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   2155篇
  免费   129篇
  国内免费   8篇
耳鼻咽喉   12篇
儿科学   59篇
妇产科学   69篇
基础医学   309篇
口腔科学   29篇
临床医学   193篇
内科学   459篇
皮肤病学   23篇
神经病学   215篇
特种医学   134篇
外科学   306篇
综合类   6篇
预防医学   145篇
眼科学   22篇
药学   156篇
中国医学   1篇
肿瘤学   154篇
  2023年   20篇
  2022年   34篇
  2021年   74篇
  2020年   34篇
  2019年   52篇
  2018年   70篇
  2017年   50篇
  2016年   38篇
  2015年   61篇
  2014年   80篇
  2013年   117篇
  2012年   130篇
  2011年   139篇
  2010年   100篇
  2009年   87篇
  2008年   110篇
  2007年   109篇
  2006年   130篇
  2005年   109篇
  2004年   101篇
  2003年   83篇
  2002年   79篇
  2001年   64篇
  2000年   54篇
  1999年   40篇
  1998年   11篇
  1997年   16篇
  1996年   10篇
  1995年   14篇
  1994年   16篇
  1993年   6篇
  1992年   25篇
  1991年   37篇
  1990年   26篇
  1989年   25篇
  1988年   10篇
  1987年   16篇
  1986年   11篇
  1985年   15篇
  1984年   8篇
  1983年   4篇
  1982年   4篇
  1980年   5篇
  1979年   14篇
  1978年   5篇
  1977年   6篇
  1974年   7篇
  1973年   8篇
  1970年   5篇
  1967年   3篇
排序方式: 共有2292条查询结果,搜索用时 15 毫秒
61.

Introduction

Crohn’s disease is an inflammatory bowel disease that can affect the entire gastrointestinal tract. It is chronic and incurable, and the mainstay of therapy is medical management with surgical intervention as complications arise. Surgery is required in approximately 70% of patients with Crohn’s disease. Because repeat interventions are often needed, these patients may benefit from bowel-sparing techniques and minimally invasive approaches. Various bowel-sparing techniques, including strictureplasty, can be applied to reduce the risk of short-bowel syndrome.

Methods

A review of the available literature using the PubMed search engine was undertaken to compile data on the surgical treatment of Crohn’s disease.

Results and conclusion

Data support the use of laparoscopy in treating Crohn’s disease, although the potential technical challenges in these settings mandate appropriate prerequisite surgical expertise.  相似文献   
62.
Chronic elevated exposure to manganese (Mn) is associated with neurocognitive and fine motor deficits in children. However, relatively little is understood about cellular responses to Mn spanning the transition between physiologic to toxic levels of exposure. Here, we investigated the specificity, sensitivity, and time course of the Golgi Phosphoprotein 4 (GPP130) response to Mn exposure in AF5 GABAergic neuronal cells, and we determined the extent to which GPP130 degradation occurs in brain cells in vivo in rats subchronically exposed to Mn. Our results show that GPP130 degradation in AF5 cells was specific to Mn, and did not occur following exposure to cobalt, copper, iron, nickel, or zinc. GPP130 degradation occurred without measurable increases in intracellular Mn levels and at Mn exposures as low as 0.54 µM. GPP130 protein was detectable by immunofluorescence in only ~15–30% of cells in striatal and cortical rat brain slices, and Mn‐exposed animals exhibited a significant reduction in both the number of GPP130‐positive cells, and the overall levels of GPP130 protein, demonstrating the in vivo relevance of this Mn‐specific response within the primary target organ of Mn toxicity. These results provide insight into specific mechanism(s) of cellular Mn regulation and toxicity within the brain, including the selective susceptibility of cells to Mn cytotoxicity. Synapse 67:205–215, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   
63.
This study assessed technology-aided programs for helping two post-coma persons, who had emerged from a minimally conscious state and were affected by multiple disabilities, to (a) engage with leisure stimuli and request caregiver's procedures, (b) send out and listen to text messages for communication with distant partners, and (c) combine leisure engagement and procedure requests with text messaging within the same sessions. The program for leisure engagement and procedure requests relied on the use of a portable computer with commercial software, and a microswitch for the participants’ response. The program for text messaging communication involved the use of a portable computer, a GSM modem, a microswitch for the participants’ response, and specifically developed software. Results indicated that the participants were successful at each of the three stages of the study, thus providing relevant evidence concerning performance achievements only minimally documented. The implications of the findings in terms of technology and practical opportunities for post-coma persons with multiple disabilities are discussed.  相似文献   
64.
How do professionals working in pre-implantation genetic diagnosis (PGD) reflect upon their decision making with regard to ethical challenges arising in everyday practice? Two focus group discussions were held with staff of reproductive genetic clinics: one in Utrecht (The Netherlands) with PGD-professionals from Dutch PGD-centres and one in Prague (Czech Republic) with PGD-professionals working in centres in different European countries. Both meetings consisted of two parts, exploring participants’ views regarding (1) treatment requests for conditions that may not fulfill traditional indications criteria for PGD, and (2) treatment and transfer requests involving welfare-of-the-child considerations. There was general support for the view that people who come for PGD will have their own good reasons to consider the condition they wish to avoid as serious. But whereas PGD-professionals in the international group tended to stress the applicants’ legal right to eventually have the treatment they want (whatever the views of the professional), participants in the Dutch group sketched a picture of shared decision-making, where professionals would go ahead with treatment in cases where they are able to understand the reasonableness of the request in the light of the couple’s reproductive history or family experience. In the international focus group there was little support for guidance stating that welfare-of-the child considerations should be taken into account. This was different in the Dutch focus group, where shared decision-making also had the role of reassuring professionals that applicants had adequately considered possible implications for the welfare of the child.  相似文献   
65.
Progressive facial hemiatrophy (PFH) is a rare condition characterized by the slow, progressive appearance of a unilateral facial atrophy that affects the skin, subcutaneous tissue, muscle and bone. We report the case of a 60-year-old female patient whose cutaneous symptoms commenced in 1987 in the form of a purplish erythema on the left side of her face and neck, which subsequently remitted giving rise to an indurated region in the left maxillary region. Since 1995 until the present day, she has developed facial hemiatrophy on the left side accompanied by progressive osseous reabsorption of the upper maxilla and left mandible with atrophy of soft tissue. The association of the onset of PFH with progressive osteolysis of the maxilla has not been previously reported in an adult patient.  相似文献   
66.
PURPOSE: The aim of this study was to evaluate the success rate of 100 consecutive zirconia dental implants with 2 different rough surfaces after 1 year of follow-up. MATERIALS AND METHODS: One-piece zirconia dental implants (CeraRoot, Barcelona, Spain) with 1 of 2 different roughened surfaces were designed and manufactured for this study. Five different implant designs were manufactured. Standard or flapless surgical procedures were used for implant placement. Simultaneous bone augmentation or sinus elevation were performed in the cases where bone height or width was insufficient. Implants in the anterior region (canine to canine) were immediately restored with provisional prostheses. Implants placed using less than 35 N torque were splinted with composite resin using an etched and bonded approach to the neighboring teeth or implants to minimize implant mobility and failure. Definitive all-ceramic restorations were placed 4 months after implant placement (8 months for implants where bone augmentation or sinus elevation was performed). RESULTS: The study included 36 patients with a mean age of 50 years. The overall implant success rate after 1 year of follow-up was 98% in both the coated and noncoated groups. CONCLUSIONS: From the preliminary results of this investigation, it can be concluded that zirconia dental implants with roughened surfaces might be a viable alternative for tooth replacement. Further follow-up is needed to evaluate the long-term success rates of the implant surfaces studied.  相似文献   
67.
The literature has shown that low-level laser therapy accelerates the repair of cutaneous wounds. However, there is a scarcity of scientific studies that characterise the possible systemic interference of laser photobiomodulation. The aim of this research was to quantitatively evaluate blood corticosterone levels and tissue cytokine expression in cutaneous wounds of rats treated with low-level laser therapy (semiconductor diode AsGaAl, continuous emission, 9 mW, 670 nm, 0.031 W/cm2, beam with an output area of 0.28 cm2) and normal controls. A total of 36 male Wistar rats were used and randomly divided into two groups of 18 rats each. A standardised circular 6-mm-diameter wound was made in the dorsal skin region of each rat, and they were euthanised at 1, 6 and 12 h after cutaneous surgery. The blood was collected, and portions of cutaneous tissue and subcutaneous muscle were removed and cryopreserved. Corticosterone levels in the blood were measured by a radioimmunoassay technique; histological sections were submitted to the ELISA technique for analysis of tissue cytokine expression levels. At 6 h after surgery, a significant increase in corticosterone and a significant reduction in the levels of IL-1β and IL-6 in tissues of irradiated wounds were observed when compared to controls (p?<?0.05). The levels of TNF-α and IL-10 expression were not significantly different between the groups at different time intervals. Thus, this study strongly suggests a systemic and local biomodulation of low-level laser therapy as indicated by the blood levels of corticosterone and the tissue expression of IL-1β and IL-6, respectively.  相似文献   
68.
69.
Two patients with acute inferior myocardial infarction complicated by cardiogenic shock are presented. Cardiac catheterization 2 and 7 days after infarction, respectively, revealed a hemodynamic pattern resembling constrictive pericarditis. Right coronary occlusion proximal to the right ventricular marginal branches was present in both patients. Resolution of the constrictive hemodynamic pattern was demonstrated in the one survivor at repeat catheterization 7 weeks after infarction. The mechanism for constrictive hemodynamics in these patients is unclear.  相似文献   
70.
Summary The authors report data obtained from a 3-year study of CSII and humanized insulin (semi-synthetic human insulin) administered to 18 insulin-dependent subjects in the outpatient clinic. The aim of this study was to evaluate the validity of insulin pumps in long-term treatment. Metabolic parameters were significantly improved (p<0.001) in the first month and remained so with only slight alterations throughout treatment. The authors underline some metabolic problems (ketosis) caused by malfunctioning of the insulin pumps, by the difficulties with the infusion sytem or by nodular skin lesions at the infusion site. Only these lesions called for treatment to be discontinued in 4 patients. The highest incidence of nodular skin lesions was seen after one year’s uninterrupted treatment and they seem connected to the duration of treatment rather than to the patients’ negligence (inadequate hygiene, delayed needle substitution). The authors conclude that CSII treatment is valid over short-term periods, whereas it presents drawbacks over long-term administration.  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