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91.
A novel spectrofluorimetric method for determination of imatinib in pure,pharmaceutical preparation,human plasma,and human urine 下载免费PDF全文
The following paper represents a simple, highly sensitive, responsive validated and developed spectrofluorimetric method for estimation of imatinib (IMB) in its pure, commercial preparation, human urine and human blood plasma. The calibration curve was in the range 4–900 ng ml?1 for pure form and urine and 8–900 ng ml?1 for plasma in a medium contains carboxymethyl cellulose (CMC) and acetate buffer (pH 5) with excitation wavelength (λex) 230 nm and emission wavelength (λem) 307 nm. The limit of detection (LOD) was 0.37 ng ml?1 for the pure form, 0.64 ng ml?1 for human urine, and 0.70 ng ml?1 for human plasma, while the limit of quantitation (LOQ) was 1.2 for pure form, 1.91 for urine and 2.1 for plasma. The suggested method was successfully applied for evaluation of IMB in tablets within 99% mean percentage recovery. The excipients that are usually used as additives in pharmaceutical dosage form did not interfere with the suggested method. The method was efficiently used for estimation of IMB in human urine and human plasma. The effect of some cations that might be present in urine and plasma was also studied. The method was also focused on human volunteers and in vitro drug release. 相似文献
92.
Benzofurazan‐based fluorophore for the selective determination of flupentixol dihydrochloride: Application to content uniformity testing 下载免费PDF全文
One of the most commonly used drugs in treatment of schizophrenia is flupentixol dihydrochloride, therefore it is important to develop a simple, low cost and sensitive spectrofluorimetric method for the estimation of flupentixol dihydrochloride. The yellow fluorescent product that is generated from the nucleophilic substitution reaction of the free lone pair of the alcoholic hydroxyl group of the drug and 4‐chloro‐7‐nitrobenzofurazan (NBD‐Cl) in Mcllvaine buffer pH 7.0 was estimated at 510 nm (λex 460 nm). The variables that affect the development of the reaction product were explored and optimized. The linear range of this method was 0.5–2.5 μg ml?1 with a limit of quantitation equal to 0.29 μg ml?1. Our method was successfully applied for the assurance of flupentixol in tablet form with average percentage recovery of 99.08 ± 1.01% without obstruction from the basic excipients exhibits. Furthermore, our strategy was extended to study the content uniformity testing of flupentixol in Fluaxnol® tablets. 相似文献
93.
Dalia Ali Farghaly Ahmed A. Aboelwafa Manal Y. Hamza Magdy I. Mohamed 《Journal of liposome research》2018,28(2):126-136
The aim of this study was to investigate microemulsion (ME) based topical delivery system for fenoprofen calcium (FPCa) to eliminate its oral gastrointestinal adverse effects. ME was prepared by the water titration method using oleic acid as oil phase, tween 80 as a surfactant and propylene glycol as a cosurfactant. Oleic acid was selected as oil phase due to its good solubilizing capacity. ME existence region was determined using pseudo-ternary phase diagrams for preparing different formulations. Six different formulations were selected with various values of oil (25–68%), water (2–3%), and the mixture of surfactant and cosurfactant (1:1) (24–67%). The selected ME formulae were characterized for optical birefringence, transmission electron microscopy (TEM), pH, % transmittance, electronic conductivity, drug content, droplet size, rheological properties and stability evaluation. In vitro release study of FPCa from ME s through the synthetic membrane and hairless rat skin were evaluated. The optimized formula ME5 consisting of 5% w/w FPCa, 60% w/w oleic acid as oil phase, 3% w/w aqueous phase, and 32% w/w of surfactant phase containing Tween 80 and propylene glycol (1:?1) showed the highest transdermal flux and highest skin permeation rate. Finally, the % inhibition of carrageenan-induced rat paw edema of the optimized formula ME5 was highly significant (p?0.001) as compared to plain gel of FPCa. In conclusion, ME is a promising technique for topical delivery of FPCa. 相似文献
94.
95.
Dalia Gordon 《Invertebrate neuroscience : IN》1997,3(2-3):103-116
Voltage-sensitive sodium channels are responsible for the generation of electrical signals in most excitable tissues and serve
as specific targets for many neurotoxins. At least seven distinct classes of neurotoxins have been designated on the basis
of physiological activity and competitive binding studies. Although the characterization of the neurotoxin receptor sites
was predominantly performed using vertebrate excitable preparations, insect neuronal membranes were shown to possess similar
receptor sites. We have demonstrated that the two mutually competing antiinsect excitatory and depressant scorpion toxins,
previously suggested to occupy the same receptor site, bind to two distinct receptors on insect sodium channels. The latter
provides a new approach to their combined use in insect control strategy. Although the sodium channel receptor sites are topologically
separated, there are strong allosteric interactions among them. We have shown that the lipid-soluble sodium channel activators,
veratridine and brevetoxin, reveal divergent allosteric modulation on scorpion α-toxins binding at homologous receptor sites
on mammalian and insect sodium channels. The differences suggest a functionally important structural distinction between these
channel subtypes. The differential allosteric modulation may provide a new approach to increase selective activity of pesticides
on target organisms by simultaneous application of allosterically interacting drugs, designed on the basis of the selective
toxins. Thus, a comparative study of neurotoxin receptor sites on mammalian and invertebrate sodium channels may elucidate
the structural features involved in the binding and activity of the various neurotoxins, and may offer new targets and approaches
to the development of highly selective pesticides. 相似文献
96.
97.
Validated spectrofluorimetric method for determination of two phosphodiesterase inhibitors tadalafil and vardenafil in pharmaceutical preparations and spiked human plasma 下载免费PDF全文
Mohammed Abu Bakr Abu El‐Enin Mohammed El‐Sayed Abd Al‐Ghaffar Hammouda Dina Tawfik El‐Sherbiny Dalia Rashad El‐Wasseef Saadia Mahmoud El‐Ashry 《Luminescence》2016,31(1):173-178
A valid, sensitive and rapid spectrofluorimetric method has been developed and validated for determination of both tadalafil (TAD) and vardenafil (VAR) either in their pure form, in their tablet dosage forms or spiked in human plasma. This method is based on measurement of the native fluorescence of both drugs in acetonitrile at λem 330 and 470 nm after excitation at 280 and 275 nm for tadalafil and vardenafil, respectively. Linear relationships were obtained over the concentration range 4–40 and 10–250 ng/mL with a minimum detection of 1 and 3 ng/mL for tadalafil and vardenafil, respectively. Various experimental parameters affecting the fluorescence intensity were carefully studied and optimized. The developed method was applied successfully for the determination of tadalafil and vardenafil in bulk drugs and tablet dosage forms. Moreover, the high sensitivity of the proposed method permitted their determination in spiked human plasma. The developed method was validated in terms of specificity, linearity, lower limit of quantification (LOQ), lower limit of detection (LOD), precision and accuracy. The mean recoveries of the analytes in pharmaceutical preparations were in agreement with those obtained from the comparison methods, as revealed by statistical analysis of the obtained results using Student's t‐test and the variance ratio F‐test. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
98.
Anuj Kumar Bratin Sengupta Dalia Dasgupta Tamal Mandal Siddhartha Datta 《Reviews in Environmental Science and Biotechnology》2016,15(1):47-65
Rice husk ash (RHA) is the major by-product left after the burning of rice husk, which is profusely present throughout the process of the rice milling. The burnt rice husk, as RHA, in turn causes more environmental pollution and its disposal becomes a difficult problem, hence requiring serious attention from the scientific community regarding its disposal and proper reuse if possible. The major economic reason for recycling the ash is the value added products which can be generated from it. The focus is on the use of RHA as adsorbent and subsequent silica production owing to the fact that the ash is mainly composed of carbon and silica. As regards other potential applications of ash, research is still going on and some of the products, which are under development phase, have also been brought to limelight in this review. This literature review provides an effective scheme to utilize RHA and discussed process pathway for economically valuable products to provide a solution to the problem associated with its proper disposal through superior recycle of this agriculture waste. 相似文献
99.
Malu-Clair van de Beek Inge M. E. Dijkstra Henk van Lenthe Rob Ofman Dalia Goldhaber-Pasillas Nicolas Schauer Martin Schackmann Joo-Yeon Engelen-Lee Frédéric M. Vaz Wim Kulik Ronald J. A. Wanders Marc Engelen Stephan Kemp 《PloS one》2016,11(4)
X-linked adrenoleukodystrophy (ALD), a progressive neurodegenerative disease, is caused by mutations in ABCD1 and characterized by very-long-chain fatty acids (VLCFA) accumulation. Virtually all males develop progressive myelopathy (AMN). A subset of patients, however, develops a fatal cerebral demyelinating disease (cerebral ALD). Hematopoietic stem cell transplantation is curative for cerebral ALD provided the procedure is performed in an early stage of the disease. Unfortunately, this narrow therapeutic window is often missed. Therefore, an increasing number of newborn screening programs are including ALD. To identify new biomarkers for ALD, we developed an Abcd1 knockout mouse with enhanced VLCFA synthesis either ubiquitous or restricted to oligodendrocytes. Biochemical analysis revealed VLCFA accumulation in different lipid classes and acylcarnitines. Both C26:0-lysoPC and C26:0-carnitine were highly elevated in brain, spinal cord, but also in bloodspots. We extended the analysis to patients and confirmed that C26:0-carnitine is also elevated in bloodspots from ALD patients. We anticipate that validation of C26:0-carnitine for the diagnosis of ALD in newborn bloodspots may lead to a faster inclusion of ALD in newborn screening programs in countries that already screen for other inborn errors of metabolism. 相似文献
100.
The binding of the radioiodinated insect selective neurotoxin from the venom of the scorpion Androctonus australis (AaIT), to synaptic plasma membrane vesicles derived from osmotically shocked insect synaptosomes was studied under kinetic and equilibrium conditions. The integrity of these vesicles and the existence of membrane potential and its modifiability were demonstrated by assays of the uptake of the lipophilic cation tetraphenylphosphonium. It has been shown that 125I-labeled AaIT binds specifically and reversibly to a single class of noninteracting binding sites of high affinity () and low capacity (1.2–2.0 pmol/mg protein). The values of the rate association and dissociation constants k1 and k?1 are, respectively, 1.36 · 106 M?1 · s?1 and 1.9 · 10?3 s?1, and are in a good accordance with the equilibrium constant. The use of various ionophores and changes in external potassium concentration shown to modify the membrane potential of the present neuronal preparation, did not affect the binding of 125I-AaIT, thus indicating its voltage-independence. Veratridine, tetrodotoxin, sea anemone toxin and the α and β scorpion toxins specific for vertebrates did not affect the binding of 125I-AaIT. Furthermore, the above scorpion toxins were devoid of specific binding to the present insect neuronal preparation. Two additional insect toxins derived from the venom of the scorpion Buthotus judaicus, BjIT1 (spastic-excitatory toxin, homologus to the AaIT) and BjIT2 (flaccidity inducing-depressory toxin), were both shown to displace the 125I-AaIT with a high affinity (Kd = 2.2 and 1.3 nM, respectively). These data are compared and discussed in light of the information concerning the interaction of scorpion venom toxins affecting vertebrates with mammalian neuronal tissues. 相似文献