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121.
Jerry K. Jacka 《The Australian journal of anthropology》2019,30(1):35-52
In this article I consider why individuals sacrifice their lives for the collective. In the Porgera Valley of highlands Papua New Guinea, young men who are called ‘Rambos’ engage in sustained tribal conflicts due to increasing social inequalities in an area that is supposedly benefiting from socioeconomic development. The opening of the Porgera Gold Mine in 1990 ushered in an era of anticipated benefits that were hoped to transform the lives of the region's subsistence horticulturalists. Yet, anticipated flows of mining money and social benefits have largely failed to materialise. The abjection experienced by young men eventuated into a series of tribal fights, resulting in deaths, displacements, and the destruction of most infrastructure. I examine the fighting and its aftermath in relation to anthropologies of the dark and the good and argue that these polar opposites can hinder more subtle understandings of value plurality among Porgerans. 相似文献
122.
123.
The WD repeat protein FAN regulates lysosome size independent from abnormal downregulation/membrane recruitment of protein kinase C 总被引:1,自引:0,他引:1
Möhlig H Mathieu S Thon L Frederiksen MC Ward DM Kaplan J Schütze S Kabelitz D Adam D 《Experimental cell research》2007,313(12):2703-2718
FAN (factor associated with neutral sphingomyelinase [N-SMase] activation) exhibits striking structural homologies to Lyst (lysosomal trafficking regulator), a BEACH protein whose inactivation causes formation of giant lysosomes/Chediak-Higashi syndrome. Here, we show that cells lacking FAN show a statistically significant increase in lysosome size (although less pronounced as Lyst), pointing to previously unrecognized functions of FAN in regulation of the lysosomal compartment. Since FAN regulates activation of N-SMase in complex with receptor for activated C-kinase (RACK)1, a scaffolding protein that recruits and stabilizes activated protein kinase C (PKC) isotypes at cellular membranes, and since an abnormal (calpain-mediated) downregulation/membrane recruitment of PKC has been linked to the defects observed in Lyst-deficient cells, we assessed whether PKC is also of relevance in FAN signaling. Our results demonstrate that activation of PKC is not required for regulation of N-SMase by FAN/RACK1. Conversely, activation of PKC and recruitment/stabilization by RACK1 occurs uniformly in the presence or absence of FAN (and equally, Lyst). Furthermore, regulation of lysosome size by FAN is not coupled to an abnormal downregulation/membrane recruitment of PKC by calpain. Identical results were obtained for Lyst, questioning the previously reported relevance of PKC for formation of giant lysosomes and in Chediak-Higashi syndrome. In summary, FAN mediates activation of N-SMase as well as regulation of lysosome size by signaling pathways that operate independent from activation/membrane recruitment of PKC. 相似文献
124.
125.
Fragile X syndrome (FX), the most common heritable cause of mental retardation and autism, is a developmental disorder characterized by physical, cognitive, and behavioral deficits. FX results from a trinucleotide expansion mutation in the fmr1 gene that reduces levels of fragile X mental retardation protein (FMRP). Although research efforts have focused on FMRP's impact on mGluR signaling, how the loss of FMRP leads to the individual symptoms of FX is not known. Previous studies on human FX blood cells revealed alterations in the cyclic adenosine 3', 5'-monophosphate (cAMP) cascade. We tested the hypothesis that cAMP signaling is altered in the FX nervous system using three different model systems. Induced levels of cAMP in platelets and in brains of fmr1 knockout mice are substantially reduced. Cyclic AMP induction is also significantly reduced in human FX neural cells. Furthermore, cAMP production is decreased in the heads of FX Drosophila and this defect can be rescued by reintroduction of the dfmr gene. Our results indicate that a robust defect in cAMP production in FX is conserved across species and suggest that cAMP metabolism may serve as a useful biomarker in the human disease population. Reduced cAMP induction has implications for the underlying causes of FX and autism spectrum disorders. Pharmacological agents known to modulate the cAMP cascade may be therapeutic in FX patients and can be tested in these models, thus supplementing current efforts centered on mGluR signaling. 相似文献
126.
Gutin B Johnson MH Humphries MC Hatfield-Laube JL Kapuku GK Allison JD Gower BA Daniels SR Barbeau P 《Obesity (Silver Spring, Md.)》2007,15(4):1029-1035
Objective: We tested the hypothesis that visceral adiposity, compared with general adiposity, would explain more of the variance in cardiovascular disease (CVD) risk factors. Research Method and Procedures: Subjects were 464 adolescents (238 black and 205 girls). Adiposity measures included visceral adipose tissue (VAT; magnetic resonance imaging), percent body fat (%BF; DXA), BMI, and waist girth (anthropometry). CVD risk factors were fasting insulin, fibrinogen, total to high‐density lipoprotein‐cholesterol ratio, triglycerides (TGs), systolic blood pressure, and left ventricular mass indexed to height2.7. Results: After adjustment for age, race, and sex, all adiposity indices explained significant proportions of the variance in all of the CVD risk factors; %BF tended to explain more variance than VAT. Regression models that included both %BF and VAT found that both indices explained independent proportions of the variance only for total to high‐density lipoprotein‐cholesterol ratio. For TGs, the model that included both %BF and VAT found that only VAT was significant. For systolic blood pressure and left ventricular mass indexed to height2.7, anthropometric measures explained more of the variance than VAT and %BF. Discussion: The hypothesis that visceral adiposity would explain more variance in CVD risk than general adiposity was not supported in this relatively large sample of black and white adolescents. Only for TGs did it seem that VAT was more influential than %BF. Perhaps the deleterious effect of visceral adiposity becomes greater later in life as it increases in proportion to general adiposity. 相似文献
127.
Barbeau P Johnson MH Howe CA Allison J Davis CL Gutin B Lemmon CR 《Obesity (Silver Spring, Md.)》2007,15(8):2077-2085
Objective: The goal of this study was to evaluate the impact of a 10‐month after‐school physical activity (PA) program on body composition and cardiovascular (CV) fitness in young black girls. Research Methods and Procedures: Subjects were 8‐ to 12‐year‐olds recruited from elementary schools. Body composition was measured using anthropometrics {waist circumference and BMI, DXA [percentage body fat (%BF)] and bone mineral density (BMD)}, and magnetic resonance imaging [visceral adipose tissue (VAT)]. CV fitness was measured using a graded treadmill test. The intervention consisted of 30 minutes homework/healthy snack time and 80 minutes PA (i.e., 25 minutes skills instruction, 35 minutes aerobic PA, and 20 minutes strengthening/stretching). Analyses were adjusted for age, baseline value of the dependent variable, and sexual maturation (pediatrician observation). Results: Mean attendance was 54%. Compared with the control group, the intervention group had a relative decrease in %BF (p < 0.0001), BMI (p < 0.01), and VAT (p < 0.01) and a relative increase in BMD (p < 0.0001) and CV fitness (p < 0.05). Higher attendance was associated with greater increases in BMD (p < 0.05) and greater decreases in %BF (p < 0.01) and BMI (p < 0.05). Higher heart rate during PA was associated with greater increases in BMD (p < 0.05) and greater decreases in %BF (p < 0.005). Discussion: An after‐school PA program can lead to beneficial changes in body composition and CV fitness in young black girls. It is noteworthy that the control and intervention groups differed in change in VAT but not waist circumference. This suggests that changes in central adiposity can occur in response to PA, even in young children, but that waist circumference may not be a good indicator of central adiposity. 相似文献
128.
Vera L. Trainer William P. Cochlan Aleta Erickson Brian D. Bill Frank H. Cox Jerry A. Borchert Kathi A. Lefebvre 《Harmful algae》2007,6(3):449-459
Several species of the toxigenic diatom Pseudo-nitzschia, together with low concentrations of domoic acid (DA) in shellfish have been observed in Puget Sound, Washington State, since 1991. However, for the first time in September 2003, high-density blooms of Pseudo-nitzschia forced the closure of recreational, commercial, and tribal subsistence shellfish harvesting in Puget Sound. Here we report on the environmental conditions associated with shellfish closures in two inland waterways of Washington State during the Fall 2005. In Sequim Bay, shellfish harvest losses occurred on September 12 following the measurement of elevated macronutrient levels on September 2, and a bloom of P. pseudodelicatissima (up to 13 million cells/L) on September 9. Ambient NH4 concentrations >12 μM (measured on September 2) were likely due to anthropogenic sources, ostensibly from sewage inputs to Sequim Bay. The closure of a Penn Cove commercial shellfish farm on October 16 was caused by a bloom of P. australis that followed a period of sustained precipitation, elevated Skagit River flow, and persistent southeasterly winds. The relative importance of a number of environmental factors, including temperature, stratification caused by rivers, and nutrient inputs, whether natural or anthropogenic, must be carefully studied in order to better understand the recent appearance of massive blooms of toxigenic Pseudo-nitzschia in the inland waterways of Washington State. 相似文献
129.
Rama Natarajan Wei Bai Vaijayanthy Rangarajan Noe Gonzales Jia-li Gu Linda Lanting Jerry L. Nadler 《Journal of cellular physiology》1996,169(2):391-400
Platelet-derived growth factor BB (PDGF) is a potent mitogen and chemoattractant for vascular smooth muscle cells (VSMC). In the present study, we have examined the effects of PDGF on the 12-lipoxygenase (12-LO) pathway of arachidonate metabolism in porcine aortic VSMC (PVSMC). The rationale for this is previous studies showing that LO products have growth and chemotactic effects in VSMC and that another VSMC growth factor, angiotensin II, is a potent positive regulator of 12-LO activity and expression. We observed that PDGF causes a significant increase in the formation of the 12-LO product, 12-hydroxyeicosatetraenoic acid (12-HETE) in PVSMC. In addition, PDGF also markedly increased leukocyte-type 12-LO messenger RNA and protein expression. PDGF-induced PVSMC migration was inhibited significantly by two LO blockers but not by a cyclooxygenase blocker. Furthermore, although the proliferative effects of PDGF on PVSMC were not altered by cell culture under hyperglycemic conditions (25 mM glucose, HG), the chemotactic effects of PDGF as well as those of 10% fetal calf serum were significantly greater in cells cultured in HG as compared to normal glucose conditions (5.5 mM), thus indicating a potential new mechanism for the accelerated cardiovascular disease usually observed in diabetes. These results indicate a novel mechanism for the biological effects of PDGF in leading to cardiovascular disease. © 1996 Wiley-Liss, Inc. 相似文献
130.
Phenotypic plasticity is an important driver of species resilience. Often mediated by epigenetic changes, phenotypic plasticity enables individual genotypes to express variable phenotypes in response to environmental change. Barramundi (Lates calcarifer) are a protandrous (male‐first) sequential hermaphrodite that exhibits plasticity in length‐at‐sex change between geographic regions. This plasticity is likely to be mediated by changes in DNA methylation (DNAm), a well‐studied epigenetic modification. To investigate the relationships between length, sex, and DNAm in a sequential hermaphrodite, here, we compare DNAm in four conserved vertebrate sex‐determining genes in male and female barramundi of differing lengths from three geographic regions of northern Australia. Barramundi first mature as male and later sex change to female upon the attainment of a larger body size; however, a general pattern of increasing female‐specific DNAm markers with increasing length was not observed. Significant differences in DNAm between males and females of similar lengths suggest that female‐specific DNAm arises rapidly during sex change, rather than gradually with fish growth. The findings also reveal that region‐specific differences in length‐at‐sex change are accompanied by differences in DNAm and are consistent with variability in remotely sensed sea temperature and salinity. Together, these findings provide the first in situ evidence for epigenetically and environmentally mediated sex change in a protandrous hermaphrodite and offer significant insight into the molecular and ecological processes governing the marked and unique plasticity of sex in fish. 相似文献