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   3748篇
  免费   275篇
  国内免费   7篇
耳鼻咽喉   28篇
儿科学   130篇
妇产科学   59篇
基础医学   774篇
口腔科学   61篇
临床医学   239篇
内科学   962篇
皮肤病学   131篇
神经病学   281篇
特种医学   67篇
外科学   396篇
综合类   17篇
一般理论   1篇
预防医学   303篇
眼科学   70篇
药学   213篇
中国医学   15篇
肿瘤学   283篇
  2023年   35篇
  2022年   57篇
  2021年   121篇
  2020年   76篇
  2019年   134篇
  2018年   145篇
  2017年   99篇
  2016年   99篇
  2015年   110篇
  2014年   159篇
  2013年   191篇
  2012年   265篇
  2011年   314篇
  2010年   162篇
  2009年   149篇
  2008年   229篇
  2007年   198篇
  2006年   216篇
  2005年   167篇
  2004年   172篇
  2003年   171篇
  2002年   157篇
  2001年   66篇
  2000年   66篇
  1999年   54篇
  1998年   36篇
  1997年   31篇
  1996年   21篇
  1995年   18篇
  1994年   15篇
  1993年   26篇
  1992年   38篇
  1991年   31篇
  1990年   17篇
  1989年   17篇
  1988年   23篇
  1987年   15篇
  1986年   18篇
  1985年   14篇
  1984年   14篇
  1983年   11篇
  1981年   5篇
  1978年   5篇
  1976年   5篇
  1975年   8篇
  1974年   5篇
  1971年   4篇
  1970年   4篇
  1969年   5篇
  1968年   4篇
排序方式: 共有4030条查询结果,搜索用时 15 毫秒
41.
Mantle cell lymphoma (MCL) is a B-cell neoplasm with a relatively aggressive clinical course. There is a very small subgroup of patients who present with atypical lymphocytes in peripheral blood, with or without lymphocytosis, lymphadenopathy, or splenomegaly, and with an indolent clinical course. They frequently show mutated IgV(H) genes and CD5 negativity. We report an asymptomatic elderly patient who presented with a single submandibular lymphadenopathy. The biopsy showed immunophenotype and t(11;14)(q13;q32) consistent with MCL. The abnormal lymphoid population was also detected in peripheral blood and bone marrow. The patient has remained asymptomatic for 5 years without receiving any therapy. It is uncertain whether these cases represent an early-stage event in the development or an indolent form of MCL. The existence of such asymptomatic patients with an indolent clinical course should induce a strict clinical judgment in terms of therapeutic decisions.  相似文献   
42.
In approximately 25-40% of infants presenting with posterior urethral valves (PUV) renal insufficiency will develop before adolescence. In some these patients, renal dysplasia, bladder dysfunction and mismanagement may precipitate renal failure at even earlier age. The goals of this study were to determine whether long-term bladder dysfunction was more frequent in children who underwent early temporary pyelostomy than in those who underwent valve ablation, and to know if bladder dysfunction and mismanagement, in some patients, could be responsible of early renal failure. Urodynamic studies were performed in 59 boys with severe PUV divided into two groups based on initial treatment. A) Valve ablation (30 p.); B) Cutaneous pyeloureterostomy (29 p.). At the end of the study 22 boys had chronic renal failure. Of the 59 boys, 42% (25 p.) had bladders with overdistended or normal behaviour, 58% (34 p.) had bladder dysfunction (instability 37%, low compliance 15%, myogenic failure 5%). The 89% of low compliance bladders, 66% of myogenic failure and 23% of those with instability were in CRF. No difference at all was found in bladder function between boys treated as neonates by high diversion or valve ablation. Of the group in chronic renal failure (22 p.), only 7 patients (32%) had bladders with normal behaviour and in five of these patients a mismanagement was directly related with a quicker renal deterioration. The 58% of our boys with severe PUV have some type of bladder dysfunction. Neonatal pyelo-ureterostomy does not increase long-term bladder dysfunction. Surgical mismanagement should be added to bladder dysfunction as contributors to earlier renal failure.  相似文献   
43.
Purpose: To investigate possible associations between genetic markers and Primary Open-Angle Glaucoma (POAG). Methods: A number of genetic markers were typed in 84 unrelated patients with POAG and compared with a random sample of healthy individuals. The markers were Transferrin, Group Specific Component, G1m (1), G1m (2) and G3m (5) Allotypes, Adenylate Kinase, Adenosin Deaminase, Glyoxalase I and Acid Phosphatase and PCR-based markers HLA-DQA1 and D1S80. Results: No significant differences were found except the strong association between the group of POAG patients and Acid Phosphatase ACP*C allele (2 = 32.86; p < 0.0001). Conclusions: Since Acid Phosphatase gene is localized to chromosome 2p23, this result could be a first comprehensive step in the localization of POAG genes.  相似文献   
44.
The neuroactive peptide endothelin-1 has receptors distributed abundantly among subdivisions and nuclei of the visuovestibular and oculomotor systems. In previous work, we and others described the convulsive manifestations resulting from central injection of this neuropeptide, including nystagmus, oculoclonus, exophthalmos, tonic hindlimb extension, and a generalized repetitive motor disturbance called barrel-rolling. We applied the quantitative, autoradiographic [14C]deoxy-glucose method to examine the hypothesis that visuovestibular and oculomotor structures would become metabolically stimulated when endothelin was introduced into the brain via the ventricular system in conscious rats. Since previous work had demonstrated that hypermetabolic responses to endothelin in other neural systems were inhibited by an antagonist of neuronal calcium L-type channels, nimodipine, we further tested whether the increased function of vestibulooculomotor nuclei whose metabolic activity was sensitive to endothelin could be altered following nimodipine pretreatment via the ventricle. A single unilateral injection of endothelin (9 pmol in 3 l saline) into a lateral ventricle provoked significantly increased rates of glucose metabolism in 22 of 39 individual anatomical structures of the visuovestibular and oculomotor systems. Among those affected were the superficial stratum of the caudal superior colliculus (+25%), the optic tract bilaterally (+ 35 to 43%), the oculomotor cranial nerve nuclei (III, IV, VI; range of +21 to 47%), and the medial terminal nucleus of the accessory optic tract which harbors dense fields of endothelin binding sites (bilateral increase of +70 to 96%). Several other nuclei involved in the proprioceptive and visuovestibular disturbance caused by endothelin displayed increased metabolic activity, including the cuneate, gracile, sensory trigeminal, and prepositus hypoglossal nuclei, the vestibular subnuclear system, and the cerebellar flocculus. Identification of hypermetabolic responsivity to endothelin in these structures provides further information on the anatomical substrates mediating the behavioral phenomenology of endothelin-induced motor convulsions which involve the paroxysmal participation of the extraocular muscles and motor control systems producing barrel-rolling convulsions. Nimodipine pretreatment inhibited both the convulsive activity and the cerebral hypermetabolic responses to intraventricular endothelin. The results indicate that the neural systems sensitive to intraventricular endothelin become functionally active via a calcium-mediated process that may involve the neuropeptide as an intrinsic signaling molecule.  相似文献   
45.
Contribution of a retrospective series of 16 patients with type II absorptive hypercalciuria over a total of 1.041 patients undergoing metabolic study due to relapsing renal lithiasis. Clinical history of lithiasis, biochemistry prior to treatment and instituted therapy were examined in all cases. Stones composition, radiologic appearance of lithiasis and evolution of biochemical parameters after medical treatment with a mixture of phosphates were also studied.  相似文献   
46.
47.
Contribution of a case report of cutaneous horn of penis surgically treated with extensive resection of the implantation base. A well differentiated, microinvasive epidermoid carcinoma was histopathologically demonstrated on a hyperkeratosis squamous papilloma. Although underlying lesions to cutaneous horn are usually benign, malignant changes have been reported in up to one third of cases; surgical treatment should therefore include extensive resection of the implantation base.  相似文献   
48.
49.
Objective. The purpose of this investigation is to elucidate the sonographic features of abnormal major cranial sutures. Materials and methods. Eight excised synostosed suture specimens were evaluated. The high-resolution sonographic appearance was correlated with the histological section, plain radiographs, CT and MRI. Diastatic and molded sutures were also evaluated with sonography and compared with the normal cranial suture appearance. Results. Synostosed sutures demonstrated one or more of the following features: (a) loss of echo-poor fibrous gap between bony plates (five sagittal and coronal synostoses); (b) irregular thickened inner sutural margin (three lambdoid synostoses); (c) loss of bevelled edge (one lambdoid synostosis); (d) asymmetric anterior fontanelle (one coronal synostosis). Cranial molding results in an overlap of echogenic bony plates. Sutural width (the distance between bony plates) is increased in cases of elevated intracranial pressure. Conclusion. Sonography is an inexpensive, radiation-free modality which can confirm synostosis versus molding versus an underlying intracranial lesion as a cause of plagiocephaly. The high-resolution sonographic images also provide a relatively easy means to assess sutural width and may provide information in regard to increased intracranial pressure. Received: 24 March 1997 Accepted: 25 September 1997  相似文献   
50.
INTRODUCTION: Oral trans-mucosal fentanyl citrate (OTFC) is the one drug specifically developed for the management of breakthrough pain. This study assesses the long-term safety and efficacy of OTFC standard clinical conditions. Patients and methods. Six-month observational study performed on cancer patients with episodes of breakthrough pain. Safety was assessed by recording the advent of adverse events and efficacy by the evaluating the intensity of breakthrough pain. RESULTS: 174 cancer patients were recruited into the study. All adverse reactions reported were mild or moderate. OTFC was significantly faster (time to the commencement of pain relief: 12.7 +/- 11.4 vs 32.7 +/- 18.4 minutes; p < 0.001) and potent (post-treatment pain intensity: 3.4 +/- 1.5 vs 4.3 +/- 1.5; p < 0.001) than the previously-used drugs. CONCLUSIONS: This observational study confirms the good safety profile of OTFC as well as its effectiveness over long-term period treatment of breakthrough pain.  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