing composition of the running buffers on
migration times in MEKC and in RF-MEKC.
Presented at Balaton Symposium '01 on High-Performance Separation Methods, siófok, Hungary, September 2–4, 2001 相似文献
223.
224.
应用安培检测-流动注射分析法快速测定制革废液中的硫 总被引:3,自引:0,他引:3
张海英 《分析测试技术与仪器》1998,4(4):233-236
采用安培检测-流动注射分析法快速测定制革浸灰,脱毛工序废液中的硫的含量,与常规的铁氰化钾法相比,不仅分析速度快(30-60s),测定准确,而且精度和灵敏度高,检测下限为0.10μmol/L,在制革工业中有广阔的应用前景。 相似文献
225.
Fabrication of a macro segmented flow analysis (MSFA) system based on reconfiguration of the manifold by adjustment of the sample/reagent ratio, has been found to produce a sensitive method for orthophosphate analysis based on colorimetric detection at 880 nm. Optimization of sample tube length, reaction temperature and molybdate concentration in the carrier solutions has been carried out. The larger sample tube internal diameter led to the combined advantages of better sensitivities, wider working range and higher sample throughput over most existing methods. Using the optimized conditions of 50.0 cm sample tube length (1.6 mm i.d.), 37.0 °C reaction temperature and 0.0113 M molybdate concentration in the carrier solution, the calibration model for orthophosphate standard solutions was found to be linear (y = 0.04895x + 0.003561; correlation coefficient, r2=0.9970) over the working range 0.01-2.00 mg l−1 orthophosphate. The volume of the sample injected was 1.396 ml at a flow rate of 6.0 ml min−1. The sample throughput of this MSFA method was 40 samples per an hour, with a detection limit of 4.0 μg l−1, and %R.S.D.’s below 5%. The MSFA method was successfully applied to analysis of water and wastewater samples. 相似文献
226.
M. F. Webster 《Rheologica Acta》1984,23(6):582-590
There is a need to unify present hypotheses of the nature and role of the hole-pressure,p
e
, and thus provide consolidation on which to base future research and understanding. This paper is intended to meet this need. Attention is directed towards the calculation ofp
e
from the velocity and stress fields for viscoelastic fluids flowingacross rectangular holes. The constitutive models used are the Newtonian, Second-order and Maxwell models, for values of Reynolds number up to 10 and Weissenberg number up to 0.1.The numerical complications involved are studied through an investigation of the constituent parts ofp
e
. Verification of present theory is then sought, from which justification may be derived for the estimation of elasticity fromp
e
measurements. Attention is directed towards the predictions of Higashitani and Pritchard and the extension to the Tanner and Pipkin theory for Second-order fluids. The effects of variation of geometric dimensions and flow type uponp
e
are also discussed. 相似文献
227.
Gas hydrates are non-stoichiometric crystalline compounds of water with gas at a certain temperature and pressure. Compared to the thermodynamics of hydrate formation, our knowledge on the kinetics aspect is rather immature. It is well known that the kinetics of hydrate formation/dissociation plays an important role in many industrial cases, such as the exploitation of methane hydrate underground, the storage and transportation of natural gas in solid hydrate state, the inhibition of hydrate i… 相似文献
228.
The use of open-access mass spectrometry to monitor synthetic chemistry reactions, and also the integrity and purity of new chemical entities, has been a part of the medicinal chemist's tool-box for more than 5 years. Originally in our group at Wyeth Research there were two open-access methods available to the chemists, flow injection analysis (FIA) and liquid chromatography/mass spectrometry (LC/MS). The FIA method was approximately 3 min long, while the LC/MS method was approximately 20 min long (including an 8 min gradient). Within the first 2 years, the total number of open-access analyses increased by approximately 125%. It is interesting, however, that the number of LC/MS analyses increased by more than 285%. This is attributed to the fact that the chemists began using the LC/MS data to monitor reactions and also to check final product integrity and purity. In addition, the number of chemists performing parallel synthesis reactions has increased; thus, individual chemists can produce sample sets of up to 100 vials. This paper describes the implementation of new methodology, which accommodates the need for much faster run times and also the ability to acquire alternating positive and negative ion spectra within the same run. In addition, the instrument has been configured to e-mail the resulting processed data report to the submitting chemist. Several methods have been developed, including structure elucidation using in-source collision-induced dissociation (CID) and night-time analysis. The LC/MS methods for this system are described herein and are applicable to both industrial and academic synthetic chemistry optimization efforts. 相似文献
229.
用选择离子流动管质谱测定汽油和柴油蒸汽成分 总被引:2,自引:0,他引:2
采用选择离子流动管质谱(SIFT/MS)装置,以H30^ 、N0^ 为初始离子对汽油和柴油蒸汽进行了研究,质谱分析表明,汽油和柴油主要由C—H化合物组成,包括烷烃、环烷烃、烯烃、炔烃、二烯烃以及芳香烃。在这几种成分中,烷烃都占有最大的比例;汽油蒸汽和柴油蒸汽最大的区别是柴油蒸汽中长链大分子的挥发性C—H化合物所占的比例远远高于汽油蒸汽。文中还给出了以H30^ 、N0^ 为初始离子所得到的汽油蒸汽的质谱图,以及汽油、柴油蒸汽中各种成分的定量分析结果。 相似文献
230.
In a flow catalytic reactor with an autocatalytic trigger as a kinetic subsystem, the conditions have been found, in which oscillations appear. Some peculiarities of the kinetic model dynamics, where the kinetic subsystem is an autocatalytic oscillator, are investigated. 相似文献