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   138143篇
  免费   5732篇
  国内免费   302篇
耳鼻咽喉   2147篇
儿科学   4553篇
妇产科学   3051篇
基础医学   18678篇
口腔科学   4532篇
临床医学   8415篇
内科学   33831篇
皮肤病学   4251篇
神经病学   10813篇
特种医学   3320篇
外国民族医学   1篇
外科学   17249篇
综合类   710篇
一般理论   39篇
预防医学   13387篇
眼科学   3178篇
药学   9514篇
中国医学   633篇
肿瘤学   5875篇
  2023年   873篇
  2022年   666篇
  2021年   2848篇
  2020年   1427篇
  2019年   3036篇
  2018年   5211篇
  2017年   3094篇
  2016年   2899篇
  2015年   3239篇
  2014年   3697篇
  2013年   5549篇
  2012年   9641篇
  2011年   10282篇
  2010年   5154篇
  2009年   3637篇
  2008年   8125篇
  2007年   8692篇
  2006年   8072篇
  2005年   8064篇
  2004年   7180篇
  2003年   6772篇
  2002年   6374篇
  2001年   4157篇
  2000年   4731篇
  1999年   3575篇
  1998年   613篇
  1997年   399篇
  1996年   398篇
  1995年   306篇
  1992年   1461篇
  1991年   1214篇
  1990年   1086篇
  1989年   916篇
  1988年   778篇
  1987年   764篇
  1986年   778篇
  1985年   665篇
  1984年   508篇
  1983年   392篇
  1979年   468篇
  1978年   294篇
  1975年   362篇
  1974年   441篇
  1973年   455篇
  1972年   395篇
  1971年   404篇
  1970年   404篇
  1969年   397篇
  1968年   386篇
  1967年   344篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
241.
The purpose of this study was to analyze the clinical aspects in 130 patients presenting periodic lateralized epileptiform discharges (PLEDs) in their EEG and to compare these results with those found in the literature. Etiology, neurologic deficit, seizure occurrence, and evolution were studied in each patient by historical review. The recordings were obtained on 8- or 16-channel EEGs with electrode placement according to the International 10-20 System. Recordings containing PLEDs were selected. PLEDs were defined as repetitive periodic, focal, or hemispheric epileptiform discharges (spikes, spike and waves, polyspikes, sharp waves) usually recurring every 1 to 2 seconds. The statistical study was carried out via the chi(2) test using the computer program SPSS. The main etiology found in this group of patients was stroke (61 of 130 patients). Other processes found were brain infections, tumors, hematomas, and several other entities grouped together as miscellaneous (anoxic encephalopathy, subarachnoid hemorrhage, craniocerebral trauma, Creutzfeldt-Jacob disease, migraine, multiple sclerosis, and aminophylline intoxication). Half of these patients (65 of 130) developed seizures, mostly partial motor seizures. No significant relation between etiology and seizures was found (chi(2) = 2.81, P = 0.4222). Seizures recurred in 14 of 130 patients during a follow-up of 14.5 months. PLEDs were not recorded in any EEG at the time of seizure recurrence. PLEDs constitute a distinctive but uncommon EEG phenomenon of repetitive, periodic, and stereotyped lateralized complexes. In agreement with the literature, PLEDs were associated with an acute process and occurred early during the course of the illness in all patients studied and were usually associated with structural lesions, with stroke being the main etiology. Traditionally, seizures occur with PLEDs but it is also accepted that they can exist in patients who never develop epileptic activity, either clinically or electrically, as demonstrated in 50% of the patients studied. No significant association between seizures and any etiology could be found. It was not demonstrated that the occurrence of seizures may influence the outcome in any way.  相似文献   
242.
The immunofluorescence cytofluorometric reactivity pattern of monoclonal antibody Bra55 (IgG1) elicited with a non-T, non-B ALL cell line (REH), with a panel of human neoplastic hemopoietic cell lines (including non-T, non-B, T and myeloid leukemia cell lines) and with isolated peripheral blood lymphocytes, monocytes and granulocytes from healthy donors corresponded to the previously described microscopic immunofluorescence, ELISA, immunoprecipitation and immunocytochemic data indicating that this monoclonal antibody recognizes a 170-220 kDa cell surface glycoprotein (leukocyte common antigen) expressed selectively on hemopoietic cells. The purified, FITC-conjugated Bra55 monoclonal antibody was effectively inhibited in its binding to the surface of LCA-positive cells by reference anti-LCA monoclonal antibodies; no inhibition of this activity by LCA-unrelated monoclonal antibodies (such as anti-MHC class I and class II antibodies) was observed. These data confirm the previously reported hemopoietic cell specificity (anti-LCA, CD45) of the Bra55 monoclonal antibody.  相似文献   
243.
Antiepileptic drugs in schizophrenia: a review.   总被引:2,自引:0,他引:2  
The first choice group of psychotropic agents in schizophrenia is neuroleptics. However, this treatment is not effective in all patients and with every symptom. We summarize papers published on the role of antiepileptic drugs in treatment-resistant schizophrenia. We have searched the computer database system MEDLINE for relevant articles including reviews, reports of drug studies and case histories. Antiepileptic drugs can change symptoms of schizophrenia by their action on GABA-ergic neurotransmission or via anti-glutamatergic mechanisms. High doses of adjunctive benzodiazepines reduce positive symptoms, anxiety, and agitation. Carbamazepine is effective in affective symptoms of schizophrenia and influences violent behavior in psychotic patients. Its anti-kindling action may represent a promising treatment strategy for some patients with chronic course of schizophrenia. Valproate treatment leads to a decrease in positive symptoms as well as hostility. Lamotrigine is expected to influence the positive, negative, affective, and cognitive symptoms of schizophrenia. New antiepileptics (e.g., gabapentin, oxcarbazepine, topiramate, vigabatrin) present a promise as potential adjuncts to neuroleptic treatment in resistant symptoms of schizophrenia.  相似文献   
244.
245.
We report the results of a prospective and randomized trial designed to study the incidence of abdominal and pulmonary complications in gallstone surgery comparing subcostal (SI) with midline incision. The need for postoperative analgesia was lower in the SI group. There was no difference in the degree of hypoxaemia in the first two postoperative days, but there was less impairment of pulmonary function in terms of vital capacity and forced expiratory volume in 1 s (P less than 0.0001) in the SI group. SI patients also had a lower incidence of pulmonary or abdominal complications but the difference was not significant. Finally, we found a reduced hospital stay for the SI patients (P less than 0.01), probably related to a reduced postoperative analgesic requirement and an improved pulmonary function. We conclude that subcostal incision is a better approach for biliary tract surgery and should be used whenever possible.  相似文献   
246.
A group of 54 patients with the original diagnosis of polycythemia vera were subjected to cytogenetic examination. Six (17.6%) of the 34 cases examined in the period of the advanced phase of the polycythemia vera had a chromosomal change. Thirteen (65%) of the 20 patients undergoing the cytogenetic examination in the period when the polycythemia vera turned into another myeloproliferative disease showed chromosomal aberration. This suggests a relationship between the number of chromosomal changes and the transformation of the disease. No connection between the cytogenetic changes and myelosuppressive cures could be confirmed in our material. The chromosomal change 20q- considered to be the most frequent kind in the polycythemia vera was not discovered until in patients with the polycythemia vera transformed into a different myeloproliferative disease.  相似文献   
247.
The autolyzed antigen-extracted allogeneic (AAA) bone implant was placed into a 17-mm long diaphyseal periosteum-free defect in the radius in 27 rabbits. The animals were observed physically and roentgenologically every week. The continuity of the radius was evaluated macroscopically and histologically. Maximum length of the follow-up period was 114 days. The AAA implants were progressively resorbed and replaced by the recipient's bone growing from fragments of radius, restoring the continuity of diaphysis. Osteoinductive activity of the implant was transferred across a tube of a polyamide vascular prosthesis. There were no appreciable histologic signs or immune of foreign-body reaction.  相似文献   
248.
249.
Pleural effusion in patients infected with the human immunodeficiency virus   总被引:1,自引:0,他引:1  
In order to analyze the etiology, cytological and biochemical characteristics, and outcome of pleural disease in patients infected with HIV, the medical records of 86 HIV-positive patients with pleural effusion were reviewed. Controls were 106 HIV-negative patients with parapneumonic or tuberculous effusion. Most HIV-positive patients were intravenous drug abusers (95.3%). Pleural effusions in HIV-positive patients were caused by infections in 76 (89.4%) cases. Parapneumonic effusion was diagnosed in 59 patients and tuberculous pleuritis in 15 patients.Staphylococcus aureus was the most frequently isolated bacteria. Parameters for differentiating complicated cases of parapneumonic exudate from uncomplicated cases, such as pleural fluid pH<7.20 (sensitivity 80% vs. 84.3%), pleural fluid glucose<35 mg/dl (sensitivity 45% vs. 56.25%) pleural fluid LDH > 1600 Ul/l (sensitivity 85% vs. 62.50%), showed similar sensitivity in HIV-positive and HIV-negative patients. Monocytes in pleural fluid were significantly decreased in tuberculous pleuritis in HIV-positive patients (506±425 vs. 1014±1196 monocytes/ml, p<0.05). No significant differences were detected in the outcome of HIV-positive and HIV-negative patients with pleural disease. It can be concluded that the pleural effusion was of predominantly infectious etiology in HIV-positive patients from populations with a high prevalence of intravenous drug abuse. Neither the biochemical parameters in pleural fluid nor the outcome differed significantly between HIV-positive and HIV-negative patients.  相似文献   
250.
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