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971.
Ontogenetic, inter-annual and regional variations in diet were investigated for mackerel icefish, Champsocephalus gunnari, in three successive summer seasons around South Georgia. Stomach contents from 2239 C. gunnari (130–560 mm total length) were examined. A bootstrapping technique was used to calculate confidence intervals for an index of relative importance of prey categories (% IRIDC). Diet varied significantly between years and age classes but there was little regional difference in diet. In general, diet was dominated by krill, Euphausia superba and by the amphipod Themisto gaudichaudii. Smaller (younger) fish tended to prey on a higher proportion of T. gaudichaudii and small euphausiids such as Thysanoessa sp. and took smaller quantities of E. superba. In a season of poor krill availability (summer of 2003–2004) the proportion of krill in the diet, stomach fullness and fish condition (indicated by length–weight relationships) were significantly lower than in the other summer seasons. A large reduction (>80%) in the estimated annual (2005) biomass of the C. gunnari stock directly followed the season of poor krill availability. This decline was largely because of mortality of 2+ and 3+ fish, which were more krill dependent than 1+ fish. Younger fish appear to have survived, leading to an increase in the estimated population biomass in 2006.  相似文献   
972.
Objective: To evaluate the relationship between the oral health condition, the nutrient intake and the body mass index (BMI) in elderly people. Background: Impaired dentition has been associated with an inadequate consumption of key nutrients and with changes in nutritional status in elderly people. Materials and methods: The sample comprised 887 elderly people, aged 60 and over, of whom 816 underwent a clinical oral examination and were allocated into groups according to the numbers of teeth and number of posterior occluding pairs of natural teeth. Nutritional status was determined using the BMI. Dietary intake was assessed by a 24‐h diet recall interview and the data from these records were converted to nutritional intake using Diet Pro software. Differences between means were evaluated using anova , together with the Tukey test or Dunnet test, according to the normality of the data. Associations between categorical variables were tested using chi‐square analysis. Results: Ages ranged from 60 to 96 years (mean, 71.46 years), with 47% of the respondents in the 60‐to 69‐year‐old group. A high DMFT index (mean, 27.81) was observed with the missing component accounting for 88.8% of the index. Significant differences were observed between the mean intake of nutrients and the number of posterior occluding pairs of natural teeth (p < 0.05). No significant differences were found between the number of teeth and BMI. Conclusion: Nutrient intake is associated with the oral health status as defined by clinical measures.  相似文献   
973.
Most plant-based indices of biotic integrity (IBIs) developed for wetlands have focused on emergent wetlands. A Vegetation Index of Biotic Integrity (VIBI-Forest) was developed for forested wetlands in the four large ecoregions of the Ohio. Assessing the effect of human disturbance on the ecological condition of wetland forests is complicated by several factors. First, forest canopies can remain largely intact even after significant degradation of the herb and shrub stratum. Second, increases in total diversity may not be good. In forested wetlands, a major artifact of disturbance is the addition of non-wetland or wetland native or adventive plant species adapted to full sun conditions to their floras. Initial versions of the VIBI-Forest metrics were very sensitive to disturbance-induced increases in diversity. Correcting this problem required modifying or replacing metrics so that only forest dependent species were included in metric calculations. The final VIBI-Forest included metrics which evaluated each forest stratum including the ground layer (% bryophyte), herb layer (shade or seed-less vascular plant species), shrub layer (subcanopy importance value (IV), relative density of young trees), canopy (canopy IV), and composite metrics for all vertical strata (Floristic Quality Assessment Index score, % hydrophytes, % sensitive, % tolerant). Assessing wetland forest condition is further complicated by the fact that some successional communities after canopy death or destruction (shrub swamp, marsh, wet meadow) may have intrinsic value as wetland community types. The solution is not to attempt to derive a one-size-fits-all assessment method but to derive separate protocols for other successional phases that are of value or interest.  相似文献   
974.
We offered captive common voles (Microtus arvalis) a choice of 11 plant species (representing four ecological groups) growing in vivaria. Selection was evaluated by measuring (1) the biomass of each plant species consumed and (2) functional and life-history plant traits. The legume Trifolium pratense, known for its high nutrient level, and well accessible rosette forbs creating the highest biomass at the soil ground level, were mostly preferred. Voles avoided mainly grasses and the creeping forb Thymus pulegioides. The experiment showed that foraging was strongly plant species-specific. We assessed whether plant functional traits explain selective foraging in common voles. To explore this, we reanalyzed Holišová’s (1959) data about common vole stomach contents and plant trait databases. Regression tree analysis indicated that plant guild and life span were the best predictors of dietary selection, with a probability exceeding 0.5 that voles would eat more grasses and/or legumes than forbs. These results do not correspond with the feeding trial. We suggest that the voles usually consume grasses in the field because grasses are abundant and readily available, but prefer protein-rich forbs when possible.  相似文献   
975.
Understanding daily stem size variation is important as the net increment of a forest stand is ultimately determined by the accumulation of daily increment events. In this study, measurements of stem size at high spatial and temporal resolution were made using two commercial hybrid Eucalyptus clones [E. grandis × urophylla (GU) and E. grandis × camaldulensis (GC)] over a period of more than 3.5 years in order to better understand how daily stem growth is effected by variations in environmental conditions. It was evident that GU had fewer days on which net growth occurred than GC. However, when growth did occur, GU grew for longer each day and at a higher rate than GC. Thus, it still had an overall larger net stem increment during the study period. The GU clone had a markedly intermittent pattern of growth, such that growth essentially ceased under drought conditions, but responded rapidly when water became available. This confirms other findings that E. grandis × urophylla is more susceptible to drought stress than E. grandis × camaldulensis, but emphasizes that a strategy of “rapid response” when environmental conditions become temporarily non-limiting is a good one in terms of net increment at sites such as in this study.
David Michael DrewEmail:
  相似文献   
976.
In this paper, changes in physico-chemical parameters during trimmings residue composting (cation exchange capacity, germination index, self-heated, NH4/NO3 ratio and CFA/CHA ratio) in relation to environmental composting parameters (time, aeration, moisture and particle size) of the composting process were studied. A central composite experimental design was used to obtain the polynomial model for each dependent variable. Results of the modelling showed that among the studied range, moisture was the highest influenced parameter in maturity evaluation, with respect to aeration and particle size. An exception was found for CEC evolution. In this parameter, the highest influence was found for particle size. Moreover, a product with acceptable chemical properties entails operating at medium moisture content (55%) and medium-to-high particle size (3–5 cm). Moderate to low aeration (0.2 m3 air kg−1 d−1) would be the best compromise to composting this residue, due to the scarce statistical influence of this independent variable.  相似文献   
977.
根据对福建福安的3种不同茶园(天香有机茶园、北门高山茶园和溪柄平地茶园)的节肢动物群落消长动态调查。并经多样性分析,结果获知:福安3种茶园节肢动物群落的物种丰富度(s)和多样性指数(H)的大小顺序依次为:天香(S=19.64,H=2.537)〉北门(S=18.01,H=2.502)〉溪柄(S=17.59,H=2.297);而均匀度指数的大小顺序是:北门(J=0.621)〉天香(J=0.595)〉溪柄(J=0.559)。表明植被比较丰富、人为干扰较少的茶园,节肢动物群落的物种丰富度、多样性指数和均匀度指数较高,害、益虫群落易于保持较好的平衡状态,有利于减少(或不使用)化学农药、发展绿色无公害茶叶生产。  相似文献   
978.
五种食用菌氨基酸含量的测定及营养评价   总被引:12,自引:0,他引:12  
研究测定了五种食用菌中氨基酸的含量,并利用五种非生物学指标对蛋白质的营养价值进行评价。五种食用菌氨基酸种类齐全,必需氨基酸占氨基酸总量的百分比分别达到45.94%、37.62%、42.45%、41.54%、35.98%。茶树菇和姬松茸的限制性氨基酸为半胱氨酸和甲硫氨酸,鸡腿菇、香菇和黑木耳的限制性氨基酸是缬氨酸。不同的评价指标对蛋白质进行营养评价,评价结果会有所差异。  相似文献   
979.
Interleukin-6 (IL-6) is a cytokine involved in different physiologic and pathophysiologic processes including carcinogenesis. In 2003, a single nucleotide polymorphism (−174G/C) of the IL-6 gene promoter has been linked to breast cancer prognosis in node-positive (N+) breast cancer patients. Since, different studies have led to conflicting conclusions about its role as a prognostic and/or diagnostic marker. The primary aim of our study was to investigate the link between −174G/C polymorphism and breast cancer risk on the one hand, and −174G/C polymorphism and prognosis in different groups of patients: sporadic N+ breast cancers (n = 138), sporadic N− breast cancers (n = 95) and familial breast cancer (n = 60) on the other hand. The variables of interest were disease-free survival and overall survival. The secondary aim of the study was to screen IL-6 gene promoter using direct sequencing to identify new polymorphisms in our French Caucasian breast cancer population. No association or trend of association between −174G/C polymorphism of IL-6 gene promoter gene and breast cancer diagnosis or prognosis was shown, even in meta-analyses. Furthermore, we have identified four novel polymorphic sites in the IL-6 gene promoter region: −764G → A, −757C → T, −233T → A, 15C → A.  相似文献   
980.
The present study was undertaken to study the immune response in calves vaccinated with Brucella abortus strain 19, infectious bovine rhinotracheitis (IBR) vaccines in monovalent form and combined vaccine containing both antigen. The seroconversion of monovalent and combined vaccines was tested in seronegative cattle calves. IBR vaccine alone and combination with live Brucella abortus S19 vaccine elicited an anamnestic response on day 60 post booster but started declining from day 90 onwards against IBR. B. abortus S19 alone and in combination with IBR vaccine gave more than 2 log protection in mice two weeks post challenge. Fluorescence polarization assay analysis with sera samples of calves vaccinated with B. abortus S19 monovalent vaccine alone and in combination with IBR vaccine revealed the presence of B. abortus antibodies. The components of the combined vaccine did not show any evidence of interference in the development of immunity. This combined vaccine may provide economical and affordable biological for the control of brucellosis and IBR.  相似文献   
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