全文获取类型
收费全文 | 811篇 |
免费 | 64篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 27篇 |
妇产科学 | 40篇 |
基础医学 | 134篇 |
口腔科学 | 9篇 |
临床医学 | 94篇 |
内科学 | 228篇 |
皮肤病学 | 5篇 |
神经病学 | 19篇 |
特种医学 | 62篇 |
外科学 | 58篇 |
综合类 | 16篇 |
预防医学 | 82篇 |
眼科学 | 10篇 |
药学 | 59篇 |
肿瘤学 | 52篇 |
出版年
2023年 | 5篇 |
2022年 | 8篇 |
2021年 | 17篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 16篇 |
2017年 | 16篇 |
2016年 | 20篇 |
2015年 | 21篇 |
2014年 | 20篇 |
2013年 | 33篇 |
2012年 | 37篇 |
2011年 | 30篇 |
2010年 | 28篇 |
2009年 | 20篇 |
2008年 | 28篇 |
2007年 | 62篇 |
2006年 | 32篇 |
2005年 | 44篇 |
2004年 | 31篇 |
2003年 | 29篇 |
2002年 | 35篇 |
2001年 | 24篇 |
2000年 | 24篇 |
1999年 | 36篇 |
1998年 | 21篇 |
1997年 | 19篇 |
1996年 | 21篇 |
1995年 | 25篇 |
1994年 | 17篇 |
1993年 | 23篇 |
1992年 | 9篇 |
1991年 | 12篇 |
1990年 | 16篇 |
1989年 | 19篇 |
1988年 | 13篇 |
1987年 | 10篇 |
1986年 | 6篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有902条查询结果,搜索用时 0 毫秒
41.
Lobke Bastings Johan R. Westphal Catharina C. M. Beerendonk Ruud L. M. Bekkers Petra L. M. Zusterzeel Jan C. M. Hendriks Didi D. M. Braat Ronald Peek 《Journal of assisted reproduction and genetics》2016,33(12):1605-1614
Purpose
Different protocols are being used worldwide for the cryopreservation of human ovarian tissue for fertility preservation purposes. The efficiency and efficacy of the majority of these protocols has not been extensively evaluated, possibly resulting in sub-optimally cryopreserved ovarian tissue. To address the impact of this issue, we assessed the effects of two clinically successful human ovarian tissue slow-freezing cryopreservation procedures on the quality of the cryopreserved tissue.Methods
To differentiate between cryopreservation (C) versus thawing (T) related effects, four combinations of these two (A and B) very different cryopreservation/thawing protocols (ACAT, ACBT, BCAT, BCBT) were studied. Before and after cryopreservation and thawing, the percentage of living and morphologically normal follicles, as well as the overall tissue viability, was assessed.Results
Our experiments revealed that the choice of the cryopreservation protocol noticeably affected the overall tissue viability and percentage of living follicles, with a higher viability after protocol BC when compared to AC. No statistically significant differences in tissue viability were observed between the two thawing protocols, but thawing protocol BT required considerably more human effort and materials than thawing protocol AT. Tissue morphology was best retained using the BCAT combination.Conclusion
Our results indicate that extensive and systematical evaluation of clinically used protocols is warranted.42.
Dientamoeba fragilis is a globally occurring parasite that has been recognized as a causative agent of gastrointestinal symptoms. A single-round PCR was developed to detect D. fragilis DNA directly from human stool samples. The genetic diversity of D. fragilis from 93 patients and 6 asymptomatic carriers was examined by PCR followed by restriction fragment length polymorphism and sequencing of part of the small-subunit rRNA gene. The data show that D. fragilis sequences can be studied directly from fecal specimens despite the absence of a cyst stage and without the need for prior culturing. In addition, the results suggest strongly that D. fragilis shows remarkably little variation in its small-subunit rRNA gene. 相似文献
43.
Helicobacter pylori infection stimulates plasminogen activator inhibitor 1 production by gastric epithelial cells 下载免费PDF全文
Keates AC Tummala S Peek RM Csizmadia E Kunzli B Becker K Correa P Romero-Gallo J Piazuelo MB Sheth S Kelly CP Robson SC Keates S 《Infection and immunity》2008,76(9):3992-3999
Chronic infection with the gastric pathogen Helicobacter pylori significantly increases the risk of developing atrophic gastritis, peptic ulcer disease, and gastric adenocarcinoma. H. pylori strains that possess the cag pathogenicity island, which translocates CagA into the host cells, augment these risks. The aim of this study was to determine the molecular mechanisms through which H. pylori upregulates the expression of plasminogen activator inhibitor 1 (PAI-1), a member of the urokinase activator system that is involved in tumor metastasis and angiogenesis. Levels of PAI-1 mRNA and protein were examined in tissues from H. pylori-infected patients and in vitro using AGS gastric epithelial cells. In vitro, cells were infected with toxigenic cag-positive or nontoxigenic cag-negative strains of H. pylori or isogenic mutants. The amount of PAI-1 secretion was measured by enzyme-linked immunosorbent assay, and mRNA levels were determined using real-time PCR. The regulation of PAI-1 was examined using the extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor and small interfering RNA. Analysis of human biopsy samples revealed an increase in both PAI-1 mRNA and protein levels in patients with H. pylori gastritis compared to those of uninfected controls. Infection of AGS cells with H. pylori significantly increased PAI-1 mRNA expression and the secretion of PAI-1 protein. Moreover, PAI-1 mRNA and protein production was more pronounced when AGS cells were infected by H. pylori strains carrying a functional cag secretion system than when cells were infected by strains lacking this system. PAI-1 secretion was also reduced when cells were infected with either cagE-negative or cagA-negative mutants. The ectopic overexpression of CagA significantly increased the levels of PAI-1 mRNA and protein, whereas blockade of the ERK1/2 pathway inhibited H. pylori-mediated PAI-1 upregulation. These findings suggest that the upregulation of PAI-1 in H. pylori-infected gastric epithelial cells may contribute to the carcinogenic process. 相似文献
44.
There is a large population of children conceived via assisted reproductive technology (ART), which continues to increase worldwide, without a clear understanding of associated long-term outcomes. ART children are more likely to be the result of multiple pregnancies, and thus to be born prematurely or low birthweight. There is growing evidence that ART children are phenotypically and biochemically different from naturally conceived children, but the mechanism(s) leading to these changes have not been elucidated. There is a possible increased risk of rare imprinted gene disorders in these children. However, it remains unclear whether more subtle changes in DNA methylation occur commonly, leading to differences in gene expression and phenotype in ART children. Although an increased risk of cancer among ART children has been reported, the role of ART in the development of cancer has not been demonstrated. Further research and ongoing surveillance of ART children is essential to better understand the possible effects of ART on the long-term health of this population. 相似文献
45.
Isolation of endothelial cells from murine tissue 总被引:12,自引:0,他引:12
Marelli-Berg FM Peek E Lidington EA Stauss HJ Lechler RI 《Journal of immunological methods》2000,244(1-2):205-215
The isolation and long-term culture of murine endothelial cells (ECs) has often proven a difficult task. In this paper we describe a quick, efficient protocol for the isolation of microvascular endothelial cells from murine tissues. Murine lung or heart are mechanically minced and enzymatically digested with collagenase and trypsin. The single cell suspension obtained is then incubated with an anti-CD31 antibody, anti-CD105 antibody and with biotinylated isolectin B-4. Pure EC populations are finally obtained by magnetic bead separation using rat anti-mouse Ig- and streptavidin-conjugated microbeads. EC cultures are subsequently expanded and characterised. The surface molecule expression by the primary cultures of murine EC obtained from lung and heart tissue is analysed and compared to that of a murine endothelioma and of primary cultures of murine renal tubular epithelial cells. The phenotype and morphology of these cultures remain stable over 10-15 passages in culture, and no overgrowth of contaminating cells of non-endothelial origin is observed at any stage. 相似文献
46.
47.
Purpose
Clinical practice guidelines often contain ambiguities, inconsistencies, and logical errors that hamper implementation of these guidelines in practice. As guideline formalization is useful to verify the logical structure, consistency, and completeness of guidelines, several authors have argued that the formalization of guidelines concurrent with their development may improve their quality. However, experiences with such a parallel guideline development and formalization approach have not yet been reported. The goal of this study was to develop such a strategy and evaluate its application in practice.Methods
Existing methodologies for guideline development and guideline formalization were analyzed and used as a basis to develop a strategy in which guideline formalization is performed concurrently with guideline development. The developed strategy was applied in the development of a clinical practice guideline for cardiac rehabilitation.Results
A parallel guideline development and formalization strategy was developed that intertwines the processes of guideline development and guideline formalization. Central assets are early involvement of guideline formalization specialists and formalization tools, cooperation between guideline authors and guideline formalization specialists in the development of clinical algorithms, access to domain knowledge when formalization identifies inconsistencies or omissions, and formal verification of the guideline model prior to guideline dissemination. This strategy was applied in the development of a guideline for cardiac rehabilitation and helped to identify several vague and inconsistent recommendations and impracticabilities in the narrative guidelines that could be resolved before publication. In addition, the strategy ensured consistency between the narrative and formalized guideline.Conclusions
Based on our experience, formalizing a guideline concurrent with its development is feasible in practice and we recommend applying such a strategy as it can be beneficial to the quality of and consistency between the guideline's narrative and formalized version. 相似文献48.
Airin CR Simon Wouter T Gude Frits Holleman Joost BL Hoekstra Niels Peek 《Journal of medical Internet research》2014,16(10)
Background
Computer-assisted decision support is an emerging modality to assist patients with type 2 diabetes mellitus (T2DM) in insulin self-titration (ie, self-adjusting insulin dose according to daily blood glucose levels). Computer-assisted insulin self-titration systems mainly focus on helping patients overcome barriers related to the cognitive components of insulin titration. Yet other (eg, psychological or physical) barriers could still impede effective use of such systems.Objective
Our primary aim was to identify experiences with and barriers to self-monitoring of blood glucose, insulin injection, and insulin titration among patients with T2DM. Our research team developed a computer-assisted insulin self-titration system, called PANDIT. The secondary aim of this study was to evaluate patients’ perceptions of computer-assisted insulin self-titration. We included patients who used PANDIT in a 4-week pilot study as well as patients who had never used such a system.Methods
In-depth, semi-structured interviews were conducted individually with patients on insulin therapy who were randomly recruited from a university hospital and surrounding general practices in the Netherlands. The interviews were transcribed verbatim and analyzed qualitatively. To classify the textual remarks, we created a codebook during the analysis, in a bottom-up and iterative fashion. To support examination of the final coded data, we used three theories from the field of health psychology and the integrated model of user satisfaction and technology acceptance by Wixom and Todd.Results
When starting insulin therapy, some patients feared a lifelong commitment to insulin therapy and disease progression. Also, many barriers arose when implementing insulin therapy (eg, some patients were embarrassed to inject insulin in public). Furthermore, patients had difficulties increasing the insulin dose because they fear hypoglycemia, they associate higher insulin doses with disease progression, and some were ignorant of treatment targets. Patients who never used a computer-assisted insulin self-titration system felt they had enough knowledge to know when their insulin should be adjusted, but still believed that the system advice would be useful to confirm their reasoning. Furthermore, the time and effort saved with automated insulin advice was considered an advantage. Patients who had used PANDIT found the system useful if their glycemic regulation improved. Nevertheless, for some patients, the absence of personal contact with their caregiver was a drawback. While guidelines state that adjustment of basal insulin dose based on fasting plasma glucose values is sufficient, both patients who had and those who had not used PANDIT felt that such a system should take more patient data into consideration, such as lifestyle and diet factors.Conclusions
Patients encounter multiple obstacles when implementing insulin therapy. Computer-assisted insulin self-titration can increase patient awareness of treatment targets and increase their confidence in self-adjusting the insulin dose. Nevertheless, some barriers may still exist when using computer-assisted titration systems and these systems could also introduce new barriers. 相似文献49.
Sandra Vosbergen Jolien Janzen Pieter Jan Stappers Myra C.B. van Zwieten Joyca Lacroix Karin Idema Inge van den Broek Hareld M.C. Kemps Roderik A. Kraaijenhagen Niels Peek 《International journal of medical informatics》2013,82(12):1183-1194
ObjectiveWeb-based self-management services remain underutilized in current practice. Our aim was to gain insight into disease and self-management experiences of patients in early and progressive stages of coronary heart disease (CHD), to understand moderating effects of daily life experiences on the utilization of web-based self-management services and preconditions for use.MethodsWe applied generative research techniques, which stem from the field of product design and are characterized by the use of creative processes. Three groups of patients with CHD received a sensitizing package to document and reflect on their health, and were subsequently either interviewed or participated in a focus group session.ResultsIn total, 23 patients participated in this study. Emerging themes were (1) fear for recurrent events, (2) experiences with professional care, (3) the perceived inability to prevent disease progression, (4) the desire to go on living without thinking about the disease every day, (5) the social environment as a barrier to or facilitator for self-management, and (6) the need for information tailored to personal preferences.ConclusionHow patients experience their disease varies between stable and post-acute stages, as well as between early and progressive stages of CHD. Patients in post-acute stages of the disease seem to be most amenable to support, while patients in stable stages want to live their life without being reminded of their disease. In the context of self-management, web-based services should be adapted to the variation in needs that occur in the different stages of CHD and new strategies to fit such services to these needs should be developed. Furthermore, they should be tailored to patients’ individual health situation and preferences, support patient empowerment, and manage expectations regarding the progression of their disease. 相似文献
50.
Kung FT; Chen WJ; Chou HH; Ko SF; Chang SY 《Human reproduction (Oxford, England)》1997,12(8):1649-1653
We report a rare case of early-stage endometrial adenocarcinoma in a 22
year old nullipara with polycystic ovaries undergoing conservative
treatment. Pretreatment evaluation including tumour grade, depth of
myometrial invasion, tumour size, hormone receptor status and flow
cytometric analysis indicated a favourable prognosis. The patient underwent
repeat endometrial curettage and a 6 month period of therapy with megestrol
acetate and tamoxifen. A combination contraceptive pill was then prescribed
to ensure withdrawal of the menstrual cycle thereafter. Now, 1 year after
the last curettage, there is no evidence of disease. During the treatment
period, hysteroscopy allowed for a more precise approach in panoramically
examining the tumour nest in the endometrial cavity, and the subsequent
endometrial response to hormone therapy. Laparoscopy using bulldog clamps
applied to the isthmic portion of the Fallopian tubes prevented i.p. spread
of endometrial tissue from retrograde regurgitation during hysteroscopy.
Laparoscopic ovarian electrocautery resulted in the reduction of abnormal
hypervascularization on the surface of polycystic ovaries postoperatively
but caused a peri-ovarian adhesion complication. It is interesting that
this case posed a unique opportunity to demonstrate the tumour regression
under the assistance of laparoscopy and hysteroscopy.
相似文献