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121.
Meta分析及其在生态学上的应用 总被引:25,自引:2,他引:23
1Meta分析的概念和它的发展应用Meta分析(Meta-Analysis)是一种定量综合研究结果的方法.这种方法的思想起源于本世纪30年代,60年代用于教育、心理等社会科学领域,1976年由Glas命名为术语“Meta-Analysis”[1]。G... 相似文献
122.
森林流域土壤饱和渗透系数与有效孔隙度模型的研究 总被引:10,自引:7,他引:3
以长白山自然保护区内未受扰动的两种典型原始森林土壤为对象,通过野外选取原状土样,在实验室内测定其饱和渗透系数和有效孔隙度,利用回归分析法分别建立了森林土壤内饱和渗透系数和有效孔隙度随深度变化的数学模型,即Ks(z)=K0-f1lna1z和ω(z)=ω0-f2lna2z.将所得出的对数模型与Beven所提出的指数模型进行比较表明,在森林流域内对数模型不仅适用范围比指数模型广,而且精度明显高于指数模型,它更接近于野外实际情况. 相似文献
123.
Lara J. Wolfson Anna Walker Robert Hettle Xiaoyan Lu Chrispin Kambili Andrew Murungi Gerhart Knerer 《PloS one》2015,10(3)
Objective
To evaluate the cost-effectiveness of adding bedaquiline to a background regimen (BR) of drugs for multidrug-resistant tuberculosis (MDR-TB) in the United Kingdom (UK).Methods
A cohort-based Markov model was developed to estimate the incremental cost-effectiveness ratio of bedaquiline plus BR (BBR) versus BR alone (BR) in the treatment of MDR-TB, over a 10-year time horizon. A National Health Service (NHS) and personal social services perspective was considered. Cost-effectiveness was evaluated in terms of Quality-Adjusted Life Years (QALYs) and Disability-Adjusted Life Years (DALYs). Data were sourced from a phase II, placebo-controlled trial, NHS reference costs, and the literature; the US list price of bedaquiline was used and converted to pounds (£18,800). Costs and effectiveness were discounted at a rate of 3.5% per annum. Probabilistic and deterministic sensitivity analysis was conducted.Results
The total discounted cost per patient (pp) on BBR was £106,487, compared with £117,922 for BR. The total discounted QALYs pp were 5.16 for BBR and 4.01 for BR. The addition of bedaquiline to a BR resulted in a cost-saving of £11,434 and an additional 1.14 QALYs pp over a 10-year period, and is therefore considered to be the dominant (less costly and more effective) strategy over BR. BBR remained dominant in the majority of sensitivity analyses, with a 81% probability of being dominant versus BR in the probabilistic analysis.Conclusions
In the UK, bedaquiline is likely to be cost-effective and cost-saving, compared with the current MDR-TB standard of care under a range of scenarios. Cost-savings over a 10-year period were realized from reductions in length of hospitalization, which offset the bedaquiline drug costs. The cost-benefit conclusions held after several sensitivity analyses, thus validating assumptions made, and suggesting that the results would hold even if the actual price of bedaquiline in the UK were higher than in the US. 相似文献124.
Jia Xu Fengmei Lian Linhua Zhao Yufeng Zhao Xinyan Chen Xu Zhang Yun Guo Chenhong Zhang Qiang Zhou Zhengsheng Xue Xiaoyan Pang Liping Zhao Xiaolin Tong 《The ISME journal》2015,9(3):552-562
The gut microbiota is hypothesized to have a critical role in metabolic diseases, including type 2 diabetes (T2D). A traditional Chinese herbal formula, Gegen Qinlian Decoction (GQD), can alleviate T2D. To find out whether GQD modulates the composition of the gut microbiota during T2D treatment, 187 T2D patients were randomly allocated to receive high (HD, n=44), moderate (MD, n=52), low dose GQD (LD, n=50) or the placebo (n=41) for 12 weeks in a double-blinded trial. Patients who received the HD or MD demonstrated significant reductions in adjusted mean changes from baseline of fasting blood glucose (FBG) and glycated hemoglobin (HbA1c) compared with the placebo and LD groups. Pyrosequencing of the V3 regions of 16S rRNA genes revealed a dose-dependent deviation of gut microbiota in response to GQD treatment. This deviation occurred before significant improvement of T2D symptoms was observed. Redundancy analysis identified 47 GQD-enriched species level phylotypes, 17 of which were negatively correlated with FBG and 9 with HbA1c. Real-time quantitative PCR confirmed that GQD significantly enriched Faecalibacterium prausnitzii, which was negatively correlated with FBG, HbA1c and 2-h postprandial blood glucose levels and positively correlated with homeostasis model assessment of β-cell function. Therefore, these data indicate that structural changes of gut microbiota are induced by Chinese herbal formula GQD. Specifically, GQD treatment may enrich the amounts of beneficial bacteria, such as Faecalibacterium spp. In conclusion, changes in the gut microbiota are associated with the anti-diabetic effects of GQD. 相似文献
125.
A long‐term intensive lifestyle intervention and physical function: The look AHEAD Movement and Memory Study 下载免费PDF全文
126.
Xiaoyan Wang Shuxin Zhang Yongchao Dou Chi Zhang Xuemei Chen Bin Yu Guodong Ren 《PLoS genetics》2015,11(4)
All types of small RNAs in plants, piwi-interacting RNAs (piRNAs) in animals and a subset of siRNAs in Drosophila and C. elegans are subject to HEN1 mediated 3’ terminal 2’-O-methylation. This modification plays a pivotal role in protecting small RNAs from 3’ uridylation, trimming and degradation. In Arabidopsis, HESO1 is a major enzyme that uridylates small RNAs to trigger their degradation. However, U-tail is still present in null hen1 heso1 mutants, suggesting the existence of (an) enzymatic activities redundant with HESO1. Here, we report that UTP: RNA uridylyltransferase (URT1) is a functional paralog of HESO1. URT1 interacts with AGO1 and plays a predominant role in miRNA uridylation when HESO1 is absent. Uridylation of miRNA is globally abolished in a hen1 heso1 urt1 triple mutant, accompanied by an extensive increase of 3’-to-5’ trimming. In contrast, disruption of URT1 appears not to affect the heterochromatic siRNA uridylation. This indicates the involvement of additional nucleotidyl transferases in the siRNA pathway. Analysis of miRNA tailings in the hen1 heso1 urt1 triple mutant also reveals the existence of previously unknown enzymatic activities that can add non-uridine nucleotides. Importantly, we show HESO1 may also act redundantly with URT1 in miRNA uridylation when HEN1 is fully competent. Taken together, our data not only reveal a synergistic action of HESO1 and URT1 in the 3’ uridylation of miRNAs, but also independent activities of multiple terminal nucleotidyl transferases in the 3’ tailing of small RNAs and an antagonistic relationship between uridylation and trimming. Our results may provide further insight into the mechanisms of small RNA 3’ end modification and stability control. 相似文献
127.
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130.
Bin Jiao Xiaoyan Liu Lin Zhou Maggie Haitian Wang Yafang Zhou Tingting Xiao Weiwei Zhang Rui Sun Mary Miu Yee Waye Beisha Tang Lu Shen 《PloS one》2015,10(12)
Recently, a number of single nucleotide polymorphisms (SNPs) were identified to be associated with late-onset Alzheimer disease (LOAD) through genome-wide association study data. Identification of SNP-SNP interaction played an important role in better understanding genetic basis of LOAD. In this study, fifty-eight SNPs were screened in a cohort of 229 LOAD cases and 318 controls from mainland China, and their interaction was evaluated by a series of analysis methods. Seven risk SNPs and six protective SNPs were identified to be associated with LOAD. Risk SNPs included rs9331888 (CLU), rs6691117 (CR1), rs4938933 (MS4A), rs9349407 (CD2AP), rs1160985 (TOMM40), rs4945261 (GAB2) and rs5984894 (PCDH11X); Protective SNPs consisted of rs744373 (BIN1), rs1562990 (MS4A), rs597668 (EXOC3L2), rs9271192 (HLA-DRB5/DRB1), rs157581 and rs11556505 (TOMM40). Among positive SNPs presented above, we found the interaction between rs4938933 (risk) and rs1562990 (protective) in MS4A weakened their each effect for LOAD; for three significant SNPs in TOMM40, their cumulative interaction induced the two protective SNPs effects lost and made the risk SNP effect aggravate for LOAD. Finally, we found rs6656401-rs3865444 (CR1-CD33) pairs were significantly associated with decreasing LOAD risk, while rs28834970-rs6656401 (PTK2B-CR1), and rs28834970-rs6656401 (PTK2B-CD33) were associated with increasing LOAD risk. In a word, our study indicates that SNP-SNP interaction existed in the same gene or cross different genes, which could weaken or aggravate their initial single effects for LOAD. 相似文献