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   1022篇
  免费   55篇
  国内免费   20篇
耳鼻咽喉   43篇
儿科学   17篇
妇产科学   40篇
基础医学   85篇
口腔科学   47篇
临床医学   90篇
内科学   187篇
皮肤病学   11篇
神经病学   53篇
特种医学   40篇
外科学   236篇
综合类   61篇
一般理论   1篇
预防医学   47篇
眼科学   11篇
药学   47篇
肿瘤学   81篇
  2023年   9篇
  2022年   25篇
  2021年   41篇
  2020年   17篇
  2019年   30篇
  2018年   44篇
  2017年   39篇
  2016年   23篇
  2015年   32篇
  2014年   38篇
  2013年   49篇
  2012年   52篇
  2011年   90篇
  2010年   45篇
  2009年   56篇
  2008年   64篇
  2007年   76篇
  2006年   59篇
  2005年   56篇
  2004年   57篇
  2003年   53篇
  2002年   38篇
  2001年   9篇
  2000年   7篇
  1999年   10篇
  1998年   9篇
  1997年   8篇
  1996年   4篇
  1995年   3篇
  1994年   2篇
  1993年   2篇
  1992年   3篇
  1991年   4篇
  1990年   2篇
  1988年   7篇
  1987年   4篇
  1984年   2篇
  1983年   2篇
  1979年   1篇
  1977年   1篇
  1976年   3篇
  1975年   1篇
  1974年   1篇
  1972年   2篇
  1970年   2篇
  1969年   2篇
  1968年   2篇
  1967年   3篇
  1966年   2篇
  1965年   1篇
排序方式: 共有1097条查询结果,搜索用时 15 毫秒
71.
72.
73.
The purpose of our study was to systematically evaluate gastric acid output in children with long-lasting gastro-esophageal reflux (GER) in order to assess its mechanism and the need for anti-acid treatment. The investigation was carried out in 20 males and 10 females, aged 7.5 +/- 3.8 years, with prolonged (>15 months) clinical manifestations of GER. All underwent routine ambulatory 24-h esophageal pH-monitoring and measurement of gastric acid secretion including gastric basal (BAO) (micromol/kg/h), maximal (MAO) and peak acid outputs (PAO) after pentagastrin (6 microg/kg sec) stimulation. Children with heartburn or abdominal pain underwent upper fiber-endoscopy. In group A (moderate GER, n=12), patients had a normal reflux index (pH<4 below 5.2% of total recording time) despite abnormal Euler and Byrne scoring (median 57, 95% confidence interval 53.5-73.4). In group B (severe GER, n=18, among whom 5 were with grade III esophagitis), reflux index was >5.2%. When considering all children, esophageal pH (%) was significantly correlated with MAO and PAO, r=0.33, p=0.05 and r=0.37, p=0.04, respectively. Children of group B exhibited significantly higher BAO (75, 53.96-137.81), MAO (468, 394.1-671.3) and PAO (617, 518.8-782.3) than those of group A, BAO (27, 10.8-38.5), MAO (266, 243.2-348.2) and PAO (387, 322.5-452.7), p<0.05). The five children of group B with severe esophagitis exhibited significantly higher BAO, MAO and PAO than the other 13 children from the same group and those of group A, p<0.05. Children with long-lasting and severe GER hyper-secrete gastric acid. Individual variations in gastric acid secretion probably account for variations in gastric acid inhibitor requirements. Anti-secretory treatment is justified in children with long-lasting GER and high pH-metric reflux index.  相似文献   
74.
75.
OBJECTIVE: We conducted this retrospective study to determine accuracy of frozen section examination of endocervical margin during cold knife conization. METHODS: Between June 1993 and June 2001, 310 consecutive patients underwent cervical conization for squamous intraepithelial lesion or stage IA1 cervical cancer. Before 1997, the surgical specimens of 149 patients were processed following a standard pathological procedure (historical group). After 1997, a frozen section of the upper endocervical margin was processed during surgery for 161 patients. If the upper endocervical margin was involved with intraepithelial neoplasia, the surgeon performed a second resection if possible. Results of the frozen section examination were compared with the final diagnoses to determine sensitivity, specificity, and positive and negative predictive values. The usefulness of this procedure was evaluated by comparison of positive margin status rate with the one of the historical control group. RESULTS: For the diagnosis of intraepithelial neoplasia involving the endocervical margin, the sensitivity, specificity, and positive and negative predictive values of frozen section were 91%, 100%, 100%, and 98%, respectively. Eleven patients had definitive positive endocervical margin in the frozen section group (three false negatives, six patients without additional resection, and two patients with intraepithelial neoplasia involving the upper margin of the additional resection) and 17 patients in the historical group (P =.16). CONCLUSION: Frozen section examination of the endocervical margin of cervical specimen obtained during cold knife conization is highly accurate. Its clinical relevance has to be demonstrated in a multicenter study.  相似文献   
76.
Objective: We hypothesized that among neonates with necrotizing entercolitis (NEC), important epidemiologic and outcome differences exist between those with early-onset vs. those with late-onset NEC.Methods : We reviewed all records of neonates cared for in the King Fahad University Hospital during the past ten years who had the diagnosis of NEC. We separated cases into two groups depending on age at diagnosis. Specifically, we termed “early-onset” those cases diagnosed during the first seven days of life, and “late-onset” those diagnosed thereafter. We compared, in the two groups, gestational age, clinical signs at onset, laboratory data, surgical findings, complications, and mortality.Results: From 1989 to 1999, 37 cases of stage lla (or higher) NEC were diagnosed; 25 “early-onset “ and 12 “late-onset”. Neonates with “earlyonset” NEC were more mature (35.4 ±2.5 weeks gestation) than those with “late-onset” (27.7 ±2.8 weeks, P = 0.0001), were more likely to have feedings begun in the first 48 hours of life (P = 0.0002), and more likely to have feeding increments of >25 ml/kg/day (P=0.03). Neonates with “late-onset” NEC were more likely to present with vomiting (P=0.003) and apnea (P=0.001), and were more likely to have ileal rather than colonic necrotic lesions, short bowel syndrome, and mortality (P = 0.03).Conclusion: During the past 10 years at the King Fahad University Hospital, cases of early and late-onset NEC have had distinct epidemiologic and outcome features. Recognizing these differences may be useful in prognostication and counseling  相似文献   
77.
Central venous access is important in both assessment and treatment of the patient. In modern clinical practice, a percutaneous approach is preferred. The well-established subclavian and internal jugular vein catheterization techniques, however, still carry the risk of major acute complications. In this article we describe a trial study of a percutaneous brachiocephalic vein catheterization technique conducted on a total of 74 cadavers undergoing autopsy. Relying on constant and easily recognizable anatomical landmarks, we performed a total of 128 catheterizations of the right and left brachiocephalic veins. The success of catheterization was ascertained by regional dissection. Our results show very high reproducibility with a success rate of about 97% on the first attempt of catheterization on both right and left sides. Equally important, collateral injury of neighboring structures was consistently absent. We propose the introduction of this rather overlooked approach into clinical practice.  相似文献   
78.
BACKGROUND: Two-stage exchange arthroplasty remains the standard treatment of infection at the site of a total knee arthroplasty. The clinical and functional outcomes associated with the use of an articulating antibiotic spacer for two-stage revision for infection are not well established. We conducted a retrospective study to evaluate the outcomes associated with the use of the PROSTALAC articulating spacer between the first and second stages. METHODS: Fifty-eight patients underwent two-stage revision total knee arthroplasty for infection between January 1997 and December 1999. Of these, fifty-four were alive at the time of follow-up and forty-seven were available for inclusion in the present retrospective study. In all patients, a prosthesis of antibiotic-loaded acrylic cement (the PROSTALAC system) was implanted during the first stage after débridement. The amount of osteolysis that occurred between the stages and the range of motion of the knee joint were measured. After two years of follow-up, outcomes were assessed with use of the WOMAC, Oxford-12, and SF-12 instruments as well as a satisfaction questionnaire. RESULTS: At a minimum of two years (average, forty-one months) after revision arthroplasty, two patients (4%) had had a recurrence of infection. The amount of bone loss was unchanged between stages, and the range of movement of the knee improved from 78.2 degrees before the first stage to 87.1 degrees at two years. The average normalized WOMAC function and pain scores were 68.9 and 77.1, respectively; the average Oxford-12 score was 67.3; the average SF-12 mental and physical scores were 53.7 and 41.2, respectively; and the average satisfaction score was 71.7. CONCLUSION: A revision operation for infection at the site of a total knee replacement with use of an articulating spacer was associated with reasonable function and satisfaction scores. These findings may be related to the articulating features of the PROSTALAC system, which permits full active movement of the knee in the early postoperative period.  相似文献   
79.
THE CURRENT SITUATION: Preeclampsia is associated with increased risk of adverse maternal (abruptio placentae, HELLP syndrome, eclampsia.) and perinatal death. Its prevention, therefore, is of particular importance. The latter must be determined together with the group of women who would benefit from it. THE INTEREST OF ASPIRIN: The best studied preventive treatment is low dose aspirin. The various studies on low-dose aspirin have confirmed its safety in pregnant women. These studies, in small cohorts of selected patients at risk or in large series of women with moderate risk, show that the use of aspirin is associated with a 15% reduction in the risk of preeclampsia. OTHER THAN ASPIRIN: Other preventive treatments, such as calcium have not demonstrated their efficacy, or their effect requires confirmation, such as with anti-oxidants or low molecular weight heparin. IN PRACTICE: The prevention of preeclampsia currently relies on low-dose aspirin started at the beginning of pregnancy. The moderate benefit of such prevention justifies its administration in patients at high risk, selected on their obstetrical past history.  相似文献   
80.
Several fused triazolo and ditriazoloquinoxaline derivatives such as 1-aryl-4-chloro-[1,2,4]triazolo[4,3-a]quinoxalines (3a-d), 4-alkoxy[1,2,4]triazolo[4,3-a]quinoxalines (4a,b), 4-substituted-amino-[1,2,4] triazolo[4,3-a]quinoxalines (5a-h), 1-(aryl)-[1,2,4]triazolo[4,3-a]quinoxalin-4(5H)-thione (6), 4-(arylidenehydrazino)1-phenyl-[1,2,4]triazolo[4,3-a]quinoxalines (10a-e) and [1,2,4]ditriazolo[4,3-a:3',4'-c]quinoxaline derivatives (11-13) have been synthesized and some of these derivatives were evaluated for antimicrobial and antifungal activity in vitro. It was found that compounds 3a and 9b possess potent antibacterial activity compared to the standard tetracycline.  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