全文获取类型
收费全文 | 688篇 |
免费 | 67篇 |
出版年
2023年 | 3篇 |
2022年 | 14篇 |
2021年 | 26篇 |
2020年 | 13篇 |
2019年 | 17篇 |
2018年 | 14篇 |
2017年 | 19篇 |
2016年 | 23篇 |
2015年 | 25篇 |
2014年 | 27篇 |
2013年 | 52篇 |
2012年 | 53篇 |
2011年 | 41篇 |
2010年 | 19篇 |
2009年 | 26篇 |
2008年 | 26篇 |
2007年 | 27篇 |
2006年 | 31篇 |
2005年 | 35篇 |
2004年 | 27篇 |
2003年 | 26篇 |
2002年 | 12篇 |
2001年 | 19篇 |
2000年 | 19篇 |
1999年 | 11篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 14篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1986年 | 3篇 |
1985年 | 8篇 |
1984年 | 11篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1979年 | 7篇 |
1977年 | 3篇 |
1971年 | 3篇 |
1969年 | 3篇 |
1968年 | 3篇 |
1967年 | 8篇 |
1963年 | 2篇 |
1959年 | 2篇 |
排序方式: 共有755条查询结果,搜索用时 15 毫秒
121.
122.
Discriminating species of Sinipta Stål (Orthoptera: Acrididae) from Uruguay based on morphological,ethological and molecular data
下载免费PDF全文
![点击此处可从《Entomological Science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Eulalia Clemente Estrellita Lorier María‐Dolores GarcÍa Alejandro López‐lópez Juan‐José Presa 《Entomological Science》2018,21(2):225-240
Two species of the genus Sinipta, S. dalmani and S. hectorisperonii, exist in Uruguay, the latter reported here for the first time. Both species have quite similar morphological features and can only be distinguished by slight details, which have led to misidentifications in the past. Specimens from both taxa were studied in order to detect suitable characters to distinguish them and to clarify their taxonomic status, by integrating previously unstudied morphological, biological and molecular characteristics. Detailed structures of the stridulatory file of both sexes were studied and described for the first time, and the sounds produced by both species were studied and described on the basis of recordings made in captivity with an analog recorder. The signal was digitized and analyzed using Avisoft software. Three different types of sound were described for both species: calling song, courtship song and disturbance song. Oscillograms and frequency spectra were provided, and the physical characteristics of the sounds of interest for species identification were established. Finally, molecular studies showed that the two taxa are reciprocally monophyletic groups. The combined results of the analyses suggest that the two studied taxa are distinct species, and point to features suitable for their identification. 相似文献
123.
Vanessa Capone Emanuela Clemente Elena Restelli Antonella Di Campli Samantha Sperduti Francesca Ornaghi Laura Pietrangelo Feliciano Protasi Roberto Chiesa Michele Sallese 《生物化学与生物物理学报:疾病的分子基础》2018,1864(10):3164-3180
Loss-of-function mutations in the SIL1 gene are linked to Marinesco-Sjögren syndrome (MSS), a rare multisystem disease of infancy characterized by cerebellar and skeletal muscle degeneration. SIL1 is a ubiquitous adenine nucleotide exchange factor for the endoplasmic reticulum (ER) chaperone BiP. The complexity of mechanisms by which loss of SIL1 causes MSS is not yet fully understood. We used HeLa cells to test the hypothesis that impaired protein folding in the ER due to loss of SIL1 could affect secretory trafficking, impairing the transport of cargoes essential for the function of MSS vulnerable cells. Immunofluorescence and ultrastructural analysis of SIL1-knocked-down cells detected ER chaperone aggregation, enlargement of the Golgi complex, increased autophagic vacuoles, and mitochondrial swelling. SIL1-interefered cells also had delayed ER-to-plasma membrane transport with retention of Na+/K+-ATPase and procollagen-I in the ER and Golgi, and increased apoptosis. The PERK pathway of the unfolded protein response was activated in SIL1-interfered cells, and the PERK inhibitor GSK2606414 attenuated the morphological and functional alterations of the secretory pathway, and significantly reduced cell death. These results indicate that loss of SIL1 is associated with alterations of secretory transport, and suggest that inhibiting PERK signalling may alleviate the cellular pathology of SIL1-related MSS. 相似文献
124.
Martial Bernoux Maria Da Conceio Santana Carvalho Boris Volkoff Carlos Clemente Cerri 《Global Change Biology》2001,7(7):779-787
This paper presents a first approximation of net CO2 fluxes from mineral soil due to land use, land‐use changes and forestry (LULUCF) activities in Brazil for the periods 1970–90 and 1975–95. The methodology employed is an adaptation of the approach proposed by the IPCC in ‘Revised 1996 guidelines for national greenhouse gas inventories’, which is based on the variations in soil C stocks as a function of changes in land‐use activities. The calculation was done separately for each Brazilian state and subsequently summarized for all of Brazil. The annual fluxes for Brazil indicate a net emission of CO2 to the atmosphere, which decreased from 93.3 Tg CO2 for the period 1970–90 to 46.4 Tg CO2 for the period 1975–95. This corresponded to yearly net emission rates of 11.0 g CO2 m?2 year?1 for the 1970–90 period and 5.5 g CO2 m?2 year?1 for the 1975–95 period. Within each administrative region, considerable differences in the yearly emission rates between the states could be observed. Several sources of uncertainties could be identified. The most important uncertainties were linked to the impact factor values, which represent changes in native C stock associated with conversion of the native vegetation to agricultural use. 相似文献
125.
126.
Recombinant Mitochondrial Manganese Containing Superoxide Dismutase Protects Against Ochratoxin A‐Induced Nephrotoxicity
下载免费PDF全文
![点击此处可从《Journal of cellular biochemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
127.
New Treatment of Medullary and Papillary Human Thyroid Cancer: Biological Effects of Hyaluronic Acid Hydrogel Loaded With Quercetin Alone or in Combination to an Inhibitor of Aurora Kinase
下载免费PDF全文
![点击此处可从《Journal of cellular physiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
128.
Natural underlying mtDNA heteroplasmy as a potential source of intra‐person hiPSC variability
下载免费PDF全文
![点击此处可从《The EMBO journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ester Perales‐Clemente Alexandra N Cook Jared M Evans Samantha Roellinger Frank Secreto Valentina Emmanuele Devin Oglesbee Vamsi K Mootha Michio Hirano Eric A Schon Andre Terzic Timothy J Nelson 《The EMBO journal》2016,35(18):1979-1990
Functional variability among human clones of induced pluripotent stem cells (hiPSCs) remains a limitation in assembling high‐quality biorepositories. Beyond inter‐person variability, the root cause of intra‐person variability remains unknown. Mitochondria guide the required transition from oxidative to glycolytic metabolism in nuclear reprogramming. Moreover, mitochondria have their own genome (mitochondrial DNA [mtDNA]). Herein, we performed mtDNA next‐generation sequencing (NGS) on 84 hiPSC clones derived from a cohort of 19 individuals, including mitochondrial and non‐mitochondrial patients. The analysis of mtDNA variants showed that low levels of potentially pathogenic mutations in the original fibroblasts are revealed through nuclear reprogramming, generating mutant hiPSCs with a detrimental effect in their differentiated progeny. Specifically, hiPSC‐derived cardiomyocytes with expanded mtDNA mutations non‐related with any described human disease, showed impaired mitochondrial respiration, being a potential cause of intra‐person hiPSC variability. We propose mtDNA NGS as a new selection criterion to ensure hiPSC quality for drug discovery and regenerative medicine. 相似文献
129.
Javier Ribal M. Loreto Fenollosa Purificación García-Segovia Gabriela Clemente Neus Escobar Neus Sanjuán 《The International Journal of Life Cycle Assessment》2016,21(5):631-645
Purpose
This study aims to develop a model with which to build diets taking into account nutritional, climate change and economic aspects. A case study is used to test the proposed model, consisting of finding the optimal menus for school children in Spain from combinations of 20 starters, 20 main dishes and 7 desserts for a 20-day planning period.Methods
An optimizing technique, specifically integer goal programming, is used as a means of designing diets which take into account the aforementioned aspects. Goal programming (GP) is used to design those menus that meet, or nearly meet, all the requirements with respect to caloric content, caloric share among macronutrients, nutrients to encourage and nutrients to limit, while reducing the carbon footprint (CFP) and the lunch budget. In order to have real, acceptable dishes, a school catering company provided information about the typical dishes they serve. The CFP of each dish was assessed, based on literature about life cycle assessment and CFP studies on food products. The nutritional value of each dish was obtained from databases, whereas prices were gathered from a wholesaler.Results and discussion
After solving the goal programming model for several CFP and budget goals, the results show reductions with respect to the average CFP of between ?13 and ?24 %, and reductions with respect to the average budget between ?10 and ?15 % while maintaining the nutritional aspects similar to the average of the proposed menus. The results show that a wide range of budget is available, maintaining an almost constant CFP and meeting nutritional requirements to a similar degree; therefore, it is possible to avoid trade-offs between the CFP and the budget. The analysis of the dishes selected shows how the optimization model, in general, avoids the dishes which have a high CFP and high price and which are low in iron content, but high in protein and cholesterol.Conclusions
Goal programming constitutes a suitable tool for designing diets which are economically, environmentally and nutritionally sustainable. Its flexibility enables specific issues to be studied, such as the existence of possible trade-offs between budget and CFP, attained by changing the budget and the CFP goals. By means of an iterative process, new dishes could be introduced or the existing ones could be improved, thus providing catering companies with useful information.130.
Carlos Landa-Solís Julio Granados-Montiel Anell Olivos-Meza Carmina Ortega-Sánchez Mónica Cruz-Lemini Cecilia Hernández-Flores María Eugenia Chang-González Ricardo Gómez García Brenda Olivos-Díaz María Cristina Velasquillo-Martínez Carlos Pineda Clemente Ibarra 《Cell and tissue banking》2016,17(1):137-145
Mobilized peripheral blood (MPB) bone marrow cells possess the potential to differentiate into a variety of mesenchymal tissue types and offer a source of easy access for obtaining stem cells for the development of experimental models with applications in tissue engineering. In the present work, we aimed to isolate by magnetic activated cell sorting CD90+ cells from MPB by means of the administration of Granulocyte-Colony Stimulating Factor and to evaluate cell proliferation capacity, after thawing of the in vitro culture of this population of mesenchymal stem cells (MSCs) in sheep. We obtained a median of 8.2 ± 0.6 million of CD90+ cells from the 20-mL MPB sample. After thawing, at day 15 under in vitro culture, the mean CD90+ cells determined by flow cytometry was 92.92 ± 1.29 % and cell duplication time determined by crystal violet staining was 47.59 h. This study describes for the first time the isolation, characterization, and post-in vitro culture thawing of CD90+ MSCs from mobilized peripheral blood in sheep. This population can be considered as a source of MSCs for experimental models in tissue engineering research. 相似文献