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   999篇
  免费   31篇
  国内免费   10篇
耳鼻咽喉   1篇
儿科学   54篇
妇产科学   10篇
基础医学   79篇
口腔科学   10篇
临床医学   65篇
内科学   135篇
皮肤病学   30篇
神经病学   28篇
特种医学   98篇
外科学   147篇
综合类   261篇
预防医学   38篇
眼科学   4篇
药学   33篇
肿瘤学   47篇
  2023年   1篇
  2022年   3篇
  2021年   11篇
  2020年   4篇
  2019年   6篇
  2018年   8篇
  2017年   8篇
  2016年   11篇
  2015年   33篇
  2014年   18篇
  2013年   24篇
  2012年   28篇
  2011年   26篇
  2010年   52篇
  2009年   55篇
  2008年   42篇
  2007年   51篇
  2006年   63篇
  2005年   50篇
  2004年   60篇
  2003年   29篇
  2002年   28篇
  2001年   23篇
  2000年   23篇
  1999年   32篇
  1998年   42篇
  1997年   50篇
  1996年   52篇
  1995年   32篇
  1994年   31篇
  1993年   10篇
  1992年   12篇
  1991年   8篇
  1990年   11篇
  1989年   9篇
  1988年   16篇
  1987年   10篇
  1986年   13篇
  1985年   7篇
  1984年   12篇
  1983年   4篇
  1982年   7篇
  1981年   6篇
  1980年   4篇
  1979年   2篇
  1978年   3篇
  1977年   4篇
  1976年   2篇
  1975年   2篇
  1974年   2篇
排序方式: 共有1040条查询结果,搜索用时 15 毫秒
71.
Leiomyoma of the vagina is a very rare tumour of the lower urogenital tract. These slow‐growing masses may be asymptomatic or present with pain, dyspareunia or urinary symptoms. Rarely, these tumours may present with life‐threatening haemorrhage. These hypervascular tumours are treated by surgical excision. Preoperative embolization therefore may aid in devascularization of these tumours before surgical excision. We present the MRI features of a case of vaginal leiomyoma, which was managed by preoperative embolization and was then excised in toto. To the best of our knowledge, this is the first report where preoperative embolization was performed before excision of a vaginal leiomyoma with minimal peroperative blood loss.  相似文献   
72.
BACKGROUND: The short-term course of schizophrenia is reported to be better in some developing country settings. The long-term course in such settings, however, has rarely been studied. AIMS: To examine the long-term course and mortality of schizophrenia in patients with a poor 2-year course. METHOD: The report is based on two incidence cohorts of first-contact patients in urban and rural Chandigarh, India, originally recruited for the World Health Organization Determinants of Outcome of Severe Mental Disorders study. Patients were assessed using standardised instruments at 2- and 15-year follow-ups. RESULTS: Ninety-two per cent of the patients with a poor 2-year course had a poor long-term course and 47% died - a nine times higher mortality rate than among patients with other 2-year course types. CONCLUSIONS: In this developing country setting, a poor 2-year course was strongly predictive of poor prognosis and high mortality, raising questions about the adequacy of care for such patients.  相似文献   
73.
Paracetamol is the commonest agent employed in self poisoning, however it is not clear whether adolescents possess insight into the serious complications associated with its misuse. Using a one page questionnaire, the availability, usage, and knowledge of toxicity of paracetamol among 1147 American and British adolescents was assessed. Although 90% of all students recognised that paracetamol could kill, the great majority of students overestimated the lethal dose. In addition, while knowledge regarding side effects of paracetamol was poor the drug was widely available to, and used by, the study population. It is proposed that gross overestimation of the number of tablets required to kill, poor understanding of paracetamol side effects, and wide availability of the drug contribute to its frequent use in adolescent suicidal behaviour. The inclusion of some over-the-counter medications in school drug education programs in addition to tighter control of the availability of paracetamol may help reduce the problem of adolescent self poisoning.  相似文献   
74.
This paper highlights the abuse potential of the codeine containing cough syrups, which may take two forms. One, experimental abuse in school or college students which later persists in a dependent pattern. Two, pre-existing opioid abusers, as a substitute which starts after the school or college years. The short term treatment outcome is better in the former group in that they are able to maintain abstinence for a relatively longer period.  相似文献   
75.
76.
77.
Eleven women with a history of infertility and uterine leiomyomas underwent magnetic resonance (MR) imaging of the pelvis prior to myomectomy. Nine also underwent preoperative pelvic ultrasonography (US), and ten underwent hysterosalpingography. All studies were interpreted prospectively by independent observers. With each imaging modality, the location (one of 11 anatomic segments), size, and appearance of detected uterine leiomyomas were determined and compared with surgical and histologic findings. Among the nine patients who underwent both MR and US, the sensitivity (85%) and accuracy (94%) of MR imaging for abnormal segments was significantly better than that of US (sensitivity = 69%, P = .015; accuracy = 87%, P = .043). For the ten patients who underwent both MR and hysterosalpingography, the sensitivity (91%) and accuracy (96%) of MR imaging was better than that of hysterosalpingography (sensitivity = 18%, P = .0005; accuracy = 72%, P = .0005). The specificities of the three modalities did not significantly differ (100%, 97%, and 98% for MR, US, and hysterosalpingography, respectively). These data suggest that MR imaging is superior to US or hysterosalpingography for preoperatively locating uterine leiomyomas.  相似文献   
78.
79.
1. Magnolol is an active component of Magnolia officinalis. It is 1000-times more potent than α-tocopherol in inhibiting lipid peroxidation in rat heart mitochondira. In the present study, the in vivo antiarrhythmic and anti-ischaemic effects of magnolol in coronary ligated rats were investigated. 2. Male Sprague-Dawley rats were anaesthetized with urethane. Magnolol, at dosages of 10?7, 10?8 and 10?9 g/kg, was adminstered intravenously 15 min before ligation of the coronary artery. 3. The incidence and duration of ventricular tachycardia and ventricular fibrillation during 30 min coronary ligation were significantly reduced by magnolol. Ventricular arrhythmias during 10 min reperfusion after the relief of coronary ligation were also reduced. 4. In rats subjected to 4h coronary ligation, 10?7 and 10?8 g/kg magnolol significantly reduced infarct size. 5. We conclude that magnolol may protect the myocardium against ischaemic injury and suppress ventricular arrhythmia during ischaemia and reperfusion.  相似文献   
80.
Considerable amounts of GTP, GMP, adenosine, guanine, and adenine accumulated in Neurospora crassa when a culture grown on low phosphate (0.01%) medium was transferred to a high phosphate (1%) medium. The levels of alkaline phosphatase, nucleotidase, and nucleosidase decreased by 2.4, 5.4, and 3 folds, respectively, in cultures grown on high phosphate medium. Substrate kinetics of these enzymes revealed that: (1) alkaline phosphatase isolated from the organism grown on low phosphate medium demonstrates nonlinear reciprocal plots with two distinct apparent Km values for β-glycerophosphate compared to one apparent Km value (associated with 32% decrease in the apparent Vmax value) obtained with that grown on high phosphate medium; (2) nucleotidases and nucleosidases isolated from organisms cultivated on low phosphate and high phosphate media showed the same apparent Km values, 0.25 mM for nucleotidase and 0.909 mM for nucleosidase. There was, however, >3 times decrease in the catalytic activity of the latter enzymes isolated from organisms grown on high phosphate medium as compared to those grown on low phosphate. Inclusion of inorganic phosphate in standard assay mixtures of the three enzymes resulted in a considerable inhibition in the catalytic activities of all of them. High levels of phosphate in the medium caused marked repression of three out of six of alkaline phosphatase, two out of three of nucleotidase, and one out of two of nucleosidase isozymic forms detected in the low phosphate grown culture.  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