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991.
Form differences between biological structures can be evaluated using several approaches. When landmark data are available, a recently proposed method (euclidean-distance matrix analysis) seems to be able to differentiate between size and shape differences. This method also localizes those areas which differ most between the two structures. We have applied it to analyze the sexual dimorphism in dental arch form in a sample of 50 men and 45 women. Subjects ranged in age between 20 and 27 years, and had sound dentitions. Fourteen landmarks, corresponding to the centers of gravity (centroids) of the occlusal surfaces of all permanent teeth (right second molar to left second molar), were individualized on the dental casts of subjects. All the possible linear distances between pairs of teeth were computed, thus creating four mean form matrices (one for each arch within sex). Gender differences were tested by using euclidean-distance matrix analysis. No significant differences were demonstrated in the shape of arches, while male arches proved to be slightly bigger than female arches. © 1993 Wiley-Liss, Inc.  相似文献   
992.
993.
Different models of tubificid spermatozeugmata   总被引:2,自引:2,他引:0  
The structure of the spermatozeugmata of different tubificid species belonging to the subfamilies Tubificinae, Limnodriloidinae and Phallodrilinae was compared to the one of Tubifex tubifex. It was concluded that the spermatozeugmata of Tubificoides and Clitellio (Tubificinae) were very similar to the Tubifex ones in having a parallel arrangement of the central fertilizing sperm surrounded by a cortex made of packed atypical spermatozoa. On the contrary, Kaketio ineri and Marcusaedrilus tuber (Limnodriloidinae) and Bathydrilus formosus (Phallodrilinae) show an organization typical for each species but different from that of Tubifex mainly in lacking a double sperm line. A more comprehensive definition of the spermatozeugmata is proposed and more attention to the morphology of the sperm bundles when describing new oligochaete species is suggested, since it is possible to use this information for taxonomic and phylogenetic purposes.  相似文献   
994.
995.
Whole-body cryotherapy (WBC) covers a wide range of therapeutic applications and consists of briefly exposing the body to extremely cold air. In sports medicine, WBC is used to improve recovery from muscle injury; however, empirical studies on its application to this area are lacking. To fill this gap, we compared changes in immunological parameters (C3, IgA, IgM, IgG, C-reactive protein, PGE2), cytokines (IL-2, IL-8, IL-10), adhesion molecules (sICAM-1), and muscle enzymes (creatine kinase [CK], lactate dehydrogenase [LAD]) before and after WBC in 10 top-level Italian National team rugby players. The subjects underwent five sessions on alternate days once daily for 1 week. During the study period, the training workload was the same as that of the previous weeks. Compared to baseline values, immunological parameters remained unchanged, while CK and LAD levels significantly decreased after treatment. No alterations in immunological function were observed but there is a decrease in pro-inflammatory cytokine/chemokine and an increase in anti-inflammatory cytokine.As measured by changes in serum CK and LAD concentrations, and cytokines pathway, short-term cold air exposure was found to improve recovery from exercise-induced muscle injury and/or damage associated with intense physical training.  相似文献   
996.
&#  &#  Gianluca Polgar  &#  &#  &#  &#  &# 《水生生物学报》2014,38(1):75-86
大弹涂鱼Boleophthalmus pectinirostris间断分布于西太平洋海岸带东亚与马来西亚马六甲海峡,但马来西亚种群的分类地位尚存争议。研究使用线粒体ND5基因序列(718 bp)与核位点Rag1基因序列(1395 bp)对西北太平洋海岸带11个地点的45尾大弹涂鱼属鱼类进行系统发育关系重建,结果表明大弹涂鱼包括东亚与马来西亚两个单系群,两者形成姊妹群关系。GMYC分析、*BEAST物种树支持大弹涂鱼东亚谱系和马来西亚谱系是不同种。分子测定年龄分析表明大弹涂鱼东亚谱系与马来西亚谱系之间的分化时间为2.73百万年。因此,西北太平洋海岸带大弹涂鱼是复合体,包括两个物种:东亚种群是大弹涂鱼Boleophthalmus pectinirostris sensu stricto,而马来西亚种群是隐存种Boleophthalmus sp.。大弹涂鱼与隐存种之间的物种分化可能是晚上新世冰期海平面下降产生的地理隔离以及间冰期洋流对基因交流的阻碍两方面相互作用的结果。    相似文献   
997.
Substrate supply and protist grazing are two of the most important forces that determine the composition and properties of bacterial assemblages. General ecological theory predicts that the relative importance of these factors is changing with the environmental productivity. In the present study, the interplay between bottom-up and top-down control was studied in a productivity gradient simulated in one-stage chemostats containing natural assemblages of freshwater bacteria and heterotrophic nanoflagellates. Bacterial assemblages in the chemostats differed strongly with respect to their morphological, physiological and compositional properties in the presence versus the absence of predators. However, theses differences were modified by the productivity gradient. Whereas in predator-free chemostats the mean abundance and biomass of bacteria increased proportionally with increasing substrate supply, in treatments that included flagellates bacterial production was largely channelled into predator biomass. The bacterial morphological diversity increased along the productivity gradient with increasing substrate input but even more so with predators. Proportional to the increasing substrate supply, predation shifted the remaining bacteria towards morphologically inedible forms. Predation also caused shifts in bacterial substrate-utilization profiles, and in bacterial community composition, as analysed by terminal restriction fragment length polymorphism of PCR-amplified 16S-rRNA genes. Without predators, bacterial richness increased along the productivity gradient whereas with predators bacterial richness was higher at intermediate substrate levels. In accordance with ecological theory, these results demonstrated that predators influence all of the major characteristics of bacterial assemblages but the magnitude of this effect is modulated by the productivity of the system.  相似文献   
998.
Breastfeeding is now generally recognized as a critical factor in protecting newborns against infections. An important mechanism responsible for the antibacterial and antiviral effects of breast milk is the prevention of pathogen adhesion to host cell membranes mediated by a number of glycoconjugates, also including glycoproteins. A number of approaches to describe the complexity of human milk proteome have provided only a partial characterization of restricted classes of N-linked glycoproteins. To achieve this objective, profiling N-linked glycoproteins of human milk was performed by Hydrophilic Interaction LC (HILIC) and MS analysis. Glycopeptides were selectively enriched from the protein tryptic digest of human milk samples. Oligosaccharide-free peptides obtained by peptide N-glycosidase F (PNGase F) treatment were characterized by a shotgun MS-based approach, allowing the identification of N-glycosylated sites localized on proteins. Using this strategy, 32 different glycoproteins were identified and 63 N-glycosylated sites encrypted in them were located. The glycoproteins include immunocompetent factors, membrane fat globule-associated proteins, enzymes involved in lipid degradation and cell differentiation, specific receptors, and other gene products with still unknown functions.  相似文献   
999.
Background: Increased visceral adipose tissue (VAT) is a risk factor for an unfavorable cardio‐metabolic profile and fatty liver. Individuals with human immunodeficiency virus (HIV) on highly active antiretroviral therapy (HAART) can be associated with metabolic syndrome (MS) and higher visceral fat. However, the potential link between cardiac adiposity, emerging index of visceral adiposity, and fatty liver is still unexplored. Objective: To evaluate whether echocardiographic epicardial adipose tissue, index of cardiac adiposity, could be related to serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity, surrogate markers of fatty liver, in HIV‐infected patients with (HIV+MS+) and without HAART‐associated MS (HIV+MS‐). Methods and Procedures: This was a cross‐sectional observational study on 57 HIV+MS+ patients, 52 HIV+MS? and 57 HIV‐negative subjects with MS (HIV?MS+), as control group. Epicardial fat thickness and intra‐abdominal VAT were obtained by echocardiography and magnetic resonance imaging (MRI), respectively. Serum ALT and AST activity, plasma adiponectin levels, and MS biochemical parameters were measured. Results: Echocardiographic epicardial fat thickness was correlated with MRI‐VAT (r = 0.83, P < 0.01), AST/ALT ratio (r = 0.77, P < 0.01), ALT (r = 0.58, P < 0.01), AST (r = 0.56, P < 0.01), and adiponectin (r = ?0.45, P < 0.01) in HIV+MS+. MRI‐VAT and AST/ALT ratio were the best correlates of epicardial fat thickness (r 2 = 0.45, P < 0.01). Discussion: This study shows for the first time a clear relationship of epicardial fat, index of cardiac and visceral adiposity, and serum ALT and AST activity, markers of fatty liver, in subjects with increased visceral adiposity and cardio‐metabolic risk. This correlation seems to be independent of overall adiposity and rather function of excess visceral adiposity.  相似文献   
1000.
Objective: Echocardiographic epicardial adipose tissue is a new index of cardiac and visceral adiposity with great potential as a diagnostic tool and therapeutic target. In this study, we sought to provide threshold values of echocardiographic epicardial fat thickness associated with metabolic and anthropometric risk factors. Methods and Procedures: Epicardial fat thickness was measured in 246 consecutive white subjects (120 women, 126 men, median age 46 years (30–65), median BMI 32 kg/m2 (22–52), median waist circumference 100.5 cm (85–140)), who underwent routine transthoracic echocardiogram for standard clinical indications. Metabolic syndrome (MetS), Insulin resistance, BMI, and waist circumference categories were identified and epicardial fat was calculated. Results: Among 246 subjects, 58% had MetS. These subjects showed median values of epicardial fat thickness of 9.5 and 7.5 mm (in men and women, respectively), significantly higher than those found in subjects without MetS (no MetS) (P < 0.001). Receiver operating characteristics (ROC) analysis showed that epicardial fat thickness of 9.5 and 7.5 mm maximize the sensitivity and specificity to predict MetS, in men and women, respectively. In separate analyses, median epicardial fat thickness values of 9.5 and 7.5 mm were cutoff points associated with high abdominal fat in men and women, respectively. When insulin sensitivity was considered separately, epicardial fat thickness of 9.5 mm was associated with insulin resistance. Discussion: Median values of 9.5 and 7.5 mm should be considered the threshold values for high‐risk echocardiographic epicardial fat thickness in white men and women, respectively. Echocardiographic epicardial fat measurement may be of help for cardiometabolic risk stratification and therapeutic interventions targeting the fat.  相似文献   
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