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   1371篇
  免费   97篇
  国内免费   10篇
耳鼻咽喉   6篇
儿科学   21篇
妇产科学   39篇
基础医学   186篇
口腔科学   66篇
临床医学   157篇
内科学   254篇
皮肤病学   32篇
神经病学   215篇
特种医学   39篇
外科学   157篇
综合类   10篇
预防医学   109篇
眼科学   25篇
药学   89篇
中国医学   5篇
肿瘤学   68篇
  2024年   3篇
  2023年   24篇
  2022年   27篇
  2021年   50篇
  2020年   31篇
  2019年   58篇
  2018年   62篇
  2017年   34篇
  2016年   56篇
  2015年   41篇
  2014年   61篇
  2013年   88篇
  2012年   109篇
  2011年   118篇
  2010年   80篇
  2009年   53篇
  2008年   97篇
  2007年   82篇
  2006年   62篇
  2005年   72篇
  2004年   52篇
  2003年   43篇
  2002年   28篇
  2001年   11篇
  2000年   10篇
  1999年   7篇
  1998年   7篇
  1997年   6篇
  1996年   4篇
  1995年   6篇
  1994年   6篇
  1993年   3篇
  1992年   4篇
  1990年   3篇
  1989年   3篇
  1988年   3篇
  1986年   3篇
  1983年   2篇
  1982年   6篇
  1980年   3篇
  1978年   3篇
  1977年   6篇
  1976年   5篇
  1973年   2篇
  1972年   4篇
  1969年   5篇
  1968年   9篇
  1967年   5篇
  1959年   2篇
  1957年   3篇
排序方式: 共有1478条查询结果,搜索用时 156 毫秒
1.
Caring for patients with end-stage kidney disease (ESKD) in the United States is challenging, due in part to the complex epidemiology of the disease's progression as well as the ways in which care is delivered. As CKD progresses toward ESKD, the number of comorbidities increases and care involves multiple healthcare providers from multiple subspecialties. This occurs in the context of a fragmented US healthcare delivery system that is traditionally siloed by provider specialty, organization, as well as systems of payment and administration. This article describes the role of care fragmentation in the delivery of optimal ESKD care and identifies research gaps in the evidence across the continuum of care. We then consider the impact of care fragmentation on ESKD care from the patient and health system perspectives and explore opportunities for system-level interventions aimed at improving care for patients with ESKD.  相似文献   
2.
Crohn's disease is a complex disorder, with multiple genetic traits. A frameshift mutation (Leu1007fsinsC) and two missense mutations (Gly908Arg and Arg702Trp) in the NOD2/CARD15 gene are strongly associated with susceptibility to Crohn's disease. The presence of one of these risk alleles confers a 2- to 4-fold increase in the risk of developing Crohn's disease, and the presence of two mutant alleles increases the risk over 20-fold. To facilitate the analysis of these polymorphisms, we developed three LightCycler assays to detect the missense mutations Arg702Trp and Gly908Arg and the frameshift mutation Leu100fsinsC in the NOD2/ CARD15 gene. All three assays can be run simultaneously on one LightCycler using identical cycling parameters. Analysis of 53 DNAs from Crohn's patients helped to identify carriers at allele frequencies similar to other Caucasian populations. The sequencing of such DNAs confirmed the accuracy of the assays. In conclusion, we present three rapid and robust assays to detect the Arg702Trp, the Gly908Arg and the Leu1007fsinsC ins mutations in the NOD2/CARD15 gene [corrected]  相似文献   
3.
A single intramuscular injection of 2 mg estradiol valerate (EV) results in neuronal degeneration and β-endorphin depletion in the hypothalamic arcuate nucleus of adult female rats. We have hypothesized that peroxidase-positive astrocytes in this brain region oxidize estrogens and catecholestrogens to semiquinone radicals which mediate oxidative neuronal injury. In the present study, dietary administration of the potent antioxidant 21-aminosteroid, U-74389F, completely blocked EV-induced β-endorphin depletion in the hypothalami of adult female rats. Neither EV nor 21-aminosteroid treatment had any effect on hypothalamic concentrations of neuropeptide Y and Met-enkephalin, confirming that the estradiol lesion is fairly selective for the β-endorphin cell population. The present findings support the hypothesis that the toxic effect of estradiol on hypothalamic β-endorphin neurons is mediated by free radicals.  相似文献   
4.
Background Tension-free incisional hernia repair using alloplastic material increasingly replaces conventional repair techniques. This change resulted in a decreased recurrence rate (50% vs. 10%, respectively). Recently, laparoscopic approaches for the intraperitoneal tension-free mesh application have been introduced. The decreased trauma at the incision site and the reduction in wound infections appear to be the main advantages. The aim of the present study was to evaluate the early and long-term complications as well as patients’ contentment. Methods Laparoscopic hernia repair with intraperitoneal polytetrafluroethylene (PTFE) mesh implantation was performed on 62 patients at the Klinikum Grosshadern between 2000 and 2005 (29 males, 33 females age 60.7). Intra- and postoperative complications were registered prospectively and retrospectively analyzed. In addition, 57 patients were evaluated for recurrence, postoperative pain and patient contentment (median follow-up 409 days). Results A low complication rate was observed in our patient collective. One trocar bleeding occurred. Three patients presented with wound hematoma. The recurrence rate was 8% (2/25). Sixty-two percent of the patients were free of complaints postoperatively. Eighty-five percent would once again choose the laparoscopic approach for incisional hernia repair. Conclusion The laparoscopic technique was associated with a low recurrence rate, a small rate of wound infections and high patient comfort. Thus, the laparoscopic approach for mesh implantation appears to be a safe and effective method for the treatment of incisional hernias. The efficiency for laparoscopic intraperitoneal mesh implantation, however, should be further evaluated within a prospectively randomized multicenter trial. M. Stickel and M. Rentsch contributed equally.  相似文献   
5.
M Carpani de Kaski  R Rentsch  S Levi    H J Hodgson 《Gut》1995,37(5):613-616
The association between corticosteroid treatment and gastric ulcer healing is controversial. The effects of corticosteroids on experimental ulcer healing in the rat were studied and the effect of coadministration of a prostaglandin E1 analogue was determined. Forty male adult rats were divided into five groups and pretreated for 10 days as follows: (a) control, (b) prednisolone (10 mg/kg), (c) prednisolone and misoprostol (300 micrograms/kg), (d) misoprostol, and (e) indomethacin (2 mg/kg) Gastric ulcer was induced by applying a cryoprobe to the serosal surface of the stomach. Healing was assessed by determining the ulcer size at three and six days. Mucosal regenerative activity at the ulcer edge was assessed by quantitating DNA synthesis in cells by immunohistochemical techniques using monoclonal antibodies to detect expression of proliferating cell nuclear antigen (PCNA) and incorporated 5-bromo-5-iododeoxyuridine (BrdU). Compared with control rats, the rate of healing and the mucosal regenerative activity were significantly reduced in rats treated with prednisolone and indomethacin (p < 0.05). Coadministration of misoprostol and corticosteroids reversed the delay in healing and the reduction in mucosal regeneration induced by corticosteroids alone. With misoprostol alone, the ulcer size and the number of epithelial cells that actively synthesised DNA did not differ from control animals. A comparison between the two immunohistochemical markers of cell proliferation showed a highly significant correlation between the two techniques (r = 0.64, p < 0.005), indicating that the simpler PCNA technique should prove valuable in assessing regeneration in experimental ulcer disease.  相似文献   
6.
7.
Inflammatory events during Leishmania braziliensis infection in mice were investigated. Large lesions were directly correlated with the inflammatory reaction but not with parasite burden. Different L. braziliensis strains induce different paces of chemokine expression patterns, leading to diverse cell recruitment and differential inflammatory responses.  相似文献   
8.
Microinvasive ductal carcinoma of the breast, namely ductal carcinoma in situ with microinvasion (T1mic) as defined by the American Joint Committee on Cancer (AJCC) Staging Manual, is a rare disease, although it is increasing because of widespread use of mammography. The aim of the present study was to describe the clinicopathological and immunohistochemical features of this entity. Twenty-eight patients who were diagnosed as T1mic from January 1997 to August 2002 were studied by using 3-5 mm-thick serial sections with hematoxylin-eosin staining. Immunohistochemical staining for the estrogen receptor (ER), progesterone receptor (PR), p53, Ki-67, and HER-2 were performed. All 28 patients were female, with a mean age of 48.8 years. Twenty-six patients (93%) revealed mammographic abnormalities on routine examination. All foci of the invasions were measured using an ocular micrometer. Invasive foci consisted of isolated cells or cell clusters, or appeared as a tongue-like projection of tumor through the basement membrane of the duct of ductal carcinoma in situ (DCIS). The mean number of invasive foci was 3, and the mean size was 0.6 mm. We found that high nuclear grade and predominant comedo subtype of DCIS components were 57.1% and 46.4%, respectively. Twenty-four cases (86%) demonstrated necrosis of DCIS components. Microinvasion was often associated with periductal stromal reaction (71.5%) and/or a lymphocytic infiltration (78.6%). All patients, excluding two, received axillary resection (the mean number of lymph nodes examined per case was 12), and none had lymph node metastasis. The positive expression of ER and PR strongly related to low grade nuclei and non-comedo subtype; however, the positive expression of HER-2 and P53 related to high grade nuclei and comedo subtype (P<0.01). Ki-67 expression was significantly higher in the high grade nuclei group than in the low grade group (P<0.01). Our study suggested that high nuclear grade and comedo DCIS were more aggressive and more common with microinvasion, and that microinvasion is more likely to be multifocal.  相似文献   
9.
Objective: The Child Behavior Checklist (CBCL; T. M. Achenbach,1991), when used to assess the behavior of children with diabetes,may contain confounds because some behavioral items can havea physiologic etiology, and may skew reports of behavioral disturbance. Methods: Two techniques were used to disentangle possible scoringconfounds in the behavioral ratings of children with and withoutdiabetes: (1) the Somatic Complaints scale was deleted, or (2)Diabetes Items, identified a priori with 89% agreement by ninemedical personnel, were deleted. Results: As expected, with traditionally scored protocols, childrenwith diabetes obtained higher Internalizing and Total BehaviorProblem scores than controls. This group difference persistedwhether the Somatic Complaints scale or the Diabetes Items weredeleted. Conclusions: Compared to controls, children with diabetes obtainedmildly elevated scores on six of the eight CBCL scales, regardlessof scoring method, suggesting that their mildly elevated behavioralprofile is not confounded by physiologic symptomatology.  相似文献   
10.
Presently, in our society, thousands of children, adolescents, and adults are physically, mentally, and emotionally traumatized from exposure to domestic violence (DV). Exposure to DV, defined here as male violence against their female partners, occurs among all ethnic, cultural, socioeconomic, geographical, and racial groups. DV can lead to depression, negative self‐esteem, and general psychological distress in women. Children exposed to DV have an increased risk of behavioral, emotional, and social problems. DV shelters often provide group counseling and support services for battered women, children, and adolescents residing there, but the programs do not reach the majority of women living in the broader community. Furthermore, few studies have examined the effectiveness and efficacy of support group treatment intervention programs for battered women and children. This is due, in part, to the methodological difficulties inherent in this design. As a way to meet the needs of families that have experienced DV, academic researchers from a Midwestern university and a director of counseling services from a local domestic violence agency have partnered to offer a psycho‐educational intervention designed to  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