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   1587篇
  免费   57篇
  国内免费   2篇
耳鼻咽喉   12篇
儿科学   82篇
妇产科学   22篇
基础医学   159篇
口腔科学   84篇
临床医学   133篇
内科学   292篇
皮肤病学   21篇
神经病学   134篇
特种医学   29篇
外科学   282篇
综合类   35篇
预防医学   63篇
眼科学   60篇
药学   171篇
中国医学   9篇
肿瘤学   58篇
  2023年   14篇
  2022年   15篇
  2021年   49篇
  2020年   29篇
  2019年   45篇
  2018年   45篇
  2017年   37篇
  2016年   45篇
  2015年   51篇
  2014年   56篇
  2013年   95篇
  2012年   133篇
  2011年   161篇
  2010年   75篇
  2009年   77篇
  2008年   95篇
  2007年   84篇
  2006年   81篇
  2005年   67篇
  2004年   60篇
  2003年   64篇
  2002年   74篇
  2001年   14篇
  2000年   4篇
  1999年   18篇
  1998年   11篇
  1997年   6篇
  1996年   11篇
  1995年   4篇
  1994年   7篇
  1993年   4篇
  1992年   13篇
  1991年   11篇
  1990年   13篇
  1989年   5篇
  1988年   6篇
  1987年   5篇
  1986年   4篇
  1985年   6篇
  1984年   5篇
  1979年   3篇
  1978年   3篇
  1977年   4篇
  1976年   3篇
  1975年   3篇
  1974年   4篇
  1971年   3篇
  1967年   5篇
  1966年   4篇
  1965年   4篇
排序方式: 共有1646条查询结果,搜索用时 15 毫秒
1.
BACKGROUND CONTEXT: Pseudoaneurysm of the aorta in association with vertebral tuberculosis is a rare phenomenon. With the resurgence of human immunodeficiency virus (HIV) and associated resistant tuberculosis, this life-threatening complication requires greater awareness. PURPOSE: Our purpose is to report the rare presentation and successful management of tubercular pseudoaneurysm of the aorta in association with vertebral tuberculosis, and to highlight the clinicoradiological features for early and prompt diagnosis of this potentially fatal, but treatable, disease. STUDY DESIGN: A single case report and overview of the disease comprises the design of this study. PATIENT SAMPLE: The patient, already surgically intervened, is a 27-year-old male with increasing abdominal and back pain, upper motor neuron signs, and constitutional signs and symptoms. OUTCOME MEASURES: At 33 months follow-up, there is complete resolution of the signs and symptoms, and the patient is back to his previous vocation. METHODS: The diagnosis was confirmed by magnetic resonance imaging and contrast computed tomography. Endoaneurysmorrhaphy of the pseudoaneurysm along with a complete course of antitubercular treatment was given to the patient, and he has presently been followed up for 33 months. RESULTS: The patient's signs and symptoms have been completely resolved without any recurrence. CONCLUSION: Despite the use of modern chemotherapy and imaging techniques, this disastrous complication still occurs and reinforces the need for early suspicion, diagnosis, surgical resection, and antitubercular therapy along with close postoperative follow-up to prevent recurrence. With the resurgence of HIV (and other immunocompromised states) associated and resistant tuberculosis, we should be more alert than ever to this life-threatening complication.  相似文献   
2.
3.
An increased incidence of sudden death has been reported in chronic alcoholism. To assess electrical vulnerability of the heart, action potential responses, and the role of the sympathetic system, a well-nourished canine model has been studied intact under chloralose anesthesia after 1 year of ethanol consumption at 36% of caloric intake. Two alcoholic groups were compared with controls (Group 1). In Group 2 myocardial vulnerability was assessed after chronic EtOH and superimposed acute administration. In Group 3 basal vulnerability was related to circulating norepinephrine and release of neurohormone from the myocardium. Subsequently the responsiveness to catecholamine infusion was determined. To assess vulnerability an electrode catheter was placed in the right ventricular apex. The basal ventricular fibrillation threshold (VFT) was reduced to 27 +/- 3 ma in Group 2 versus 43 +/- 1.0 in Group 1. Acute infusion of ethanol in Group 2 further reduced the threshold. Group 3 had a reduced basal VFT. Baseline arterial plasma levels of norepinephrine were 8-fold higher and coronary venous levels 13 times higher in the alcoholic group than in Group 1. However, VFT was not responsive to infused epinephrine, compared with Group 1 controls. In vitro study of superfused ventricular tissue from Group 3 revealed that basal action potential amplitude, overshoot, and resting potential were comparable with normals. Basal repolarization time (90%) was 198 +/- 12 msec in Group 3 versus 215 +/- 6 msec in Group 1 (p less than 0.05). After acute EtOH, repolarization time was shortened to 170 +/- 8.6 in Group 1 at 90 mg% ethanol (p less than 0.002), with minimal further change up to 280 mg%.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
4.
Summary  In this unusual case there was a difficulty in diagnosis on the basis of histopathological reporting. On the grounds of clinical suspiscion one has to try to find out the proper diagnosis by advanced diagnostic methods like immunohistochemistry.  相似文献   
5.
6.
Verticillium dahliae is an important soil-borne fungal pathogen that causes vascular wilt diseases in a large variety of important crop plants. Due to its persistence in the soil, control of Verticillium wilt relies heavily on soil fumigation. The global ban on methyl bromide, a highly effective soil fumigant, poses an urgent need to develop alternative control measures against Verticillium wilt; and these might be more forthcoming with a better understanding of the molecular and cellular mechanisms that underpin the pathogenicity of V. dahliae. In this study, we assessed the role in growth, development, and pathogenicity of VMK1, a gene encoding a mitogen-activated protein (MAP) kinase (hence, Verticillium MAP Kinase 1). Disruption of VMK1 via Agrobacterium tumefaciens-mediated transformation, in two V. dahliae isolates, one from lettuce and the other from tomato, resulted in severely reduced virulence in diverse host plants, suggesting that VMK1 is essential for pathogenicity and that the MAP kinase-mediated signaling pathway has a conserved role in fungal pathogenicity. The vmk1 mutants also exhibited reduced conidiation and microsclerotia formation, suggesting that the gene is important for multiple cellular processes. P.R. and R.G.B. equally contributed to the work  相似文献   
7.
A critical function for type I interferons in cancer immunoediting   总被引:8,自引:0,他引:8  
'Cancer immunoediting' is a process wherein the immune system protects hosts against tumor development and facilitates outgrowth of tumors with reduced immunogenicity. Although interferon-gamma (IFN-gamma) is known to be involved in this process, the involvement of type I interferons (IFN-alpha/beta) has not been elucidated. We now show that, like IFN-gamma, endogenously produced IFN-alpha/beta was required for the prevention of the growth of primary carcinogen-induced and transplantable tumors. Although tumor cells are important IFN-gamma targets, they are not functionally relevant sites of the actions of the type I interferons. Instead, host hematopoietic cells are critical IFN-alpha/beta targets during development of protective antitumor responses. Therefore, type I interferons are important components of the cancer immunoediting process and function in a way that does not completely overlap the functions of IFN-gamma.  相似文献   
8.
The present study analyzes the morphological, histochemical, and ultrastructural aspects of the pathogenesis of 6-mercaptopurine (6MP)-induced cleft palate in hamster fetuses. Gross and light microscopic observations indicated that 6MP stunts the growth of vertical palatal shelves and thus induces cleft palate. Ultrastructural analysis showed that, in contrast to controls, 6MP-induced alterations were first seen in the mesenchymal cells 24 hr after drug administration. The initial alterations were characterized by swelling of the nuclear membrane. During the next 12 hr, lysosomes were seen first in the mesenchymal cells and then in the cells of the medial edge epithelium (MEE) of the developing palatal primordia. The appearance of lysosomes was temporally abnormal and was interpreted as a sublethal response to 6MP treatment. Subsequently, the nuclear alterations and the lysosomes diminished; and 48 hr after 6MP administration, they were absent from the palatal tissues. Ninety hours after 6MP administration, unlike the controls (in which the palatal shelves were already fused), changes were seen at the epithelial-mesenchymal interface in the developing cleft palatal shelves. These changes were characterized by breakdown of the basal lamina and epithelial-mesenchymal contacts. Eventually, at term, the MEE of the vertical shelf stratified. It was suggested that 6MP affected cytodifferentiation in the palatal tissues during the critical phase of early vertical shelf development and thereby induced cleft palate.  相似文献   
9.
A case is described of psychotic depression that worsened during a course of three bilateral ECTs per week, but responded to administration of two bilateral ECTs three times per week. For some patients, ECTs may need to be given more than three times per week to obtain remission.  相似文献   
10.
ObjectiveTo assess the implementation of a mobile dispensing service to improve opioid users’ access to methadone maintenance therapy.MethodsIn March 2019, we started mobile methadone dispensing in an urban underprivileged locality in Delhi, India. The doctor was available only at the main community drug treatment clinic for clinical services, while the nurse dispensed methadone from a converted ambulance. We involved patients in identifying community leaders for sensitization and in deciding the location and timings for dispensing. We conducted a retrospective chart review of the programme data collected during delivery of clinical services. We compared the numbers of patients registered for methadone therapy and their retention and adherence to therapy in the 12-month periods before and after implementation of the mobile service.FindingsThe number of patients registered for therapy at the clinic increased from 167 in the year before implementation to 671 in the year after. A significantly higher proportion of patients were retained in therapy at 3, 6 and 9 months after enrolment; 9-month retention rates were 19% (32/167 patients) and 45% (44/97 patients) in the year before and after implementation, respectively. There was no significant difference in patients’ adherence to therapy between the two periods. Challenges included providing suitable dispensing hours for patients in employment and concerns of local community near to the dispensing sites.ConclusionIt is feasible to dispense methadone by a mobile team in an urban setting, with better retention rates in therapy compared with dispensing through a stationary clinic.  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