全文获取类型
收费全文 | 5352篇 |
免费 | 443篇 |
国内免费 | 357篇 |
出版年
2024年 | 9篇 |
2023年 | 60篇 |
2022年 | 153篇 |
2021年 | 241篇 |
2020年 | 168篇 |
2019年 | 216篇 |
2018年 | 196篇 |
2017年 | 118篇 |
2016年 | 230篇 |
2015年 | 322篇 |
2014年 | 360篇 |
2013年 | 381篇 |
2012年 | 467篇 |
2011年 | 479篇 |
2010年 | 281篇 |
2009年 | 268篇 |
2008年 | 311篇 |
2007年 | 285篇 |
2006年 | 235篇 |
2005年 | 188篇 |
2004年 | 167篇 |
2003年 | 162篇 |
2002年 | 126篇 |
2001年 | 94篇 |
2000年 | 89篇 |
1999年 | 65篇 |
1998年 | 30篇 |
1997年 | 43篇 |
1996年 | 54篇 |
1995年 | 30篇 |
1994年 | 27篇 |
1993年 | 25篇 |
1992年 | 48篇 |
1991年 | 29篇 |
1990年 | 22篇 |
1989年 | 18篇 |
1988年 | 24篇 |
1987年 | 21篇 |
1986年 | 13篇 |
1985年 | 13篇 |
1984年 | 8篇 |
1983年 | 17篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1977年 | 4篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1965年 | 3篇 |
排序方式: 共有6152条查询结果,搜索用时 15 毫秒
191.
UPA2 and ZmRAVL1: Promising targets of genetic improvement of maize plant architecture 总被引:1,自引:0,他引:1
正Maize (Zea mays ssp. mays) is a major staple crop, with the highest tonnage among cereal crops worldwide(FAO 2014). Over the past century, maize yields have increased about 8-fold in the US central Corn Belt (from1,287 kg/ha in the 1930s to 11,084 kg/ha in 2017, http://m entary 相似文献
192.
Yutian Zou Shaoquan Zheng Xinpei Deng Anli Yang Yanan Kong Maryam Kohansal Xiaoqian Hu Xiaoming Xie 《Journal of cellular and molecular medicine》2020,24(17):9507-9517
The circular RNA, CDR1as/ciRS‐7, functions as a vital regulator in various cancers; however, the predictive value of CDR1as remains controversial. Therefore, a comprehensive analysis for clarifying the precise diagnostic and prognostic value of CDR1as in solid tumours is needed. A literature review of several databases was conducted for identifying potential studies. Pooled odds ratios (ORs) and hazard ratios (HRs) were used for evaluating the diagnostic accuracy variables and survival. Overall, 15 studies (1787 patients) and 11 studies (1578 patients) were included for diagnostic and prognostic outcome syntheses, respectively. Up‐regulated CDR1as expression was found to be correlated with worse clinicopathological characteristics, including the T status, N status, histological grade, TNM stage and distant metastasis. The synthesized sensitivity was 0.72 (95% confidence interval [CI], 0.65‐0.79), and the specificity was 0.80 (95% CI, 0.74‐0.86). The positive likelihood ratio (LR), negative LR and diagnostic odds ratio (DOR) were 3.70, 0.34 and 10.80, respectively. The area under the receiver operator characteristic curve was 0.84 (95% CI, 0.80‐0.87). In the pooled prognostic analysis, patients with high CDR1as expression had worse overall survival (HR = 2.40, P < 0.001) and disease‐free survival (HR = 1.74, P < 0.001). These results suggest that CDR1as is a reliable diagnostic and prognostic biomarker with high accuracy and efficiency, which may potentially facilitate clinical decisions on solid tumours in the future. 相似文献
193.
Lingbo Kong Biao Wang Xiaobin Yang Baorong He Dingjun Hao Liang Yan 《Journal of cellular and molecular medicine》2020,24(6):3271-3281
In the ageing skeleton, the balance of bone reconstruction could commonly be broken by the increasing of bone resorption and decreasing of bone formation. Consequently, the bone resorption gradually occupies a dominant status. During this imbalance process, osteoclast is unique cell linage act the bone resorptive biological activity, which is a highly differentiated ultimate cell derived from monocyte/macrophage. The erosive function of osteoclasts is that they have to adhere the bone matrix and migrate along it, in which adhesive cytoskeleton recombination of osteoclast is essential. In that, the podosome is a membrane binding microdomain organelle, based on dynamic actin, which forms a cytoskeleton superstructure connected with the plasma membrane. Otherwise, as the main adhesive protein, integrin regulates the formation of podosome and cytoskeleton, which collaborates with the various molecules including: c-Cbl, p130Cas, c-Src and Pyk2, through several signalling cascades cross talking, including: M-CSF and RANKL. In our current study, we discuss the role of integrin and associated molecules in osteoclastogenesis cytoskeletal, especially podosomes, regulation and relevant signalling cascades cross talking. 相似文献
194.
目的:研究布地奈德福莫特罗粉吸入剂(ST)联合孟鲁斯特对支气管哮喘急性发作期(ASBA)患者肺功能及血清细胞因子水平的影响。方法:选择2015年2月到2017年8月在我院治疗的86例ASBA患者作为研究对象,根据随机数字表法将患者分成观察组(n=43)以及对照组(n=43),对照组予以ST治疗,观察组则在此基础上联合孟鲁司特治疗,两组均治疗3个月,对比两组患者治疗前及治疗3个月后的肺功能、细胞因子水平、咳嗽评分、St·George's呼吸疾病问卷(SGRQ)以及用药安全性。结果:治疗后两组患者的第1秒的用力呼气容积(FEV1)、用力肺活量(FVC)及FEV1/FVC均较治疗前升高,且观察组高于对照组(P0.05)。治疗后两组患者的白细胞介素-4(IL-4)、白细胞介素-5(IL-5)、γ-干扰素(INF-γ)及肿瘤坏死因子-α(TNF-α)水平均较治疗前降低,且观察组低于对照组(P0.05)。治疗后两组患者的咳嗽评分较治疗前升高,且观察组高于对照组(P0.05),而治疗后两组患者的SGRQ评分均较治疗前降低,且观察组低于对照组(P0.05)。观察组不良反应的总发生率为20.93%,与对照组的16.28%相比无统计学差异(P0.05)。结论:ASBA给予ST联合孟鲁司特治疗能够有效改善患者的症状,缓解机体炎症反映的同时还可有效改善患者肺功能和生活质量,其用药安全性较好。 相似文献
195.
Kong Wen-Hua Zhao Rong Zhou Jun-Bo Wang Fang Kong De-Guang Sun Jian-Bin Ruan Qiong-Fang Liu Man-Qing 《中国病毒学》2020,35(6):752-757
Virologica Sinica - The immense patient number caused by coronavirus disease 2019 (COVID-19) global pandemic brings the urge for more knowledge about its immunological features, including the... 相似文献
196.
Yi Wang Jiabao Xu Lingchao Kong Tang Liu Lingbo Yi Hongjuan Wang Wei E. Huang Chunmiao Zheng 《Microbial biotechnology》2020,13(2):572-583
Human intestinal microbiota is important to host health and is associated with various diseases. It is a challenge to identify the functions and metabolic activity of microorganisms at the single-cell level in gut microbial community. In this study, we applied Raman microspectroscopy and deuterium isotope probing (Raman–DIP) to quantitatively measure the metabolic activities of intestinal bacteria from two individuals and analysed lipids and phenylalanine metabolic pathways of functional microorganisms in situ. After anaerobically incubating the human faeces with heavy water (D2O), D2O with specific substrates (glucose, tyrosine, tryptophan and oleic acid) and deuterated glucose, the C–D band in single-cell Raman spectra appeared in some bacteria in faeces, due to the Raman shift from the C–H band. Such Raman shift was used to indicate the general metabolic activity and the activities in response to the specific substrates. In the two individuals' intestinal microbiota, the structures of the microbial communities were different and the general metabolic activities were 76 ± 1.0% and 30 ± 2.0%. We found that glucose, but not tyrosine, tryptophan and oleic acid, significantly stimulated metabolic activity of the intestinal bacteria. We also demonstrated that the bacteria within microbiota preferably used glucose to synthesize fatty acids in faeces environment, whilst they used glucose to synthesize phenylalanine in laboratory growth environment (e.g. LB medium). Our work provides a useful approach for investigating the metabolic activity in situ and revealing different pathways of human intestinal microbiota at the single-cell level. 相似文献
197.
Dan Wang Li Tian Dan-Dan Zhang Jian Song Shuang-Shuang Song Chun-Mei Yin Lei Zhou Yan Liu Bao-Li Wang Zhi-Qiang Kong Steven J. Klosterman Jun-Jiao Li Jie Wang Ting-Gang Li Sabiu Adamu Krishna V. Subbarao Jie-Yin Chen Xiao-Feng Dai 《Molecular Plant Pathology》2020,21(5):667-685
Secreted small cysteine-rich proteins (SCPs) play a critical role in modulating host immunity in plant–pathogen interactions. Bioinformatic analyses showed that the fungal pathogen Verticillium dahliae encodes more than 100 VdSCPs, but their roles in host–pathogen interactions have not been fully characterized. Transient expression of 123 VdSCP-encoding genes in Nicotiana benthamiana identified three candidate genes involved in host–pathogen interactions. The expression of these three proteins, VdSCP27, VdSCP113, and VdSCP126, in N. benthamiana resulted in cell death accompanied by a reactive oxygen species burst, callose deposition, and induction of defence genes. The three VdSCPs mainly localized to the periphery of the cell. BAK1 and SOBIR1 (associated with receptor-like protein) were required for the immunity triggered by these three VdSCPs in N. benthamiana. Site-directed mutagenesis showed that cysteine residues that form disulphide bonds are essential for the functioning of VdSCP126, but not VdSCP27 and VdSCP113. VdSCP27, VdSCP113, and VdSCP126 individually are not essential for V. dahliae infection of N. benthamiana and Gossypium hirsutum, although there was a significant reduction of virulence on N. benthamiana and G. hirsutum when inoculated with the VdSCP27/VdSCP126 double deletion strain. These results illustrate that the SCPs play a critical role in the V. dahliae–plant interaction via an intrinsic virulence function and suppress immunity following infection. 相似文献
198.
199.
Psychiatric genomics research with African populations comes with a range of practical challenges around translation of psychiatric genomics research concepts, procedures, and nosology. These challenges raise deep ethical issues particularly around legitimacy of informed consent, a core foundation of research ethics. Through a consideration of the constitutive function of language, the paper problematises like‐for‐like, designative translations which often involve the ‘indigenization’ of English terms or use of metaphors which misrepresent the risks and benefits of research. This paper argues that effective translation of psychiatric genomics research terminology in African contexts demands substantive engagement with African conceptual schemas and values. In developing attenuated forms of translational thinking, researchers may recognise the deeper motivational reasons behind participation in research, highlighting the possibility that such reasons may depart from the original meaning implied within informed consent forms. These translational issues might be ameliorated with a critical re‐examination of how researchers develop and present protocols to institutional ethics review boards. 相似文献