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421.
A role for proteins S3 and S14 in the 30 S ribosomal subunit 总被引:1,自引:0,他引:1
Small ribosomal subunits prepared by the method of Kirillov et al. (Kirillov, S. V., Makhno, V. I., Peshin, N. N., and Semenkov, Yu. P. (1986) Nucleic Acids Res. 5, 4305-4315) are active but fail to reconstitute. The inability to reconstitute is due to a deficiency in proteins S3 and S14. Supplementation of the protein component with pure S3 and S14 leads to an enhancement of the activity of the reconstituted product. Our results provide evidence that these two proteins are involved in assembly but may not be required once the 30 S subunit has been properly assembled. 相似文献
422.
R Manjunath R F Graziano W R Green 《Journal of immunology (Baltimore, Md. : 1950)》1986,136(6):2271-2279
Two variant subclones, called cl.18-5 and cl.18-12, were derived from the AKR.H-2bSL1 tumor cell line that were, in contrast to the parental cells, selectively insusceptible to H-2-restricted anti-AKR/Gross virus cytotoxic T lymphocytes (CTL). Cell surface expression of viral envelope (env) and group-specific antigens (gag) on these CTL-resistant variants were analyzed and compared with the expression of these antigens on AKR.H-2bSL1 and two other CTL-susceptible clones, cl.1 and cl.5, also derived from AKR.H-2bSL1. Although normal levels of gag-encoded and H-2 antigens were displayed on the CTL-resistant variants, the expression of five distinct determinants of viral gp70 antigen as defined by monoclonal antibodies was significantly decreased on these CTL-resistant variants relative to their expression on the CTL-susceptible cell lines. However, similar dramatic changes in cell surface gp70 antigen expression were undetectable as defined by anti-gp70-specific antiserum. Immunoprecipitation and gel electrophoretic analysis revealed that gp70 molecules from cl.18-5 cells had a lower m.w. than those of AKR.H-2bSL1, but there were no differences in the m.w. of gp70 antigens from AKR.H-2bSL1, cl.5, and cl.18-12 cells. Expression of the five gp70 antigenic determinants mentioned above was completely restored by exposure of cl.18-5 and cl.18-12 cells to the halogenated pyrimidine, iododeoxyuridine (IudR). Treatment of cl.18-5 and cl.18-12 cells with IudR simultaneously restored CTL susceptibility of these cells to anti-AKR/Gross virus CTL without affecting gag and H-2 antigen expression. Viral gp70 antigen immunoprecipitated from IudR-treated cl.18-5 cells had a mobility slightly lower, but different from that of untreated cl.18-5 cells. Pulse-labeling with [35S]-methionine showed that IudR treatment of cl.18-5 cells caused the expression of an additional high m.w. gp70 precursor protein originally absent in untreated cl.18-5 cells but present on parental AKR.H-2bSL1 cells. Collectively, these results pointed to the involvement of viral gp70 antigenic determinants in the recognition of AKR/Gross virus-induced tumor targets by anti-AKR/Gross virus CTL. 相似文献
423.
424.
Graziano Pesole Grazia Dellisanti Giuliano Preparata Cecilia Saccone 《Journal of molecular evolution》1995,41(6):1124-1127
Through a simple computer simulation, we provide clear evidence that the base composition of nucleotide sequences should be taken into account to obtain accurate estimates of the genetic distances between homologous nucleotide sequences. We tested several stochastic models and demonstrated clearly that the inferred estimates of the number of substitutions are strongly dependent on the a priori conditions superimposed in the model, i.e., equiprobability in base composition and/or transition transversion ratio. In general, the more a priori assumptions there are, the more inaccurate the results. Whereas, rather accurate estimates are obtained with stochastic methods, which take into account base composition and do not superimpose unverified a priori conditions.
Correspondence to: G. Pesole 相似文献
425.
426.
A stable rat macrophage-derived cell line (RMSV1) was established by transformation of primary peritoneal exudate cells with the SV40 virus. The RMSV1 cell line was used as a model to study the regulation of the interleukin-6 (IL6) gene expression in rate macrophages with respect to lipopolysaccharides (LPS), interleukin-1 (IL1) and glucocorticoids. The IL6 mRNA level in RMSV1 cell lines was induced 20-fold within 4 h by LPS, whereas IL1 had no effect. The glucocorticoids were able to inhibit completely the induction of the IL6 mRNA synthesis by LPS, indicating the negative regulation of the IL6 gene expression by glucocorticoids. 相似文献
427.
Prof. Dr. Gabriele Carannante Dr. Roberto Graziano Dr. Gerardo Pappone Dr. Daniela Ruberti Prof. Dr. Lucia Simone 《Facies》1999,40(1):1-24
Summary In the Late Cretaceous the carbonate platforms modified the organization of their depositional systems owing to vast and complex
geologic events. In this view, detailed analyses have been made on Senonian shelf-to-slope rudist-bearing limestones resting
on pre-Coniacian erosive surfaces or slope facies in the Nurra region (northwestern Sardinia, Italy), in the central-southern
Apennines and in the Gargano area (central-southern Italy). The main characteristic of the analyzed deposits is the spreading
of rudists in a context of foramol-type calcite-dominated benthonic sediment-producer communities.
The reconstructed Senonian depositional environments match a large complex of unprotected shelves that produced loose, diagenetically
stable mollusc-dominated bioclastic debris which were not involved in significantin situ cementation processes. High energy episodes led to repeated and more or less total remobilization of the sedimentary sheet.
On the shelves, both storm- and wind-induced currents and waves exercised a strong driving control on the sedimentary arrangement
of the shifting biogenic sediments. The latter constituted large coalescing sheets of winnowed, loose, fine-to-coarse skeletal
sands. Sandy sediments were easily involved in remobilization processes across the shelves toward the redepositional sites.
Transport modality largely depended on the granular composition of the sediments. The early and almost continuous sweeping
of the finer fraction (bioeroded-derived silt) resulted in an effective pre-sorting of the skeletal debris stored in the Senonian
open shelf settings.In situ preservation potentiality of the produced skeletal material was low and huge amounts of sands may have concurred in forming
slope aprons.
In the studied successions a two-stage evolution is documented during the Senonian.
Owing to the peculiar characteristics of the foramol-type open shelves (e.g., physiography, sediment production and composition),
the sediment distribution patterns of the Senonian rudist-bearing carbonate factories and their response to sea level fluctuations
were strongly modified with respect to the commonly accepted carbonate platform chlorozoan standard model. Major progradational
episodes of marginal sands occurred during both relative lowstands and terminal highstands of sea level. During transgressive
phases only where the sediment production was sustained (southern Tethyan carbonate platforms), the rudist-bearing depositional
systems might have dampened the typical drowning tendency of the foramol open shelves. 相似文献
– | - All over the latest Turonian-early Campanian interval the rudist-bearing shallow neritic platforms retreated, with seabed opening and deepening, and an underfeeding of the slope occurred. Probably, only where rudists strongly dominated the shelf assemblages (as in the case of the southern Tethyan carbonate platforms), their relatively high rate of bioclastic sediment production and supply might partially compensate for the increased accommodation space reducing the effects of the early Senonian transgressive phase. |
– | - In the late Senonian a huge amount of foramol skeletal sands prograded over the upper slope by means of impressive gravitative flows suggesting that main depocenters moved down-slope. The persistence of healthy, producing foramol open-shelves may be inferred by the occurrence of compositionally coherent displaced skeletal sands even if reduced findings of late Campanian-Maastrichtian shallow water limestones are known characterized by a clear upward shallowing trend. A reduced accommodation space in shallow water settings may have enhanced the high off-bank sand dispersion via an increased winnowing action exerted on loose foramol-bioclastic sediments in periods in which the shelf tops were exposed to intense current winnowing. The generalized down-slope migration of the main depocenters occurred during the late Senonian regressive phase. |
428.
Granata V Graziano G Ruggiero A Raimo G Masullo M Arcari P Vitagliano L Zagari A 《Biochimica et biophysica acta》2008,1784(4):573-581
The elongation factors (EF-Tu/EF-1 alpha) are universal proteins, involved in protein biosynthesis. A detailed characterization of the stability against temperature of SsEF-1 alpha, a three-domain protein isolated from the hyperthermophilic archaeon Sulfolobus solfataricus is presented. Thermal denaturation of both the GDP-bound (SsEF-1 alpha*.GDP) and the ligand-free (nfSsEF-1 alpha) forms was investigated by means of circular dichroism and fluorescence measurements, over the 4.0-7.5 pH interval. Data indicate that the unfolding process is cooperative with no intermediate species and that the few inter-domain contacts identified in the crystal structure of SsEF-1 alpha play a role also at high temperatures. Finally, it is shown that the enzyme exhibits two different interchangeable thermally denatured states, depending on pH. 相似文献
429.
430.
Graziano A d'Aquino R Tirino V Desiderio V Rossi A Pirozzi G 《Journal of cellular biochemistry》2008,103(2):408-412
Cancer stem cells (CSCs) are tumoral cells which have stem features such as self-renewal, high migration capacity, drug resistance, high proliferation abilities. In the last 10 years the pathological meaning and the existence of CSCs have been matter of discussion and a large number of articles have been published about the role that these cells play in the development and maintenance of the tumors. Head and neck squamous-cell carcinoma (HNSCC) is the sixth most common cancer worldwide: early diagnosis of high-risk premalignant lesions are high priorities for reducing deaths due to head and neck cancer. In the last years the CSCs hypothesis has been faced also for head and neck cancer, with the aim of a better comprehension of the tumor biology and an early diagnosis. The evidence that the development of a tumor comes from a small number of cells with stem-like characteristic, could bring too to the identification of therapies against these cellular target, fundamental for maintenance and progression of the lesion. Here, a literature review has been reported about the detection of supposed CSCs in head and neck cancer. 相似文献