全文获取类型
收费全文 | 46608篇 |
免费 | 3819篇 |
国内免费 | 4245篇 |
专业分类
54672篇 |
出版年
2024年 | 128篇 |
2023年 | 629篇 |
2022年 | 1359篇 |
2021年 | 2228篇 |
2020年 | 1667篇 |
2019年 | 2035篇 |
2018年 | 1912篇 |
2017年 | 1477篇 |
2016年 | 2084篇 |
2015年 | 2968篇 |
2014年 | 3573篇 |
2013年 | 3694篇 |
2012年 | 4287篇 |
2011年 | 3865篇 |
2010年 | 2555篇 |
2009年 | 2164篇 |
2008年 | 2466篇 |
2007年 | 2132篇 |
2006年 | 2025篇 |
2005年 | 1716篇 |
2004年 | 1534篇 |
2003年 | 1465篇 |
2002年 | 1246篇 |
2001年 | 836篇 |
2000年 | 724篇 |
1999年 | 665篇 |
1998年 | 471篇 |
1997年 | 406篇 |
1996年 | 372篇 |
1995年 | 317篇 |
1994年 | 251篇 |
1993年 | 194篇 |
1992年 | 245篇 |
1991年 | 202篇 |
1990年 | 173篇 |
1989年 | 124篇 |
1988年 | 94篇 |
1987年 | 82篇 |
1986年 | 63篇 |
1985年 | 59篇 |
1984年 | 38篇 |
1983年 | 35篇 |
1982年 | 20篇 |
1981年 | 12篇 |
1980年 | 12篇 |
1979年 | 12篇 |
1978年 | 5篇 |
1976年 | 5篇 |
1972年 | 8篇 |
1970年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Xiaohu Li Xin Zhang Inam
Ullah Khan Nina
N. Guo Bing Wang Yifeng Guo Bufan Xiao Yueshan Zhang Yimin Chu Junsong Chen Fang Guo 《Bioscience reports》2022,42(2)
Background: Breast cancer is the main lethal disease among females. The combination of lobaplatin and microwave hyperthermia plays a crucial role in several kinds of cancer in the clinic, but its possible mechanism in breast cancer has remained indistinct.Methods: Mouse models were used to detect breast cancer progression. Cell growth was explored with MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulphonyl)-2H-tetrazolium) and colony formation assays. Cell migration and invasion were investigated with a transwell assay. Cell apoptosis was probed with flow cytometry. The expression of apoptosis-associated proteins was examined with Western blots.Result: Combination treatment decreased breast cancer cell viability, colony formation, cell invasion and metastasis. In addition, the treatment-induced breast cancer cell apoptosis and autophagy, activated the c-Jun N-terminal kinase (JNK) signaling pathway, suppressed the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway, and down-regulated IAP and Bcl-2 family protein expression.Conclusion: These results indicate that lobaplatin is an effective breast cancer anti-tumor agent. Microwave hyperthermia was a useful adjunctive treatment. Combination treatment was more efficient than any single therapy. The possible mechanism for this effect was mainly associated with activation of the JNK signaling pathway, inactivation of the AKT/mTOR signaling pathway and down-regulation of the Bcl-2 and IAP families. 相似文献
992.
Hye Jin Chung Dong Woon Lee Hee Suk Yoon Sang Myeong Lee Chung Gyoo Park Ho Yul Choo 《Journal of Asia》2010,13(4):277-282
Out of some isolated Heterorhabditis bacteriophora from Korea, ecological study on two isolates which had different geographical features was investigated. That is, effects of temperature and dose on the pathogenicity and reproduction of two Korean isolates of H. bacteriophora were investigated using Galleria mellonella larvae in the laboratory. The median lethal dose (LD50) decreased with increasing temperature, but increased at 35 °C. The optimal temperatures for infection were 30 °C for H. bacteriophora Jeju strain and 24 °C for H. bacteriophora Hamyang strain. The median lethal time, LT50 of H. bacteriophora Hamyang strain was recorded at 13 °C to 35 °C and that of H. bacteriophora Jeju strain was recorded at 18 °C to 30 °C. The number of established nematodes in G. mellonella larvae was significantly different depending on temperature and dose. When G. mellonella larvae were exposed to 300 infective juveniles (IJs), mortality of G. mellonella gradually increased with exposure time with H. bacteriophora Jeju strain but not with H. bacteriophora Hamyang strain. 87.5% mortality of G. mellonella was recorded by H. bacteriophora Hamyang strain after 1440 min whereas 100% mortality was recorded by H. bacteriophora Jeju strain after 4320 min. The time from infection to the first emergence of nematodes decreased with increasing temperature. Duration of emergence of the two strains in the White traps also decreased with increasing temperature. The highest progeny numbers of H. bacteriophora Jeju strain were 264,602 while those of H. bacteriophora Hamyang strain were 275,744 at the rate of 160 IJs at 24 °C. 相似文献
993.
994.
Jun Zou Jiali Zhu Shunmou Huang Entang Tian Yong Xiao Donghui Fu Jinxing Tu Tingdong Fu Jinling Meng 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,120(2):283-290
Accumulated evidence has shown that each of the three basic Brassica genomes (A, B and C) has undergone profound changes in different species, and has led to the concept of the “subgenome”.
Significant intersubgenomic heterosis was observed in hybrids between traditional Brassica napus and first generation lines of new type B. napus. The latter were produced by the partial introgression of subgenomic components from different species into B. napus. To increase the proportion of exotic subgenomic components and thus achieve stronger heterosis, lines of first generation
new type B. napus were intercrossed with each other, and subjected to intensive marker-assisted selection to develop the second generation
of new type B. napus. The second generation showed better agronomic traits and a higher proportion of introgression of subgenomic components than
did the first generation. Compared with the commercial hybrid and the hybrids produced with the first generation new type
B. napus, the novel hybrids showed stronger heterosis for seed yield during the 2 years of field trials. The extent of heterosis showed
a significant positive correlation with the introgressed subgenomic components in the parental new type B. napus. To increase the content of the exotic subgenomic components further and to allow sustainable breeding of novel lines of
new type B. napus, we initiated the development of a gene pool for new type B. napus that contained a substantial amount of genetic variation in the Ar and Cc genome. We discuss new approaches to broaden the avenue of intersubgenomic heterosis in oilseed Brassica. 相似文献
995.
Characterization and mapping of a novel mutant sms1 (senescence and male sterility 1) in rice 总被引:1,自引:0,他引:1
Wenyi Yan Shenghai Ye Qingsheng Jin Longjun Zeng Yu Peng Dawei Yan Weibing Yang Donglei Yang Zuhua He Yanjun Dong Xiaoming Zhang 《遗传学报》2010,37(1):47-55
Plant senescence plays diverse important roles in development and environmental responses.However,the molecular basis of plant senescence is remained largely unknown.A rice spontaneous mutant with the character of early senescence and male sterility (sms) was found in the breeding line NT10-748.In order to identify the gene SMS1 and the underlying mechanism,we preliminarily analyzed physiological and biochemical phenotypes of the mutant.The mutant contained lower chlorophyll content compared with the wild type control and was severe male sterile with lower pollen viability.Genetic analysis showed that the mutant was controlled by a single recessive gene.By the map-based cloning approach,we fine-mapped SMS1 to a 67 kb region between the markers Z3-4 and Z1-1 on chromosome 8 using 1,074 F2 recessive plants derived from the cross between the mutant sms1 (japonica) × Zhenshan 97 (indica),where no known gene involved in senescence or male sterility has been identified.Therefore the SMS1 gene will be a novel gene that regulates the two developmental processes.The further cloning and functional analysis of the SMS1 gene is under way. 相似文献
996.
Xin Jinge Zeng Dong Wang Hesong Sun Ning Zhao Ying Dan Yan Pan Kangcheng Jing Bo Ni Xueqin 《Probiotics and antimicrobial proteins》2020,12(1):184-193
Probiotics and Antimicrobial Proteins - Numerous studies have investigated the beneficial effects of Lactobacillus johnsonii strain BS15 on mice and broilers. This study aimed to understand the... 相似文献
997.
The Fruit Dropping Characters of Sweet Cherry and Its Interior Causes in Insufficient Chilling Zone 总被引:1,自引:0,他引:1
Guo K. B. Qiao G. Qiu Z. L. Wen Z. Yang H. Wen X. P. 《Russian Journal of Plant Physiology》2020,67(1):94-102
Russian Journal of Plant Physiology - Attempts had been made to provide evidences insight into the pattern and physiological mechanism of sweet cherry fruit dropping. However, the fruit abscission... 相似文献
998.
999.
Chanjuan Guo Michael Dannenmann Rainer Gasche Bernd Zeller Hans Papen Andrea Polle Heinz Rennenberg Judy Simon 《Plant and Soil》2013,368(1-2):519-534
Background and aims
Litter decomposition is regulated by e.g. substrate quality and environmental factors, particularly water availability. The partitioning of nutrients released from litter between vegetation and soil microorganisms may, therefore, be affected by changing climate. This study aimed to elucidate the impact of litter type and drought on the fate of litter-derived N in beech seedlings and soil microbes.Methods
We quantified 15N recovery rates in plant and soil N pools by adding 15N-labelled leaf and/or root litter under controlled conditions.Results
Root litter was favoured over leaf litter for N acquisition by beech seedlings and soil microorganisms. Drought reduced 15N recovery from litter in seedlings thereby affecting root N nutrition. 15N accumulated in seedlings in different sinks depending on litter type.Conclusions
Root turnover appears to influence (a) N availability in the soil for plants and soil microbes and (b) N acquisition and retention despite a presumably extremely dynamic turnover of microbial biomass. Compared to soil microorganisms, beech seedlings represent a very minor short-term N sink, despite a potentially high N residence time. Furthermore, soil microbes constitute a significant N pool that can be released in the long term and, thus, may become available for N nutrition of plants. 相似文献1000.
Yi‐Zhe Zhang Juncheng Lin Zhizhong Ren Chun‐Xiang Chen Daisuke Miki Si‐Si Xie Jian Zhang Ya‐Nan Chang Jing Jiang Jun Yan Qingshun Q. Li Jian‐Kang Zhu Cheng‐Guo Duan 《植物学报(英文版)》2021,63(4):707-722
Heterochromatin is widespread in eukaryotic genomes and has diverse impacts depending on its genomic context. Previous studies have shown that a protein complex, the ASI1‐AIPP1‐EDM2 (AAE) complex, participates in polyadenylation regulation of several intronic heterochromatin‐containing genes. However, the genome‐wide functions of AAE are still unknown. Here, we show that the ASI1 and EDM2 mostly target the common genomic regions on a genome‐wide level and preferentially interacts with genetic heterochromatin. Polyadenylation (poly(A) sequencing reveals that AAE complex has a substantial influence on poly(A) site usage of heterochromatin‐containing genes, including not only intronic heterochromatin‐containing genes but also the genes showing overlap with heterochromatin. Intriguingly, AAE is also involved in the alternative splicing regulation of a number of heterochromatin‐overlapping genes, such as the disease resistance gene RPP4. We provided evidence that genic heterochromatin is indispensable for the recruitment of AAE in polyadenylation and splicing regulation. In addition to conferring RNA processing regulation at genic heterochromatin‐containing genes, AAE also targets some transposable elements (TEs) outside of genes (including TEs sandwiched by genes and island TEs) for epigenetic silencing. Our results reveal new functions of AAE in RNA processing and epigenetic silencing, and thus represent important advances in epigenetic regulation. 相似文献