全文获取类型
收费全文 | 435篇 |
免费 | 21篇 |
出版年
2023年 | 1篇 |
2022年 | 11篇 |
2021年 | 18篇 |
2020年 | 4篇 |
2019年 | 9篇 |
2018年 | 8篇 |
2017年 | 3篇 |
2016年 | 18篇 |
2015年 | 27篇 |
2014年 | 17篇 |
2013年 | 28篇 |
2012年 | 35篇 |
2011年 | 45篇 |
2010年 | 21篇 |
2009年 | 20篇 |
2008年 | 15篇 |
2007年 | 38篇 |
2006年 | 22篇 |
2005年 | 31篇 |
2004年 | 18篇 |
2003年 | 22篇 |
2002年 | 13篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1981年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有456条查询结果,搜索用时 718 毫秒
371.
Kavanaugh GM Wise-Draper TM Morreale RJ Morrison MA Gole B Schwemberger S Tichy ED Lu L Babcock GF Wells JM Drissi R Bissler JJ Stambrook PJ Andreassen PR Wiesmüller L Wells SI 《Nucleic acids research》2011,39(17):7465-7476
The human DEK gene is frequently overexpressed and sometimes amplified in human cancer. Consistent with oncogenic functions, Dek knockout mice are partially resistant to chemically induced papilloma formation. Additionally, DEK knockdown in vitro sensitizes cancer cells to DNA damaging agents and induces cell death via p53-dependent and -independent mechanisms. Here we report that DEK is important for DNA double-strand break repair. DEK depletion in human cancer cell lines and xenografts was sufficient to induce a DNA damage response as assessed by detection of γH2AX and FANCD2. Phosphorylation of H2AX was accompanied by contrasting activation and suppression, respectively, of the ATM and DNA-PK pathways. Similar DNA damage responses were observed in primary Dek knockout mouse embryonic fibroblasts (MEFs), along with increased levels of DNA damage and exaggerated induction of senescence in response to genotoxic stress. Importantly, Dek knockout MEFs exhibited distinct defects in non-homologous end joining (NHEJ) when compared to their wild-type counterparts. Taken together, the data demonstrate new molecular links between DEK and DNA damage response signaling pathways, and suggest that DEK contributes to DNA repair. 相似文献
372.
In the sublingual (SL) cavity, compared with the gastrointestinal tract, tablets are subjected to minimal physiological agitation,
and a limited volume of saliva is available to facilitate disintegration and dissolution. None of the official compendial
dissolution apparatuses and methods simulate these SL conditions. In this study, a custom-made dissolution apparatus was constructed,
and a novel in vitro method that simulates SL conditions was evaluated. Several epinephrine 40 mg SL tablet formulations under development and
two commercial SL tablets, isosorbide dinitrate 5 mg and nitroglycerin 0.6 mg, were studied. The dissolution medium was 2 mL
of distilled water at 25°C. Dissolution was measured at 60 and 120 s. The novel in vitro method was validated for accuracy, reproducibility, and discrimination capability, and was compared with the official US
Pharmacopeia (USP) dissolution method using apparatus 2 (Paddle). The data obtained following the novel in vitro method were accurate and reproducible. This method was capable of detecting minor changes in SL formulations that could not
be detected using other in vitro tests. Results from the official USP dissolution method and our novel in vitro method were significantly different (p < 0.05). Results reflecting the dissolution of rapidly disintegrating tablets using simulated SL conditions were obtained
using the novel in vitro dissolution method. 相似文献
373.
374.
Nazer Famah Sourassou Rachid Hanna Koffi Negloh Johannes A. J. Breeuwer Maurice W. Sabelis 《Experimental & applied acarology》2013,61(2):173-182
Studies on intraguild interactions between phytoseiid species have shown that intraguild predation occurs and is most commonly manifested as adult females of one species feeding on juveniles of another. Whether such intraguild interactions can also occur between adult females of one species and adult males of another, is not known. Herein, we report on intraguild interactions between adults of the two sexes in cross-pairing experiments involving three related phytoseiid species (Neoseiulus paspalivorus, N. baraki and N. neobaraki) that are potential candidates for controlling the coconut mite Aceria guerreronis, a serious pest of coconut palms in tropical countries. For comparative reasons, the experiments were repeated with larvae instead of males, and with only males or only females of two different species together. In the presence of an ample supply of prey, females of N. neobaraki never fed on individuals of their own species, yet appeared to be very aggressive against males, as well as larvae of the other two phytoseiid species. They also fed on females of N. paspalivorus, but rarely on females of N. baraki. Males of N. neobaraki did not suffer mortality when together with females of either of the two other phytoseiid species. Males of N. baraki did not suffer predation from females of N. paspalivorus, but males of N. paspalivorus suffered some mortality (15 %) from N. baraki females. Larvae of each of the three species were vulnerable to intraguild predation by heterospecific adult females, except for N. neobaraki larvae when together with N. baraki females. The absence or presence of intraguild predation is largely explained by the size ratios of the individuals that were put together: large individuals feed on smaller ones, but never the reverse. For each sex, size declines in the following order: N. neobaraki > N. baraki > N. paspalivorus. Moreover, for each species, females are larger than males and males are larger than larvae. Strikingly, however, females did not kill males and larvae of their own species. We propose that niche competition between related phytoseiid species is not only determined by intraguild predation on heterospecific larvae, but also by imposing great mortality on males from the intraguild prey because phytoseiid females being pseudo-arrhenotokous require insemination to produce offspring of both sexes. 相似文献
375.
Svenja Deuchler Clemens Wagner Pankaj Singh Michael Müller Rami Al-Dwairi Rachid Benjilali Markus Schill Hanns Ackermann Dimitra Bon Thomas Kohnen Benjamin Schoene Michael Koss Frank Koch 《PloS one》2016,11(3)
Purpose
To evaluate the efficacy of the virtual reality training simulator Eyesi to prepare surgeons for performing pars plana vitrectomies and its potential to predict the surgeons’ performance.Methods
In a preparation phase, four participating vitreoretinal surgeons performed repeated simulator training with predefined tasks. If a surgeon was assigned to perform a vitrectomy for the management of complex retinal detachment after a surgical break of at least 60 hours it was randomly decided whether a warmup training on the simulator was required (n = 9) or not (n = 12). Performance at the simulator was measured using the built-in scoring metrics. The surgical performance was determined by two blinded observers who analyzed the video-recorded interventions. One of them repeated the analysis to check for intra-observer consistency. The surgical performance of the interventions with and without simulator training was compared. In addition, for the surgeries with simulator training, the simulator performance was compared to the performance in the operating room.Results
Comparing each surgeon’s performance with and without warmup trainingshowed a significant effect of warmup training onto the final outcome in the operating room. For the surgeries that were preceeded by the warmup procedure, the performance at the simulator was compared with the operating room performance. We found that there is a significant relation. The governing factor of low scores in the simulator were iatrogenic retinal holes, bleedings and lens damage. Surgeons who caused minor damage in the simulation also performed well in the operating room.Conclusions
Despite the large variation of conditions, the effect of a warmup training as well as a relation between the performance at the simulator and in the operating room was found with statistical significance. Simulator training is able to serve as a warmup to increase the average performance. 相似文献376.
In Moroccan Arabic, like in many other Afroasiatic languages, certain nouns may have more than one plural form. For instance, t ? es ? wera ‘photo’ has plurals t ? s ? awer and t ? s ? werat. However, their diminutive systematically resorts to -at suffixation in the plural. The aim of this study is twofold. First, it presents an interface approach which aims to determine the structural location of number and capture the empirical contrast between broken and sound plurals. It is argued that the sound plurals are associated with the standard Num projection, whereas the broken plurals are associated lower in the structure with the n projection. Second, it provides a templatic analysis of the diminutive formation, showing that the diminutive and the internal plural markers compete for the same templatic position. External evidence for the analysis is drawn from the phenomenon of emphasis spread. The nP is presented as the maximal domain of emphasis spread in nouns. 相似文献
377.
Hassler M Singh S Yue WW Luczynski M Lakbir R Sanchez-Sanchez F Bader T Pearl LH Mittnacht S 《Molecular cell》2007,28(3):371-385
The retinoblastoma susceptibility protein, Rb, has a key role in regulating cell-cycle progression via interactions involving the central "pocket" and C-terminal regions. While the N-terminal domain of Rb is dispensable for this function, it is nonetheless strongly conserved and harbors missense mutations found in hereditary retinoblastoma, indicating that disruption of its function is oncogenic. The crystal structure of the Rb N-terminal domain (RbN), reveals a globular entity formed by two rigidly connected cyclin-like folds. The similarity of RbN to the A and B boxes of the Rb pocket domain suggests that Rb evolved through domain duplication. Structural and functional analysis provides insight into oncogenicity of mutations in RbN and identifies a unique phosphorylation-regulated site of protein interaction. Additionally, this analysis suggests a coherent conformation for the Rb holoprotein in which RbN and pocket domains directly interact, and which can be modulated through ligand binding and possibly Rb phosphorylation. 相似文献
378.
Rachid Z Katsoulas A Williams C Larroque AL McNamee J Jean-Claude BJ 《Bioorganic & medicinal chemistry letters》2007,17(15):4248-4253
Steps toward the identification of combi-molecules with strong abl tyrosine kinase (TK) inhibitory property and significant DNA damaging potential are described. The optimized combi-molecule 13a was shown to induce approximately twofold stronger abl TK inhibitory activity than Gleevec and high levels of DNA damage in chronic myelogenous leukemic cells. 相似文献
379.
The inhibition of the ubiquitin-dependent proteasome system (UPS) via specific drugs is one type of approach used to combat cancer. Although it has been suggested that UPS inhibition prevents the rapid decay of AU-rich element (ARE)-containing messages, very little is known about the cellular mechanisms leading to this effect. Here we establish a link between the inhibition of UPS activity, the formation of cytoplasmic stress granules (SGs), and mRNA metabolism. The assembly of the SGs requires the phosphorylation of the translation initiation factor eIF2alpha by a mechanism involving the stress kinase GCN2. On prolonged UPS inhibition and despite the maintenance of eIF2alpha phosphorylation, SGs disassemble and translation recovers in an Hsp72 protein-dependent manner. The formation of these SGs coincides with the disassembly of processing bodies (PBs), known as mRNA decay entities. As soon as the SGs assemble, they recruit ARE-containing messages such as p21(cip1) mRNA, which are stabilized under these conditions. Hence, our findings suggest that SGs could be considered as one of the players that mediate the early response of the cell to proteasome inhibitors by interfering temporarily with mRNA decay pathways. 相似文献
380.