全文获取类型
收费全文 | 1047篇 |
免费 | 42篇 |
国内免费 | 6篇 |
出版年
2023年 | 10篇 |
2022年 | 18篇 |
2021年 | 25篇 |
2020年 | 26篇 |
2019年 | 14篇 |
2018年 | 20篇 |
2017年 | 21篇 |
2016年 | 33篇 |
2015年 | 52篇 |
2014年 | 46篇 |
2013年 | 62篇 |
2012年 | 80篇 |
2011年 | 76篇 |
2010年 | 36篇 |
2009年 | 41篇 |
2008年 | 48篇 |
2007年 | 49篇 |
2006年 | 40篇 |
2005年 | 36篇 |
2004年 | 68篇 |
2003年 | 46篇 |
2002年 | 41篇 |
2001年 | 14篇 |
2000年 | 21篇 |
1999年 | 12篇 |
1998年 | 10篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1992年 | 6篇 |
1991年 | 11篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1966年 | 4篇 |
排序方式: 共有1095条查询结果,搜索用时 921 毫秒
81.
Agricola Joachim Charlotta Nilsson Said Aboud Muhammad Bakari Eligius F. Lyamuya Merlin L. Robb Mary A. Marovich Patricia Earl Bernard Moss Christina Ochsenbauer Britta Wahren Fred Mhalu Eric Sandstr?m Gunnel Biberfeld Guido Ferrari Victoria R. Polonis 《PloS one》2015,10(4)
Vaccine-induced HIV antibodies were evaluated in serum samples collected from healthy Tanzanian volunteers participating in a phase I/II placebo-controlled double blind trial using multi-clade, multigene HIV-DNA priming and recombinant modified vaccinia Ankara (HIV-MVA) virus boosting (HIVIS03). The HIV-DNA vaccine contained plasmids expressing HIV-1 gp160 subtypes A, B, C, Rev B, Gag A, B and RTmut B, and the recombinant HIV-MVA boost expressed CRF01_AE HIV-1 Env subtype E and Gag-Pol subtype A. While no neutralizing antibodies were detected using pseudoviruses in the TZM-bl cell assay, this prime-boost vaccination induced neutralizing antibodies in 83% of HIVIS03 vaccinees when a peripheral blood mononuclear cell (PBMC) assay using luciferase reporter-infectious molecular clones (LucR-IMC) was employed. The serum neutralizing activity was significantly (but not completely) reduced upon depletion of natural killer (NK) cells from PBMC (p=0.006), indicating a role for antibody-mediated Fcγ-receptor function. High levels of antibody-dependent cellular cytotoxicity (ADCC)-mediating antibodies against CRF01_AE and/or subtype B were subsequently demonstrated in 97% of the sera of vaccinees. The magnitude of ADCC-mediating antibodies against CM235 CRF01_AE IMC-infected cells correlated with neutralizing antibodies against CM235 in the IMC/PBMC assay. In conclusion, HIV-DNA priming, followed by two HIV-MVA boosts elicited potent ADCC responses in a high proportion of Tanzanian vaccinees. Our findings highlight the potential of HIV-DNA prime HIV-MVA boost vaccines for induction of functional antibody responses and suggest this vaccine regimen and ADCC studies as potentially important new avenues in HIV vaccine development.
Trial Registration
Controlled-Trials ISRCTN90053831 The Pan African Clinical Trials Registry ATMR2009040001075080 (currently PACTR2009040001075080) 相似文献82.
Abdelghani?GhazdaliEmail author Abdelilah?Hakim Amine?Laghrib Nezha?Mamouni Said?Raghay 《Theoretical biology & medical modelling》2015,12(1):25
Background
The electrocardiogram (ECG) is a diagnostic tool that records the electrical activity of the heart, and depicts it as a series of graph-like tracings, or waves. Being able to interpret these details allows diagnosis of a wide range of heart problems. Fetal electrocardiogram (FECG) extraction has an important impact in medical diagnostics during the mother pregnancy period. Since the observed FECG signals are often mixed with the maternal ECG (MECG) and the noise induced by the movement of electrodes or by mother motion, the separation process of the ECG signal sources from the observed data becomes quite complicated. One of its complexity is when the ECG sources are dependent, thus, in this paper we introduce a new approach of blind source separation (BSS) in the noisy context for both independent and dependent ECG signal source. This approach consist in denoising the observed ECG signals using a bilateral total variation (BTV) filter; then minimizing the Kullbak-Leibler divergence between copula densities to separate the FECG signal from the MECG one.Results
We present simulation results illustrating the performance of our proposed method. We will consider many examples of independent/dependent source component signals. The results will be compared with those of the classical method called independent component analysis (ICA) under the same conditions. The accuracy of source estimation is evaluated through a criterion, called again the signal-to-noise-ratio (SNR). The first experiment shows that our proposed method gives accurate estimation of sources in the standard case of independent components, with performance around 27 dB in term of SNR. In the second experiment, we show the capability of the proposed algorithm to successfully separate two noisy mixtures of dependent source components - with classical criterion devoted to the independent case - fails, and that our method is able to deal with the dependent case with good performance.Conclusions
In this work, we focus specifically on the separation of the ECG signal sources taken from skin two electrodes located on a pregnant woman’s body. The ECG separation is interpreted as a noisy linear BSS problem with instantaneous mixtures. Firstly, a denoising step is required to reduce the noise due to motion artifacts using a BTV filter as a very effective one-pass filter for denoising. Then, we use the Kullbak-Leibler divergence between copula densities to separate the fetal heart rate from the mother one, for both independent and dependent cases.83.
Maria P. Rebollo Khalfan A. Mohammed Brent Thomas Shaali Ame Said Mohammed Ali Jorge Cano Alba Gonzalez Escalada Moses J. Bockarie 《PLoS neglected tropical diseases》2015,9(3)
BackgroundLymphatic filariasis (LF) is targeted for elimination through annual mass drug administration (MDA) for 4–6 years. In 2006, Zanzibar stopped MDA against LF after five rounds of MDA revealed no microfilaraemic individuals during surveys at selected sentinel sites. We asked the question if LF transmission was truly interrupted in 2006 when MDA was stopped.ConclusionsOur findings indicated ongoing transmission of LF on Pemba in 2012. Moreover, we presented evidence from previous studies that LF transmission was also active on Unguja shortly after stopping MDA in 2006. Based on these observations the government of Zanzibar decided to resume MDA against LF on both islands in 2013. 相似文献
84.
Introduction
Tuberculosis (TB) is a significant public health problem and the diagnosis in human immunodeficiency virus (HIV)—infected individuals is challenging. The use of mycobacterial culture remains an important complementary tool and optimizing it has important benefits. We sought to determine the effect of an increase in the number of specimens evaluated, addition of nutritional supplementation to the culture medium, sputum appearance and volume on diagnostic yield and time to detection of pulmonary TB among smear-negative, HIV-infected adults.Methods
In this prospective study conducted at the Tshwane District Hospital and Academic TB Laboratory, Pretoria, South Africa we collected three sputum specimens an hour apart from presumptive TB cases at an antiretroviral treatment site. We analysed specimens from 236 patients. Specimen appearance and volume were recorded. All specimens were processed for culture using both standard and supplemented media.Results
A single specimen identified 79% of PTB cases using standard media; the second and third specimens added 12.5% and 8.3% respectively. Media supplementation, sputum appearance and specimen volume had no effect on culture yield or contamination rates. The mean time to detection was reduced from 19.8 days in standard cultures to 11.8 days in nutrient supplemented cultures (p = 0.002). For every 1 ml increase in sputum volume, time to detection was decreased by a factor of 0.797 (p = 0.011).Conclusion
Use of an inexpensive culture supplement substantially reduced time to detection and could contribute to reducing treatment delay among HIV-infected cases. 相似文献85.
Tumaini J. Nagu Said Aboud Ramadhani Mwiru Mecky Matee Wafaie Fawzi Ferdinand Mugusi 《PloS one》2015,10(4)
Background
Surveillance and effective management of drug resistance is important to sustaining tuberculosis (TB) control efforts. We aimed to determine resistance rates to first line anti tuberculosis drugs and to describe factors associated with the resistance to any of the first line anti tuberculosis drugs in Dar es Salaam Tanzania.Materials
Newly diagnosed, TB patients with neither history of tuberculosis treatment nor isoniazid prophylaxis were included into the study. Sputum specimens were cultured on either mycobacteria growth indicator tube 960 (MGIT 960) or Lowenstein Jenstein (LJ) medium supplemented with either glycerol (GLJ) or pyruvate (PLJ). Drug susceptibility for isoniazid, rifampicin, streptomycin and ethambutol was determined by either Lowenstein–Jensen (LJ) medium or mycobacteria growth indicator tube 960 (MGIT 960).Results
A total of 933 newly diagnosed TB patients, were included into the study. Multi drug resistance (MDR) tuberculosis was detected among 2 (0.2%) patients. Resistance to any of the four tested drugs was detected among 54 (5.8%) patients. Mono-resistance to isoniazid, rifampicin, streptomycin and ethambutol were 21(2.3%), 3 (0.3%), 13 (1.4%), 9 (1.0%) respectively.Conclusion
Primary resistance to first line anti tuberculosis drugs is still low in this setting. Continued vigilance including periodic national surveillance of anti-tuberculosis resistance is recommended. 相似文献86.
87.
Said El?Shamieh Marion Neuillé Angélique Terray Elise Orhan Christel Condroyer Vanessa Démontant Christelle Michiels Aline Antonio Fiona Boyard Marie-Elise Lancelot Mélanie Letexier Jean-Paul Saraiva Thierry Léveillard Saddek Mohand-Sa?d Olivier Goureau José-Alain Sahel Christina Zeitz Isabelle Audo 《American journal of human genetics》2014,94(4):625-633
88.
Yousra Ben Khadra Khaled Said Michael Thorndyke Pedro Martinez 《Biochemical genetics》2014,52(3-4):166-180
Regeneration in echinoderms has proved to be more amenable to study in the laboratory than the more classical vertebrate models, since the smaller genome size and the absence of multiple orthologs for different genes in echinoderms simplify the analysis of gene function during regeneration. In order to understand the role of homeobox-containing genes during arm regeneration in echinoderms, we isolated the complement of genes belonging to the Hox class that are expressed during this process in two major echinoderm groups: asteroids (Echinaster sepositus and Asterias rubens) and ophiuroids (Amphiura filiformis), both of which show an extraordinary capacity for regeneration. By exploiting the sequence conservation of the homeobox, putative orthologs of several Hox genes belonging to the anterior, medial, and posterior groups were isolated. We also report the isolation of a few Hox-like genes expressed in the same systems. 相似文献
89.
90.
Said Galai Ferid Limam M. Nejib Marzouki 《World journal of microbiology & biotechnology》2010,26(8):1341-1347
A bacterial strain AAP56, isolated from a polluted soil (from Kelibia city) and identified as Stentrophomonas maltophilia, was particularly interesting for its ability to decolorize recalcitrant dyes of an industrial effluent: SITEX Black. The
final percentage decolorization 60% was shown by bacterial culture after incubation in LB medium at 30°C under shaking conditions.
The decolorization was closely correlated with the metabolic bacterial growth. The replacement of yeast extract in LB medium
composition by soya flour was clearly efficient to enhance the percentage decolorization by 20% and also to reduce the growth
medium cost 60-fold. The bacteria were able to reduce 23% from the initial COD and 28% from the initial BOD5 of the effluent. The immobilization of bacterial cells in calcium alginate beads improved by 25% the effectiveness of the
biotransformation within 24 h in batch conditions. The potential of a downflow fixed column reactor (DFCR) to decolorize SITEX
Black was evaluated under dilution rate. The best decolorization percentage (82%) was recorded at 0.3 h−1. This bioprocess seems to be a potentially useful method to remediate the colored textile wastewater. 相似文献