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991.
J. Francisco-Ortega H. J. Newbury B. V. Ford-Lloyd 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1993,87(1-2):264-270
Random Amplified Polymorphic DNA (RAPD) was used to generate molecular markers to trace the origin of the fodder legume tagasaste (Chamaecytisus proliferus (L. fil.) Link ssp. palmensis (H. Christ) Kunkel) in the Canary Islands. Results from multivariate analyses of data through Two Way Indicator Species Analysis (TWINSPAN) and Detrended Correspondence Analysis (DECORANA) showed that genotypes collected on the island of La Palma exhibited a wider range of variation than those from the other islands. This supports the existing hypothesis that tagasaste originated on La Palma and emphasizes the importance of conserving and evaluating germ plasm from this island. 相似文献
992.
Asim K. Dutta-Roy Margaret J. Gordon Derek J. Leishman Brian J. Paterson Garry G. Duthie William P. T. James 《Molecular and cellular biochemistry》1993,123(1-2):139-144
An -tocopherol-binding protein has been isolated and purified from rabbit heart cytosol. The purified protein had an apparent molecular mass of 14,200, as derived from SDS-PAGE. The content of the protein in rabbit heart was around 11.8 g per g of tissue. The binding of -tocopherol to the purified protein was rapid, reversible, and saturable. Neither nor tocopherol could displace the bound -tocopherol from the protein, suggesting a high specificity for -tocopherol. -Tocopherol-binding protein did not bind oleate. Transfer of -tocopherol from liposomes to mitochodria was stimulated 8-fold in the presence of the binding protein, suggesting that this protein may be involved in the intracellular transport of -tocopherol in the heart. 相似文献
993.
Javier Turnay Nieves Olmo alfredo Jiménez María A. Lizarbe José G. Gavilanes 《Molecular and cellular biochemistry》1993,122(1):39-47
-Sarcin is a ribosome inactivating protein produced by the mouldAspergillus giganteus. The effect of this protein on eight different tumour cell lines has been studied in the absence of any agent affecting membrane permeability. The protein is cytotoxic for all the tumour cell lines considered. -Sarcin modifies the cell proliferation pattern by inhibiting the protein biosynthesis of the cultured cells. No membrane damage produced by -sarcin has been observed by measuring lactic dehydrogenase leakage. Alteration on the cell mitochondrial activity has not been detected upon treatment with -sarcin. Differences on the extent of the protein binding to the cells have been observed by flow cytometric measurements. The kinetic analysis of the protein biosynthesis inhibition produced by -sarcin reveals an -sarcin concentration-dependent lag phase followed by a first order decrease of the protein synthesis rate. This parameter is dependent on the external -sarcin concentration. A saturable component for the action of -sarcin is also deduced from these experiments. Results are discussed in terms of the protein passage across the cell membrane as the potential rate-limiting step for the action of -sarcin. 相似文献
994.
Rhizopus is a zygomycetous genus. Several species of this taxon may infect humans and lower animals. Seventeen isolates ofRhizopus species in three distinct morphological groups were studied: the stolonifer group (sporangiophores greater than 1 mm in height, sporangial diameters of 100–275 µm, branched rhizoids); the arrhizus group (sporangiophores greater than 1 mm in height, branched rhizoids, sporangial diameters of 100–240 µm); and the microsporus group (sporangiophores less than 0.8 mm in height, sporangial diameters less than 100 µm, simple rhizoids). Maximal growth temperatures were characteristic: the stolonifer group grew at 30°C, the arrhizus group grew at 36°C, and the microsporus group grew at 45°C. The DNA mol% G + C base composition of all isolates ranged from 34.9 to 40.2% Species within the three groups were grouped by DNA differences. The arrhizus group was most distinctive with a value of 34.9–36.3%; the stolonifer and microsporus groups had G + C values of 37.0–39.3% and 37.8–40.2%, respectively. Our research clarifies and defines the G-C values of the three important groups ofRhizopus species. 相似文献
995.
Patrick van Dijck Kristina Schoonjans Paolo Sassone-Corsi Johan Auwerx Guido Verhoeven 《Molecular and cellular biochemistry》1993,125(2):127-136
The hepatic expression of the 2u gene family is controlled by a variety of hormones including steroids, growth hormone and insulin. The mechanisms by which these hormones affect -globulin expression are only partially understood. Recently we isolated and characterized clone RAP 01, an 2u-globulin gene expressed in the liver. In preliminary experiments we noted that partial hepatectomy, a procedure which results in a sharp rise in the level of the oncoproteins c-Fos and c-Jun, also causes a transient induction of the messenger RNA corresponding to clone RAP 01. Using the DNAseI footprinting technique we were able to show that this clone contains a TPA (phorbol 12-myristate 13-acetate)-responsive element (TRE) in its first intron. This element (denoted as element X) is identical to the consensus AP-1 binding site (TGACTCAG) and is protected by rat liver nuclear extracts as well as by purified c-Jun. Gel retardation experiments show that an oligonucleotide containing the TRE consensus sequence competes for binding of liver nuclear proteins to element X and that antibodies directed against the M2 peptide of the mouse Fos protein or the PEP-2 peptide of Jun prevent the formation of specific complexes with the same element. Moreover, element X functions as a TRE in transfected BWTG3 hepatoma cells treated with TPA. Co-transfection withfos andjun expression vectors mimics the effects of TPA suggesting that AP-1 is in fact the mediator of the observed response. It is concluded that the first intron of RAP 01 contains a functional Fos-Jun element. 相似文献
996.
The effect of -alanyl-L-histidinato zinc (AHZ) on bone metabolism was investigated in osteoblastic MC3T3-El cells. Cells were cultured for 3 days at 37°C in a CO2 incubator in plastic dishes containing -modified minimum essential medium supplemented with 10% fetal bovine serum. After the cultures, the medium was exchanged for that containing 0.1% bovine serum albumin plus various concentrations of AHZ or other reagents, and the cells were cultured further for appropriate periods of time. The presence of AHZ (10–7–10–5M) stimulated the proliferation of cells. AHZ (10–6 and 10–5M) increased deoxyribonucleic acid (DNA) content in the cells with 48hr-culture. This increase was completely blocked by the presence of cycloheximide (10–6M) or hydroxyurea (10–3M). Also, the presence of cycloheximide (10–6M) completely inhibited the AHZ (10–5M)-induced increase in the proliferation of cells. Meanwhile, parathyroid hormone (10–7M), estrogen (10–9M) and insulin (10–M) significantly increased cellular DNA content. However, these hormonal effects clearly lowered in comparison with that of AHZ (10–5M). Dibutyryl cyclic AMP (10–4M) and zinc sulfate (10–5M) did not cause a significant increase in cellular DNA content. The present results support the view that AHZ has a direct specific proliferative effect on osteoblastic cellsin vitro and that this effect is dependent on protein synthesis. 相似文献
997.
When clinical isolates ofSporothrix schenckii were inoculated onto the apices of living or dead sphagnum moss plants maintained under growth chamber conditions, populations of the fungus, assessed by standard dilution plate methods, increased swiftly up to about 70-fold on moist, dead plants but did not increase on the live moss. Light and scanning electron microscopy revealed fungal growth and sporulation on and within dead plants, but no evidence of either on live plants. These data provide indirect support for the contention thatS. schenckii does not grow on living sphagnum in bogs, but rather that sporotrichosis epidemics associated with sphagnum moss are likely to result from contamination of the dead plants at some point(s) in the chain of events during or after harvest. One practical implication of our results is that precautions should be taken to insure that sphagnum moss is stored dry and that it is not wetted any sooner than necessary before use. We also report here improvement of the Mycose isolation medium by an increase in cycloheximide from 400 to 800 mg/l, chloramphenicol from 50 to 250 mg/l, and the addition of rifampicin at 20 mg/l. 相似文献
998.
Placing the clawed toad Xenopus laevis on a black background stimulates the melanotrope cells in the pars intermedia of the pituitary gland to release proopiomelanocortin (POMC)-derived peptides, including -MSH and N-acetyl-endorphin. In this study three types of secretory granules, electron-dense(130 nm Ø), moderately electron-dense ( 160 nm Ø) and electronlucent ( 180 nm Ø), have been identified in these cells. Apparently, only dark granules are formed by the Golgi apparatus and lucent granules release their contents via exocytosis. Immuno-electron microscopy (immunogold double labelling) of glutaraldehyde-fixed and freeze-substituted material shows that desacetyl--MSH and N-acetyl--endorphin coexist in all three granule types. Quantification of immunostaining revealed that immunoreactivities to these peptides are lowest in the dark granules and highest in the light ones. It is proposed that intragranular processing of POMC to immunoreactive desacetyl--MSH and N-acetyl--endorphin involves an increase in granule size and a decrease in granule electron density. Black background-induced activation of the melanotrope cell is reflected by an increase in immunoreactivity of the secretory granules to each of the antisera. This suggests that cell activation stimulates the formation of peptides by intragranular processing of POMC and/or of intermediate POMC-processing products. In addition, cell activation evoked an increase in the percentage of the granule population that reacts with anti-N-acetyl--endorphin, probably by stimulating intragranular acetylation of -endorphin. Apparently, this acetylation is a regulated event that occurs in the cytoplasm, independently from the acetylation of desacetyl--MSH which takes place near the plasmalemma at the time of granule exocytosis. 相似文献
999.
DNA fingerprint bands applied to linkage analysis with quantitative trait loci in chickens 总被引:9,自引:0,他引:9
Y. Plotsky A. Cahaner A. Haberfeld J. Hillel U. Lavi S. J. Lamont 《Animal genetics》1993,24(2):105-110
Summary
An efficient approach to detect association between quantitative traits and bands of DNA fingerprint patterns uses intra-family tail analysis, which compares fingerprints of DNA mixes from individuals at the two tails of a phenotypic distribution. In analysis of 67 paternal half-sibs of a meat-type chicken family, of 57 sire bands generated by two probes, one sire-specific band (S6–6) was associated with abdominal fat deposition. The band effect was estimated by a linear model analysis to be 0–88 standard deviations, or about 30% of the family mean. The association between band S6–6 and abdominal fat was further examined by testing progeny of paternal half-sibs of the chickens which were used in the tail analysis, establishing genetic linkage between the DNA marker and a genetic locus affecting abdominal fat deposition. 相似文献
An efficient approach to detect association between quantitative traits and bands of DNA fingerprint patterns uses intra-family tail analysis, which compares fingerprints of DNA mixes from individuals at the two tails of a phenotypic distribution. In analysis of 67 paternal half-sibs of a meat-type chicken family, of 57 sire bands generated by two probes, one sire-specific band (S6–6) was associated with abdominal fat deposition. The band effect was estimated by a linear model analysis to be 0–88 standard deviations, or about 30% of the family mean. The association between band S6–6 and abdominal fat was further examined by testing progeny of paternal half-sibs of the chickens which were used in the tail analysis, establishing genetic linkage between the DNA marker and a genetic locus affecting abdominal fat deposition. 相似文献
1000.
Sharon X. Chen Charles C. Hardin Harold E. Swaisgood 《Journal of Protein Chemistry》1993,12(5):613-625
Incubation of -lactoglobulin with immobilized trypsin at 5–10°C results in a time-dependent release of several fragments of the core domain in yields approaching 15%. Digests were fractionated by ion-exchange chromatography with a Mono Q HR5/5 column and analyzed after disulfide reduction by polyacrylamide gel electrophoresis in sodium dodecylsulfate. Three fragments with approximate molecular weights of 13.8, 9.6, and 6.7 kD were identified. The fraction from ion-exchange chromatography yielding the 6.7 kD fraction after disulfide reduction was further characterized because it was most homogeneous and gave the highest yield. The C-terminal cleavage site of the 6.7 kD core fragment appeared to be Lys100 or Lys101 as determined by C-terminal amino acid analysis. The exact masses, after reduction with dithiothreitol, are 6195 and 6926 as determined by laser desorption mass spectrometry, corresponding to residues 48–101 and 41–100. Prior to reduction, -lactoglobulin C-terminal residues 149–162 are connected to these core domain fragments as shown by C-terminal analysis and mass spectrometry. Structural studies indicate that these 7.9 and 8.6 kD core domain fragments released by immobilized trypsin retain much of their native structure. CD spectra indicate the presence of antiparallel -sheet structure similar to the native protein but the -helix is lost. Spectra in the aromatic region indicate the existence of tertiary structure. Moreover, structural transitions in urea are completely reversible as measured by CD spectra, although the extrapolated G
D
H20
and the urea concentration at the transition midpoint are lower than for the native protein. The core domain fragments also display apH-dependent binding to immobilizedtrans-retinal as does intact protein. A single endotherm is obtained for both core domain fragments and native protein upon differential scanning calorimetry, but again, the domain is less stable as indicated by a transition peak maxima of 56.9°C as compared with 81.1°C for native protein.Abbreviations used: CD, circular dichroism; CPG, controlled pore glass; DSC, differential scanning calorimetry; DTT, dithiothreitol; FPLC, fast flow liquid chromatography; HPLC, high-performance liquid chromatography; PITC, phenylisothiocyanate; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; TEA, triethylamine; UV, ultraviolet. 相似文献