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921.
基于微顺序注射-阀上实验室,采用磷钼蓝分光光度法测定了海水中总磷,对实验参数进行了优化,并选取了海水中主要成分离子进行了干扰实验。结果表明,海水中总磷质量浓度在0.009~1mg/L范围内与吸光度呈线性关系(r=0.9995),方法的检出限为0.003mg/L。该法测定秦皇岛黄金海岸表层海水中总磷浓度为0.090mg/L,与国标法测定结果0.088mg/L无显著性差异;测定含磷浓度为0.20mg/L的人工海水,相对标准偏差(RSD)为2.4%,样品加标回收率为94.4%~95.7%;海水中主要离子对本实验方法测定产生的干扰在5%以内。 相似文献
922.
In the present investigation, few 3-(substitutedphenyl)-1-[2-(1-hydroxy-ethyl)]-1H-benzimidazol-1-yl)prop-2-en-1-ones are EGFR antagonist are designed, by molecular docking analysis. The synthesized compounds were tested for their in vitro anticancer activity by propidium iodide fluorescent assay and Trypan blue viability assay against colorectal cancer cell lines (HCT116) and non-small cell lung cancer cell lines (H460). Human Epithelial Kidney cell lines (HEK) are used as normal cell lines for studying effect of drug on non-cancerous cells within human body. Evaluation of cytotoxic studies of synthesized compounds CHL(1–8) reveal that compound CHL1 [IC50 = 7.31 and 10.16 μM against HCT116 and H460 cell lines respectively, by PI assay] and CHL8 [IC50 = 12.52 and 6.83 against HCT116 and H460 μM cell lines respectively] possess promising cytotoxic activity. 相似文献
923.
An analytical method combining off-line flow-through extraction of a soil micro-sample (mass around 100 mg, packed into a short HPLC glass column) and direct on-column large-volume injection (LVI up to 1.00 mL) of a methanol-water soil extract onto a conventional C18 RP HPLC column enabled fast (within 3.5 minutes) trace micro-analysis of the relatively new chiral pesticides epoxiconazole (E) and novaluron (N), respectively. Linear calibration curves were evaluated from UV detection (230 nm) data in the range from 0.1 to 5 mg/kg in three most abundant Slovak agricultural soils. LOD (confidence band) at the levels 0.08-0.11 mg/kg and LOQ 0.4-0.6 mg/kg and LOD (S/N = 3) at the levels 0.007-0.018 mg/kg and LOQ (S/N = 10) 0.024-0.060 mg/kg, respectively, of dry soil were achieved. Recovery of pesticides in the overall LVI method including flow-through 130-200 mg soil micro-sample extraction was: for epoxiconazole from 74 to 85% and from 56% to 90% for novaluron with reproducibility within +/- 6% RSD. This fast (30 min) and simple method consists of just three steps which are short column filling with a solid micro-sample; flow-through liquid extraction and direct large-volume injection RP HPLC DAD analysis. The method is prepared for automation and further analysis of enantiomers of both investigated pesticides by achiral-chiral column switching techniques. 相似文献
924.
This communication presents a study on the simultaneous determination of thermolabile N-methylcarbamate and organophosphorus insecticides in cereal products by gas chromatography-mass spectrometry. The thermal stability of the multiple insecticides was evaluated with conventional hot splitless injection and on-column injection. The results obtained by GC-MS with these two injection techniques were compared in terms of the recovery, the limit of detection, the limit of qualification, and the reproducibility. With on-column injection, the pesticide recoveries in cereal samples were better than 82%, with relative standard deviations lower than 5.4%. The limits of qualification for most insecticides were in the range of 0.009-0.08 mg/kg, i. e. lower than the maximum residue limits established for insecticides in cereal products by the European Union. The long-term stability using on-column injection for analysis of insecticides in real samples was evaluated and normal chromatographic performance could be obtained within 50 analyses. The results revealed that it was possible for application of on-column injection in the analysis of thermolabile multiple insecticides in food sample after comprehensive sample clean-up, despite the highly contaminated nature of the column system. 相似文献
925.
Wang M Zhao L Liu M Lin JM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,66(4-5):1222-1227
A weak chemiluminescent (CL) emission was observed in the decomposition of peroxomonosulfate (HSO5-), which would be accelerated in the presence of trace amounts of cobalt (II). The mechanism was due to the production of singlet oxygen (1O2). Interestedly, riboflavin can enhance the CL and the CL intensity was strongly dependent on riboflavin concentration. Based on this phenomenon, a flow injection analysis (FIA) CL method was established for the determination of riboflavin. Additionally, the possible CL mechanism is proposed based on the kinetic curve of the CL reaction, CL spectra, UV-vis spectra and fluorescent spectra. The CL intensity was correlated linearly with concentration of riboflavin over the range of 1.0x10(-4) to 1.0x10(-8) g mL-1; the detection limit was 9.0x10(-9) g mL-1(S/N=3); the relative standard deviation was 1.4% for 9x10(-7) g mL-1 riboflavin (n=11). Furthermore, this method was applied to the determination of riboflavin in real tablets and injections successfully. 相似文献
926.
A simple, rapid flow injection chemiluminescence (FI-CL) method has been developed for selective determination of acenaphthylene (ACY), based on the CL produced in the reaction of tris(2,2′-bipyridine)ruthenium(III) (Ru(bipy)33+) and ACY in an acidic buffer solution. Under the optimum experimental conditions, the calibration curve was linear over the range 5.0 × 10−3 to 4.0 × 10−7 mol L−1 for ACY. The detection limit (S/N = 3) was 2.0 × 10−7 mol L−1 and the relative standard deviation of 10 replicate measurements was 2.3% for 5.0 × 10−5 mol L−1 of ACY. Selectivity of CL reaction of ACY from other 15 polycyclic aromatic hydrocarbons (PAHs) was investigated by flow injection method. The method was applied to determine the ACY content in soil. 相似文献
927.
Norouzi P Ganjali MR Daneshgar P Dinarvand R Moosavi-Movahedi AA Saboury AA 《Analytica chimica acta》2007,590(1):74-80
In this work a novel method for the fast monitoring of lidocaine in flow-injection systems has been developed. The fast Fourier transform continuous cyclic voltammetry (FFTCV) at gold microelectrode in flowing solution system was used for determination of lidocaine in its pharmaceutical formulation. The presented technique was very simple, precise, accurate, time saving and economical, compared with all of the previously reported methods. The recommended technique demonstrated some advantages over other reported methods. Firstly, there was no need for the oxygen removal from the test solution. Secondly, a picomolar detection limit was achieved, and additionally, the method was fast enough for the determination of any such compound, in a wide variety of chromatographic methods. The method was linear across the concentration range of 240-1.1 × 105 pg mL−1 (r = 0.996) with a limit of detection and quantitation 117.3 and 240 pg mL−1, respectively. As a conclusion this system offers the requisite accuracy, sensitivity, precision and selectivity to assay lidocaine in injections. 相似文献
928.
Flow injection (FI) methodology, using diffuse reflectance in the visible region of the spectrum, for the analysis of nickel, precipitated in the form of dimethylglyoximate, is presented. A reflectance cell, constructed in polytetrafluoroethylene, using a LED (light emitting diode) as light source and a LDR (light dependent resistor) as detector, is described. The analytical signal (S) correlates with nickel concentration (C) between 1.6 × 10−4 and 6.6 × 10−4 mol L−1. This correlation is described by the equation S = −1.108 + 3.314 × 104C − 2.081 × 107C2 (r = 0.9996). The experimentally observed limit of detection is about 1.3 × 10−4 mol L−1, as in lower concentrations the formation of precipitate is not observed. The experimental quantitation limit is about 1.6 × 10−4 mol L−1. The mean R.S.D. (relative standard deviation) is about 2.7%. Samples containing nickel were analyzed and the results obtained in this method were compared with those of other methods using the statistical Student's t-test. 相似文献
929.
A simple flow injection chemiluminescence (FI-CL) method was proposed for the determination of nitrofurazone. Strong CL signal was generated during the reaction of nitrofurazone with H2O2 and N-bromosuccinimide (NBS) in alkaline condition. The CL signal was proportional to the nitrofurazone concentration in the range 1.0 × 10−7 to 1.0 × 10−5 g mL−1. The detection limit was 2 × 10−8 g mL−1 nitrofurazone and the relative standard deviation was less than 4% (6.0 × 10−6 g mL−1 nitrofurazone, n = 11). The proposed method was successfully applied to the determination of nitrofurazone in compound furacillin nasal drops, human plasma and urine samples. The CL reaction mechanism was also discussed briefly. Singlet oxygen generated in the reaction between H2O2 and NBS was suggested to be participated in the CL reaction. 相似文献
930.
Hantash J Bartlett A Oldfield P Dénès G O'Rielly R David F 《Analytical and bioanalytical chemistry》2007,387(1):351-357
A flow-injection biosensor-like system based on a nonenzymatic approach has been developed to determine the carbamate pesticide
carbaryl in complex biological samples without lengthy and expensive extraction steps. Molecularly imprinted polymeric beads
were used to immobilize carbaryl from biological samples. pH variation permitted the elution of carbaryl from the binding
cavity to the flow cell. A pH electrode was used to detect changes in the charge of carbaryl in the sample solution resulting
from the protonation and deprotonation of the molecule over different pH ranges. At pH 2.0, the secondary amine group is protonated,
giving a (+1) charge to the carbaryl molecule. At pH 8.0, the ionized carbaryl loses a proton to become neutral, changing
the local pH of the flow cell. The pH change at the flow cell generated by the deprotonation of carbaryl ion in alkaline medium
was used to determine the carbaryl concentration. Parameters influencing the performance of the system were optimized for
use in the detection procedure. The validated biosensor-like system had a carbaryl detection limit of 10.0 μg/mL and a response
that was linear (r
2 > 0.98) over the concentration range of 10.0–00 μg/mL. 相似文献