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   9408篇
  免费   587篇
  国内免费   50篇
耳鼻咽喉   69篇
儿科学   171篇
妇产科学   130篇
基础医学   1052篇
口腔科学   197篇
临床医学   753篇
内科学   2282篇
皮肤病学   237篇
神经病学   422篇
特种医学   511篇
外科学   2081篇
综合类   150篇
现状与发展   30篇
预防医学   359篇
眼科学   120篇
药学   459篇
中国医学   20篇
肿瘤学   1002篇
  2023年   229篇
  2022年   95篇
  2021年   149篇
  2020年   127篇
  2019年   115篇
  2018年   168篇
  2017年   169篇
  2016年   163篇
  2015年   202篇
  2014年   257篇
  2013年   239篇
  2012年   335篇
  2011年   383篇
  2010年   289篇
  2009年   254篇
  2008年   371篇
  2007年   444篇
  2006年   382篇
  2005年   392篇
  2004年   385篇
  2003年   365篇
  2002年   354篇
  2001年   353篇
  2000年   362篇
  1999年   344篇
  1998年   158篇
  1997年   138篇
  1996年   129篇
  1995年   103篇
  1994年   71篇
  1993年   105篇
  1992年   214篇
  1991年   178篇
  1990年   178篇
  1989年   187篇
  1988年   165篇
  1987年   168篇
  1986年   143篇
  1985年   160篇
  1984年   105篇
  1983年   92篇
  1982年   50篇
  1979年   76篇
  1978年   60篇
  1977年   46篇
  1975年   47篇
  1974年   48篇
  1973年   47篇
  1971年   48篇
  1968年   44篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
The reductive retention of62Cu-PTSM was comparatively studied in the brain and Ehrlich ascites tumor cells by electron spin resonance spectrometry and nonradioactive Cu-PTSM. In the brain, only the mitochondrial fraction showed the ability to reduce Cu-PTSM, and the other subcellular fractions did not. In contrast, the cytosolic fraction of Ehrlich ascites tumor cells was the specific site of Cu-PTSM reduction. It was therefore considered that the retention of Cu-PTSM in the brain is closely related to mitochondrial reduction, most probably involving the mitochondrial electron transport system.  相似文献   
22.
A 48-year-old woman was admitted because of increased bloody sputum. Since she had had a history of repeated thrombotic episodes including venous thrombosis in the lower limbs (21 year old) and pulmonary emboli developing into pulmonary infarction (41 years old), the patient was treated with anti-coagulant therapy using Warfarin for 7 years. Warfarin was discontinued after admission and heparin was administered instead at a relatively low dose of 5,000 units daily, resulting in a considerable diminution of hemoptysis. Unfortunately however, it caused a relapse of active thrombosis associated not only with a significant increase of the product of fibrinolysis (FDP), LDH and GOT but with a concomitant decrease of the platelet count. Hematological examinations concerning coagulation and fibrinolysis remained within a normal range except for the serum concentration of antithrombin III (AT III) and its functional property with regard to the heparin cofactor, which were 8.8 mg/dl and 48%, respectively. Since the findings were consistent with congenital deficiency of AT III, some members of her family were also examined. The concentration of AT III and its activity in the patient's son and her daughter deteriorated in a similar manner, indicating that this was a definite case of congenital deficiency of AT III. The clinical manifestations of 87 cases with congenital AT III deficiency, belonging to 24 families reported in Japan were reviewed.  相似文献   
23.
Magnetic resonance cholangiopancreatography (MRCP) was performed in 35 patients to evaluate the feasibility of its use as a postsurgical imaging technique after resection of the pancreas. The surgical procedures performed were: pancreatoduodenectomy in 22 patients, segmental pancreatectomy in 1, distal pancreatectomy in 7, and pyroluspreserving pancreatoduodenectomy in 5. The pancreatic duct was shown in its entirety in 24 of the 35 patients (68.6%) and was partially visualized in 8 patients (22.9%), but the intrahepatic and extrahepatic bile ducts were visualized completely in all patients. Furthermore, MRCP was able to demonstrate lesions in 3 of 6 patients who had shown clinical evidence of recurrence. The visualization of the pancreatic and bile duct system was satisfactory despite anatomical changes brought about by resection of the pancreas. Thus, we conclude that MRCP is an appropriate follow-up screening test for patients with suspected abnormalities of the biliary and pancreatic duct system.  相似文献   
24.
The purpose of this study was to examine the effect of orthographic familiarity on free recall of Katakana words which were read aloud. Two experiments were conducted to compare Katakana items with Hiragana ones about recall performance in incidental learning paradigm, in which subjects were instructed to perform a reading aloud task. In Experiment I, an immediate recall test was used. Number of correct free recall for high imagery items was larger than low imagery ones. In Experiment II, 30-s delay was inserted between an orienting task and a recall test. The recall performance indicated the superiority of Hiragana items. This result showed that the higher orthographic familiarity of stimulus item was, the poorer performance of its recall. It was interpreted in terms of the effect of cognitive effort on recall.  相似文献   
25.
Defecography in multiple sclerosis patients with severe constipation   总被引:3,自引:0,他引:3  
Gill  KP; Chia  YW; Henry  MM; Shorvon  PJ 《Radiology》1994,191(2):553
  相似文献   
26.
27.
A 74-year-old man with combined valvular disease with a recent cerebral infarction was admitted. While undergoing thorough examination for valvular disease, absent right superior vena cava (RSVC) and persistent left superior vena cava (PLSVC) were recognized. Chest X-ray film suggested a right arch protrusion, and CT and venogram confirmed the diagnosis. During surgery, replacement of the mitral and aortic valves and annuloplasty of the tricuspid valve were performed. A blood draining cannula was inserted in retrograde fashion from the coronary sinus into the PLSVC, without any difficulties in the tricuspid valve repair. Due to bradycardic atrial fibrillation, we believed that it would be difficult to insert an endocardial electrode postoperatively, hence myocardial electrode was placed in the right ventricular wall. Absent RSVC combined with PLSVC is very rare, and a patient who underwent combined valve surgery with this rare anatomical abnormality is herein presented.  相似文献   
28.
The present study was designed to examine the selectivity of 3H-CGP-12177 (4-(3-t-butylamino-2-hydroxypropoxy)-[5,7-3H]benzimidazole-2-one hydrochloride) for beta 1- and beta 2-adrenergic receptors by the Scatchard and the displacement analysis. The plots of specific binding obtained from the Scatchard analysis using 3H-CGP12177 for the rat myocardium membrane were uniphasic when the non-specific binding was determined by the use of 10 microM I-propranolol, and the Kd and Bmax values were 408.53 +/- 67.20 pM and 12.27 +/- 0.83 fmoles/mg protein, respectively. On the other hand, two binding sites were observed in the displacement curve when I-metoprolol was used as a competitor. The existence of these two binding sites implied the selectivity of 3H-CGP12177 to beta-adrenoceptors because 3H-CGP12177 was 1.8-fold more selective towards beta 1-adrenoceptors than beta 2-adrenoceptors. In addition, these two binding sites could be regarded as beta 1- and beta 2-adrenergic receptors from the evaluation of the binding characteristics beta-adrenoceptors by the displacement analysis using beta-selective antagonists. Thus, 3H-CGP12177, a hydrophilic radioligand, was useful for the binding assay of beta-adrenoceptors in rat myocardial membranes.  相似文献   
29.
The effectiveness of Tc-99m bleomycin (BLM) and Tc(V)-99m DMSA are compared with that of Ga-67 citrate, which is currently the most widely used agent. In four patients with lipomatous tumors, the clinical significance of tumor imaging with each of these three agents is discussed and compared. Results indicate that both Tc-99m BLM and Tc(V)-99m DMSA are superior in detecting the extension or localization of liposarcomas.  相似文献   
30.
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