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   33271篇
  免费   1941篇
  国内免费   269篇
耳鼻咽喉   445篇
儿科学   598篇
妇产科学   491篇
基础医学   4074篇
口腔科学   1553篇
临床医学   2724篇
内科学   8942篇
皮肤病学   392篇
神经病学   3353篇
特种医学   1305篇
外科学   5282篇
综合类   93篇
一般理论   6篇
预防医学   1395篇
眼科学   546篇
药学   1727篇
中国医学   72篇
肿瘤学   2483篇
  2024年   32篇
  2023年   360篇
  2022年   669篇
  2021年   1256篇
  2020年   745篇
  2019年   1022篇
  2018年   1207篇
  2017年   957篇
  2016年   1067篇
  2015年   1130篇
  2014年   1459篇
  2013年   1777篇
  2012年   2777篇
  2011年   2672篇
  2010年   1499篇
  2009年   1363篇
  2008年   2145篇
  2007年   2256篇
  2006年   2029篇
  2005年   1842篇
  2004年   1642篇
  2003年   1495篇
  2002年   1297篇
  2001年   262篇
  2000年   235篇
  1999年   241篇
  1998年   240篇
  1997年   201篇
  1996年   153篇
  1995年   140篇
  1994年   126篇
  1993年   106篇
  1992年   117篇
  1991年   93篇
  1990年   80篇
  1989年   54篇
  1988年   85篇
  1987年   61篇
  1986年   44篇
  1985年   63篇
  1984年   52篇
  1983年   43篇
  1982年   46篇
  1981年   29篇
  1980年   24篇
  1979年   41篇
  1978年   30篇
  1977年   22篇
  1973年   31篇
  1972年   26篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The grumose degeneration observed in the dentate nuclei of 7 cases of progressive supranuclear palsy (PSP) was studied with a panel of antibodies which included 2 neurofilaments, Tau and ubiquitin. Dentate nucleus neurons were negative with all antibodies except ubiquitin which showed a slightly positive homogeneous pattern of staining. The amorphous material surrounding swollen or normal neurons was strongly positive for neurofilament and subunits and numerous torpedoes were observed in the granular layer of the cerebellar cortex. Our results confirm that grumose degeneration consists in degeneration of terminal axons of Purkinje cells in the dentate nucleus. The positivity of dentate nucleus neurons for ubiquitin may support the concept of synaptic dysfunction between Purkinje cells and dentate nucleus neurons.  相似文献   
42.
The increased use of Ultrasonography (US) has led to increased detection of simple hepatic cysts. For symptomatic cysts treatment is necessary. Until some years ago surgery was the only therapy. We have treated a large number of patients with Percutaneous Alcohol Sclerotherapy (PAS) and evaluated retrospectively the efficacy of this approach.Data on 21 patients with symptomatic simple hepatic cysts were reviewed retrospectively. Cysts had a mean diameter of 9 cm (range: 7–15 cm). PAS was always performed under local anesthesia and US guidance. 25% of the volume was replaced with 95% ethanol and then completely aspirated after 20–30 minutes.No complications or deaths occurred. In all patients symptoms disappeared after treatment. In 15 out of 21 cases there was no evidence of residual cyst on US, computed tomography (CT) or magnetic resonance (MRI). In 6 patients with shorter follow-up, cysts showed a mean reduction in diameter of 50%. The mean follow-up was 18 months (range 6–60 months).We conclude that PAS is easy with low risk for the patients and with good long-term results; it should therefore become the procedure of choice for simple hepatic cysts.  相似文献   
43.
The paper describes a study carried out in 40 patients affected by lichen sclerosus (LS) of the vulva. The mean age of patients was 60.9 years (range 27-83) and 31 were in menopause. Patients were divided randomly into two groups of 20. The symptoms (itching, burning, pain, dyspareunia), clinical aspects (atrophy, hyperkeratosis, sclerosis) and histological alterations (atrophy of the epithelium, edema, inflammatory infiltrate, fibrosis) were quantified in each patient by a score. The mean scores relating to the three parameters examined were then calculated for each group. One group was treated with testosterone propionate 2% and the other with a strong synthetic corticosteroid, clobetasol dipropionate 0.05%. After 24 weeks of treatment patients were again evaluated in relation to clinical (symptoms and clinical aspects) and histological parameters, following the procedure used before the start of treatment. The mean scores obtained were then compared with those before the start of treatment. Statistical analyses were performed using Student's t-test. Testosterone was found to be effective in relation to symptoms but no significant change was observed in relation to clinical aspects and histological alterations. It also caused major secondary effects which led to the suspension of treatment in one patient. Clobetasol was shown to be highly effective both in relation to symptoms and in terms of clinical aspects and histological alterations, and did not cause any noteworthy collateral effects, especially contact dermatitis. In the context of the objective parameters examined in this study, sclerosis and hyperkeratosis were easily modified by corticosteroid treatment in comparison to atrophy, especially in those patients with a longer duration of disease.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
44.
45.
The action of multiple liability genes is responsible for complex phenotypes at the same time, a single gene, could control several phenotypic features. This is the case of human period 3 gene (hper3), mainly involved in the setting of the biologic clock. Some variants of this gene, besides being associated with the Delayed Sleep Phase Syndrome, showed a key role in determining evening preference rather than morning one. According to this rationale, we hypothesized that this gene could influence circadian mood fluctuations, in mood disorders. Our study demonstrated that rare genetic variants of hper3 are significantly associated to a number of mood disorders features, such as age of onset, response to SSRIs treatment, circadian mood oscillations and characteristics of temperament. These preliminary results could shed further light on the involvement of circadian genes in various aspects of physiological and psychopathological mechanisms of the brain.  相似文献   
46.
47.
48.
The incidence of invasive fungal infection is increasing especially in the field of transplantation, affecting as many as 50% of bone marrow transplant (BMT) patients with neutropenia and 5-20% of solid-organ transplant (SOT) recipients. Fusarium species are soil saprophytes and plant pathogens. They may cause superficial mycoses or important opportunistic infections in patients with bone marrow suppression and neutropenia, they have been rarely described in solid organ recipients, and up to now there have been no reports of such infection in isolated liver transplanted patients. We describe a case of disseminated Fusarium solani infection with hepatic localization in a liver transplanted patient that resolved with the administration of amphotericin B. Our observation confirms that Fusarium spp. are emerging pathogens that may most frequently affect not only BMT patients and patients with hematological malignancies, but also SOT patients. They may cause both localized and disseminated infection. In conclusion, Fusarium spp. etiology should be considered in the context of infectious diseases following liver transplantation.  相似文献   
49.
In the present study we evaluated the effects of climacteric modifications on body weight and fat distribution. From women attending a menopause clinic we selected 2175 untreated, normal healthy women who were divided into three groups: premenopausal (n = 540), perimenopausal (n = 750) and postmenopausal (n = 885), and compared them with 354 postmenopausal women receiving different forms of hormone replacement therapy (HRT). The total body fat tissue mass and distribution were analyzed using dual-energy X-ray absorptiometry. Body weight and body mass index (BMI) were significantly higher in perimenopausal and postmenopausal than in premenopausal women. Mean total body fat and fat as a percentage of soft tissue were significantly (p < 0.05) higher in the perimenopausal and postmenopausal groups than in the premenopausal group. Fat tissue and regional fat tissue as a percentage of total fat tissue were higher in the trunk (p < 0.0001) and arms (p < 0.0001) in perimenopausal and postmenopausal than in premenopausal women. In postmenopausal women, leg fat tissue was significantly (p < 0.05) lower than in premenopausal and perimenopausal groups. Total body and leg lean tissue were significantly lower (p < 0.05) in postmenopausal than in premenopausal and perimenopausal women. In age-matched women with similar BMI, total body fat as a percentage of soft tissue was significantly (p < 0.001) higher in the perimenopausal and postmenopausal groups than in the premenopausal group. As for body fat distribution, fat as a percentage of total fat tissue was significantly higher in the trunk (p < 0.0001) region in perimenopausal and postmenopausal women compared with the premenopausal group. In the legs, fat as a percentage of total fat tissue was significantly higher (p < 0.05) in the premenopausal than in the postmenopausal group. In the arms a slight but not significant (p < 0.18) difference was shown in fat distribution between the three untreated groups. In age-matched HRT-treated postmenopausal women, the fat tissue was similar to that in the premenopausal group. The present results confirm that endocrine changes during the menopausal transition, rather than the aging process, are related to changes in body weight and fat distribution. Perimenopausal and postmenopausal women show a shift to a central, android fat distribution that can be counteracted by HRT.  相似文献   
50.
Nitric oxide (NO) production has been described using a 2-compartment model for the synthesis and movement of NO in both the alveoli and the airways. The alveolar concentration of NO (CaNO), an indirect marker of the inflammatory state of the distal portions of the lung, can be deduced through exhalation at multiple flow rates. Our objective was to determine reference values for CaNO. The fraction of exhaled NO (FeNO) was measured in 33 healthy individuals at a rate of 50 mL/s; the subjects then exhaled at 10, 30, 100, and 200 mL/s to calculate CaNO. A chemiluminescence analyzer (NIOX Aerocrine) was used to perform the measurements. The mean (SD) FeNO was 15 (6) ppb. The mean CaNO was 3.04 (1.30) ppb. These values of CaNO measured in healthy individuals will allow us to analyze alveolar inflammatory behavior in respiratory and systemic processes.  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