全文获取类型
收费全文 | 1582篇 |
免费 | 152篇 |
国内免费 | 76篇 |
出版年
2024年 | 4篇 |
2023年 | 22篇 |
2022年 | 39篇 |
2021年 | 76篇 |
2020年 | 54篇 |
2019年 | 55篇 |
2018年 | 62篇 |
2017年 | 42篇 |
2016年 | 63篇 |
2015年 | 99篇 |
2014年 | 117篇 |
2013年 | 121篇 |
2012年 | 141篇 |
2011年 | 131篇 |
2010年 | 69篇 |
2009年 | 63篇 |
2008年 | 85篇 |
2007年 | 70篇 |
2006年 | 46篇 |
2005年 | 60篇 |
2004年 | 43篇 |
2003年 | 38篇 |
2002年 | 31篇 |
2001年 | 24篇 |
2000年 | 27篇 |
1999年 | 31篇 |
1998年 | 8篇 |
1997年 | 14篇 |
1996年 | 23篇 |
1995年 | 8篇 |
1994年 | 14篇 |
1993年 | 3篇 |
1992年 | 19篇 |
1991年 | 10篇 |
1990年 | 16篇 |
1989年 | 12篇 |
1988年 | 12篇 |
1987年 | 4篇 |
1986年 | 8篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
排序方式: 共有1810条查询结果,搜索用时 656 毫秒
41.
Imbs A. B. Ermolenko E. V. Grigorchuk V. P. Dang L. T. P. 《Russian Journal of Marine Biology》2021,47(4):312-317
Russian Journal of Marine Biology - To assess the biodiversity of symbiotic dinoflagellates (SD) in hydrocorals, we compared the molecular species compositions of four SD lipid classes such as... 相似文献
42.
Gang Chen Dongxia Feng Li Zhang Baoqi Dang Huixiang Liu Zhong Wang 《Cell biochemistry and biophysics》2013,66(3):671-680
This study aimed to investigate the expression of the Nemo-like kinase (NLK) in the brain after experimental subarachnoid hemorrhage (SAH) in rats. A total of 90 rats were randomly divided into six groups: control group, day 1, day 3, day 5, day 7, and day 14. Day 1, day 3, day 5, day 7, and day 14 groups were all SAH groups in which the rats were killed on days 1, 3, 5, 7, and 14, respectively. In SAH groups, autologous arterial blood was injected into cisterna magna once on day 0. Cross-sectional area of basilar artery was measured by H&E staining. Immunostaining and immunoblotting experiments were performed to detect the expression of NLK protein. Real-time polymerase chain reaction was used to analyze the presence and quantity of NLK mRNA. The level of oxidative stress in the artery was also measured. The basilar arteries exhibited vasospasm after SAH and became the most severe on day 3. The expressions of NLK protein and mRNA were decreased remarkably in SAH groups compared with the control group. The down-regulated expression of NLK was detected after SAH and the low ebb was on day 3, which was oppositely the peak time of oxidative stress. The expression of NLK was present mainly in the neurons in the brain and smooth muscle cells in the basilar artery. NLK is decreasingly expressed in an opposite time-course to the development of cerebral vasospasm (CVS) and SAH-induced brain injury in this rat experimental model of SAH and these findings might have important implications during the administration of specific NLK agonist to prevent or reduce CVS or neuronal apoptosis caused by SAH. 相似文献
43.
Mei Zeng Baofeng Chen Yufeng Qing Wenguang Xie Wantai Dang Mingcai Zhao 《Nucleosides, nucleotides & nucleic acids》2013,32(7):455-465
Glut9 is highly expressed in the human kidney proximal convoluted tubular and plays a crucial role in the regulation of plasma urate levels. The gene effects were stronger among women. Our results show that 17-β-estradiol (E2) through ER (estrogen receptor) β downregulates Glut9 protein expression on human renal tubular epithelial cell line (HK2). Intriguingly, E2 does not affect the expression of Glut9 mRNA. ERβ is linked to PTEN, the PTEN gene negatively regulates the PI3K/AKT pathway, and the PI3K/AKT pathway inhibition may lead to autophagy. Further study indicates that ERβ may affect the expression of Glut9 though autophagy. 相似文献
44.
Zhigang Chen Xin He Wenjie Xia Qi Huang Zhigang Zhang Jun Ye Chao Ni Pin Wu Dang Wu Jinghong Xu Fuming Qiu Jian Huang 《PloS one》2013,8(12)
Background
The prognostic value of HIFs in colorectal cancer was evaluated in a large number of studies, but the conclusions were inconclusive. Meanwhile, clinicopathologic differences of HIF-1α and HIF-2α were rarely compared in recent studies.Methodology
Identical search strategies were used to search relevant literatures in the PubMed and Web of Science databases. The prognostic significances and clinicopathological differences of HIFs in CRC were analyzed.Principal Findings
A total of 23studies comprising 2984 CRC patients met the inclusion criteria. The results indicated that overexpressed HIFs were significantly associated with increase of mortality risk, including overall survival (OS) (HR 2.06 95%CI 1.55–2.74) and disease free survival (HR 2.84, 95%CI 1.87–4.31). Subgroup analysis revealed that both overexpressed HIF-1α and HIF-2α had correlations with worse prognosis. The pooled HRs were 2.01 (95% CI: 1.55–2.6) and 2.07(95% CI: 1.01–4.26). Further subgroup analysis on HIF-1α was performed by study location, number of patients, quality score and cut-off value. The results showed that HIF-1α overexpression was significantly associated with poor OS, particularly in Asian countries (HR 2.3, 95% CI: 1.74–3.01), while not in European or other countries. In addition, overexpression of HIF-1α was closely related with these clinicopathological features, including Dukes'' stages (OR 0.39, 95% CI: 0.17–0.89), UICC stages (OR 0.42 95% CI: 0.3–0.59), depth of invasion (OR 0.71, 95% CI: 0.51–0.99), lymphnode status (OR 0.49, 95% CI: 0.32–0.73) and metastasis (OR 0.29, 95% CI: 0.11–0.81). While overexpression of HIF-2α was only associated with grade of differentiation (OR 0.48, 95% CI: 0.29–0.81).Conclusions
This study showed that both HIF-1α and HIF-2α overexpression were associated with an unfavorable prognosis. HIF-1α overexpression seemed to be associated with worse prognosis in Asian countries. Additionally, HIF-1α and HIF-2α indicated distinct clinicopathologic features. 相似文献45.
46.
47.
hOGG1 Ser326Cys Polymorphism and Risk of Hepatocellular Carcinoma among East Asians: A Meta-Analysis
Wenjun Wang Shuangsuo Dang Yaping Li Mingzhu Sun Xiaoli Jia Rui Wang Jingkun Liu 《PloS one》2013,8(4)
Background
The hOGG1 gene encodes a DNA glycosylase enzyme responsible for DNA repair. The Ser326Cys polymorphism in this gene may influence its repair ability and thus plays a role in carcinogenesis. Several case-control studies have been conducted on this polymorphism and its relationship with the risk of hepatocellular carcinoma (HCC) among East Asians. However, their results are inconsistent.Methods
We performed a meta-analysis of published case-control studies assessing the association of the hOGG1 Ser326Cys polymorphism with HCC risk among East Asians. PubMed, EMBASE, SCI, BIOSIS, CNKI and WanFang databases were searched. A random-effect model was used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). Analyses were conducted for additive, dominant and recessive genetic models.Results
Eight studies were identified involving 2369 cases and 2442 controls assessing the association of the hOGG1 Ser326Cys polymorphism with HCC risk among East Asians. Applying a dominant genetic model, only in the Chinese population, the Cys allele was significantly associated with increased risk of HCC (OR 1.56, 95% CI 1.12–2.17). However, two studies influenced this finding according to sensitivity analysis. Furthermore, considerable heterogeneity and bias existed among Chinese studies.Conclusion
There is limited evidence to support that the hOGG1 Ser326Cys polymorphism is associated with HCC risk among East Asians. Well-designed and large-sized studies are required to determine this relationship. 相似文献48.
Kenneth K. Poon Bich N. Dang Jessica A. Davila Christine Hartman Thomas P. Giordano 《PloS one》2013,8(3)
Objective
Little is known about the treatment outcomes of undocumented Hispanic immigrants with HIV infection. We sought to compare the treatment outcomes of undocumented and documented patients 12-months after entering HIV care.Methods
We conducted a retrospective cohort study of antiretroviral-naive patients 18 years and older attending their first visit at Thomas Street Health Center in Houston, Texas, between 1/1/2003 and 6/30/2008. The study population of 1,620 HIV-infected adults included 186 undocumented Hispanic, 278 documented Hispanic, 986 Black, and 170 White patients. The main outcome measures were retention in care (quarter years with at least one completed HIV primary care provider visit) and HIV suppression (HIV RNA <400 copies/mL), both measured 12-months after entering HIV care.Results
Undocumented Hispanic patients had lower median initial CD4 cell count (132 cells/mm3) than documented Hispanic patients (166 cells/mm3; P = 0.186), Black patients (226 cells/mm3; P<0.001), and White patients (264 cells/mm3; P = 0.001). However, once in care, undocumented Hispanic patients did as well or better than their documented counterparts. One year after entering HIV care, undocumented Hispanics achieved similar rates of retention in care and HIV suppression as documented Hispanic and White patients. Of note, black patients were significantly less likely to have optimal retention in care (adjusted odds ratio [aOR] 0.65, CI = 0.45–0.94) or achieve HIV suppression (aOR 0.32, CI = 0.17–0.61) than undocumented Hispanics.Conclusions
Undocumented Hispanic persons with HIV infection enter care with more advanced disease than documented persons, suggesting testing and/or linkage to care efforts for this difficult-to-reach population need intensification. Once diagnosed, however, undocumented Hispanics have outcomes as good as or better than other racial/ethnic groups. Safety net providers for undocumented immigrants are vital for maintaining individual and public health. 相似文献49.
Xiangjing Fu Xiaolong Gao Shengfang He Di Huang Peng Zhang Xinglong Wang Shuxia Zhang Ruyi Dang Shuanghui Yin Enqi Du Zengqi Yang 《PloS one》2013,8(3)
Nanobodies (or variable domain of the heavy chain of the heavy-chain antibodies, VHHs) are single-domain antigen-binding fragments derived from camelid heavy chain antibodies. Their comparatively small size, monomeric behavior, high stability, high solubility, and ability to bind epitopes inaccessible to conventional antibodies make them especially suitable for many therapeutic and biotechnological applications. In this paper, for the first time, we created the immunized Camelus Bactrianus VHH yeast two-hybrid (Y2H) library according to the Clontech Mate & Plate library construction system. The transformation efficiency and titer of the VHH Y2H library were 7.26×106 cfu/3 µg and 2×109 cfu/ml, which met the demand for Y2H library screening. Using as an example the porcine circovirus type 2 (PCV2) Cap protein as bait, we screened 21 positive Cap-specific VHH sequences. Among these sequences, 7 of 9 randomly selected clones were strongly positive as indicated by enzyme-linked immunosorbent assay, either using PCV2 viral lysis or purified Cap protein as coated antigen. Additionally, the immunocytochemistry results further indicated that the screened VHHs could specifically detected PCV2 in the infected cells. All this suggests the feasibility of in vivo VHH throughput screening based on Y2H strategy. 相似文献
50.
Yaling Zhao Hong Yan Roger J. Marshall Shaonong Dang Ruihai Yang Qiang Li Xueying Qin 《PloS one》2013,8(4)