全文获取类型
收费全文 | 1052篇 |
免费 | 125篇 |
国内免费 | 1篇 |
出版年
2022年 | 8篇 |
2021年 | 23篇 |
2020年 | 7篇 |
2019年 | 15篇 |
2018年 | 21篇 |
2017年 | 17篇 |
2016年 | 28篇 |
2015年 | 35篇 |
2014年 | 47篇 |
2013年 | 41篇 |
2012年 | 74篇 |
2011年 | 70篇 |
2010年 | 35篇 |
2009年 | 37篇 |
2008年 | 62篇 |
2007年 | 50篇 |
2006年 | 49篇 |
2005年 | 44篇 |
2004年 | 50篇 |
2003年 | 36篇 |
2002年 | 42篇 |
2001年 | 21篇 |
2000年 | 31篇 |
1999年 | 20篇 |
1998年 | 17篇 |
1997年 | 18篇 |
1996年 | 13篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 10篇 |
1992年 | 14篇 |
1991年 | 13篇 |
1990年 | 22篇 |
1989年 | 19篇 |
1988年 | 21篇 |
1987年 | 19篇 |
1986年 | 14篇 |
1985年 | 15篇 |
1984年 | 8篇 |
1983年 | 10篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 10篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1973年 | 7篇 |
1971年 | 4篇 |
1967年 | 4篇 |
1966年 | 4篇 |
排序方式: 共有1178条查询结果,搜索用时 31 毫秒
91.
92.
Christelle Oliver-Dussault Alexis Ascah Mariannick Marcil Jimmy Matas Sylvie Picard Philippe Pibarot Yan Burelle Christian F. Deschepper 《Molecular and cellular biochemistry》2010,345(1-2):271-282
The adaptation to chronic hypoxia confers long-lasting cardiac protection against acute ischemia–reperfusion injury. Protein kinase C (PKC) appears to play a role in the cardioprotective mechanism but the involvement of individual PKC isoforms remains unclear. The aim of this study was to examine the effects of chronic intermittent hypoxia (CIH; 7,000 m, 8 h/day) and acute administration of PKC-δ inhibitor (rottlerin, 0.3 mg/kg) on the expression and subcellular distribution of PKC-δ and PKC-ε in the left ventricular myocardium of adult male Wistar rats by Western blot and quantitative immunofluorescence microscopy. CIH decreased the total level of PKC-ε in homogenate without affecting the level of phosphorylated PKC-ε (Ser729). In contrast, CIH up-regulated the total level of PKC-δ as well as the level of phosphorylated PKC-δ (Ser643) in homogenate. Rottlerin partially reversed the hypoxia-induced increase in PKC-δ in the mitochondrial fraction. Immunofluorescent staining of ventricular cryo-sections revealed increased co-localization of PKC-δ with mitochondrial and sarcolemmal membranes in CIH hearts that was suppressed by rottlerin. The formation of nitrotyrosine as a marker of oxidative stress was enhanced in CIH myocardium, particularly in mitochondria. The expression of total oxidative phosphorylation complexes was slightly decreased by CIH mainly due to complex II decline. In conclusion, up-regulated PKC-δ in CIH hearts is mainly localized to mitochondrial and sarcolemmal membranes. The inhibitory effects of rottlerin on PKC-δ subcellular redistribution and cardioprotection (as shown previously) support the view that this isoform plays a role in the mechanism of CIH-induced ischemic tolerance. 相似文献
93.
Alban Franco Aude Jouaux Michel Mathieu Pascal Sourdaine Christophe Lelong Kristell Kellner Clothilde Heude Berthelin 《Cell and tissue research》2010,340(1):201-210
To understand the processes involved in tissue remodeling associated with the seasonal reproductive cycle of the oyster Crassostrea gigas, we used immunodetection and expression measurements of proliferating cell nuclear antigen (PCNA). The expression of the
PCNA gene was measured by real-time polymerase chain reaction in the whole gonadal area compared with laser microdissected
gonad and storage tissue. Results underlined the advantage of the laser microdissection approach to detect expression, mainly
for early stages of spermatogenesis. In the storage tissue, PCNA expression was reduced in the gonadal tubules, but immunolabeled
hemocytes and vesicular cells were detected when the storage tissue was being restored. In the gonadal tubules, the PCNA gene
was more highly expressed in males than in females. As soon as spermatogenesis was initiated, PCNA expression showed a high
and constant level. In females, the expression level increased gradually until the ripe stage. The immunological approach
established the involvement of peritubular cells in gonadal tubule expansion during early gametogenesis. In both sexes, gonial
mitosis was immunodetected throughout the reproductive cycle. In males, the occurrence of two types of spermatogonia was ascertained
by differential immunolabeling, and intragonadal somatic cell proliferation was noted. As expected, immunolabeling was never
observed from stage II spermatocytes to spermatozoa. In females, positively stained cells were detected from oogonia to growing
oocytes with various labeled intracellular locations. 相似文献
94.
The use of TNF-α antagonists has substantially improved the care of many patients with inflammatory and autoimmune diseases. However, approximately one third of such patients fail to respond well to treatment, regardless of the antagonist used or of the underlying disease. The mechanisms underlying these failures are analyzed in this review, and proposals made concerning how best to adapt therapeutic decisions in these instances. 相似文献
95.
Bruno Meunier Brigitte Picard Thierry Astruc Roland Labas 《Histochemistry and cell biology》2010,134(3):307-317
An accurate characterisation of muscle fibres is essential for studying muscle plasticity. During some transient events such
as ageing, myogenesis, physical activity or conversion of muscle to meat, the morphological parameters and/or the fibre type
distribution may change. Nowadays, this information is generally obtained using immunohistology techniques, but these analyses
are acknowledged to be laborious and time-consuming. In fact, each myofibre, from thousands, must be measured individually
and its expression profile in response to different anti-myosin antibodies must be established step by step. In this paper,
we describe a new histological approach using double-labelling (laminin, myosin) serial sections, fluorescence microscopy
visualisation and, finally, semi-automatic image analysis. The goal of the study was to propose a tool allowing faster fibre
type characterisation, including the identification of hybrid fibres from pure ones. The steps in the image processing prone
to subjectivity have been fully automated. On the other hand, the expert retained control of all image analysis procedures
requiring visual diagnosis. The tool that we developed with the Visilog software allowed a rapid and objective fibre typing
and morphometric characterisation of two different bovine muscles. The results were in agreement with our previous histological
and densitometric assays. The method and the tool proved to be potentially more efficient than other techniques used in our
institute or described in the literature. A more global evaluation will be considered in other laboratories as well as on
other animal species. 相似文献
96.
97.
Aurélie Gardarin Stéphane Chédin Gilles Lagniel Jean‐Christophe Aude Emmanuel Godat Patrice Catty Jean Labarre 《Molecular microbiology》2010,76(4):1034-1048
Cadmium (Cd2+) is a very toxic metal that causes DNA damage, oxidative stress and apoptosis. Despite many studies, the cellular and molecular mechanisms underlying its high toxicity are not clearly understood. We show here that very low doses of Cd2+ cause ER stress in Saccharomyces cerevisiae as evidenced by the induction of the unfolded protein response (UPR) and the splicing of HAC1 mRNA. Furthermore, mutant strains (Δire1 and Δhac1) unable to induce the UPR are hypersensitive to Cd2+, but not to arsenite and mercury. The full functionality of the pathways involved in ER stress response is required for Cd2+ tolerance. The data also suggest that Cd2+‐induced ER stress and Cd2+ toxicity are a direct consequence of Cd2+ accumulation in the ER. Cd2+ does not inhibit disulfide bond formation but perturbs calcium metabolism. In particular, Cd2+ activates the calcium channel Cch1/Mid1, which also contributes to Cd2+ entry into the cell. The results reinforce the interest of using yeast as a cellular model to study toxicity mechanisms in eukaryotic cells. 相似文献
98.
Bonnet M Cassar-Malek I Chilliard Y Picard B 《Animal : an international journal of animal bioscience》2010,4(7):1093-1109
The lean-to-fat ratio, that is, the relative masses of muscle and adipose tissue, is a criterion for the yield and quality of bovine carcasses and meat. This review describes the interactions between muscle and adipose tissue (AT) that may regulate the dynamic balance between the number and size of muscle v. adipose cells. Muscle and adipose tissue in cattle grow by an increase in the number of cells (hyperplasia), mainly during foetal life. The total number of muscle fibres is set by the end of the second trimester of gestation. By contrast, the number of adipocytes is never set. Number of adipocytes increases mainly before birth until 1 year of age, depending on the anatomical location of the adipose tissue. Hyperplasia concerns brown pre-adipocytes during foetal life and white pre-adipocytes from a few weeks after birth. A decrease in the number of secondary myofibres and an increase in adiposity in lambs born from mothers severely underfed during early pregnancy suggest a balance in the commitment of a common progenitor into the myogenic or adipogenic lineages, or a reciprocal regulation of the commitment of two distinct progenitors. The developmental origin of white adipocytes is a subject of debate. Molecular and histological data suggested a possible transdifferentiation of brown into white adipocytes, but this hypothesis has now been challenged by the characterization of distinct precursor cells for brown and white adipocytes in mice. Increased nutrient storage in fully differentiated muscle fibres and adipocytes, resulting in cell enlargement (hypertrophy), is thought to be the main mechanism, whereby muscle and fat masses increase in growing cattle. Competition or prioritization between adipose and muscle cells for the uptake and metabolism of nutrients is suggested, besides the successive waves of growth of muscle v. adipose tissue, by the inhibited or delayed adipose tissue growth in bovine genotypes exhibiting strong muscular development. This competition or prioritization occurs through cellular signalling pathways and the secretion of proteins by adipose tissue (adipokines) and muscle (myokines), putatively regulating their hypertrophy in a reciprocal manner. Further work on the mechanisms underlying cross-talk between brown or white adipocytes and muscle fibres will help to achieve better understanding as a prerequisite to improving the control of body growth and composition in cattle. 相似文献
99.
Nestor Laurier Engone Obiang Alfred Ngomanda Raymonde Mboma Thomas Nzabi Alfred Ngoye Lydia Atsima Léopold Ndjélé Jean‐Pierre Mate Christophe Lomba Nicolas Picard 《Oikos》2010,119(10):1643-1653
When considering all trees irrespective of their species, natural tropical rain forests typically exhibit spatial patterns that range from random to regular. The regularity is often interpreted as a footprint of tree competition. Using 23 permanent sample plots totalling 61 ha in the rain forests of central Africa, we characterized their spatial patterns and modelled those that exhibited regularity by a Strauss point process. This Strauss process is obtained as a Markov point process whose interaction function is an exponential function of a competition index commonly used in forestry. The parameter of this Strauss process characterizes the strength of competition. The 23 plots in central Africa differed in tree density and basal area, and could be discriminated depending on the type of spatial patterns: plots having a large basal area with respect to their density had a non regular pattern, whereas those having a small basal area with respect to their density had a regular pattern. For those plots that exhibited regularity, average tree size could be used to predict the strength of competition. The parameter of the Strauss process was significantly related to the average size by a linear relationship, such that competition decreases as average tree size increases. This relationship extrapolated to a null value of the Strauss parameter when average tree size reaches 32 cm in diameter. This relationship between average tree size and spatial pattern is a testable feature for future studies on the relationship between competition and spatial pattern in natural forests. 相似文献
100.