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991.
992.
Pui Yan Jenny Chung Greet Beyens Steven Boonen Socrates Papapoulos Piet Geusens Marcel Karperien Filip Vanhoenacker Leon Verbruggen Erik Fransen Jan Van Offel Stefan Goemaere Hans-Georg Zmierczak René Westhovens Jean-Pierre Devogelaer Wim Van Hul 《Human genetics》2010,128(6):615-626
Paget’s disease of bone (PDB) is one of the most frequent metabolic bone disorders (1–5%), next to osteoporosis, affecting individuals above age 55. Sequestosome1 mutations explain a part of the PDB patients, but still the disease pathogenesis in the remaining PDB patients is largely unknown. Therefore, association studies investigating the relationship between genetic polymorphisms and sporadic PDB have been performed to find the genetic risk variants. Previously such studies indicated a role of the OPG and RANK gene. The latter was recently confirmed in a genome-wide association study (GWAS) which also indicated the involvement of chromosomal regions harbouring the CSF1 and OPTN gene. In this study, we sought to replicate these findings in a Belgian and a Dutch population. Similar significant results were obtained for the single nucleotide polymorphisms and the haplotypes. The most significant results are found in the CSF1 gene region, followed by the OPTN and TNFRSF11A gene region (p values ranging from 1.3 × 10?4 to 3.8 × 10?8, OR = 1.523–1.858). We next obtained significant association with a polymorphism from the chromosomal region around the TM7SF4 gene (p = 2.7 × 10?3, OR = 1.427), encoding DC-STAMP which did not reach genome-wide significance in the GWAS, but based on its function in osteoclasts it can be considered a strong candidate gene. After meta-analysis with the GWAS data, p values ranged between 2.6 × 10?4 and 8.8 × 10?32. The calculated cumulative population attributable risk of these four loci turned out to be about 67% in our two populations, indicating that most of the genetic risk for PDB is coming from genetic variants close to these four genes. 相似文献
993.
For the survival of individual isolates of gram-negative bacteria Pseudomonas putida, Achromobacter xylosoxidans, and the gram-positive bacterium Bacillus megaterium, in an environment polluted with crude oil products, the production of catalases exhibiting both catalase and dianisidine-peroxidase
activity is important. Electrophoretic resolution of cell-free extracts of aerobically grown strains in Luria–Bertani medium
during exponential phase revealed distinctive expression of catalatic and peroxidatic activities detected with 3,3′-diaminobenzidine
tetrahydrochloride. A considerable diversity in microbial catalase and peroxidase responses to 20 or 40 mM H2O2 stress, resulted from hydroperoxidase’s variant of original isolates, indicating an environmental selective pressure. However,
catalase was important for the adaptation of cultures to high concentration of 60 mM H2O2. Appreciable differences in the sensitivity to toxic effect of H2O2 (20 or 40 mM) treatment between individual isolates and their adapted variants during growth were observed until the middle
of exponential phase, but they were insignificant at the entry to stationary phase. Isolates also exhibited a considerable
diversity in catalases responses to phenolic contaminants 1 and 2 mM o- or p-phenylenediamine. Catalase activity of bacterium P. putida was visibly stimulated only by p-phenylenediamine and not by its positional isomer o-PDA. This study contributes to a better understanding of the role catalases play in bacterial responses to a polluted environment. 相似文献
994.
Jutta Ludwig-Müller Kathrin Denk Jerry D. Cohen Marcel Quint 《Journal of Plant Growth Regulation》2010,29(2):242-248
Although polar transport and the TIR1-dependent signaling pathway of the plant hormone auxin/indole-3-acetic acid (IAA) are
well characterized, understanding of the biosynthetic pathway(s) leading to the production of IAA is still limited. Genetic
dissection of IAA biosynthetic pathways has been complicated by the metabolic redundancy caused by the apparent existence
of several parallel biosynthetic routes leading to IAA production. Valuable complementary tools for genetic as well as biochemical
analysis of auxin biosynthesis would be molecular inhibitors capable of acting in vivo on specific or general components of
the pathway(s), which unfortunately have been lacking. Several indole derivatives have been previously identified to inhibit
tryptophan-dependent IAA biosynthesis in an in vitro system from maize endosperm. We examined the effect of one of them, 6-fluoroindole,
on seedling development of Arabidopsis thaliana and tested its ability to inhibit IAA biosynthesis in feeding experiments in vivo. We demonstrated a correlation of severe
developmental defects or growth retardation caused by 6-fluoroindole with significant downregulation of de novo synthesized
IAA levels, derived from the stable isotope-labeled tryptophan pool, upon treatment. Hence, 6-fluoroindole shows important
features of an inhibitor of tryptophan-dependent IAA biosynthesis both in vitro and in vivo and thus may find use as a promising
molecular tool for the identification of novel components of the auxin biosynthetic pathway(s). 相似文献
995.
An analysis of long-term changes in abundance of hibernating bats as revealed from the annual monitoring programme conducted
in four mountain regions of the Western Carpathians (Muránska planina Mts, Revúcka vrchovina Mts, Slovensky kras Mts, Štiavnické
vrchy Mts) during the period 1992–2009 is providing in the paper. Data from 52 hibernacula were analysed. Among 18 bat species
recorded, an apparent population increase of three most abundant thermophilous and originally cave dwelling species of bats,
Rhinolophus hipposideros, R. ferrumequinum, Myotis myotis, was observed. In other bat species (e.g., R. euryale, M. emarginatus, M. mystacinus, M. dasycneme, Barbastella barbastellus), population trends could not be detected and because of data scarcity, they should be evaluated from more extensive datasets
obtained from a wide range of hibernacula or from a completely different type of evidence. 相似文献
996.
Recent studies have suggested that treatment of glucocorticoid to immature growth hormone (GH)-producing cell line, MtT/S cells, dramatically induced the accumulation of GH-containing secretory granules in the cytosol and differentiated into mature GH-producing cells. However, the molecular mechanism of glucocorticoid-induced GH-containing secretory granule biogenesis in the MtT/S cells remains unknown. In the present study, we found that GH mRNA expression was facilitated by application of glucocorticoid. We artificially increased GH synthesis by transfection of green fluorescent protein-tagged GH (GH-GFP) gene. We found that the artificial elevation of GH expression in the cells did not accumulate the secretory granules in the cytosol, whereas glucocorticoid-induced the biogenesis of granules in GH-GFP-expressing MtT/S cells. We next performed DNA microarray and real-time RT-PCR analysis and found that glucocorticoid significantly altered the expression of membrane trafficking-related protein, syntaxin11 (Syx11). Immunocytochemical analysis further demonstrated that Syx11 positive structures were well colocalized with GH-containing granules in both MtT/S cells and rat anterior pituitary gland. Our findings indicate that glucocorticoid regulate the expression of Syx11 and facilitate the biogenesis and the trafficking of GH-containing granules in the MtT/S cells. 相似文献
997.
We performed all-atom molecular dynamics simulations studying the partition of ions and the ionic current through the bacterial porin OmpF and two selected mutants. The study is motivated by new, interesting experimental findings concerning their selectivity and conductance behavior at neutral pH. The mutations considered here are designed to study the effect of removal of negative charges present in the constriction zone of the wild-type OmpF channel (which contains, on one side, a cluster with three positive residues, and on the other side, two negatively charged residues). Our results show that these mutations induce an exclusion of cations from the constriction zone of the channel, substantially reducing the flow of cations. In fact, the partition of ions inside the mutant channels is strongly inhomogeneous, with regions containing an excess of cations and regions containing an excess of anions. Interestingly, the overall number of cations inside the channel is larger than the number of anions, this excess being different for each protein channel. We found that the differences in ionic charge inside these channels are justified by the differences in electric charge between the wild-type OmpF and the mutants, following an electroneutral balance. 相似文献
998.
999.
1000.
During periods of high energy demand an animal may be constrained by a physiological maximum to its energy intake rate. Predictions by allometric equations describing this maximum for endotherms were significantly surpassed during a few recent laboratory experiments on birds and mammals, being given access to food 24 h day?1. How relevant this is in the field remains to be assessed. We predicted that Bewick's swans Cygnus columbianus bewickii might surpass this maximum during stopover on their migration. We determined intake rate by measuring initial and final biomass density, and dividing the biomass difference by the feeding time required to reach this difference. This feeding time was given by the functional response. After conversion to daily energy intake rates, these exceeded the previously assumed maximum on two of the three stopover sites studied. The exception was a stopover site where daily foraging time was limited by the tidal cycle. Our study confirms that intake rates may exceed the formerly generally supposed maximum under natural conditions when foraging is possible day and night. 相似文献