全文获取类型
收费全文 | 370篇 |
免费 | 27篇 |
出版年
2024年 | 2篇 |
2023年 | 6篇 |
2022年 | 3篇 |
2021年 | 14篇 |
2020年 | 9篇 |
2019年 | 4篇 |
2018年 | 14篇 |
2017年 | 18篇 |
2016年 | 17篇 |
2015年 | 18篇 |
2014年 | 28篇 |
2013年 | 25篇 |
2012年 | 37篇 |
2011年 | 26篇 |
2010年 | 14篇 |
2009年 | 11篇 |
2008年 | 21篇 |
2007年 | 18篇 |
2006年 | 12篇 |
2005年 | 13篇 |
2004年 | 23篇 |
2003年 | 10篇 |
2002年 | 11篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1977年 | 1篇 |
排序方式: 共有397条查询结果,搜索用时 15 毫秒
41.
Gautam Sharma Nagendra Boopathy Senguttuvan Sandeep Singh Rajnish Juneja Vinay K Bahl 《Indian pacing and electrophysiology journal》2012,12(6):274-277
Central venous stenosis after the insertion of a permanent pacemaker is a well recognized complication. This late complication is encountered when there is a need to change the pacemaker lead or extract it. We describe a young male who had such a complication after many years after right side pacemaker implantation. The lesion was managed percutaneously leading to placement of a new lead from the left side. 相似文献
42.
Veerapathran A Joshi R Goswami K Dogra S Moodie EE Reddy MV Kalantri S Schwartzman K Behr MA Menzies D Pai M 《PloS one》2008,3(3):e1850
Background
Although interferon-gamma release assays (IGRA) are promising alternatives to the tuberculin skin test, interpretation of repeated testing results is hampered by lack of evidence on optimal cut-offs for conversions and reversions. A logical start is to determine the within-person variability of T-cell responses during serial testing.Methodology/Principal Findings
We performed a pilot study in India, to evaluate the short-term reproducibility of QuantiFERON-TB Gold In Tube assay (QFT) among 14 healthcare workers (HCWs) who underwent 4 serial QFT tests on day 0, 3, 9 and 12. QFT ELISA was repeated twice on the same sets of specimens. We assessed two types of reproducibility: 1) test-retest reproducibility (between-test variability), and 2) within-person reproducibility over time. Test-retest reproducibility: with dichotomous test results, extremely high concordance was noticed between two tests performed on the same sets of specimens: of the 56 samples, the test and re-test results agreed for all but 2 individuals (κ = 0.94). Discordance was noted in subjects who had IFN-γ values around the cut-off point, with both increases and decreases noted. With continuous IFN-γ results, re-test results tended to produce higher estimates of IFN-γ than the original test. Within-person reproducibility: when continuous IFN-γ data were analyzed, the within-person reproducibility was moderate to high. While persons with negative QFT results generally stayed negative, positive results tended to vary over time. Our data showed that increases of more than 16% in the IFN-γ levels are statistically improbable in the short-term.Conclusions
Conservatively assuming that long-term variability might be at least twice higher than short-term, we hypothesize that a QFT conversion requires two conditions to be met: 1) change from negative to positive result, and 2) at least 30% increase in the baseline IFN-γ response. Larger studies are needed to confirm our preliminary findings, and determine the conversion thresholds for IGRAs. 相似文献43.
ASAP3 is a focal adhesion-associated Arf GAP that functions in cell migration and invasion 总被引:2,自引:0,他引:2
Ha VL Bharti S Inoue H Vass WC Campa F Nie Z de Gramont A Ward Y Randazzo PA 《The Journal of biological chemistry》2008,283(22):14915-14926
ASAP3, an Arf GTPase-activating protein previously called DDEFL1 and ACAP4, has been implicated in the pathogenesis of hepatocellular carcinoma. We have examined in vitro and in vivo functions of ASAP3 and compared it to the related Arf GAP ASAP1 that has also been implicated in oncogenesis. ASAP3 was biochemically similar to ASAP1: the pleckstrin homology domain affected function of the catalytic domain by more than 100-fold; catalysis was stimulated by phosphatidylinositol 4,5-bisphosphate; and Arf1, Arf5, and Arf6 were used as substrates in vitro. Like ASAP1, ASAP3 associated with focal adhesions and circular dorsal ruffles. Different than ASAP1, ASAP3 did not localize to invadopodia or podosomes. Cells, derived from a mammary carcinoma and from a glioblastoma, with reduced ASAP3 expression had fewer actin stress fiber, reduced levels of phosphomyosin, and migrated more slowly than control cells. Reducing ASAP3 expression also slowed invasion of mammary carcinoma cells. In contrast, reduction of ASAP1 expression had no effect on migration or invasion. We propose that ASAP3 functions nonredundantly with ASAP1 to control cell movement and may have a role in cancer cell invasion. In comparing ASAP1 and ASAP3, we also found that invadopodia are dispensable for the invasive behavior of cells derived from a mammary carcinoma. 相似文献
44.
The effects of fluoride on the photosynthetic electron transport chain have been studied in spinach thylakoid membranes. Inhibition
in photosystem (PS) 2 electron transport rates and a subsequent increase in PS 1 electron transport rate indicated a possibility
of state transitions being a mechanism of fluoride action. This hypothesis was further confirmed by the increase in fluorescence
emission F735/685 at 77 K, a decrease in variable to maximum fluorescence ratio (Fv/Fm) at room temperature and increase in the absorption cross section of PS 1 suggesting that fluoride affects distribution of
the excitation energy in favour of PS 1 at the expense of PS 2. 相似文献
45.
We report the occurrence of a freshwater medusa from a laboratory aquarium in Ranchi, Bihar, India. The consistent emergence of these medussae coincided with sunny days after heavy and prolonged rainfall in the months of August to October. The material showed similarity with Limnocnide indica Annandale and L. nepalensis Dumont but differed in many respects, and is given the status of a distinct species, Limnocnida biharensis n.sp.Author to whom all correspondence should be addressed.Author to whom all correspondence should be addressed. 相似文献
46.
This study was designed for investigating the effect of Asparagus racemosus (AR) extract and chitosan (CTN) in facilitating the permeation of carvedilol (CDL) across rat epidermis. Transdermal flux
of carvedilol through heat-separated rat epidermis was investigated in vitro using vertical Keshary–Chien diffusion cells. Biophysical and microscopic manifestations of epidermis treated with AR extract,
CTN, and AR extract–CTN mixture were investigated by using differential scanning calorimetry, transepidermal water loss, scanning
electron microscopy (SEM), and transmission electron microscopy (TEM). Biochemical estimations of cholesterol, sphingosine,
and triglycerides were carried out for treated excised as well as viable rat epidermis. The antihypertensive activity of the
patches in comparison with that of oral carvedilol was studied in deoxycorticosterone acetate-induced hypertensive rats. The
permeation of carvedilol across excised rat epidermis was significantly higher (p < 0.05) when AR extract, CTN, or AR extract–CTN mixture was used as donor vehicle as compared to propylene glycol/ethanol
(7:3) mixture. Epidermis obtained after 12 h treatment of viable rat skin with AR extract–CTN mixture showed significantly
higher (p < 0.05) permeability to CDL as compared to that after treatment with AR extract or CTN alone. Further, the application of
patches containing AR extract–CTN mixture resulted in sustained release of CDL which was able to control the hypertension
in deoxycorticosterone acetate-induced hypertensive rats through 36 h. Estimation of micro constituents in rat epidermis revealed
maximum extraction of cholesterol, sphingosine, and triglycerides after treatment with AR extract–CTN mixture. This was manifested
in altered lipid and protein-specific thermotropic transitions. Further, increase in intercellular space, disordered lipid
structure, and corneocyte detachment as observed in SEM and TEM suggested great potential of AR extract for use as percutaneous
permeation enhancer. The developed transdermal patches of CDL containing AR extract–CTN mixture exhibited better performance
as compared to oral administration in controlling hypertension in rats. 相似文献
47.
Helen Louise May-Simera Qin Wan Balendu Shekhar Jha Juliet Hartford Vladimir Khristov Roba Dejene Justin Chang Sarita Patnaik Quanlong Lu Poulomi Banerjee Jason Silver Christine Insinna-Kettenhofen Dishita Patel Mostafa Lotfi May Malicdan Nathan Hotaling Arvydas Maminishkis Rupa Sridharan Kapil Bharti 《Cell reports》2018,22(1):189-205
48.
Aarti Yadav Rajnish Kumar Aditya Sunkaria Nitin Singhal 《Journal of biomolecular structure & dynamics》2016,34(5):993-1007
Glyoxalase-I (GLO-I) is a component of the ubiquitous detoxification system involved in the conversion of methylglyoxal (MG) to d-lactate in the glycolytic pathway. MG toxicity arises from its ability to form advanced glycation end products. GLO-I has been reported to be frequently overexpressed in various types of cancer cells. In this study, we performed structure-based virtual screening of focused flavonoids commercial library to identify potential and specific inhibitors of GLO-I. The compounds were ranked based on Glide extra precision docking score and five hits (curcumin, quercetin, morin, naringin and silibinin) were selected on the basis of their interaction with active site amino acid residues of GLO-I. Mixed mode QM/MM calculation was performed on the top-scoring hit to ascertain the role of zinc ion in ligand binding. In addition, the identified hits were subjected to MM/GBSA binding energy prediction, ADME prediction and similarity studies. The hits were tested in vitro for cell viability, and GLO-I inhibition. Naringin (ST072162) was found to be most potent inhibitor of GLO-I among the identified hits with highest glide XP dock score of ?14.906. These findings suggest that naringin could be a new scaffold for designing inhibitors against GLO-I with potential application as anticancer agents. 相似文献
49.
Federica Calì Sanjay Kumar Bharti Roberta Di Perna Robert M. Brosh Jr Francesca M. Pisani 《Nucleic acids research》2016,44(2):705-717
We present evidence that Tim establishes a physical and functional interaction with DDX11, a super-family 2 iron-sulfur cluster DNA helicase genetically linked to the chromosomal instability disorder Warsaw breakage syndrome. Tim stimulates DDX11 unwinding activity on forked DNA substrates up to 10-fold and on bimolecular anti-parallel G-quadruplex DNA structures and three-stranded D-loop approximately 4–5-fold. Electrophoretic mobility shift assays revealed that Tim enhances DDX11 binding to DNA, suggesting that the observed stimulation derives from an improved ability of DDX11 to interact with the nucleic acid substrate. Surface plasmon resonance measurements indicate that DDX11 directly interacts with Tim. DNA fiber track assays with HeLa cells exposed to hydroxyurea demonstrated that Tim or DDX11 depletion significantly reduced replication fork progression compared to control cells; whereas no additive effect was observed by co-depletion of both proteins. Moreover, Tim and DDX11 are epistatic in promoting efficient resumption of stalled DNA replication forks in hydroxyurea-treated cells. This is consistent with the finding that association of the two endogenous proteins in the cell extract chromatin fraction is considerably increased following hydroxyurea exposure. Overall, our studies provide evidence that Tim and DDX11 physically and functionally interact and act in concert to preserve replication fork progression in perturbed conditions. 相似文献
50.
Bharti P. Bawanthade Ashok A. Mistry Nilesh Ugemuge Isha S. Chaudari Sanjay J. Dhoble 《Luminescence》2024,39(4):e4736
In recent trends, radiation falls under the narrowband ultraviolet-B region (305–315 nm) widely used in phototherapy lamp applications in the treatment of skin diseases. In this paper, we report a Gd3+-doped NaYF4 luminescent material synthesized for the first time using the low-temperature co-precipitation method. It crystallized into a face-centred cubic structure, as confirmed by X-ray diffraction characterization techniques and Rietveld refinement. The photoluminescence property of the as-prepared sample shows a highly intense, sharp emission band obtained at 311 nm, which belongs to the narrowband ultraviolet-B region and corresponds to the transition of the 6P7/2→8S7/2 level of the Gd3+ ions under 272 nm excitation (8S7/2 to 6IJ). The transitions of the Gd3+ ions are detected entirely with different concentrations of Gd3+ ions. Scanning electron microscopy analysis indicated that the average particle was 288 nm. The critical distance for energy transfer was calculated to be equal to 11.5017 Å. Dipole–dipole interaction is responsible for energy transfer, as analyzed by Dexter theory. These excellent optical characteristics, together with their highly efficient and low-cost synthesis approach, indicate that synthesized NaYF4:Gd3+ phosphors have excessive potential for phototherapeutic lamp applications. 相似文献