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   1642篇
  免费   45篇
  国内免费   2篇
耳鼻咽喉   7篇
儿科学   5篇
妇产科学   2篇
基础医学   174篇
口腔科学   90篇
临床医学   120篇
内科学   261篇
皮肤病学   15篇
神经病学   307篇
特种医学   58篇
外科学   284篇
综合类   8篇
预防医学   20篇
眼科学   17篇
药学   169篇
肿瘤学   152篇
  2022年   9篇
  2021年   12篇
  2020年   10篇
  2019年   18篇
  2018年   12篇
  2017年   9篇
  2016年   13篇
  2015年   17篇
  2014年   12篇
  2013年   25篇
  2012年   26篇
  2011年   45篇
  2010年   15篇
  2009年   18篇
  2008年   51篇
  2007年   57篇
  2006年   52篇
  2005年   60篇
  2004年   66篇
  2003年   65篇
  2002年   58篇
  2001年   51篇
  2000年   71篇
  1999年   65篇
  1998年   18篇
  1997年   19篇
  1996年   13篇
  1995年   13篇
  1994年   13篇
  1993年   19篇
  1992年   58篇
  1991年   67篇
  1990年   54篇
  1989年   72篇
  1988年   75篇
  1987年   74篇
  1986年   72篇
  1985年   57篇
  1984年   46篇
  1983年   35篇
  1982年   15篇
  1980年   12篇
  1979年   13篇
  1978年   11篇
  1977年   9篇
  1975年   9篇
  1974年   8篇
  1973年   7篇
  1971年   8篇
  1970年   9篇
排序方式: 共有1689条查询结果,搜索用时 15 毫秒
31.
We report a successful surgical case of billowing mitral leaflet syndrome combined with severe mitral regurgitation. A 45-year-old man suffered from congestive heart failure and admitted our institution for precise examination. A heart murmur was pointed out by a medical examination at his high school, and mitral valve prolapse was detected by echocardiography at 23 year of age. No medication was applied because he showed no symptom. From 44 year of age, he noted palpitation on exercise. Holter monitor showed blocked PAC and Wenckebach A-V block, and transesophageal echocardiography indicated severe mitral regurgitation due to the billowing of voluminous both leaflets. At his operation, we recognized the billowing of both leaflets with torn chordae, and size of the mitral valve orifice was 8.5 x 5 cm. The huge mitral valve was replaced with a CarboMedics 31M prosthetic valve by plicating mattress stitches of native mitral annulus. Histopathologic findings showed accumulation of acid mucopolysaccharide. Postoperative echocardiography showed reduction of the left ventricular volume and preservation of the left ventricular function. Relatively slow progression of the billowing mitral leaflet syndrome did not cause apparent symptoms of heart failure in this patient. Therefore, proper selection of the procedure and timing of surgical treatments might be important for successful long-term results after operation of the billowing mitral leaflet syndrome.  相似文献   
32.
Placement of stents for the tracheal or carinal stenosis have a meaning of maintaining the airway. Failure of the stenting causes death. In cases of severe airway stenosis and low pulmonary function, the pulmonary support method should be performed instead of intubation and mechanical ventilation. Generally, PCPS (percutaneous cardio-pulmonary support system) is used as a pulmonary support. This method was very useful to place stents for airway stenosis. We concluded that PCPS was useful in emergency cases, and in cases of severe fixed type airway stenosis and low pulmonary function it had be on stand-by.  相似文献   
33.
We designated EEGs with marked and irregular beta waves in basic patterns as "irregular beta patterns" on the basis that these patterns are related with particular symptoms such as dysphoria, irritability and autonomic symptoms and they implicate choice of therapeutic agents. Because of good response to antiepileptic agents in patients with "irregular beta patterns" along with EEG characteristics, we hypothesized that the prevalence of "irregular beta patterns" is higher in epileptics than in other psychiatric patients. In the present study, we tested this hypothesis, investigating actual frequencies of these patterns among different diagnostic categories for all patients whose EEG were recorded in all the first-visit patients to the Outpatient Clinic, Department of Neuropsychiatry of the Tokyo University Hospital during one year period of 1986. Before starting this investigation, we checked the interrater reliability for these patterns. Therefore, two studies are reported here. In Study 1, five raters judged 98 EEG recordings blindly (43 epileptics and 55 healthy subjects). As a result, the generalized Kappa of 0.473 was obtained, indicating our agreement level was moderate or fair. This result lends support to our contention that irregular beta patterns are reliably judged. In Study 2, we judged the EEG recordings (137 schizophrenics, 62 affective disorders, 43 epileptics and 55 healthy controls) and calculated the prevalence rate of "irregular beta patterns" among the diagnostic categories. The results show that the prevalence rates of "irregular beta patterns" among psychiatric disorders and normal controls were 13% (18/137) in schizophrenics, 11% (7/62) in affective disorders, 14% (6/43) in epileptics and 4% (2/55) in healthy controls. These rates did not differ significantly among the three disorders. Thus, our hypothesis was not supported. The clinical significance of these patterns is discussed.  相似文献   
34.
PURPOSE: The F-box protein S-phase kinase-associated protein 2 (Skp2) is one of the positive regulators of the cell cycle that promote ubiquitin-mediated proteolysis of the cyclin-dependent kinase inhibitor p27. In this study, we investigated the significance of Skp2 expression in human non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Clinicopathologic features and immunohistochemical expression of Skp2 and p27 proteins were studied in 138 patients with NSCLC. Survival analyses were performed using the Kaplan-Meier method and the Cox regression model. To analyze the role of Skp2 in vitro, NSCLC cells were transfected with an Skp2-expressing vector or small interfering RNA. RESULTS: Skp2 was overexpressed in males, smokers, patients with squamous cell carcinomas, and patients with poorly differentiated cancers (P = .034, < .0001, < .0001, and .002, respectively). The multivariant analysis revealed that Skp2 expression is an independent prognostic factor for survival in NSCLC. An inverse relationship of Skp2 with p27 expression was observed (P = .012), and patients with both a higher expression of Skp2 and a lower expression of p27 showed a significantly unfavorable prognosis (P = .0002). In vitro ectopic expression of Skp2 in NSCLC cells reduced the protein level of p27. Conversely, induction of Skp2 siRNA increased the protein level of p27, leading to growth inhibition in NSCLC cells. CONCLUSION: Skp2 overexpression is closely associated with the suppression of p27 and the aggressiveness in NSCLC. It also could be a therapeutic target in NSCLC.  相似文献   
35.
Although exfoliative dermatitis (erythroderma) secondary to malignancy is commonly associated with lymphomas or leukemias, coincident gastrointestinal (GI) malignancy and erythroderma is rare. The authors recently encountered a patient with gallbladder carcinoma presenting as erythroderma. A 77-yr-old Japanese man presented with a 3-mo history of erythematous eruptions with pruritus over almost the entire body. After confirming the diagnosis of erythroderma, asymptomatic gallbladder carcinoma was found. Further investigations detected no malignancies in other organs. An extended cholecystectomy was performed. Histologic examination of resected specimens revealed poorly differentiated adenocarcinoma with negative resection margins. The eruptions with pruritus resolved within 1 wk after the operation. This is the first report, to our knowledge, of coincident biliary malignancy and erythroderma. The experience of the current patient suggests that erythroderma secondary to GI malignancy may resolve spontaneously after curative resection of the tumor.  相似文献   
36.
This study was designed to assess whether phencyclidine (PCP)-induced behaviors in rats were potentiated after two days' withdrawal from chronic methysergide (a 5-HT2 receptor blocker) treatment (10 mg/kg per day i.p. for 12 days), in order to confirm the involvement of 5-hydroxytryptamine (5-HT) neurons in PCP actions. The PCP (10 mg/kg)-induced behaviors (head-twitch, head-weaving, turning and backpedalling) were attenuated by successive pretreatment with PCP (10 mg/kg per day i.p. for 12 days), while PCP- and 5-methoxy-N,N-dimethyltryptamine (2 mg/kg)-induced head-twitch increased significantly after the repeated methysergide treatment was stopped. The development of tolerance to PCP-induced head-twitch was antagonized by pretreatment with methysergide. Furthermore, Scatchard plots of specific [3H]ketanserin binding at the 5-HT2 receptors and [3H]PCP binding at the PCP receptors in the methysergide group revealed significant increases in binding capacity (Bmax) with no change in affinity (Kd). On the contrary, after development of tolerance to PCP, there were significant decreases in Bmax of [3H]ketanserin binding with no change in affinity. PCP can thus displace [3H]ketanserin at the 5-HT2 receptor site, but not [3H]5-HT at the 5-HT1 receptor site. These facts indicate that PCP may produce head-twitch via an agonistic interaction with 5-HT2 receptor sites.  相似文献   
37.
38.
Small cell carcinoma is a rare form of ovarian cancer with a poor prognosis. It is divided into two types, the hypercalcemic and the pulmonary type, of which the latter is extremely rare. A 49-year-old woman presented with an acute abdomen and was suspected to have torsion of a left ovarian tumor, which was followed up with an emergency operation. Postoperative pathological examination gave a diagnosis of the pulmonary type of ovarian small cell carcinoma. Six courses of paclitaxel and carboplatin therapy were given as adjuvant chemotherapy. The patient has survived for 36 months without recurrence. Here we present an extremely rare patient with the pulmonary type of ovarian small cell carcinoma.  相似文献   
39.
We investigated the effects of N-allylnormetazocine (SKF 10,047) and morphine on the stereotyped behaviors induced by the intraperitoneal injection of phencyclidine (PCP). PCP-induced turning and backpedalling were significantly potentiated by pretreatment with SKF 10,047 (10 mg/kg) but sniffing and head weaving were not. On the other hand, pretreatment with morphine dose-dependently attenuated PCP-induced sniffing and head weaving, but not turning and backpedalling. These results suggest that PCP-induced stereotypy may be mediated by not only a sigma opioid receptor but also some other receptors. In addition, each component of PCP-induced stereotypy may be controlled by different opioid systems and/or neuronal systems.  相似文献   
40.
Summary  We report a rare case with tetralogy of Fallot (TOF) and agenesis of the internal carotid artery (ICA) who presented serious intracerebral haematomas. In the literature, this is the first documented case having these complications simultaneously. Extreme hypoxic insults followed by recovery were detected by O2 saturation monitor before two bleeds. Chronic brain hypoxia could make the vasculature weak, which was shown in the histological examination.  A 2-year-old girl was transferred to us with a general convulsion due to intracerebral haematoma. She had been showing general cyanosis from birth due to TOF. Repeated intracerebral haemorrhages ended her life. Histological study showed dilated vascular channels in the subarachnoid space and necrotizing vasculature obstructed by fibrinous thrombi adjacent to the haematoma. Fibrosis of the vessel wall with infiltration of macrophages suggested subacute or chronic lesions rather than acute necrosis due to the multiple haemorrhages. The intracerebral haematomas and agenesis of the ICA were observed as unilateral hemispheric vascular complications of TOF. Chronic brain hypoxia could play an important role in weakening the vessel wall and erythrocytosis caused obstructing thrombi. We speculate these factors generated the intracerebral haematomas.  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