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81.
Mestres J 《Proteins》2005,58(3):596-609
The recent availability of crystal structures for several diverse cytochromes P450 (CYPs) offers the possibility to perform an up-to-date comparative analysis to identify the degree of structure conservation among this superfamily of enzymes specially relevant for their involvement in drug metabolism and toxicity. A set of 9 CYPs sharing between 10% and 27% sequence identity was selected, including 7 class I (CYP 101, 107, 108, 119, 121, 51, and 55) and two class II (CYP 102, and 2C5) structures. After obtaining a multiprotein structure superimposition, a structure-based sequence alignment was derived. Mapping the level of three-dimensional structural conservation onto the sequence alignment revealed that over 28% of the alignment positions have the Calpha carbons of their residues within a root-mean-square deviation (RMSD) of 2 A. This degree of structure conservation is found to be generally preserved, even when the structure undergoes dramatic conformational changes. Performing the analysis on 4 members of the CYP2 family (CYP 2B4, 2C5, 2C8, and 2C9), the percentage of alignment positions within 2 A RMSD amounted to 73%, increasing to over 85% when only structures in a closed conformation are considered. The present findings suggest that it should be plausible to derive models of overall good quality for the major CYP2 metabolizing forms (CYP 2A6, 2C19, 2D6, and 2E1), whereas high levels of uncertainty are still likely to be expected in models for the remaining 2 major P450 metabolizing forms (CYP 1A2 and 3A4), with the corresponding implications for their potential applicability in drug design activities.  相似文献   
82.
This short communication includes comments on a single sentence cited from a recent paper by C. Ricotta. I discuss shortly the relationship between diversity and classification as well as the possibility of expressing diversity for continuous variables.Asimple example shows that the notion of diversity can be expanded to situations without an underlying classification. I suggest an evenness formula based on absolute deviations from the perfectly even distribution. If expressed for species data and multiplied by number of species in the community, this becomes an easily interpretable diversity measure. It is stressed that conventional diversity formulae cannot be informative on community structure, but there is a solution.  相似文献   
83.
The purpose of this study is to suggest practical planning principles, which are absent in landscape ecology planning, according to which the spatial completeness of the watershed is derived from native Korean Feng-Shui (). Landscape ecology planning principles are used widely in contemporary planning projects in terms of patch, corridor, matrix and network of landscape pattern. However, landscape indices for planning principles are complicated and constrained, and so are limited to applications for site and eco-village plannings. Native Korean Feng-Shui is different from Chinese Feng-Shui in that it is aimed at theoretical completeness in terms of aspect and topographical shape, based on the concept of ideal Myung-dang () to complete the space, according to local conditions in the physiognomy of the watershed. The complementary method is called Bi-bo () in native Korean Feng-Shui. These principles have been applied in traditional Korean villages, leading to consistent location choices and fractal patterns in land use. Furthermore, Bi-bo woodlands and ponds have been introduced to achieve spatial completeness in the landscape structure of the village.  相似文献   
84.
We examined long-term ecological change in two Hudson River tributaries, the Wappinger and Fishkill Creek watersheds in Dutchess County, New York State. Fish data spanning 65 years (1936, 1988, 1992, and 2001) and shorter term macroinvertebrate data (1988, 2001) were used to assess the influence of land use practices. Between 1988 and 2001, macroinvertebrate index Biotic Assessment Profile (BAP) improved by 113–165% in the Fishkill Creek watershed, and fish Index of Biotic Integrity (IBI) improved by 117–140%. Fish IBI and fish species richness were significantly different (p < 0.01) between the watersheds, with Wappinger Creek in better condition. Long-term fish IBI scores showed degradation in both watersheds since the 1930s. Changes in species composition suggest community homogenization on par with overall changes in the fish fauna of New York. Most notable were increases in tolerant species and declines in intolerant or moderately tolerant species. Whereas Fishkill Creek IBIs showed decline in 1988 relative to 1936, followed by improvement, Wappinger Creek declined monotonically in environmental quality. Development has intensified in both watersheds, but Fishkill Creek is improving while Wappinger Creek watershed is undergoing less mitigated degradation. We find that older, semi-quantitative data can be used to construct environmental quality indicators, and can be of great use for measuring long-term change.  相似文献   
85.
The need for standardized biodiversity assessment methods to enable biodiversity quality to be measured is outlined. A general approach to sampling is suggested. The results of the use of this sampling process are given for two case studies of different taxonomic groups. The data assessment is made easier by the use of a bespoke computer program. Examples of the program output are presented. The advantage of this standardized measurement of biodiversity compared to species lists and the use of indicator species are outlined in the case studies macrofungi and butterflies. It was shown that the biodiversity quality of sites can be compared by the use of a range of measured biodiversity indices in a way that allows sites to be compared through time or between sites/treatments. In one case (butterflies), data that have been collected systematically in a recording scheme have been analyzed retrospectively and yielded valuable information on changes in biodiversity quality. The uses of this method in establishing baselines in restoration ecology are discussed. The importance of restoration ecology in the conservation of biodiversity could be underlined by the use of the methods presented in this article.  相似文献   
86.
L Yan  A Wang  L Chen  W Shang  M Li  Y Zhao 《Gene》2012,506(2):350-354
The present study investigated the expression of the apoptosis-related genes fas-associated via death domain (FADD) and Bcl-2 in the endometrium during the window of implantation in polycystic ovary syndrome (PCOS) patients. The aim was to explore the role of cell apoptosis in endometrial receptivity during this period. The subjects were divided into experimental and control group. The experimental group comprised 12 infertile women with PCOS, and the control group comprised 12 women who were infertile because of tubal pathological factors but had normal menstrual cycles. Endometria were collected by biopsy 7d after ovulation. Six samples from each group were randomly selected and subjected to gene chip analyses. The expression of endometrial FADD and Bcl-2 was determined by immunohistochemistry, and cell apoptosis was detected by the TUNEL method. Compared with the control group, 194 differentially expressed genes were found in the PCOS group, 102 of which were upregulated and 92 were downregulated. The differentially expressed genes were divided into 15 types according to function. Among the nine genes related to cell apoptosis, five (including Bcl-2) were upregulated and four were downregulated (including FADD). Bcl-2 expression during the window of implantation in the PCOS group increased compared with the control group, showing a significant difference (P<0.05). FADD expression in the PCOS group notably decreased compared with that in the control group, which also showed a significant difference (P<0.05). Cell apoptosis analysis showed a significant difference between the average apoptotic indices in the PCOS and control groups (P<0.05). Significant differences were observed between the endometrial gene expression in the PCOS and control groups. The decrease in cell apoptosis during the window of implantation in PCOS patients may be one of the causes of the reduced endometrial receptivity.  相似文献   
87.
Morphological (growth, Fulton's condition factor), physiological (per cent dry mass, total lipid content) and behavioural (activity levels) response patterns of carp gudgeon Hypseleotris spp. were examined in response to food deprivation during a 56 day experiment. Considerable variability in the nature and magnitude of these response patterns was observed, suggesting that caution should be taken when interpreting changes in the health of small-bodied fishes based on individual response variables.  相似文献   
88.
Ghrelin is a 28-amino acid peptide that has significant effects on appetite and growth in humans and animals. The aim of this study was to examine 4th instar larvae of the pest insect Lymantria dispar L. after ghrelin treatment. Parameters included changes in nutritional indices (efficiency of conversion of ingested food, efficiency of conversion of digested food, approximate digestibility); midgut and fat body mass; total proteases, trypsin and leucine aminopeptidase activities in the midgut; number, height and width of columnar and goblet cells and their nuclei in the midgut epithelium and detection of ghrelin-like immunoreactivity in the midgut tissue. Four subpicomolar injections of ghrelin (0.3pmol) or physiological saline (control) were applied every 24h. The nutritional indices were higher in the ghrelin treated than in the control group. Ghrelin treatment was also associated with elevation of midgut mass, induced digestive enzyme activities, increased fat body mass and morphometric changes in columnar and goblet cells. This is the first report of the presence of ghrelin-like hormone in endocrine cells of an insect midgut. Such information provides additional evidence for application of this relatively simple model system in the future studies of the mechanisms underlying of digestion and energy balance in more complex organisms.  相似文献   
89.
Background To determine systolic and diastolic function using transthoracic echocardiography in the baboon (Papio hamadryas). Methods Transthoracic echocardiography was performed in eight non‐pregnant female and six pregnant baboons according to American Society of Echocardiography recommendations. Results Haemodynamic measurements were obtained from fourteen baboons. Compared to non‐pregnant baboons, pregnant baboons demonstrated: (mean ± SD, pregnant vs. healthy) increased cardiac output (1615 ± 121 ml/minutes vs. 1317 ± 134 ml/minutes P = 0.001) due to an increased heart rate [120 ± 11 beats per minute (BPM) vs. 105 ± 6 BPM P = 0.018]. The inter‐observer and intra‐observer variability (mean difference ± SD) for the left ventricular outflow tract diameter was 0.05 ± 0.07 cm and 0.01 ± 0.03 cm respectively. There was minimal impact to the animal’s daily activities. Conclusions Transthoracic echocardiography was applicable and reproducible for the assessment of haemodynamics in baboons thus enabling translation of animal results to human studies.  相似文献   
90.
The intermediate disturbance hypothesis (IDH) and the dynamic equilibrium model (DEM) are influential theories in ecology. The IDH predicts large species numbers at intermediate levels of disturbance and the DEM predicts that the effect of disturbance depends on the level of productivity. However, various indices of diversity are considered more commonly than the predicted number of species in tests of the hypotheses. This issue reaches beyond the scientific community as the predictions of the IDH and the DEM are used in the management of national parks and reserves. In order to compare responses with disturbance among measures of biodiversity, we used two different approaches of mathematical modelling and conducted an extensive meta-analysis. Two-thirds of the surveyed studies present different results for different diversity measures. Accordingly, the meta-analysis showed a narrow range of negative quadratic regression components for richness, but not evenness. Also, the two models support the IDH and the DEM, respectively, when biodiversity is measured as species richness, but predict evenness to increase with increasing disturbance, for all levels of productivity. Consequently, studies that use compound indices of diversity should present logical arguments, a priori, to why a specific index of diversity should peak in response to disturbance.  相似文献   
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