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991.
992.
R. Geoff B.?SmithEmail author J. Doland?Nichols Jerome K.?Vanclay 《Biodiversity and Conservation》2005,14(10):2447-2463
In subtropical rainforest in eastern Australia, changes in the diversity of trees were compared under natural conditions and
eight silvicultural regimes over 35 years. In the treated plots basal area remaining after logging ranged from 12 to 58 m^{2}/ha.
In three control plots richness differed little over this period. In the eight treated plots richness per plot generally declined
after intervention and then gradually increased to greater than original diversity. After logging there was a reduction in
richness per plot and an increase in species richness per stem in all but the lightest selective treatments. The change in
species diversity was related to the intensity of the logging, however the time taken for species richness to return to pre-logging
levels was similar in all silvicultural treatments and was not effected by the intensity of treatment. These results suggest
that light selective logging in these forests mainly affects dominant species. The return to high diversity after only a short
time under all silvicultural regimes suggests that sustainability and the manipulation of species composition for desired
management outcomes is possible. 相似文献
993.
Synthesis and evaluation of isatin derivatives as effective SARS coronavirus 3CL protease inhibitors
Chen LR Wang YC Lin YW Chou SY Chen SF Liu LT Wu YT Kuo CJ Chen TS Juang SH 《Bioorganic & medicinal chemistry letters》2005,15(12):3058-3062
N-Substituted isatin derivatives were prepared from the reaction of isatin and various bromides via two steps. Bioactivity assay results (in vitro tests) demonstrated that some of these compounds are potent and selective inhibitors against SARS coronavirus 3CL protease with IC50 values ranging from 0.95 to 17.50 microM. Additionally, isatin 4o exhibited more potent inhibition for SARS coronavirus protease than for other proteases including papain, chymotrypsin, and trypsin. 相似文献
994.
Corbett DF Heightman TD Moss SF Bromidge SM Coggon SA Longley MJ Roa AM Williams JA Thomas DR 《Bioorganic & medicinal chemistry letters》2005,15(18):4014-4018
High-throughput screening of an array of biphenylmethylamines synthesised by high-throughput solid-phase chemistry resulted in the identification of compounds with high-affinity for the 5-ht5A receptor. The structure-activity relationship within this series and further array synthesis led to the identification of the biphenylmethylamine derivative 11, a potent and selective 5-ht5A receptor antagonist. 相似文献
995.
Lu Z Bohn J Rano T Rutkowski CA Simcoe AL Olsen DB Schleif WA Carella A Gabryelski L Jin L Lin JH Emini E Chapman K Tata JR 《Bioorganic & medicinal chemistry letters》2005,15(23):5311-5314
Efforts directed to identifying potent HIV protease inhibitors (PI) have yielded a class of compounds that are not only very active against wild-type (NL4-3) HIV virus but also very potent against a panel of PI-resistant viral isolates. Chemistry and biology are described. 相似文献
996.
997.
Amino acid residues that are involved in functional interactions in proteins have strong evolutionary pressure to remain unchanged and consequently their substitution patterns are different from those that are noninteracting. To characterize and quantify the differences between amino acid substitution patterns due to structural restraints and those under functional restraints, we have made a comparative analysis of families of homologous proteins. Residues classified as having the same amino acid type, secondary structure, accessibility, and side-chain hydrogen bonds are shown to be better conserved if they are close to the active site. We have focused on enzyme families for this analysis since they have functional sites that are easily defined by their catalytic residues. We have derived new sets of environment-specific substitution tables, which we term function-dependent environment-specific substitution tables, where amino acid residues are classified according to their distance from the functional sites. The residues that are within a distance of 9 A from the active site have distinct amino acid substitution patterns when compared to the other sites. The function-dependent environment-specific substitution tables have been tested using the sequence-structure homology recognition program FUGUE and the results compared with the recognition performance obtained using the standard environment-specific substitution tables. Significant improvements are obtained in both recognition performance and alignment accuracy using the function-dependent environment-specific substitution tables (P-value = 0.02, according to the Wilcoxon signed rank test for alignment accuracy). The alignments near the active site are greatly improved with pronounced improvements at lower percentage identities (less than 30%). 相似文献
998.
999.
It is unclear why there are so many more neurons in sensory cortex than in the sensory periphery. One possibility is that these "extra" neurons are used to overcome cortical noise and faithfully represent the acoustic stimulus. Another possibility is that even after overcoming cortical noise, there is "excess representational bandwidth" available and that this bandwidth is used to represent conjunctions of auditory and nonauditory information for computation. Here, we discuss recent data about neuronal reliability in auditory cortex showing that cortical noise may not be as high as was previously believed. Although at present, the data suggest that auditory cortex neurons can be more reliable than those in the visual cortex, we speculate that the principles governing cortical computation are universal and that visual and other cortical areas can also exploit strategies based on similarly high-fidelity activity. 相似文献
1000.
Vanek T Halík J Vanková R Valterová I 《Bioscience, biotechnology, and biochemistry》2005,69(2):321-325
Both enantiomers and the racemate of alpha-pinene were transformed by Picea abies cells immobilised on alginate. The main products were cis- and trans-verbenol, the later being further transformed to verbenone. The enantiomeric purity of each product more or less corresponded to that of the substrate. Transformation by free cells was faster than that by the immobilised cells. The ratio of products differed to some extent between the transformation by free and immobilised cells. 相似文献