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91.
目前对于结核分枝杆菌进入潜伏期的机制以及再激化的原因知之甚少,一个重要的原因是缺乏潜伏感染(LTBI)动物模型,完整的LTBI模型应包括两种类型,一是低剂量荷菌的持续性感染模型,另一种为潜伏感染模型,即Cornell模型的改进型。综合使用柯氏量表评分、脾肺荷菌数、诱导的IFN-γ和TNF-α水平、组织中IL-10和IL-4的表达、脏器中特异性抗原负荷以及激素诱导TB复发的时间、潜伏感染相关基因的表达水平等指标可以比较准确、客观、特异性的评价小鼠LTBI模型的反应性。  相似文献   
92.
摘要 目的:分析川崎病患儿并发冠状动脉损伤(CAL)的危险因素,并构建和评价川崎病患儿并发CAL的预测模型。方法:选取2019年1月~2022年5月我院收治的342例川崎病患儿,根据是否并发CAL分为CAL组和非CAL组。收集所有患儿临床资料,采用单因素和多因素Logistic回归分析川崎病患儿并发CAL的影响因素,并构建预测模型,H-L检验和受试者工作特征(ROC)曲线检验预测模型拟合优度和对川崎病患儿并发CAL的预测价值。结果:342例川崎病患儿CAL发生率为16.67%(57/342)。单因素分析显示,CAL组发热持续时间≥10 d、静脉注射免疫球蛋白(IVIG)治疗延迟、IVIG无反应比例和单核细胞比例(MO%)、嗜酸性粒细胞比例(EO%)、C反应蛋白(CRP)、红细胞沉降率(ESR)、降钙素原(PCT)、心肌肌钙蛋白I(cTnI)、肌酸激酶同工酶(CK-MB)水平高于非CAL组(P均<0.05)。多因素Logistic回归分析显示,发热持续时间≥10 d、IVIG治疗延迟、IVIG无反应和MO%、CRP、ESR、PCT、cTnI升高为川崎病患儿并发CAL的独立危险因素(P均<0.05)。H-L检验川崎病患儿并发CAL的预测模型拟合效果良好。ROC曲线分析显示,该模型预测川崎病患儿并发CAL的曲线下面积(AUC)为0.911(95%CI:0.876~0.939)。结论:发热持续时间≥10 d、IVIG治疗延迟、IVIG无反应和MO%、CRP、ESR、PCT、cTnI升高为川崎病患儿并发CAL的危险因素,根据危险因素构建的川崎病患儿并发CAL预测模型价值较高。  相似文献   
93.
Solid, well-grounded teachers can be instrumental in solving the problems facing our schools and students because it is successful teachers who are the most valuable, in-school contributors to our students' success. The importance of teacher preparation programs (TPPs) in developing quality teachers has been reinforced by researchers who have demonstrated that preparation linked directly to practice benefits teachers in their first year of teaching. In contrast, federal legislation and government officials' statements suggest that TPPs are responsible for many of the problems facing public education, which has resulted in additional regulations and systems designed to evaluate TPPs' success in preparing effective teachers, including graduates' knowledge of appropriate content. In order to analyze the status of TPP evaluation as it relates to arts education, past models for TPP assessment are reviewed, newer models are discussed, and the possible effects on teacher evaluation processes are outlined. Early research and scholarly writing into the noted and projected effect of these models are discussed as well as suggestions and implications for future models and research into TPP effectiveness.  相似文献   
94.
The ubiquitous, eukaryotic, high-mobility group box (HMGB) chromosomal proteins promote many chromatin-mediated cellular activities through their non-sequence-specific binding and bending of DNA. Minor-groove DNA binding by the HMG box results in substantial DNA bending toward the major groove owing to electrostatic interactions, shape complementarity, and DNA intercalation that occurs at two sites. Here, the structures of the complexes formed with DNA by a partially DNA intercalation-deficient mutant of Drosophila melanogaster HMGD have been determined by X-ray crystallography at a resolution of 2.85 Å. The six proteins and 50 bp of DNA in the crystal structure revealed a variety of bound conformations. All of the proteins bound in the minor groove, bridging DNA molecules, presumably because these DNA regions are easily deformed. The loss of the primary site of DNA intercalation decreased overall DNA bending and shape complementarity. However, DNA bending at the secondary site of intercalation was retained and most protein-DNA contacts were preserved. The mode of binding resembles the HMGB1 box A-cisplatin-DNA complex, which also lacks a primary intercalating residue. This study provides new insights into the binding mechanisms used by HMG boxes to recognize varied DNA structures and sequences as well as modulate DNA structure and DNA bending.  相似文献   
95.
Biological conservation is not only about facts and technical measures concerning ecology, rather it must also consider values. This pertains to both the balancing of various human interests and also to the ethical evaluation of human actions towards nature. Here we discuss how environmental ethics can be incorporated into conservation decisions, and what implications the inclusion of ethical valuation has for the practice of conservation biology. While this is done mostly on a rather abstract level, we illustrate this here by applying ethical theory to a case study: the options for management of the introduced North American beaver (Castor canadensis) in the very south of Chile (Navarino Island). The beaver is an exotic species to the area and has substantially altered the ecological systems of the region. We discuss different options for dealing with the beaver (eradicate, control, tolerate, promote) from the viewpoint of anthropocentric environmental ethics and biocentric ethics. The results of our analysis demonstrate the value of ethical discussions in clarifying and underpinning arguments for and against specific actions. At the same time, they also show that ethical arguments do not decrease the need for sound scientific data but, on the contrary, may even increase this demand. We also highlight that the conclusions regarding adequate actions to be taken vary depending on the specific ethical theory embraced.
Kurt JaxEmail:
  相似文献   
96.
97.
Summary The relative efficiency of seven extractants for estimating available Cu in sierozem soils of Haryana was studied. Bulk samples of 15 soils ranging in neutral normal amm. acetate extractable Cu from 0.12 to 0.20 ppm were subjected to screen-house study. The quantities of Cu extracted with neutral normal amm. acetate, Morgan’s reagent (pH 4.8)N ammonium acetate (pH 4.8), 0.1N HCl, 0.02M EDTA, critrate-EDTA and DTPA from soils were examined for their correlation with responses of maize in terms of Bray’s percentage yield and percentage Cu uptake. The highest coefficient of correlation was obtained between Cu extractable with neutral 1N NH4OAc and Bray’s per cent yield and per cent Cu uptake. All other methods showed lower values of correlation. The critical level of available Cu estimated with use of neutral normal NH4OAc was 0.16 ppm. Below this value, responses to applied Cu can be expected.  相似文献   
98.
Kyoto has a tradition of positively protecting scenic landscapes. However, a question has arisen about the effectiveness of the present legislative system on biodiversity conservation because most laws aim to essentially preserve the aesthetic value of the landscape. It is necessary to identify gaps in the present conservation system to develop an effective conservation policy for the city. The authors propose a practical method of analysis for wildlife habitat conservation planning without wildlife distribution information, which is the usual situation in many cities, and discuss the usefulness and limitations of the method by applying it to Kyoto. The proposed method relies on both of the following two assumptions: (1) the physical properties of the environment are closely related to the potential vegetation communities and (2) the conservation or restoration of rare or extinct vegetation communities ensures diverse wildlife habitats, contributing to biodiversity enhancement in a region. Thus it should be deemed a supplementary analysis to other types of analyses employing endangered, umbrella and/or flagship species in the planning process. A unique aspect of the method is to evaluate land potential, which is important for long-term conservation planning and the determination of target vegetation communities in restoration projects. In Kyoto, this revealed that the candidates for vegetation communities, prioritized for conservation and restoration, were appropriate. Moreover, identifying physiotopes corresponding with none of the existing vegetation communities was another advantage providing useful information for restoration planning. However, it was considered that a filtering process, with auxiliary information about the trend of vegetation communities over time, was necessary after applying the proposed method.  相似文献   
99.
目的:了解并评价社区卫生服务机构基本药物合理使用情况,为基层基本药物合理用药提供参考意见。方法:对社区卫生服务机构进行抽样调查,通过对处方进行抽样和对医生进行抽样问卷调查,根据医疗机构合理用药评价指标对处方基本药物使用情况进行评价,并分析可能导致不合理用药的相关因素。结果:单张处方平均使用药品数为:城区(4.9±1.2)个,农村(213±0.7)个;每100张处方抗生素使用比例:城区78.9%,农村57.3%,其中两联使用比例分别为20.1%和32.4%;人均药费:城区为(36.9±5.2)元,农村为(21.3±4.7)元;参加合理用药培训的医生所开处方药品合理使用的比率是98.0%,而未参加过培训的医生合理用药的比率是77.1%,经卡方检验,差异有统计学意义,P〈0.05。结论:社区卫生服务机构存在一定的基本药物使用不合理现象,对医生加强基本药物合理使用的培训可以提高基本药物合理使用率。  相似文献   
100.
Juan Wu 《生态学报》2011,31(1):1-7
Heihe River is the second largest inland river in northwest China which flows through Qinghai Province, Gansu Province and Inner Mongolia Autonomous Region. Because of the rapid development of social economy, the sharp increase of water utilization in the middle reaches and the aggravation of contradiction of supply and demand on water resources, the water to the lower reaches decreases and the ecological environment deteriorates constantly. According to the severe situation of ecology system depravation in Heihe River basin, Chinese government decided to invest 2.35 billion RMB to carry out 3 years ecological management in Heihe River basin from August in 2001. After 3 years ecological management, the depravation of ecological environment is controlled effectively. This paper researches the ecological management engineering in the upper reaches of Heihe River and evaluates the effect of the ecological management engineering. The methods of field sampling and measuring are used to obtain the index indicating the ecology change in the upper reaches of Heihe River in 2006. The effects of fencing grassland, fencing natural forest, and artificial afforestation to the ecology are evaluated. The result suggests that: Firstly, in fencing grassland area, the yield of grass had increased by 42–113%, average height of the grass had increased by 60–100%, and the degree of coverage had increased by 67–100%. Secondly, in fencing natural forests area, the degree of coverage had increased by 15–33%, the shade density had increased by 50–100%, average height had increased by 80–125%, and the crown size had increased by 63–186%. Thirdly, the growth increment of the trees in artificial afforestation area is bigger than that outside artificial afforestation area. In conclusion, ecological management leads to obvious ecological effect in the upper reaches of Heihe River.  相似文献   
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