全文获取类型
收费全文 | 40688篇 |
免费 | 3324篇 |
国内免费 | 3554篇 |
出版年
2024年 | 66篇 |
2023年 | 425篇 |
2022年 | 1035篇 |
2021年 | 1711篇 |
2020年 | 1257篇 |
2019年 | 1532篇 |
2018年 | 1436篇 |
2017年 | 1160篇 |
2016年 | 1619篇 |
2015年 | 2431篇 |
2014年 | 2854篇 |
2013年 | 3030篇 |
2012年 | 3714篇 |
2011年 | 3231篇 |
2010年 | 2151篇 |
2009年 | 1932篇 |
2008年 | 2330篇 |
2007年 | 2028篇 |
2006年 | 1923篇 |
2005年 | 1680篇 |
2004年 | 1534篇 |
2003年 | 1397篇 |
2002年 | 1180篇 |
2001年 | 913篇 |
2000年 | 794篇 |
1999年 | 732篇 |
1998年 | 474篇 |
1997年 | 397篇 |
1996年 | 361篇 |
1995年 | 322篇 |
1994年 | 261篇 |
1993年 | 211篇 |
1992年 | 265篇 |
1991年 | 218篇 |
1990年 | 185篇 |
1989年 | 145篇 |
1988年 | 104篇 |
1987年 | 118篇 |
1986年 | 78篇 |
1985年 | 53篇 |
1984年 | 34篇 |
1983年 | 55篇 |
1982年 | 20篇 |
1981年 | 17篇 |
1980年 | 13篇 |
1979年 | 18篇 |
1978年 | 15篇 |
1977年 | 14篇 |
1972年 | 13篇 |
1970年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
A new application of antibodies is to use them as macromolecular chaperones. Protein antigens usually have multiple epitopes, thus, there may be a plurality of antibodies binding to one antigen. However, not all antibodies that bind to one antigen could act as a chaperone. Experiments show that some screened anti-human creatine kinase single chain antibodies (scFV) could assist in the folding and stabilizing of the enzyme, while others could not. We built the model of the single chain antibody (scFv-A4) that increased the stability of human creatine kinase (HCK) by the homology modeling method. Epitopes of human creatine kinase were predicted by computer and then the binding of scFv-A4 and HCK was modeled with computer. The calculation results were further combined with the peptide array membrane experiment results to obtain reliable models for the scFv-A4-HCK complex. Based on the above study we gave an explanation about how scFv-A4 could act as a macromolecular chaperone assisting the folding of HCK. This study provides an approach for predicting antigen-antibody binding mode and also a useful theoretical guidance for the study of antibodies'' chaperone-like function. 相似文献
942.
Background
Contradictory results have been reported regarding the association between leptin level and breast cancer. Therefore, a meta-analysis was performed to investigate this issue.Methods
Published literature from PubMed and the Chinese National Knowledge Infrastructure (CNKI) Database was retrieved. This study was performed based on different cases and control groups. The combined effect () with 95% confidence interval (CI) was calculated using fixed-effects or random-effects model analysis.Results
Overall, the mean serum leptin level of case groups was significantly higher than that of control groups. A) For 9 studies comparing breast cancer cases and healthy controls the combined effect was 0.58 with 95% CI (0.48, 0.68). B) For 4 studies comparing premenopausal breast cancer cases and healthy controls the was 0.32 (0.12, 0.52). C) For 5 studies comparing postmenopausal cases and healthy controls the was 0.65 (0.46, 0.84). D) For 4 studies comparing breast cancer cases and breast benign controls the was 0.38 (0.17, 0.59). E) For 2 studies comparing premenopausal breast cancer cases and breast benign controls the was 0.33 (-0.25, 0.91). F) For 6 studies comparing postmenopausal breast cancer cases and breast benign controls the was 0.39 (0.19, 0.60). G) For 4 studies comparing lymph node metastasis positive cases and negative controls the was 0.72 (0.45, 1.00). H) For 3 studies comparing breast benign cases and healthy controls the was 0.71 (0.41, 1.01).Conclusion
This meta-analysis suggests that leptin level plays a role in breast cancer and has potential for development as a diagnostic tool. 相似文献943.
High risk subtype HPV16 early oncoprotein E6 contributes host cell immortalization and transformation through interacting with a number of cellular factors. ING4 is one member of the inhibitor of growth (ING) family of type II tumor suppressors and it has been shown to be involved in regulating p53 function. However, the effect and mechanism of HPV16 E6 on ING4 function remain elusive. In this study, we report HPV16 E6 combines with ING4 in vivo and in vitro. The ING4 induced p53 acetylation and its combining with p53 were attenuated by HPV16 E6 independent of p53 degradation. The enhancing function of ING4 on p53 mediated apoptosis was diminished when HPV16 E6 existed. These findings reveal that ING4 may be a common target of oncogenic viruses for driving host cell carcinogenesis. 相似文献
944.
945.
946.
947.
Objective
The flood after a typhoon may lead to increase in patients with cellulitis of lower limbs. However, the microbiological features of these cases are rarely reported. We conducted a study of patients with lower extremity cellulitis after a typhoon followed in southern Taiwan to study the risk factors of cellulitis and the bacteriological features of the patients.Methods
We reviewed all the medical records of cellulitis at emergency departments of two teaching hospitals in southern Taiwan 30 days before and after the landing of Typhoon Morakot and collected data on the demographic and bacteriological characteristics. In addition, we evaluated the relationship between the daily number of patients and the rainfall in the Tainan area.Results
The number of cellulitis patients increased from 183 to 344 during the 30-day period after the typhoon. The number peaked in the third and fourth days and lasted for 3 weeks. The proportion of patients with water immersion of the affected limb was higher after the typhoon (6% vs. 37%, odds ratio [OR]: 9.0, 95% Confidence interval [CI]: 4.7–17.2). We found cultures from the infected limbs with immersion had more polymicrobial (73% vs. 26%, OR: 7.8, 95% CI: 3.2–19.2) and Gram-negative bacilli infection (86% vs. 34%, OR: 11.8, 95% CI: 4.1–34.5).Conclusions
Flood arose from Typhoon Morakot caused increases in cellulitis patients, which lasted for 3 weeks. Antibiotic treatment that were effective to both Gram-positive cocci and Gram-negative bacilli are recommended for patients with limbs emerged in the water. 相似文献948.
949.
Jun Ni Jan D. Reinhardt Xia Zhang Mingyue Xiao Ling Li Hong Jin Xianmin Zeng Jianan Li 《PloS one》2013,8(10)
Background
This study aimed to evaluate the effectiveness of a rehabilitation intervention on physical dysfunction (PDF) and post-traumatic stress disorder (PTSD) in fracture victims 50 months after the Sichuan earthquake of 2008 and to identify risk factors for PTSD.Methods
This is a retrospective cohort study. Four hundred and fifty-nine earthquake-related fracture victims from Mianzhu city, Sichuan Province who did not qualify for disability pension participated. Two hundred and forty-five subjects received regular rehabilitation and 214 did not. Muscle strength, joint range of motion (ROM),sensory function, and sit-to-stand balance capacity were evaluated to assess PDF. The PTSD Checklist-Civilian Version (PCL-C) was administered to screen for PTSD. An ordinary least square regression was used to predict PTSD, and a logistic regression was used to predict PDF. In addition a Least Angle Regression (LARS) was carried out for PTSD to study the effects of rehabilitation and PDF at the same time.Results
Unadjusted and adjusted group differences in physical dysfunction (p<0.01) and PTSD prevalence (p<0.05) were significant in favor of the rehabilitation group. In addition, being female, average or above family income, having witnessed death and fearfulness were found risk factors for PTSD symptoms 50 months after the earthquake. Both PDF and rehabilitation were selected predictors by LARS demonstrating opposite effects.Conclusion
PDF and PTSD were significantly reduced by the rehabilitation intervention. Future medical intervention strategies should consider rehabilitation in order to assist survivors in dealing with both physical and psychological effects of natural disaster. 相似文献950.
MicroRNAs (miRNAs), approximately 22-nucleotide non-coding RNA molecules, regulate a variety of pivotal physiological or pathological processes, including embryonic development and tumorigenesis. To obtain comprehensive expression profiles of miRNAs in human embryos, we characterized miRNA expression in weeks 4-6 of human embryonic development using miRNA microarrays and identified 50 human-embryo-specific miRNAs (HES-miRNAs). Furthermore, we selected three non-conserved or primate-specific miRNAs, hsa-miR-638, -720, and -1280, and examined their expression levels in various normal and tumor tissues. The results show that expression of most miRNAs is extremely low during early human embryonic development. In addition, the expression of some non-conserved or primate-specific miRNAs is significantly different between tumor and the corresponding normal tissue samples, suggesting that the miRNAs are closely related to the pathological processes of various tumors. This study presents the first comprehensive overview of miRNA expression during human embryonic development and offers immediate evidence of the relationship between human early embryonic development and tumorigenesis. 相似文献