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131.
A.?EspinosaEmail author R.?Harnden J.?Walker 《Systemic Practice and Action Research》2005,17(6):573-589
A combination of recent cybernetic discourse provides guidelines for reconsidering our way of thinking about the relationship between government and the governed. With reference to contemporary understanding of natural biological systems and complexity, it is possible to reformulate a language that has tended to be dominated by notions of competition and survival of the fittest. Instead we can perhaps move toward reconsidering social systems in terms of a more dynamic and equitable understanding of the fit and structural dance of different systems, and postulate that the motor for progress is the coexistence of difference rather than might over right. This paper synthesizes the somewhat different insights of Stafford Beer and the Santiago School of Cognition, and reports on a real-world initiative that sought to instantiate governance as a phenomenon constituted by the governed. Technological developments of the knowledge age are proposed as supporting such democratic initiatives. 相似文献
132.
The endolithic environment, the pore space of rocks, is a ubiquitous habitat for microorganisms on the Earth and is an important target of the search for life elsewhere in the Solar System. Photosynthetic, endolithic microbial communities commonly inhabit the outer millimetres to centimetres of all rocks exposed to the Earth's surface. In the most extreme terrestrial climates, such as hot and cold deserts, endolithic microorganisms are often the main form of life. The endolithic microhabitat gives protection from intense solar radiation and desiccation, and it provides mineral nutrients, rock moisture and growth surfaces. Here we describe the discovery and identification of the constituents of an extremely acidic (pH 1) endolithic microbial community inhabiting the pore space of rocks in the geothermal environment of Yellowstone National Park, USA. Subjected to silica mineralization, such endolithic communities constitute biomarkers that can become fossilized and potentially preserved in the geological record. Remnants of these communities could serve as biosignatures and provide important clues about ancient life associated with geothermal environments on the Earth or elsewhere in the Solar System. 相似文献
133.
Summary Lactate dehydrogenase (LDH) activity was studied in the ovaries of immature rats treated with pregnant mare serum gonadotropin (PMS). LDH activity increased sharply at 36 h after PMS injection in the ovarian tissue as well as in the blood. It was suggested that the increase of LDH activity in the ovary may be related to its increasing ability to secret estrogen. 相似文献
134.
CO 2 -dependent oxygen evolution by envelope-free chloroplasts 总被引:3,自引:0,他引:3
135.
Growth processes in teeth distinguish modern humans from Homo erectus and earlier hominins. 总被引:3,自引:0,他引:3
A modern human-like sequence of dental development, as a proxy for the pace of life history, is regarded as one of the diagnostic hallmarks of our own genus Homo. Brain size, age at first reproduction, lifespan and other life-history traits correlate tightly with dental development. Here we report differences in enamel growth that show the earliest fossils attributed to Homo do not resemble modern humans in their development. We used daily incremental markings in enamel to calculate rates of enamel formation in 13 fossil hominins and identified differences in this key determinant of tooth formation time. Neither australopiths nor fossils currently attributed to early Homo shared the slow trajectory of enamel growth typical of modern humans; rather, both resembled modern and fossil African apes. We then reconstructed tooth formation times in australopiths, in the approximately 1.5-Myr-old Homo erectus skeleton from Nariokotome, Kenya, and in another Homo erectus specimen, Sangiran S7-37 from Java. These times were shorter than those in modern humans. It therefore seems likely that truly modern dental development emerged relatively late in human evolution. 相似文献
136.
Spatial heterogeneity has been examined only recently as a factor in studies of ecosystem processes. The effect of this factor on desert organisms is exemplified in the ""fertile island"" a concentration of essential soil nutrients under perennial shrubs. In this study we examined fertile island patterns in undisturbed desert areas and on abandoned roadways to see at what rate and magnitude these fertile patches reappeared after disturbance. Small-scale examination of patterns of soil P, organic matter, moisture, and bulk density showed that soils beneath Larrea tridentata (DC.) Cov. shrubs on the roads lacked the tight circular gradient in these variables that was characteristic of soils beneath control shrubs, even 88 years after road abandonment. The nature of the initial soil disturbance altered both spatial patterns of soil N and temporal patterns of fertile island development. Fertile island patterns for total soil N, available P, and organic matter were more circular than patterns for bulk density, texture, or pH. We suggest that patterns of soil heterogeneity may develop first for elements that may be limiting to desert shrub growth (N, P, organic matter), followed by spatial development in other less limiting soil factors (bulk density, texture, pH). 相似文献
137.
138.
Action Research in Management—Ethical Dilemmas 总被引:1,自引:1,他引:0
This paper discusses the application of the guiding ethical principles for the conduct of research involving human subjects in an action research project in a membership-based community psychiatric disability organization. Action research is a collaborative process of critical inquiry between the researcher and the people in the situation, in this case the management executive. The relationship between the researcher and manager participants in a long-term action research project gives rise to ethical dilemmas related to participant selection and voluntary participation, informed consent, decision making, anonymity and confidentiality, conflicting and different needs. The process and strategies implemented to address them are discussed. 相似文献
139.
Mills RE Walter K Stewart C Handsaker RE Chen K Alkan C Abyzov A Yoon SC Ye K Cheetham RK Chinwalla A Conrad DF Fu Y Grubert F Hajirasouliha I Hormozdiari F Iakoucheva LM Iqbal Z Kang S Kidd JM Konkel MK Korn J Khurana E Kural D Lam HY Leng J Li R Li Y Lin CY Luo R Mu XJ Nemesh J Peckham HE Rausch T Scally A Shi X Stromberg MP Stütz AM Urban AE Walker JA Wu J Zhang Y Zhang ZD Batzer MA Ding L Marth GT McVean G Sebat J Snyder M Wang J Ye K Eichler EE Gerstein MB Hurles ME Lee C McCarroll SA 《Nature》2011,470(7332):59-65
Genomic structural variants (SVs) are abundant in humans, differing from other forms of variation in extent, origin and functional impact. Despite progress in SV characterization, the nucleotide resolution architecture of most SVs remains unknown. We constructed a map of unbalanced SVs (that is, copy number variants) based on whole genome DNA sequencing data from 185 human genomes, integrating evidence from complementary SV discovery approaches with extensive experimental validations. Our map encompassed 22,025 deletions and 6,000 additional SVs, including insertions and tandem duplications. Most SVs (53%) were mapped to nucleotide resolution, which facilitated analysing their origin and functional impact. We examined numerous whole and partial gene deletions with a genotyping approach and observed a depletion of gene disruptions amongst high frequency deletions. Furthermore, we observed differences in the size spectra of SVs originating from distinct formation mechanisms, and constructed a map of SV hotspots formed by common mechanisms. Our analytical framework and SV map serves as a resource for sequencing-based association studies. 相似文献
140.
Xiao B Sanders MJ Underwood E Heath R Mayer FV Carmena D Jing C Walker PA Eccleston JF Haire LF Saiu P Howell SA Aasland R Martin SR Carling D Gamblin SJ 《Nature》2011,472(7342):230-233
The heterotrimeric AMP-activated protein kinase (AMPK) has a key role in regulating cellular energy metabolism; in response to a fall in intracellular ATP levels it activates energy-producing pathways and inhibits energy-consuming processes. AMPK has been implicated in a number of diseases related to energy metabolism including type 2 diabetes, obesity and, most recently, cancer. AMPK is converted from an inactive form to a catalytically competent form by phosphorylation of the activation loop within the kinase domain: AMP binding to the γ-regulatory domain promotes phosphorylation by the upstream kinase, protects the enzyme against dephosphorylation, as well as causing allosteric activation. Here we show that ADP binding to just one of the two exchangeable AXP (AMP/ADP/ATP) binding sites on the regulatory domain protects the enzyme from dephosphorylation, although it does not lead to allosteric activation. Our studies show that active mammalian AMPK displays significantly tighter binding to ADP than to Mg-ATP, explaining how the enzyme is regulated under physiological conditions where the concentration of Mg-ATP is higher than that of ADP and much higher than that of AMP. We have determined the crystal structure of an active AMPK complex. The structure shows how the activation loop of the kinase domain is stabilized by the regulatory domain and how the kinase linker region interacts with the regulatory nucleotide-binding site that mediates protection against dephosphorylation. From our biochemical and structural data we develop a model for how the energy status of a cell regulates AMPK activity. 相似文献