全文获取类型
收费全文 | 2790篇 |
免费 | 488篇 |
国内免费 | 54篇 |
出版年
2024年 | 29篇 |
2023年 | 119篇 |
2022年 | 122篇 |
2021年 | 190篇 |
2020年 | 170篇 |
2019年 | 219篇 |
2018年 | 152篇 |
2017年 | 123篇 |
2016年 | 131篇 |
2015年 | 132篇 |
2014年 | 204篇 |
2013年 | 272篇 |
2012年 | 122篇 |
2011年 | 145篇 |
2010年 | 82篇 |
2009年 | 91篇 |
2008年 | 82篇 |
2007年 | 109篇 |
2006年 | 88篇 |
2005年 | 68篇 |
2004年 | 83篇 |
2003年 | 70篇 |
2002年 | 63篇 |
2001年 | 40篇 |
2000年 | 33篇 |
1999年 | 40篇 |
1998年 | 29篇 |
1997年 | 40篇 |
1996年 | 33篇 |
1995年 | 32篇 |
1994年 | 29篇 |
1993年 | 25篇 |
1992年 | 29篇 |
1991年 | 11篇 |
1990年 | 20篇 |
1989年 | 6篇 |
1988年 | 16篇 |
1987年 | 7篇 |
1986年 | 9篇 |
1985年 | 13篇 |
1984年 | 13篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有3332条查询结果,搜索用时 15 毫秒
911.
《Cell reports》2020,30(2):525-540.e7
- Download : Download high-res image (125KB)
- Download : Download full-size image
912.
Long Yan Yixuan Wu Li Li Jun Wu Feiyan Zhao Zheng Gao Wenjing Liu Tianda Li Yong Fan Jie Hao Jianqiao Liu Hongmei Wang 《Cell proliferation》2020,53(12)
ObjectivePremature ovarian insufficiency (POI) is a refractory disease that seriously affects female fertility. Growing body of evidence has indicated mesenchymal stem cells (MSCs) as promising resources in regenerative medicine. In this study, we treated POI patients with umbilical cord‐derived MSCs (UCMSCs) and then investigated the restoration of ovarian function and clinical outcomes through follow‐ups.Materials and methodsSixty‐one patients diagnosed with POI participated in this study. UCMSCs were isolated and cultured according to GMP standards, and then transplanted to the patients’ ovary by orthotopic injection under the guidance of vaginal ultrasound. We monitored side effects, vital signs and changes in clinical and collected haematological and imaging parameters during the follow‐ups.ResultsAll patients showed normal clinical behaviour without serious side effects or complications relevant to the treatment. Transplantation of UCMSCs rescued the ovarian function of POI patients, as indicated by increased follicular development and improved egg collection. POI patients who experienced shorter amenorrhoea durations (<1 year) seemed to obtain mature follicles more easily after stem cell therapy, and patients with better ovarian conditions (pre‐operative antral follicles) were more likely to derive the better outcomes by UCMSC injection. Four successful clinical deliveries were obtained from POI patients after UCMSC transplantation, and all of these babies are developed normally.ConclusionsThe clinical trial result sugggests a possible therapy for POI by UCMSC transplantation. 相似文献
913.
《Journal of receptor and signal transduction research》2013,33(1):36-41
Context: Heart failure (HF) is a progressive deterioration in heart function associated with overactivity of the sympathetic nervous system. Elevated sympathetic nervous system activity down regulates the β-adrenergic signal system, suppressing β-adrenoceptors (β-ARs)-mediated contractile support in the failing heart.Objective: We investigated the effects of β2-AR gene transfer on shortening amplitude of isolated ventricular myocytes under chronic exposure to isoprenaline (ISO), and further determine the contributions of β1-AR and β2-AR to the contraction.Materials and methods: Cardiomyocytes were isolated from adult rat hearts and then transfected with β2-AR gene using an adenovirus vector. Four hours after the infection, cardiomyocytes were treated with ISO for another 24 hours to imitate high levels of circulating catecholamines in HF. Western blotting was performed to measure myocardial protein expression of β2-AR. Video-based edge-detection system was used to evaluate basal and ISO-stimulated shortening amplitudes of cardiomyocytes.Results: β2-AR gene transfer increased β2-AR protein content. Chronic ISO stimulation produced a negative inotropic response, whereas acute ISO stimulation showed a positive inotropic response. β2-AR gene transfer had no significant effects on shortening amplitude of cardiomyocytes under normal conditions, but enhanced the blunted contraction of cardiomyocytes under pathological conditions induced by chronic ISO stimulation, and the effect was inhibited by β1-AR antagonist, CGP 20712A, instead of β2-AR antagonist, ICI 118,551.Discussion and conclusions: We conclude that β2-AR gene transfer in isolated ventricular myocytes under chronic ISO stimulation improves cellular contraction, and the beneficial effects might be mediated by improving β1-adrenoceptor responsiveness. 相似文献
914.
Jennifer Miao Shi Huang Yan Ru Su Carrie A. Lenneman Meera Wright Frank E. Harrell 《Biomarkers》2013,18(7):704-708
AbstractContext: Improved left ventricular ejection fraction (LVEF) following administration of recombinant human Neuregulin-1β (NRG), epidermal growth factor (EGF) involved in cardiomyocyte repair/survival, has been observed in patients with systolic heart failure (HF).Methods: Serum NRG was measured by ELISA in 248 patients with NYHA class I–IV HF.Results: NRG exhibited a marginally significant effect on LVEF trajectory over 11?months (p?=?0.07). There is no apparent level of NRG that predicts improved survival.Conclusions: There is a potential relationship between serum NRG and improved LVEF, indicating the need to investigate the utility of NRG in predicting HF outcomes, including LVEF maintenance. 相似文献
915.
Upregulation of Fas in epithelial ovarian cancer reverses the development of resistance to Cisplatin
This study was to investigate the role of Fas in the development of Cisplatin-resistant ovarian cancer. On the cellular level, Fas expression was significantly reduced in Cisplatin resistant A2780 (A2780/CP) cells compared with A2780 cells. Fas silence with siRNA would promote tumor cell lines proliferation, facilitate tumor cell cycle transition of G1/S, prevent cell apoptosis, and promote cell migration. Expression of drug resistance gene was negatively correlated to Fas. In nude mice metastasis model of human ovarian carcinoma by subcutaneous transplantation, after Ad-Fas injected intratumorly, we found that upregulation of Fas could inhibit transplantation tumor tissue growth and reduce the expression of drug resistance gene. Our results indicated that upregulation of Fas in epithelial ovarian cancer reversed the development of resistance to Cisplatin. In conclusion, our findings suggested that Fas might act as a promising therapeutic target for improvement of the sensibility to Cisplatin in ovarian cancer. [BMB Reports 2015; 48(1): 30-35] 相似文献
916.
OL Garibay-Cerdenares VI Hernández-Ramírez JC Osorio-Trujillo D Gallardo-Rincón P Talamás-Rohana 《Cell Adhesion & Migration》2015,9(5):394-405
Haptoglobin (Hp) is an acute-phase protein that is produced by the liver to capture the iron that is present in the blood circulation, thus avoiding its accumulation in the blood. Moreover, Hp has been detected in a wide variety of tissues, in which it performs various functions. In addition, this protein is considered a potential biomarker in many diseases, such as cancer, including ovarian carcinoma; however, its participation in the cancerous processes has not yet been determined. The objective of this work was to demonstrate the expression of Hp and its receptor CCR2 in the ovarian cancer cells and its possible involvement in the process of cell migration through changes in the rearrangement of the actin cytoskeleton using western blot and wound-healing assays and confirming by confocal microscopy. Ovarian cancer cells express both Hp and its receptor CCR2 but only after exposure to ascitic fluid, inducing moderated cell migration. However, when the cells are exposed to exogenous Hp, the expression of CCR2 is induced together with drastic changes in the actin cytoskeleton rearrangement. At the same time, Hp induced cell migration in a much more efficient manner than did ascitic fluid. These effects were blocked when the CCR2 synthetic antagonist RS102895 was used to pretreat the cells. These results suggest that Hp-induced changes in the cell morphology, actin cytoskeleton structure, and migration ability of tumor cells, is possibly “preparing” these cells for the potential induction of the metastatic phenotype. 相似文献
917.
R. J. Achttien J. B. Staal S. van der Voort H. M. Kemps H. Koers M. W. A. Jongert E. J. M. Hendriks 《Netherlands heart journal》2015,23(1):6-17
Rationale
To improve the quality of exercise-based cardiac rehabilitation (CR) in patients with chronic heart failure (CHF) a practice guideline from the Dutch Royal Society for Physiotherapy (KNGF) has been developed.Guideline development
A systematic literature search was performed to formulate conclusions on the efficacy of exercise-based intervention during all CR phases in patients with CHF. Evidence was graded (1–4) according the Dutch evidence-based guideline development criteria.Clinical and research recommendations
Recommendations for exercise-based CR were formulated covering the following topics: mobilisation and treatment of pulmonary symptoms (if necessary) during the clinical phase, aerobic exercise, strength training (inspiratory muscle training and peripheral muscle training) and relaxation therapy during the outpatient CR phase, and adoption and monitoring training after outpatient CR.Applicability and implementation issues
This guideline provides the physiotherapist with an evidence-based instrument to assist in clinical decision-making regarding patients with CHF. The implementation of the guideline in clinical practice needs further evaluation.Conclusion
This guideline outlines best practice standards for physiotherapists concerning exercise-based CR in CHF patients. Research is needed on strategies to improve monitoring and follow-up of the maintenance of a physical active lifestyle after supervised CR. 相似文献918.
目的:慢性心力衰竭(CHF)患者终末期阶段常发生左室(LV)重塑和心脏性恶病质,有研究称Ghrelin可能对CHFLV功能和能量代谢产生保护作用。本文旨在探讨Ghrelin对CHF大鼠LV功能紊乱和心源性恶病质的作用。方法:建立左冠状动脉结扎术和假手术组,手术后4周,给予大鼠Ghrelin或生理盐水3周。用超声心动图和心脏导管术监测结果。结果:与给予安慰剂组相比,用Ghrelin治疗的CHF和假手术组,血浆GH和胰岛素样生长因子1明显升高(t=1.49,t=0.71,P0.05)。与Sham-Placebo组相比,CHF-Placebo组大鼠体重明显减轻(t=2.18,P0.05)。然而与CHF-Placebo组相比,CHF-Ghrelin组大鼠,体重(t=3.89,P0.05),心输出量(t=3.28,P0.05),LV dP/dtmax(t=3.90,P0.05)明显增加。Ghrelin增加了CHF大鼠心脏舒张压,抑制LV扩大,增加LV缩短分数。结论:长期注射Ghrelin可改善CHF大鼠LV功能紊乱,减缓LV重构和心脏性恶病质的发展,有望为CHF的治疗提供新的途径和方法。 相似文献
919.
摘要目的:探讨采用硬膜外分娩镇痛中途转行硬膜外剖宫产麻醉失败的相关因素并对其进行分析。方法:选择来我院进行硬膜
外分娩镇痛转而形硬膜外剖宫产麻醉的产妇218 例,根据硬膜外麻醉失败的定义将其划分为成功组和失败组,对两组的一般资
料、产程中的平均动脉压、硬膜外分娩镇痛情况分别进行比较分析。结果:成功组192 例,失败组26例,两组产妇在一般资料上无
差异(P>0.05),在转行剖宫产前成功组平均动脉压显著低于失败组(P<0.05),补救给药的次数上成功组显著低于失败组(P<0.
05),在镇痛持续时间上成功组显著少于失败组(P<0.05)。结论:影响硬膜外剖宫产麻醉失败的危险因素是分娩镇痛时需要补救给
药的次数增加以及镇痛所持续的时间延长,对于出现此类危险因素的产妇,应改变剖宫产麻醉方式,以最大限度地降低剖宫产麻
醉的失败率,这对于母婴并发症的减少起着积极的作用。 相似文献
920.
李娜孙朝阳周波郭恩松卢豪陈刚翁丹卉Δ 《现代生物医学进展》2014,14(8):1467-1470
目的:卵巢癌是女性生殖致死率最高的恶性肿瘤。Cdk1作为细胞周期依赖性激酶中的核心分子,对肿瘤细胞的发生发展具有重要作用。本文旨在探讨Cdk1蛋白在上皮性浆液性卵巢癌中的表达情况,并分析其表达水平与患者临床病理特征、化疗反应及预后之间的关系。方法:采用免疫组化法检测68例浆液性卵巢癌中Cdk1蛋白的表达情况,并结合临床资料分析Cdk1蛋白的表达水平在浆液性卵巢癌患者中的意义。结果:Cdk1在浆液性卵巢癌患者中具有不同程度的阳性表达,其表达水平和患者的年龄、病理分化程度、淋巴结转移情况及临床分期无明显相关性(P0.05),但是其高表达与化疗耐药明显相关(P=0.040)。化疗耐药的卵巢癌患者中Cdk1的蛋白表达明显高于化疗敏感组,并且生存分析发现,高表达Cdk1的患者预后较差。结论:本研究证明Cdk1在浆液性卵巢癌中有较高表达,并且Cdk1的表达与卵巢癌化疗后复发有关,高的Cdk1表达预示着较差的预后。Cdk1可能是晚期浆液性卵巢癌治疗的新靶点。 相似文献