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   33301篇
  免费   2086篇
  国内免费   265篇
耳鼻咽喉   443篇
儿科学   602篇
妇产科学   496篇
基础医学   4096篇
口腔科学   1562篇
临床医学   2741篇
内科学   8959篇
皮肤病学   405篇
神经病学   3390篇
特种医学   1308篇
外科学   5307篇
综合类   93篇
一般理论   6篇
预防医学   1397篇
眼科学   544篇
药学   1729篇
中国医学   75篇
肿瘤学   2499篇
  2023年   334篇
  2022年   649篇
  2021年   1258篇
  2020年   751篇
  2019年   1027篇
  2018年   1209篇
  2017年   960篇
  2016年   1073篇
  2015年   1134篇
  2014年   1461篇
  2013年   1782篇
  2012年   2783篇
  2011年   2682篇
  2010年   1507篇
  2009年   1371篇
  2008年   2154篇
  2007年   2266篇
  2006年   2037篇
  2005年   1846篇
  2004年   1644篇
  2003年   1501篇
  2002年   1301篇
  2001年   268篇
  2000年   240篇
  1999年   251篇
  1998年   243篇
  1997年   203篇
  1996年   154篇
  1995年   146篇
  1994年   130篇
  1993年   107篇
  1992年   124篇
  1991年   100篇
  1990年   90篇
  1989年   57篇
  1988年   92篇
  1987年   70篇
  1986年   50篇
  1985年   69篇
  1984年   59篇
  1983年   47篇
  1982年   49篇
  1981年   31篇
  1980年   24篇
  1979年   41篇
  1978年   32篇
  1977年   23篇
  1974年   23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
71.
Total extrusion of the talus without recovery of the bone is a very unusual injury. The authors present a case of a 25-year-old man who sustained an open total enucleation of the talus in a motorcycle accident. The talus was not recovered at the scene of the accident. An immediate tibiocalcaneal stabilization was performed by using an external fixator. In the postoperative period, a polymicrobic infection was observed and treated with parenteral antibiotics. Nine months after injury, the patient developed an infection of both the empty space and the distal third of the tibia. A wound debridement with tibial sequestrectomy and insertion of gentamicin-impregnated polymethylmethacrylate beads was performed. Three months later, after multiple negative bacteriologic examinations, a tibiocalcaneal arthrodesis with staples and autogenous bone graft was performed. Because of a pseudoarthrosis, the patient underwent a revision of the arthrodesis by retrograde tibiocalcaneal nailing, achieving clinical and radiographic success. The definitive treatment of total enucleation of the talus is still controversial because of its rarity and the high rate of complications, such as avascular necrosis, osteomyelitis, and ankle stiffness. In this case, without recovery of the talus, retrograde nailing afforded good stability by bypassing the bone defects.  相似文献   
72.
The aim of the present study was to determine the effect of aspirin and indomethacin on epidermal growth factor (EGF) secretion in duodenal tissue fragments cultivated in vitro. The fragments were obtained from healthy subjects by gastroscopy, cultured in McCoy's medium and gassed with 95% O2 and 5% CO2 at 37 degrees C. After an incubation of 30 min, the culture medium was decanted, and the quantity of hormone determined by radioimmunoassay. The mean EGF level detected in the medium was 10.94 ng/mg protein tissue. The addition of aspirin (final concentration 10(-7) M) to the medium reduced mean EGF levels to 7.5 ng/mg (p less than 0.05), whereas aspirin 10(-8) M did not produce such a modification. The addition of indomethacin (final concentration 10(-8) M) decreased mean EGF levels to 5.37 ng/mg (p less than 0.001). In all experimental conditions, the addition of anti-somatostatin (SRIF) antibodies determined a remarkable increase in EGF (p less than 0.01). The results of this study show aspirin and indomethacin to be direct, not SRIF-mediated inhibitors of EGF release.  相似文献   
73.
The authors review the evidence supporting the therapeutic use of gangliosides in autonomic neuropathies, with particular reference to those occurring in Chagas’ disease.  相似文献   
74.
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   
75.
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   
76.
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   
77.
78.
Appearance of esophageal peristalsis in treated idiopathic achalasia   总被引:1,自引:0,他引:1  
The authors studied 22 patients with severe dysphagia, and follow-up studies showed the appearance of some esophageal peristalsis for the first time in three of these patients after Heller myotomy. Comparison of pre- and postoperative clinical, radiological, and manometric data of these three subjects and the data of the other 19 patients showed no statistically significant differences between the two groups of patients either before or after cardiomyotomy except for the unusual appearance of esophageal peristalsis after surgery. According to these results it is not possible to predict which patients will develop peristalsis after cardiomyotomy. The different motor pattern observed after surgery might suggest the existence of a different pathogenesis underlying the esophageal motor disorders in these two groups of patients.  相似文献   
79.
Partial seizures and migraine   总被引:1,自引:0,他引:1  
Epilepsy and migraine, despite some common features, have quite different pathophysiological mechanisms. Studies carried out on large population samples have shown that the relationships between migraine and epilepsy may be of the following type: associated attacks, with migraine and seizures occurring quite independently of one another; combined attacks, with the two types of attacks succeeding one another in time; basilar artery migraine with seizures and marked EEG abnormalities; benign epilepsies with occipital discharges, migraine and intercalated seizures. We report four cases of particular interest.  相似文献   
80.
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   
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