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   43149篇
  免费   2128篇
  国内免费   222篇
耳鼻咽喉   326篇
儿科学   850篇
妇产科学   712篇
基础医学   5547篇
口腔科学   1085篇
临床医学   2811篇
内科学   10695篇
皮肤病学   669篇
神经病学   3032篇
特种医学   1529篇
外科学   8124篇
综合类   204篇
一般理论   1篇
预防医学   1365篇
眼科学   492篇
药学   3203篇
中国医学   184篇
肿瘤学   4670篇
  2023年   198篇
  2021年   786篇
  2020年   449篇
  2019年   615篇
  2018年   763篇
  2017年   586篇
  2016年   712篇
  2015年   784篇
  2014年   1027篇
  2013年   1200篇
  2012年   1926篇
  2011年   1998篇
  2010年   1154篇
  2009年   961篇
  2008年   1862篇
  2007年   1976篇
  2006年   1948篇
  2005年   2012篇
  2004年   2044篇
  2003年   2012篇
  2002年   2037篇
  2001年   1731篇
  2000年   1645篇
  1999年   1618篇
  1998年   633篇
  1997年   503篇
  1996年   436篇
  1995年   385篇
  1994年   383篇
  1993年   341篇
  1992年   1011篇
  1991年   950篇
  1990年   837篇
  1989年   917篇
  1988年   788篇
  1987年   715篇
  1986年   756篇
  1985年   686篇
  1984年   446篇
  1983年   385篇
  1982年   208篇
  1981年   192篇
  1979年   310篇
  1978年   243篇
  1977年   210篇
  1975年   211篇
  1974年   187篇
  1973年   173篇
  1971年   176篇
  1969年   165篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
61.
Antibodies to brain proteins in paraneoplastic cerebellar degeneration   总被引:2,自引:0,他引:2  
A 68-year-old man had subacute cerebellar degeneration and a non-Hodgkin's lymphoma. Using an immunoblotting method, we found serum antibodies to rat cerebral 250-kd and 110-kd and cerebellar 110-kd acidic cytoplasmic proteins. The antibodies did not react unless the antigens were prepared soon after death with protease inhibitors. Two hundred fifty-kd and 110-kd proteins are minor components of soluble cytoplasmic proteins of the brain. The molecular weights differed from other soluble brain-specific proteins already characterized.  相似文献   
62.
63.
Electrical stimulation of several brain sites produces profound analgesia in humans, and inhibits nocifensor reflexes in animal studies. Responses of the dorsal horn nociceptive neurons evoked by stimulation onto the receptive fields are also inhibited by brain stimulation. These brain sites are Periaqueductal Gray Matter (PAG), Nucleus Raphe Magnus (NRM), Nucleus Reticularis magnocellularis (NRmc), Locus Coeruleus (LC), Lateral Hypothalamus, and others. We have explained in a general way the mechanism of these stimulation produced analgesia. The mechanism of PAG stimulation analgesia is partly due to an activation of serotonin containing neurons which descend from NRM to the spinal dorsal horn and activated by PAG stimulation. Activation of NRM neurons may produce inhibition of the nociceptive neurons of the dorsal horn by the mechanism of direct postsynaptic inhibition. Currently there is no evidence to support the theory of presynaptic inhibition. Endogenous opioid peptides do not play an important role in PAG stimulation analgesia. On the other hand, the mechanism of NRmc or LC stimulation analgesia may be due to an activation of noradrenaline containing neurons which similarly inhibit the dorsal horn nociceptive neurons in the spinal cord. At present, it still remains unknown whether endogenous opioid peptides play an important role in this type of analgesia.  相似文献   
64.
This report concerns the long-term outcome of living donor liver transplantation (LDLT) for pediatric patients at a single center. Between June 1990 and December 2003, a total of 600 LDLTs, including 568 primary transplantations and 32 retransplantations, were performed for pediatric patients, who were immunosuppressed with FK506 and low-dose corticosteroids. Patient survival at 1, 5, and 10 years were 84.6%, 82.4%, and 77.2%, respectively, and the corresponding findings for graft survivals were 84.1%, 80.9%, and 74.5%. Multivariate analysis demonstrated that fulminant hepatic failure (FHF), a graft vs. body weight (GBWR) ratio of <0.8, and ABO-incompatible transplants were independently associated with both patient and graft survival. The retransplantation rate was 6%, and 55 patients (9.7%) have been completely weaned off immunosuppressants. Long-term patient and graft survival after pediatric LDLT for a large cohort of children at our hospital were found to be as good as those for cadaveric liver transplantation, although this series includes 13% liver transplantations with ABO-incompatible donors, which are obviously inferior in patient and graft survival. To obtain better outcomes for patients with FHF and for patients with ABO-incompatible transplants, immunosuppressive therapy needs to be improved.  相似文献   
65.
Neoplastic angioendotheliosis has rarely been described as a respiratory disease. A patient is described with pulmonary vascular involvement induced by neoplastic angioendotheliosis in pulmonary vessels.  相似文献   
66.
We present herein the rare case of a young man who was found to have a solitary tumor in the right upper lobe of his lung by a routine chest X-ray. The tumor was removed by thoracoscopic surgery, and pathological examinations confirmed the diagnosis of a primary lymphangioma of the lung. A brief review of the available literature on this extremely rare type of benign tumor follows the case report.  相似文献   
67.
Ketogenic capacity of mitochondria from the remnant liver of 70% hepatectomized rats was studied in relation to mitochondrial phosphorylative activity. Ketogenic capacity increased to a maximum of 6.04 +/- 0.39 from 3.84 +/- 0.13 of control, with an enhancement of mitochondrial phosphorylative activity 6 hr after hepatectomy, and then decreased to normal levels within 24 hr. Adenylate energy charge, (ATP + 1/2ADP)/(ATP + ADP + AMP), of the remnant liver decreased to 0.825 +/- 0.006 as compared to 0.849 +/- 0.002 of control 6 hr after operation. At 12 hr, total ketone body concentrations of the arterial blood increased concomitant with a fall in ketone body ratio (acetoacetate/3-hydroxybutyrate) which reflects the decreased liver mitochondrial redox (NAD+/NADH) state. These findings suggest that an enhancement of mitochondrial fatty acid oxidation and ketogenesis occurs concomitant with an enhancement of mitochondrial phosphorylative activity in the remnant liver in response to a decreased energy charge after 70% hepatectomy.  相似文献   
68.
Using high resolution ultrasonography (US), diagnostic accuracy of thrombi in each venous segment of lower limbs and qualitative evaluation of thrombi in deep vein thrombosis (DVT) were investigated. The subjects were 106 lower limbs in 81 patients. The thrombi in common femoral vein (CFV), were diagnosed by compression technique and, were qualitatively analysed by echogenicity and consistency. Venography was performed in 18 limbs and histologic tests of thrombi were made in 6 limbs. The total accuracy of US was 100% for diagnosis of DVT, but was 83% for diagnosis of its extent. The total accuracy of US in each segment was greater than 90%, but the sensitivity of iliac veins was less than 90%. The thrombi in CFV were divided into 3 types and 8 sub-types. Type A was homogenous, type B was heterogenous, and type C was contracted echo. The types of us were consistent with results of histologic tests. We concluded that high resolution US is available for screening test for diagnosis of DVT and that qualitative evaluation of thrombi by US is a useful clinical test for selection of more adequate treatments.  相似文献   
69.
Binding profile of SM-9018, a novel antipsychotic candidate   总被引:3,自引:0,他引:3  
The present study employed various receptor-binding assays to clarify the biochemical characteristics of SM-9018. SM-9018 possessed very high affinity for 5-HT2, D2 and 5-HT1A receptors (Ki = 0.61, 1.4 and 2.9 nM, respectively), and it had moderate affinity for alpha 1 and D1 receptors (Ki = 17 and 41 nM, respectively). However, SM-9018 had only negligible affinity for alpha 2, opiate, glutamate, phencyclidine, benzodiazepine and GABAA receptors. These results suggest that SM-9018 may be a novel antipsychotic agent with binding affinity for 5-HT2 and 5-HT1A receptors.  相似文献   
70.
A foregut cyst is formed as a result of abnormal budding and pinching of the tracheobronchial tree when bronchial buds develop to form the primitive respiratory tree. Foregut cysts are clinically classified as bronchogenic, esophageal, enterogastric, or ciliated hepatic. We present a foregut cyst that occurred in the retroperitoneum and was difficult to distinguish from other retroperitoneal cystic mass lesions. Magnetic resonance imaging was useful in revealing the cyst's continuity to adjacent organs. Received: 19 June 1995/Accepted: 23 July 1995  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