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971.
The morphology of gelatin nanoparticles loaded with three different drugs (Tizanidine hydrochloride, Gatifloxacin and Fluconazole) and their characteristics of entrapment and release from gelatin nanoparticles were investigated by the analysis on nanoparticle size distribution, SEM and FT-IR in this study. The particles were prepared by nanoprecipitation using water and ethanol as a solvent and a nonsolvent, respectively. The exclusion of a crosslinking agent from the procedure led the system to have an irregularly-shaped morphology. Nonetheless, the uncrosslinked case of Gatifloxacin loading generally led to a more homogeneous population of nanoparticles than the uncrosslinked case of Tizanidine hydrochloride loading. No loading was achieved in the case of Fluconazole, whereas both Tizanidine hydrochloride and Gatifloxacin are observed of being capable of being loaded by nanoprecipitation. Tizanidine hydrochloride-loaded, blank and Gatifloxacin-loaded nanoparticles yielded, under crosslinked condition, 59.3, 23.1 and 10.6% of the used dried mass. The crosslinked Tizanidine hydrochloride-loaded particles showed the loading efficiency of 13.8%, which was decreased to 1.1% without crosslinking. A crosslinker such as glutaraldehyde is indispensable to enhance the Tizanidine hydrochloride-loading efficiency. To the contrary, the Gatifloxacin-loading efficiency for crosslinked ones was lower by a factor of 2-3 times than that for uncrosslinked ones. This is due to the carboxylic groups of Gatifloxacin and the aldehyde groups of glutaraldehyde competing with each other during the crosslinking process, to react with the amino groups of gelatin molecules. The loading efficiency of gelatin nanoparticles reported by other investigators greatly varies. Nevertheless, the loading efficiency reported by us is in good agreement with the drug-loading data of gelatin nanoparticles reported by other investigators. The 80% of loaded Tizanidine hydrochloride was released around 15 h after start-up of the release experiment, while the 20% of loaded Gatifloxacin was released more rapidly, as free Gatifloxacin, than the loaded Tizanidine hydrochloride and it showed the trend of sustained slow release during the remaining period of its release experiment. Furthermore, the result of comparative FT-IR analysis is consistent to that of the corresponding drug release study. 相似文献
972.
973.
974.
Williams JD Khan AR Harden EA Hartline CB Jefferson GM Keith KA Prichard MN Zemlicka J Peet NP Bowlin TL 《Bioorganic & medicinal chemistry》2012,20(12):3710-3718
A second-generation series of substituted methylenecyclopropane nucleosides (MCPNs) has been synthesized and evaluated for antiviral activity against a panel of human herpesviruses, and for cytotoxicity. Although alkylated 2,6-diaminopurine analogs showed little antiviral activity, the compounds containing ether and thioether substituents at the 6-position of the purine did demonstrate potent and selective antiviral activity against several different human herpesviruses. In the 6-alkoxy series, antiviral activity depended on the length of the ether carbon chain, with the optimum chain length being about four carbon units long. For the corresponding thioethers, compounds containing secondary thioethers were more potent than those with primary thioethers. 相似文献
975.
Microbial transformation of silybin (1), the major flavonolignan of milk thistle (Silybum marianum, Asteraceae), resulted in the isolation of four metabolites. The structures of the isolated metabolites were determined by spectroscopic methods. One phase I metabolite was produced by Beauveria bassiana and was characterized as 8-hydroxysilybin (2). Three phase II metabolites were produced by two Cunninghamella species and were identified as 2,3-dehydrosilybin-3-O-β-d-glucoside (3), obtained from Cunninghamella species; and silybin-7-sulfate (4) and 2,3-dehydrosilybin-7-sulfate (5), obtained from Cunninghamella blakesleana. Compared to 1 (IC(50) 284 μg/mL), the generated metabolites displayed varying levels of antioxidant activities in the DPPH free-radical scavenging assay. 相似文献
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977.
Poliovirus causes flaccid paralysis through the destruction of motor neurons in the CNS. Susceptibility to its infection is mainly due
to the interaction in between the surface capsid proteins and its receptors on the host cell surface, important for binding,
penetration and other necessary events during early infection. Receptor modification is a new approach to treat viral diseases by
the modification of target proteins structure. Binding domains are modified in an effective way to make it difficult for the virus to
recognize it. In this study, tolerant and intolerant induced mutations in the poliovirus receptor, VP1 and VP2 were identified and
substituted in the seed sequence to get the modified versions. Substitutions causing changes in initial folding were short listed and
further analyzed for high level folding, physiochemical properties and interactions. Highest RMSD values were observed in
between the seed and the mutant K90F (3.265 Å) and Q130W (3.270Å) respectively. The proposed substitutions were found to have
low functional impact and thus can be further tested and validated by the experimental researchers. Interactions analyses proved
most of the substitutions having decreased affinity for both the VP1 and VP2 and thus are of significant importance against
poliovirus. This study will play an important role for bridging computational biology to other fields of applied biology and also
will provide an insight to develop resistance against viral diseases. It is also expected that same approach can also be applicable
against other viruses like HCV, HIV and other in near future. 相似文献
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979.
SO Bafeel IA Arif MA Bakir AA Al Homaidan AH Al Farhan HA Khan 《Genetics and molecular research : GMR》2012,11(3):1934-1941
DNA barcoding is currently gaining popularity due to its simplicity and high accuracy as compared to the complexity and subjective biases associated with morphology-based identification of taxa. The standard chloroplast DNA barcode for land plants recommended by the Consortium for the Barcode of Life (CBOL) plant working group needs to be evaluated for a wide range of plant species. We therefore tested the potential of the rbcL marker for the identification of wild plants belonging to diverse families of arid regions. Maximum likelihood tree analysis was performed to evaluate the discriminatory power of the rbcL gene. Our findings showed that using rbcL gene sequences enabled identification of the majority of the samples (92%) to genus level and only 17% to species level. 相似文献
980.
Elizabeth?S?DidierEmail author Chie?Sugimoto Lisa?C?Bowers Imtiaz?A?Khan Marcelo?J?Kuroda 《Immunity & ageing : I & A》2012,9(1):25