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   30412篇
  免费   1498篇
  国内免费   191篇
耳鼻咽喉   427篇
儿科学   532篇
妇产科学   546篇
基础医学   3881篇
口腔科学   744篇
临床医学   2103篇
内科学   8237篇
皮肤病学   527篇
神经病学   2459篇
特种医学   957篇
外科学   4965篇
综合类   122篇
一般理论   2篇
预防医学   1152篇
眼科学   434篇
药学   1924篇
中国医学   46篇
肿瘤学   3043篇
  2022年   241篇
  2021年   521篇
  2020年   291篇
  2019年   359篇
  2018年   513篇
  2017年   414篇
  2016年   493篇
  2015年   523篇
  2014年   706篇
  2013年   899篇
  2012年   1435篇
  2011年   1559篇
  2010年   867篇
  2009年   794篇
  2008年   1443篇
  2007年   1583篇
  2006年   1535篇
  2005年   1459篇
  2004年   1492篇
  2003年   1475篇
  2002年   1501篇
  2001年   984篇
  2000年   982篇
  1999年   870篇
  1998年   407篇
  1997年   314篇
  1996年   295篇
  1995年   275篇
  1994年   236篇
  1993年   200篇
  1992年   642篇
  1991年   669篇
  1990年   571篇
  1989年   577篇
  1988年   556篇
  1987年   510篇
  1986年   448篇
  1985年   451篇
  1984年   335篇
  1983年   253篇
  1982年   120篇
  1979年   247篇
  1978年   139篇
  1977年   145篇
  1974年   133篇
  1973年   127篇
  1972年   144篇
  1971年   128篇
  1969年   138篇
  1967年   129篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
31.
Hyperlipidemia, hypertension, and diabetes mellitus (DM) are well-established risk factors for cardiovascular disease. We analyzed the cardiovascular events in hyperlipidemic patients with or without DM who were administered open-labeled simvastatin in groups stratified by blood pressure level using data from the Japan Lipid Intervention Trial (J-LIT). Hyperlipidemic patients with DM (n=6,288) had significantly more cardiovascular events than those without DM (n=33,933). The incidence rates of total cardiovascular events in the Non-DM and DM groups were 15.40 and 25.76 per 1,000 patients for the 6-year period, respectively. The relative risk of total cardiovascular events in the DM vs. the Non-DM group was 1.68, and the relative risk was significantly higher in the DM than in the Non-DM group. The relative risks of total cardiovascular events were significantly higher in DM and Non-DM patients whose systolic blood pressure (SBP) was greater than or equal to 130 mmHg compared to that of Non-DM patients whose SBP was less than 130 mmHg, and in DM and Non-DM patients whose diastolic blood pressure (DBP) was greater than or equal to 80 mmHg compared to that of Non-DM patients whose DBP was less than 80 mmHg. In all groups stratified by SBP and DBP, relative risks of total cardiovascular events were higher in DM patients than in Non-DM patients. For patients with hypercholesterolemia and DM, blood pressure should be strictly controlled in order to prevent both coronary events and stroke. These results are in good agreement with the JNC 7 and the ESH/ESC guidelines for DM patients, which recommended that the SBP and DBP be less than 130 and 80 mmHg, respectively.  相似文献   
32.
33.
PURPOSE: To determine the effect of an interposition nerve graft on sexual function after radical prostatectomy. METHODS: This study includes 64 patients, without hormonal therapy, who underwent a radical prostatectomy and intraoperative electrophysiological confirmation of cavernous nerve preservation. Twelve patients underwent a unilateral interposition sural nerve graft (UNG) for the resected neurovascular bundle. Twenty-one and 31 patients underwent bilateral nerve-sparing (BNS) and unilateral nerve-sparing (UNS) surgery without a nerve graft, respectively. As the age of patients was significantly younger in the UNG group than in the other groups, age-matched analysis also was conducted. Sexual function, evaluated by a self-administered questionnaire using the University of California Los Angeles-Prostate Cancer Index, was compared statistically among the three groups. RESULTS: In the age-matched analysis, the postoperative sexual function (SXF) score of the UNG group showed an intermediate level of recovery between those of the BNS and UNS groups at 12 months and reached the same level as the score at 12 months of the BNS group at 18 months postoperatively. The difference in the SXF score between the UNG and UNS groups began to appear after 6 months postoperatively and increased steadily with time. However, the background factors, such as the baseline SXF score, the usage rate of phosphodiesterase 5 inhibitors, and the rate of comorbidities were different between the UNG and UNS groups. CONCLUSIONS: The difference of the SXF score between the UNG and UNS groups increased with time after 6 months postoperatively. However, it might be difficult at present to attribute a better recovery of the SXF score to the nerve graft because of the difference in the background factors between the groups.  相似文献   
34.
Abstract:   A 66-year-old man was referred to our hospital with chest discomfort and shortness of breath. Seven months previously he had undergone a laparoscopic left nephroureterectomy for a left renal pelvic tumor and was given two cycles of adjuvant chemotherapy (methotrexate, epirubicin and cisplatin). Echocardiogram showed an 8-mm sized mass extending from the right atrium into the right ventricle. On computed tomography, multiple lung tumors, as well as the right atrial and ventricular mass, were seen. The patient died of acute heart failure caused by right ventricular outflow obstruction. On autopsy, a right atrial and ventricular metastasis of the initial transitional cell carcinoma was found. The patient's cause of death was acute heart failure as a result of cardiac metastasis of his initial renal pelvic carcinoma.  相似文献   
35.
Some reports have been written about hypokalemic periodic paralysis dealing with cardiac dysfunction and arrhythmia during the paralytic attack. However, no reports have been written about the cardiac function during the attack in cases of normokalemic periodic paralysis. So, we investigated cardiac function in two patients with normokalemic periodic paralysis. A 3.0 g dose of KCl was administered orally to the patients (1 male, 1 female) and 10 healthy volunteers (5 males, 5 females). Cardiac function by using ejection time (ET)/pre-ejection period (PEP), grasping power, and the level of plasma catecholamine were measured during the paralytic attack. Changes in the patients were compared with those in the volunteers. Next, a 3.0 g dose of KCl was administered to the patient, followed by intravenous dosing of 10% NaCl (50 ml) after which ET/PEP and grasping power measured. Lastly, a 60 mg dose of diltiazem, a 10 mg dose of nifedipine or a 80 mg dose of verapamil were administered, followed by a 3.0 g dose of KCl after which ET/PEP and grasping power were measured again. Thirty minutes after the administration of KCl, the grasping power decreased remarkably, from 32.0 kg to 17.0 kg in the male patient and from 30.0 kg to 20.0 kg in the female patient. By contrast, the ET/PEP showed a clear increase, from 3.47 to 6.17 in the male patient and from 2.84 to 5.45 in the female patient. Grasping power of the volunteers, however, did not change remarkably (avg. 40.3 kg before vs. 40.9 kg after in the males and avg. 26.9 kg before vs. 26.0 kg after in the females) and ET/PEP of the volunteers did not change remarkably (avg. 3.37 before vs. 3.17 after in the males and avg. 3.30 before vs. 3.43 after in the females). No significant changes were found in the levels of plasma catecholamine during the paralytic attack.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
36.
Effects of adrenergic alpha-1-blocking agent, prazosin, in the treatment of detrusor external-sphincter dyssynergia (DSD) were evaluated in both experimental and clinical aspects. Experimentally, in the urethral pressure profile in dogs, the maximum urethral closing pressure was depressed after intravenous injection of 1 mg prazosin. When experimental DSD was obtained in dogs by stimulating electrically the unilateral 2nd sacral root, intra-venous injection of 1 mg prazosin inhibited contraction of the external urethral sphincter. Clinically, 74 patients with DSD based on neurogenic bladder from cerebral vascular attack (CVA) (13 cases) and spinal cord injury (61 cases) were retrospectively surveyed in terms of therapeutical effects of prazosin for DSD. Spinal cord injury was subdivided to 4 groups for clinical evaluation; cervical cord injury (C) with complete paralysis, thoracic cord injury (Th) with complete paralysis, lumbar cord injury (L) with complete paralysis and spinal cord injury with incomplete paralysis. Patients with CVA and spinal cord injury with incomplete paralysis showed good response rates in subjective improvement, 69% and 60% respectively. However, those with spinal cord injury with complete paralysis showed a poor response (28% for C, 23% for Th and 14% for L). The amount of residual urine significantly decreased after treatment, in all the groups except that of lumbar cord injury with complete paralysis. In all the groups, however, even after the drug treatment the amount of residual urine ranged from 80 to 170 ml and the rates of needing clean intermittent catheterization unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
37.
Vasopressin, a hormone secreted from the posterior lobe of the hypophysis, has endocrinological and antidiuretic effects; it contracts vessels and smooth muscles, especially intestinal smooth muscle. In the present study, we investigated the role of vasopressin (Pitressin: arginine-vasopressin) in elimination of intestinal gas on excretory urography reading. Sixty outpatients were randomly divided into six groups. In Group I, the routine procedure was employed, i.e. laxatives the previous night and NPO the morning of the examination. In Groups II to VI, different dose regimens were employed: 6 or 10 units of Pitressin was administered by subcutaneous injection 30 minutes prior to injection of a contrast medium, with or without NPO. Intestinal gas elimination was evaluated by X-ray films taken before and after injection of Pitressin. The efficacy was rated by four grades. There were no significant differences in the gas elimination or occurrence of side effects between any two groups. Younger patients seemed to respond quickly to Pitressin and good effects were obtained. These results indicate that the pretreatment for excretory urography with 6 units of Pitressin without NPO may be a safe and effective alternative method for elimination of intestinal gas, in particular for young patients.  相似文献   
38.
Four of 82 patients with Guillain-Barré syndrome (GBS) and 1 of 12 with multifocal motor neuropathy (MMN), who previously had had Mycoplasma pneumoniae infections, had serum antibody to galactocerebroside (Gal-C). Two patients with GBS without mycoplasma infection also had anti-Gal-C antibody, whereas none of the normal or the disease controls had it. As Gal-C is a major glycolipid antigen in myelin, anti-Gal-C antibody may function in the pathogenesis of autoimmune demyelinative neuropathies. Mycoplasma pneumoniae appears to be an important preceding infectious agent in autoimmune neuropathies with anti-Gal-C antibody. © 1995 John Wiley & Sons, Inc.  相似文献   
39.
Activation of an endogenous opioid system has been associated with an elevation in pain threshold during late pregnancy and the early postpartum period in rats. It is well established that endogenous opiates are involved in the physiological regulation on prolactin secretion. This study examined the influence of lactation on pregnancy-induced analgesia during the early postpartum period in rats. Three tests (colorectal distension, tail-flick and hot-plate) were used to assess each animal's response to painful stimuli. After determining pregnant baseline values, one group of rats (lactating, n = 21) were mated and retested on Day 7 and 21 of gestation and 1, 3, 5, 7 and 14 days after parturition. A non-lactating group of animals (n = 14) whose pups were removed immediately after delivery was tested in the same manner. On Day 21 of gestation significantly higher thresholds and longer latencies were observed. On Day 1 and 3 in both lactating and non-lactating rats, the values were still elevated. No significant difference was observed during the early postpartum period between the two groups. This study confirms the existence, in rats, of pregnancy-induced analgesia late in pregnancy and the early postpartum period. The analgesia during the early postpartum period is not influenced by lactation.  相似文献   
40.
N Ogawa  Y H Sora  M Saito  T Shimazu 《Brain research》1988,451(1-2):115-118
The effects of hypothalamic hormones and electrolytic lesioning of the ventromedial hypothalamic nuclei (VMH) on histidyl-proline diketopiperazine (cyclo(His-Pro] binding in the rat liver were studied. VMH-lesioning markedly decreased cyclo(His-Pro) binding in the liver. Scatchard analysis revealed that the loss of cyclo(His-Pro) binding induced by VMH lesioning was due to a decrease in the number and affinity of binding sites. Somatostatin (SS) administration decreased cyclo(His-Pro) binding. The SS-induced changes in cyclo(His-Pro) binding were due to changes in the binding affinity. On the other hand, the administration of TRH or LH-RH did not affect cyclo(His-Pro) binding in the liver, although cyclo(His-Pro) has been proposed to be a metabolite of TRH. These findings suggest that the hypothalamus may regulate the cyclo(His-Pro) binding sites in the liver probably by controlling pancreatic SS secretion, since a VMH-lesion is reported to cause hypersecretion of pancreatic SS.  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