首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1781篇
  免费   107篇
  国内免费   12篇
耳鼻咽喉   11篇
儿科学   78篇
妇产科学   101篇
基础医学   275篇
口腔科学   50篇
临床医学   132篇
内科学   324篇
皮肤病学   57篇
神经病学   135篇
特种医学   32篇
外科学   136篇
综合类   35篇
一般理论   1篇
预防医学   157篇
眼科学   90篇
药学   175篇
中国医学   11篇
肿瘤学   100篇
  2023年   29篇
  2022年   53篇
  2021年   90篇
  2020年   37篇
  2019年   54篇
  2018年   70篇
  2017年   50篇
  2016年   78篇
  2015年   61篇
  2014年   84篇
  2013年   104篇
  2012年   166篇
  2011年   170篇
  2010年   93篇
  2009年   63篇
  2008年   91篇
  2007年   81篇
  2006年   85篇
  2005年   73篇
  2004年   60篇
  2003年   59篇
  2002年   53篇
  2001年   21篇
  2000年   25篇
  1999年   12篇
  1998年   14篇
  1997年   7篇
  1996年   2篇
  1995年   8篇
  1994年   3篇
  1993年   4篇
  1992年   12篇
  1991年   8篇
  1990年   13篇
  1989年   7篇
  1988年   4篇
  1986年   11篇
  1985年   5篇
  1984年   5篇
  1983年   6篇
  1982年   2篇
  1981年   6篇
  1980年   6篇
  1979年   4篇
  1978年   2篇
  1977年   2篇
  1972年   1篇
  1971年   2篇
  1969年   1篇
  1966年   1篇
排序方式: 共有1900条查询结果,搜索用时 31 毫秒
41.
42.
Background: A sugar rich diet induces inflammation and insulin resistance (IR) mainly through gut microbiota alteration. Gut dysbiosis increases lipopolysaccharide (LPS) and reduces propionate and butyrate levels to impair the insulin signalling cascades by different molecular pathways, which progresses into IR. The present study was designed to investigate the effect of spectrum specific antibiotics on the modulation of gut microbiota and its signalling pathways to prevent diet-induced diabetes. Methods: Healthy male Wistar rats were divided into a non-diabetic group with a control diet (CD), a diabetic group with a high sucrose diet (HSD) and two antibiotic fed groups (linezolid and cefdinir; administered by oral gavage) along HSD. Physiological, biochemical, inflammatory and microbiome parameters were examined. Results: Cefdinir administration in HSD rats reduced fasting glucose, serum triglyceride, and cholesterol levels compared to HSD alone. In addition, cefdinir reduced serum LPS by decreasing the population of Gram-negative phyla, that is, Bacteroidetes and Proteobacteria in the fecal content. Furthermore, cefdinir treatment decreased hepatic/ileal/colonic Tlr4, Nlr1, and Nf-κB at the mRNA level. Moreover, cefdinir-treated rats had shown increased fecal butyrate and propionate and reduced acetate levels compared to HSD alone. Cefdinir treatment also induced ileal/colonic Gpr43 and Glut4 at the mRNA level after 12 weeks of administration. Conclusions: Taken together, these data suggest that administration of a Gram-negative spectrum antibiotic, that is, cefdinir, has modulated the gut microbiota, and reduced serum LPS and triglycerides, which prevented the progression of IR and inflammation in HSD rats.

A sugar rich diet induces inflammation and insulin resistance (IR) mainly through gut microbiota alteration.  相似文献   
43.
International Journal of Diabetes in Developing Countries - There is a huge burden of diabetes-related complications, both microvascular and macrovascular, in India. With the rising prevalence of...  相似文献   
44.
PURPOSE: An interval of six to eight weeks between completion of preoperative chemoradiation therapy and surgical resection of advanced rectal cancer has been described. Our purpose was to determine whether a longer time interval between completion of therapy and resection increases tumor downstaging and affects perioperative morbidity. METHODS: Forty patients with advanced adenocarcinoma of the rectum underwent preoperative chemoradiation on a prospective trial with irinotecan (50 mg/m2), 5-fluorouracil (225 mg/m2), and concomitant external-beam radiation (45-54 Gy) followed by complete surgical resection of the tumor with total mesorectal excision. The time interval between completion of chemoradiation and surgical resection ranged from 28 to 97 days. The patients were divided into two groups with 33 eligible patients: Group A (4-week to 8-week time interval; 28-56 days) and Group B (10-week to 14-week interval; 67-97 days). Tumor downstaging was compared between these two groups. The number of patients downstaged by at least one T stage, those downstaged by at least one N stage, those with pathologic complete responses, and those with only residual microscopic tumor foci were compared. Postoperative length of stay, estimated blood loss, perioperative morbidity, and sphincter-sparing procedures were also compared. Chi-squared tests and Student's t-test were calculated. RESULTS: Group A had 19 patients, and Group B had 14 patients. Patient demographics were comparable. Mean age was 52 years, and 70 percent of patients were male. There were no deaths. There were no statistical differences in perioperative morbidity, with three anastomotic leaks in Group A. Tumors were downstaged in 58 percent of patients in Group A and 43 percent of those in Group B (P = 0.61). Nodal downstaging occurred in 78 percent of Group A and 67 percent of Group B (P = 0.9). The pathologic complete response rate was 21 percent in Group A and 14 percent in Group B (P = 0.97), and a residual microfocus of tumor was found in 33 percent of patients in Group A and 42 percent of those in Group B (P = 0.90). These differences were not statistically significant. CONCLUSIONS: Perioperative morbidity is not affected by longer intervals. A longer interval between completion of neoadjuvant chemoradiation and surgical resection may not increase the tumor response rate of advanced rectal cancer in this cohort.  相似文献   
45.
A 51-year-old man with a history of stage IV angioimmunoblastic T-cell lymphoma was diagnosed with osteomyelitis of the patella. Legionella anisa was identified by 16S rRNA gene sequencing and culture. The patient had pneumonia 2 months prior to this osteomyelitis episode. L. anisa was retrospectively detected in his lung tissue by 16S rRNA gene sequencing and was considered the source of the L. anisa that caused his patella osteomyelitis.  相似文献   
46.
Background“The graying of the globe” has resulted in exponential rise in health care expenses, over-worked health care professionals and a growing patient base suffering from multiple chronic diseases, one of which is diabetes. Consumer health technologies (CHT) are considered important catalysts for empowering health care consumers to take a proactive role in managing their health and related costs. Adoption rate and usability of such devices among the aging is far from being satisfactory. Past studies noted the motivation for adoption by the aging is dependent on the suitability/relevance, perceived usability and anticipated benefits associated with usage of technological innovation. Traditional information technology (IT) development adopts a systematic approach without necessarily using a specific user model that personalizes the system to the aging user groups. The aging patient population has unique needs arising from progressive deterioration in both physiological and psychological abilities. These needs are often ignored in the design, development, trial and adoption of consumer health products resulting in low adoption and usage.ObjectivesThe main objective of this research is to investigate the user-centered design (UCD), specifically user profiles and personas, as methodological tools to inform the design and development of CHT devices for an aging population. The adoption of user profile and persona has not received much attention in health care informatics research and, in particular, research involving CHT. Our work begins to fill this void in three ways. We (1) illuminate the process of developing CHT user profiles and personas for a Chinese elder population with a demanding health care needs, i.e., self-management of chronic diabetes, with the hope that the resulting profiles and personas may be used as foundational material for informing the design, development and evaluation of CHT in other similar contexts; (2) call attention to how to further enhance and complement traditional user profile and persona techniques for CHT design by integrating cognitive structures and present behavior that drive health care thinking, future behavior and demand; (3) show how the profiles and personas can be used to inform requirements, design and implementation decisions for a technology aimed at facilitating CHT adoption and diffusion for the elderly.MethodologyTo exemplify process and application, we use an action-research methodology, where user profiles and personas of an aging patient population were developed. The resultant profiles and personas were leveraged to improve the design, development and implementation plans of a smart phone application to assist chronically ill aging Chinese diabetic population capable of disease self-management.ResultsThe results from the study show that user profile and persona can be a valuable methodological approach in capturing the conceptual model of the aging and informing the design and development decisions of CHT. The demonstration of techniques used in this study can serve as a guideline to CHT developers in bringing conceptual user modeling into the design of software interfaces targeted for users with specific health care needs. Specifically, the study provides guidance on the creation and use of profiles and personas to tap into the conceptual models of the targeted elderly population reflecting their preferences, capabilities and attitudes towards using technology in self-management care in general and the smart phone diabetes management application in particular. Insight into the mental model of the aging group has been shown to inform later stages of UCD development (e.g., the creation of prototypes and usability testing) as well as implementation and adoption strategies. The World Health Organization (WHO) predicts that by 2025, 80% of all new cases of diabetes are expected to appear in the developing countries. In fact, the number of diabetic patients in China is estimated to rise to 42.3 million in 2030 from 20.8 million in 2000. Thus, we investigate the Chinese aging population in order to demonstrate the process of developing and using user profile and persona. We hope that the resultant conceptual model of the Chinese aging diabetic population can be used in future research to guide CHT designers interested in designing health care devices for this vulnerable user group.  相似文献   
47.
P25 comprising of mixed anatase and rutile phases is known to be highly photocatalytically active compared to the individual phases. Using a facile wet chemical method, we demonstrate a ternary nanocomposite consisting of Ni and Ag nanoparticles, decorated on the surface of XTiO2 (X: P25, rutile (R)) as an efficient visible-light-driven photocatalyst. Contrary to the current perspective, RTiO2-based Ni–Ag–RTiO2 shows the highest activity with the H2 evolution rate of ∼86 μmol g−1 W−1 h−1@535 nm. Together with quantitative assessment of active Ni, Ag and XTiO2 in these ternary systems using high energy synchrotron X-ray diffraction, transmission electron microscopy coupled energy dispersive spectroscopy mapping evidences the metal to semiconductor contact via Ag. The robust photocatalytic activity is attributed to the improved visible light absorption, as noted by the observed band edge of ∼2.67 eV corroborating well with the occurrence of Ti3+ in Ti 2p XPS. The effective charge separation due to intimate contact between Ni and RTiO2via Ag is further evidenced by the plasmon loss peak in Ag 3d XPS. Moreover, density functional theory calculations revealed enhanced adsorption of H2 on Ti8O16 clusters when both Ag and Ni are simultaneously present, owing to the hybridization of the metal atoms with d orbitals of Ti and p orbitals of O leading to enhanced bonding characteristics, as substantiated by the density of states. Additionally, the variation in the electronegativity in Bader charge analysis indicates the possibility of hydrogen evolution at the Ni sites, in agreement with the experimental observations.

Robust photocatalytic activity of Ni–Ag–RTiO2 is attributed to the improved visible light absorption and effective charge separation due to intimate contact between Ni and RTiO2via Ag, as evidenced by Ti3+ in Ti 2p XPS and energy dispersive mapping.  相似文献   
48.
Periodontal bio‐repositories, which allow banking of clinically validated human data and biological samples, provide an opportunity to derive biomarkers for periodontal diagnosis, prognosis and therapeutic activities which are expected to improve patient management. This article presents the establishing of the Malaysian Periodontal Database and Biobank System (MPDBS) which was initiated in 2011 with the aim to facilitate periodontal research. Partnerships were established with collaborating centres. Policies on specimen access, authorship and acknowledgement policies were agreed upon by all participating centres before the initiation of the periodontal biobank. Ethical approval for the collection of samples and data were obtained from institutional ethics review boards. A broad‐based approach for informed consent was used, which covered areas related to quality of life impacts, genetics and molecular aspects of periodontal disease. Sample collection and processing was performed using a standardized protocol. Biobanking resources such as equipment and freezers were shared with the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS). In the development of the MPDBS, challenges that were previously faced by the MOCDTBS were considered. Future challenges in terms of ethical and legal issues will be faced when international collaborations necessitate the transportation of specimens across borders.  相似文献   
49.
50.

Objectives

This study was conducted to determine the incidence of early stasis in radioembolization using resin yttrium-90 (Y-90) microspheres, to evaluate potential contributing factors, and to review initial imaging outcomes.

Methods

Patients in whom early stasis occurred were compared with those in whom complete delivery was achieved for tumour type and vascularity, tumour : normal liver ratio (T : N ratio) at technetium-99m-macroaggregated albumin (Tc-99m-MAA) angiography, previous intra-arterial therapy, and infusion site (left, right or whole liver). Tumour response was evaluated at 3 months and defined according to whether a partial response and stable disease versus progressive disease were demonstrated.

Results

A total of 71 patients underwent 128 Y-90 infusions in which 26 (20.3%) stasis events occurred. Hypervascular and hypovascular tumours had similar rates of stasis (17.4% versus 27.8%; P = NS). The mean ± standard deviation T : N ratio was 3.03 ± 1.54 and 3.66 ± 2.79 in patients with and without stasis, respectively (P = NS). Stasis occurred in 14 of 81 (17.3%) and 12 of 47 (25.5%) infusions following previous intra-arterial therapy and in therapy-naïve territories, respectively (P = NS). Early stasis occurred in 15 of 41 (36.6%) left, 10 of 65 (15.4%) right and one of 22 (4.5%) whole liver infusions (P < 0.001). Rates of partial response and stable disease were similar in the stasis (88.3%) and non-stasis (76.0%) groups (P = NS).

Conclusions

Early stasis occurred in approximately 20% of infusions with similar incidences in hyper-and hypovascular tumours. Whole-liver therapy reduced the incidence of stasis. Stasis did not appear to affect initial imaging outcomes.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号