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   10738篇
  免费   491篇
  国内免费   28篇
耳鼻咽喉   159篇
儿科学   138篇
妇产科学   138篇
基础医学   1493篇
口腔科学   412篇
临床医学   710篇
内科学   2525篇
皮肤病学   137篇
神经病学   744篇
特种医学   622篇
外科学   1667篇
综合类   61篇
一般理论   1篇
预防医学   395篇
眼科学   264篇
药学   725篇
中国医学   20篇
肿瘤学   1046篇
  2023年   59篇
  2022年   121篇
  2021年   207篇
  2020年   107篇
  2019年   127篇
  2018年   158篇
  2017年   126篇
  2016年   167篇
  2015年   187篇
  2014年   235篇
  2013年   269篇
  2012年   463篇
  2011年   503篇
  2010年   261篇
  2009年   260篇
  2008年   412篇
  2007年   468篇
  2006年   457篇
  2005年   428篇
  2004年   447篇
  2003年   485篇
  2002年   462篇
  2001年   414篇
  2000年   465篇
  1999年   413篇
  1998年   136篇
  1997年   121篇
  1996年   95篇
  1995年   82篇
  1994年   81篇
  1993年   85篇
  1992年   322篇
  1991年   295篇
  1990年   255篇
  1989年   233篇
  1988年   230篇
  1987年   210篇
  1986年   179篇
  1985年   161篇
  1984年   127篇
  1983年   111篇
  1979年   66篇
  1978年   51篇
  1977年   53篇
  1975年   61篇
  1973年   48篇
  1972年   57篇
  1971年   47篇
  1968年   60篇
  1967年   64篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
An elderly case of idiopathic retroperitoneal fibrosis (IRPF) with bilateral ureteral obstruction was reported. A 74-year-old man was admitted with complaints of general fatigue and loss of appetite. An elastic hard mass with a smooth surface was palpated in the left upper quadrant of the abdomen. Abnormal ESR and CRP were noticed. Abdominal ultrasonography showed both a homoechoic mass which surrounded the aorta in the retroperitoneal space and bilateral hydronephrosis. Computed tomography revealed a retroperitoneal mass involving bilateral ureters. Magnetic resonance imaging demonstrated a mass with a sharp image and signal intensity. Furthermore the morphological relationship between the mass and the ureters and major vessels clearly indicated the characteristics of benign retroperitoneal fibrosis. Based upon the above findings, a diagnosis of IRPF was made. After confirming the histological diagnosis by biopsy, treatment consisting of bilateral ureterolysis, intra-abdominal transposition of ureters and oral administration of prednisolone was performed, resulting in a normalization of laboratory findings. Analysis of 86 previously cases of IRPF reported up to 1990 in Japan, revealed the peak age to be in the 7th decade with predominance in males (males: females = 57:29).  相似文献   
22.
Tumors in the area of the adrenal were detected by chance in two patients who underwent a regular physical check-up. On arteriography the tumors were found to be fed by the adrenal artery. The diagnosis was retroperitoneal schwannoma, but in both patients it was difficult to differentiate the schwannoma from an adrenal tumor preoperatively.  相似文献   
23.
A biventricular bypass type total artificial heart (BVB-TAH) utilizing two pusher-plate pumps was developed and implanted in a sheep for 48 days with excellent results. A Hall effect sensor was utilized to operate each pump independently with a full stroke at variable rates (VR). With this system, the animal's hemodynamics was kept physiologically, and all metabolic parameters except hemoglobin and hematocrit returned to normal three weeks after implantation. However, signs of infection appeared on the forty-second day, and consequently the animal fell into a state of shock. Even at that time the BVB-TAH maintained circulation by increasing pumping rate automatically. On the forty-eighth day, the animal could not stand and suffered from anuria; the experiment was then terminated after 1,140 h pumping. At autopsy, there was an enlarged heart with an atrophic change, 1,900 ml of pleural effusion, and 3,100ml of ascites fluid. Blood culture taken on the forty-seventh day yielded Acinetobacter calcoaceticus. The BVB-TAH operated in an independent VR mode maintained entire circulation, and has a capability of substituting the native heart function in any situation.  相似文献   
24.
25.
To examine the myocardial contractile response of the diabetic heart, effects of isoproterenol (ISO) and norepinephrine (NE) on perfused hearts isolated from streptozotocin (STZ)-induced diabetic rats and insulin-treated diabetic rats were evaluated. Male Sprague-Dawley rats, weighing 200-260 g, were divided into the control (C)-group, diabetes mellitus (DM)-group and diabetes mellitus treated with insulin (DMI)-group. The C group was injected with buffered vehicle. DM and DMI groups were injected intravenously with 60 mg/kg STZ on the first day. Three days after STZ injection, the DMI group was subsequently treated with 4 U of Lente insulin subcutaneously every day. At 45 days after injection of STZ, experiments were performed using a Langendorff perfused heart preparation. The heart was paced at 300 beats/min, and myocardial developed tension (T) was measured isometrically. Plasma glucose values (mg/dl) were 142.4 +/- 8.7 in C, 499.3 +/- 15.6 in DM and 370.6 +/- 27.6 in DMI group. The order of percent increase in T induced by ISO (3 X 10(-9) - 3 X 10(-8) g) was C = DMI much greater than DM, and that by NE (10(-7) - 10(-6) g) was C greater than DMI greater than DM. On the other hand, the percent increase in T induced by CaCl2 (1.1 X 10(-4) - 2.2 X 10(-3) g) and aminophylline (AMI, 0.31 X 10(-3) - 5.00 X 10(-3) g) was not significantly different among three groups. These results indicate that adrenergic receptor-mediated contractile response was significantly depressed in the diabetic heart.  相似文献   
26.
This study was designed to determine the influence of ileal pouch capacity and anal sphincteric function on the clinical outcome after ileal pouch-anal anastomosis. A total of 24 patients who had undergone ileal pouch-anal anastomosis (J pouch) for ulcerative colitis were studied. The 24-hour stool frequency was found to be inversely correlated with the sensitivity threshold volume (STV), maximal tolerance volume (MTV), and distensibility, but was independent of the maximal resting pressure and maximal squeeze pressure. Patients experiencing nocturnal fecal incontinence had maximal resting pressures that were significantly lower than those of nocturnally continent patients. Among the patients with fecal incontinence, those with frequent soiling had lower resting pressures, STV, and distensibility than the patients with intermittent spotting. In addition, the STV in patients needing nocturnal evacuation were lower than those of patients who did not evacuate after falling asleep. The conclusions are as follows. Both stool frequency and the need for nocturnal pouch evacuation correlated directly with pouch volume. Anal incontinence was more common in patients with low internal sphincteric function. In addition, frequent and gross nocturnal incontinent patients demonstrate a worse function in both the anal sphincter and reservoir than those with intermittent spotting.  相似文献   
27.
A rare case of a 25-year-old man with pulmonary aspergillosis is reported. Pulmonary bulla and eosinophilic pneumonia in the right upper lobe were diagnosed by chest roentgenogram and transbronchial lung biopsy. Because the patient developed infective bullae during steroid therapy, we performed transcutaneous thoracic drainage and right upper lobectomy. The resected lung tissue contained numerous hyphae of Aspergillus. Around the hyphae of Aspergillus, granulomatous reaction and eosinophilic infiltration were observed. Antibodies against Aspergillus were detected in the serum of the patient. The number of peripheral blood eosinophils decreased after right upper lobectomy. These findings suggest that pulmonary bullae and eosinophilic pneumonia may be a rare manifestation of pulmonary aspergillosis.  相似文献   
28.
The small intestinal disaccharidase activity and its daily variation in the diabetic rat have not been well described. Therefore, the small intestinal disaccharidase (maltase, lactase and sucrase) activity and its daily profile were studied in streptozotocin-induced diabetic rats under physiological conditions. In diabetic rats, a similar pattern of diurnal variation of disaccharidase activity to control rats was observed, while the relationships between daily change of disaccharidase activity and that of food consumption suggested that there was a different mechanism of diurnal variation in diabetic rats. On the other hand, a significant increase of mean 24-h lactase and sucrase activities was noted in diabetic rats, while that of maltase was not significant. Using the in vitro incubation method, a significant correlation between glucose concentration and lactase or sucrase activity but not maltase activity was observed. However, insulin showed no effect on disaccharidase activity. Thus we clarified the presence of a diurnal variation of disaccharidase activity and an increase in its activity in diabetic rats. This change was suggested to be derived from high plasma glucose level.  相似文献   
29.
Anterior communicating artery aneurysm was shown in a 48-year-old man who had suffered from subarachnoid hemorrhage (SAH) by cerebral angiography. Right pterional approach was performed on the 40th day after SAH. Premature ruptured occurred during aneurysmal manipulation and temporary clip (Scoville clip) was placed at the middle of the right A1 segment for fifteen minutes. the anterior communicating artery aneurysm was successfully clipped and postoperative course was uneventful. But, four days after the operation, the patient fell into coma following generalized tonic convulsion. Lumbar puncture showed fresh SAH. Consciousness recovered gradually to a lethargic state. A newly formed berry aneurysm was revealed on the righ A1 segment at the site of the temporary clip application by cerebral angiography performed on the seventh day after aneurysmal surgery. Second attack occurred on the 12th postoperative day and the patient died on the 16th day after the operation. Postmortem findings disclosed massive subarachnoid and intraventricular hemorrhage from the ruptured aneurysm at the right A1 segment. Microscopic examination of the aneurysm and the right A1 segment. microscopic examination of the aneurysm and the right A1 segment showed the extensive destruction of the artery and massive proliferation of aspergillus in the arterial wall which was prominent of its outer layer. The mechanism of the formation of the new aneurysm in this case was considered as follows: the arterial wall was primarily damaged by the temporary clip and was weakened rapidly by the invasion of aspergillus, probably producing thrombosis of the vast vasorum, hemorrhage, and necrosis in it.  相似文献   
30.
A 77-year-old woman with Stanford type A acute aortic dissecting aneurysm was successfully treated by the sutureless technique using arringed intraluminal graft. A month after the operation, re-dissection to the distal abdominal aorta occurred. Because of the poor condition of the patient and her great age, we chose an antihypertensive therapy instead of a reoperation. Two years after the operation this patient leads a sound life without any symptoms. In a case of acute aortic dissection of the aged, special consideration may be allowed to a surgical method and a decision-making for a reoperation.  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