全文获取类型
收费全文 | 1343篇 |
免费 | 58篇 |
国内免费 | 1篇 |
出版年
2023年 | 9篇 |
2022年 | 18篇 |
2021年 | 32篇 |
2020年 | 15篇 |
2019年 | 35篇 |
2018年 | 43篇 |
2017年 | 21篇 |
2016年 | 43篇 |
2015年 | 42篇 |
2014年 | 74篇 |
2013年 | 87篇 |
2012年 | 112篇 |
2011年 | 89篇 |
2010年 | 66篇 |
2009年 | 60篇 |
2008年 | 108篇 |
2007年 | 84篇 |
2006年 | 64篇 |
2005年 | 77篇 |
2004年 | 58篇 |
2003年 | 64篇 |
2002年 | 40篇 |
2001年 | 12篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 9篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 13篇 |
1992年 | 5篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 9篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1973年 | 2篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1966年 | 2篇 |
1961年 | 2篇 |
排序方式: 共有1402条查询结果,搜索用时 359 毫秒
71.
Kevin Nelson Christopher Bobba Emre Eren Tyler Spata Malak Tadres Don Hayes Jr. Sylvester M. Black Samir Ghadiali Bryan A. Whitson 《Journal of visualized experiments : JoVE》2015,(96)
The number of acceptable donor lungs available for lung transplantation is severely limited due to poor quality. Ex-Vivo Lung Perfusion (EVLP) has allowed lung transplantation in humans to become more readily available by enabling the ability to assess organs and expand the donor pool. As this technology expands and improves, the ability to potentially evaluate and improve the quality of substandard lungs prior to transplant is a critical need. In order to more rigorously evaluate these approaches, a reproducible animal model needs to be established that would allow for testing of improved techniques and management of the donated lungs as well as to the lung-transplant recipient. In addition, an EVLP animal model of associated pathologies, e.g., ventilation induced lung injury (VILI), would provide a novel method to evaluate treatments for these pathologies. Here, we describe the development of a rat EVLP lung program and refinements to this method that allow for a reproducible model for future expansion. We also describe the application of this EVLP system to model VILI in rat lungs. The goal is to provide the research community with key information and “pearls of wisdom”/techniques that arose from trial and error and are critical to establishing an EVLP system that is robust and reproducible. 相似文献
72.
73.
Samir Khatib Pierre Rochette Mehmet Cihat Alçiçek Anne-Elisabeth Lebatard François Demory Thibaud Saos 《L'Anthropologie》2014
Stratigraphic, sedimentological and paleomagnetic studies were conducted on the travertine from Denizli Basin, near Kocabas village, in the Denizli region in Turkey, following the paleontological discovery in 2002. The stratigraphic and sedimentological studies show at least two main cycles of mass travertine, separated by a fluvial deposit and overlain by a fluvio-lacustrine deposit. These travertines must have formed in environments with strong hydrodynamics (streams or waterfalls) and are preferentially located at breaks of slopes. The paleomagnetic study shows that all the quarry travertine presents reverse magnetic polarity. On the other hand, the detrital fluvio-lacustrine deposit above the travertine presents normal geomagnetic polarity, except at the top, where it is reversed. Given the presence of an archaic Homo erectus skull and Villafranchian paleontological remains in the upper travertine unit, the whole travertine dates from the upper Matuyama, and is more recent than the Olduvai event (1.78 Ma). The normal polarity recorded in the upper fluvio-lacustrine deposit could correspond to the Cobb Mountain excursion, dated to 1.22 Ma. 相似文献
74.
Samir?F. El-Mashtoly Daniel Niedieker Dennis Petersen Sascha?D. Krauss Erik Freier Abdelouahid Maghnouj Axel Mosig Stephan Hahn Carsten K?tting Klaus Gerwert 《Biophysical journal》2014,106(9):1910-1920
Coherent anti-Stokes Raman scattering (CARS) is an emerging tool for label-free characterization of living cells. Here, unsupervised multivariate analysis of CARS datasets was used to visualize the subcellular compartments. In addition, a supervised learning algorithm based on the “random forest” ensemble learning method as a classifier, was trained with CARS spectra using immunofluorescence images as a reference. The supervised classifier was then used, to our knowledge for the first time, to automatically identify lipid droplets, nucleus, nucleoli, and endoplasmic reticulum in datasets that are not used for training. These four subcellular components were simultaneously and label-free monitored instead of using several fluorescent labels. These results open new avenues for label-free time-resolved investigation of subcellular components in different cells, especially cancer cells. 相似文献
75.
76.
Samir Okasha 《Biology & philosophy》2010,25(3):425-431
This paper contains replies to the reviews of my book by Steven Downes, Massimo Pigliucci and Deborah Shelton & Rick Michod. 相似文献
77.
78.
Mehar H. Asif Shrikant S. Mantri Ayush Sharma Anukool Srivastava Ila Trivedi Priya Gupta Chandra S. Mohanty Samir V. Sawant Rakesh Tuli 《Tree Genetics & Genomes》2010,6(6):941-952
Jatropha curcas is an important non-edible oil seed tree species and is considered a promising source of biodiesel. The complete nucleotide
sequence of J. curcas chloroplast genome (cpDNA) was determined by pyrosequencing and gaps filled by Sanger sequencing. The cpDNA is a circular
molecule of 163,856 bp in length and codes for 110 distinct genes (78 protein coding, four rRNA and 28 distinct tRNA). Genome
organisation and arrangement are similar to the reported angiosperm chloroplast genome. However, in Jatropha, the infA and the rps16 genes are non-functional. The inverted repeat (IR) boundary is within the rpl2 gene, and the 13 nucleotides at the ends of the two duplicate genes are different. Repeat analysis suggests the presence
of 72 repeat regions (>30 bp) apart from the IR; of these, 48 were direct and 24 were palindromic repeats. Phylogenetic analysis
of 81 protein coding chloroplast genes from 65 taxa by maximum parsimony, maximum likelihood and minimum evolution analyses
at 100 bootstraps provide strong support for the placement of inaperturate crotonoids of which Jatropha is a member as sister to articulated crotonoids of which Manihot is a member. 相似文献
79.
Imre Mäger Emelía Eiríksdóttir Samir EL Andaloussi Ülo Langel 《生物化学与生物物理学报:生物膜》2010,1798(3):338-1672
Cell-penetrating peptides (CPPs) have shown great potency for cargo delivery both in vitro and in vivo. Different biologically relevant molecules need to be delivered into appropriate cellular compartments in order to be active, for instance certain drugs/molecules, e.g. antisense oligonucleotides, peptides, and cytotoxic agents require delivery into the cytoplasm. Assessing uptake mechanisms of CPPs can help to develop novel and more potent cellular delivery vectors, especially in cases when reaching a specific intracellular target requires involvement of a specific internalization pathway. Here we measure the overall uptake kinetics, with emphasis on cytoplasmic delivery, of three cell-penetrating peptides M918, TP10 and pVec using a quenched fluorescence assay. We show that both the uptake levels and kinetic constants depend on the endocytosis inhibitors used in the experiments. In addition, in some cases only the internalization rate is affected by the endocytosis inhibitors while the total uptake level is not and vice versa, which emphasizes importance of kinetic studies when assessing the uptake mechanisms of CPPs. Also, there seems to be a correlation between lower total cellular uptake and higher first-order rate constants. Furthermore, this may indicate simultaneous involvement of different endocytic pathways with different efficacies in the internalization process, as hypothesized but not shown earlier in an uptake kinetics assay. 相似文献
80.
Amany K. Ibrahim Mohamed M. Radwan Safwat A. Ahmed Desmond Slade Samir A. Ross Mahmoud A. ElSohly Ikhlas A. Khan 《Phytochemistry》2010,71(8-9):1014-1019
Microbial metabolism of cannflavin A (1) and B (2), two biologically active flavonoids isolated from Cannabis sativa L., produced five metabolites (3–7). Incubation of 1 and 2 with Mucor ramannianus (ATCC 9628) and Beauveria bassiana (ATCC 13144), respectively, yielded 6″S,7″-dihydroxycannflavin A (3), 6″S,7″-dihydroxycannflavin A 7-sulfate (4) and 6″S,7″-dihydroxycannflavin A 4′-O-α-l-rhamnopyranoside (5), and cannflavin B 7-O-β-d-4?-O-methylglucopyranoside (6) and cannflavin B 7-sulfate (7), respectively. All compounds were evaluated for antimicrobial and antiprotozoal activity. 相似文献