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   1159篇
  免费   36篇
  国内免费   8篇
耳鼻咽喉   15篇
儿科学   11篇
妇产科学   53篇
基础医学   65篇
口腔科学   21篇
临床医学   96篇
内科学   348篇
皮肤病学   6篇
神经病学   75篇
特种医学   44篇
外科学   229篇
综合类   6篇
预防医学   33篇
眼科学   59篇
药学   87篇
肿瘤学   55篇
  2023年   4篇
  2022年   5篇
  2021年   32篇
  2020年   24篇
  2019年   39篇
  2018年   38篇
  2017年   32篇
  2016年   32篇
  2015年   25篇
  2014年   37篇
  2013年   58篇
  2012年   80篇
  2011年   85篇
  2010年   54篇
  2009年   66篇
  2008年   103篇
  2007年   102篇
  2006年   93篇
  2005年   79篇
  2004年   59篇
  2003年   43篇
  2002年   59篇
  2001年   6篇
  2000年   7篇
  1999年   4篇
  1998年   4篇
  1997年   7篇
  1996年   5篇
  1995年   6篇
  1994年   1篇
  1992年   1篇
  1991年   3篇
  1990年   1篇
  1983年   3篇
  1982年   1篇
  1981年   1篇
  1979年   3篇
  1969年   1篇
排序方式: 共有1203条查询结果,搜索用时 328 毫秒
61.
62.
BACKGROUND: Clinical tests used for the detection of meniscal tears in the knee do not present acceptable diagnostic sensitivity and specificity values. Diagnostic accuracy is improved by arthroscopic evaluation or magnetic resonance imaging studies. The objective of this study was to evaluate the diagnostic accuracy of a new dynamic clinical examination test for the detection of meniscal tears. METHODS: Two hundred and thirteen symptomatic patients with knee injuries who were examined clinically, had magnetic resonance imaging studies performed, and underwent arthroscopic surgery and 197 asymptomatic volunteers who were examined clinically and had magnetic resonance imaging studies done of their normal knees were included in this study. For clinical examination, the medial and lateral joint-line tenderness test, the McMurray test, the Apley compression and distraction test, the Thessaly test at 5 degrees of knee flexion, and the Thessaly test at 20 degrees of knee flexion were used. For all clinical tests, the sensitivity, specificity, false-positive, false-negative, and diagnostic accuracy rates were calculated and compared with the arthroscopic and magnetic resonance imaging data for the test subjects and the magnetic resonance imaging data for the control population. RESULTS: The Thessaly test at 20 degrees of knee flexion had a high diagnostic accuracy rate of 94% in the detection of tears of the medial meniscus and 96% in the detection of tears of the lateral meniscus, and it had a low rate of false-positive and false-negative recordings. Other traditional clinical examination tests, with the exception of joint-line tenderness, which presented a diagnostic accuracy rate of 89% in the detection of lateral meniscal tears, showed inferior rates. CONCLUSIONS: The Thessaly test at 20 degrees of knee flexion can be used effectively as a first-line clinical screening test for meniscal tears, reducing the need for and the cost of modern magnetic resonance imaging methods.  相似文献   
63.
Pruritus is the most common side effect of intrathecal morphine for postoperative pain relief. Activation of central 5-hydroxytryptamine subtype 3 (5-HT3) receptors is one of its possible mechanisms. The role of 5-HT3 antagonists in the prevention of pruritus has not been clearly established. In a prospective, randomized, double-blind, placebo-controlled study, we evaluated the efficacy of prophylactic administration of ondansetron and dolasetron for the prevention of intrathecal morphine-induced pruritus. The patients were randomized into 3 groups to receive either 4 mg ondansetron IV (group O, n = 35), 12.5 mg dolasetron IV (group D, n = 35) or 5 mL placebo (group P, n = 35) 30 min before administration of spinal anesthesia with 10 to 17.5 mg of 0.5% hyperbaric bupivacaine and 0.25 mg of morphine for urologic, orthopedic, or vascular surgery. Patients were evaluated for incidence and severity of pruritus at arrival to the postanesthesia care unit and at 2, 4, 8, and 24 h postoperatively. The incidence and severity of pruritus was significantly less frequent in the ondansetron and dolasetron groups compared with placebo (34%, 20%, and 66% respectively, P < 0.01). Patients who received 5-HT3 antagonist reported significantly less total severity of pruritus compared with placebo during the first 8 h and the severe pruritus was observed only in patients within P group (P group: 4 of 35; 11%, O or D group: 0 of 35; 0%, P < 0.05). We conclude that the prophylactic use of ondansetron and dolasetron helps to reduce the incidence and severity of intrathecal morphine-induced pruritus.  相似文献   
64.
The authors reviewed 83 physeal and epiphyseal injuries of the distal tibia with intra-articular involvement. The children, aged 11 to 14 years, were treated in the authors' department during 1987 to 1999. Treatment was nonoperative for 72.25% (60/83) and surgical for 27.75% (23/83) according to specific indications. This gives the basis for a classification of these injuries. The main purpose of the study was to investigate the long-term results of these injuries according to a radiologic classification. The parameters considered were the patient's age, the mechanism of injury, and the possibility of growth deformities or functional disorders. They were studied relative to the long-term results, with a follow-up of 2 to 13 years. Regardless of treatment, varus deformity, ranging from 10 to 15 degrees in relation to the normal opposite leg, occurred in four cases. In only one case was there painful limitation of ankle joint movement; in two other children an overgrowth of the medial malleolus was detected, with no functional impairment.  相似文献   
65.
Context  Few cardiovascular outcome data are available for blacks with hypertension treated with angiotensin-converting enzyme (ACE) inhibitors or calcium channel blockers (CCBs). Objective  To determine whether an ACE inhibitor or CCB is superior to a thiazide-type diuretic in reducing cardiovascular disease (CVD) incidence in racial subgroups. Design, Setting, and Participants  Prespecified subgroup analysis of ALLHAT, a randomized, double-blind, active-controlled, clinical outcome trial conducted between February 1994 and March 2002 in 33 357 hypertensive US and Canadian patients aged 55 years or older (35% black) with at least 1 other cardiovascular risk factor. Interventions  Antihypertensive regimens initiated with a CCB (amlodipine) or an ACE inhibitor (lisinopril) vs a thiazide-type diuretic (chlorthalidone). Other medications were added to achieve goal blood pressures (BPs) less than 140/90 mm Hg. Main Outcome Measures  The primary outcome was combined fatal coronary heart disease (CHD) or nonfatal myocardial infarction (MI), analyzed by intention-to-treat. Secondary outcomes included all-cause mortality, stroke, combined CVD (CHD death, nonfatal MI, stroke, angina, coronary revascularization, heart failure [HF], or peripheral vascular disease), and end-stage renal disease. Results  No significant difference was found between treatment groups for the primary CHD outcome in either racial subgroup. For amlodipine vs chlorthalidone only, HF was the only prespecified clinical outcome that differed significantly (overall: relative risk [RR], 1.37; 95% confidence interval [CI], 1.24-1.51; blacks: RR, 1.46; 95% CI, 1.24-1.73; nonblacks: RR, 1.32; 95% CI, 1.17-1.49; P<.001 for each comparison) with no difference in treatment effects by race (P = .38 for interaction). For lisinopril vs chlorthalidone, results differed by race for systolic BP (greater decrease in blacks with chlorthalidone), stroke, and combined CVD outcomes (P<.001, P = .01, and P = .04, respectively, for interactions). In blacks and nonblacks, respectively, the RRs for stroke were 1.40 (95% CI, 1.17-1.68) and 1.00 (95% CI, 0.85-1.17) and for combined CVD were 1.19 (95% CI, 1.09-1.30) and 1.06 (95% CI, 1.00-1.13). For HF, the RRs were 1.30 (95% CI, 1.10-1.54) and 1.13 (95% CI, 1.00-1.28), with no significant interaction by race. Time-dependent BP adjustment did not significantly alter differences in outcome for lisinopril vs chlorthalidone in blacks. Conclusions  In blacks and nonblack subgroups, rates were not lower in the amlodipine or lisinopril groups than in the chlorthalidone group for either the primary CHD or any other prespecified clinical outcome, and diuretic-based treatment resulted in the lowest risk of heart failure. While the improved outcomes with chlorthalidone were more pronounced for some outcomes in blacks than in nonblacks, thiazide-type diuretics remain the drugs of choice for initial therapy of hypertension in both black and nonblack hypertensive patients.   相似文献   
66.
67.
Atherosclerosis is by far the leading cause of mortality and morbidity in patients with end stage renal disease undergoing chronic hemodialysis (HD). Vascular endothelial cell adhesion molecules like the intercellular adhesion molecule-1 (ICAM-1) and the vascular cell adhesion molecule-1 (VCAM-1) are involved in the pathogenesis of atherosclerosis. Their soluble forms (sICAM-1, sVCAM-1) are considered potential serum markers of endothelial activation and atherosclerosis. The aim of this study was to clarify the influence of the HD procedure on the levels of sICAM-1 and sVCAM-1 in patients with end stage renal disease. We evaluated 35 clinically stable patients (18 males, 17 females, mean age 61 +/- 12) on chronic HD treatment. Diabetes mellitus coexisted in eight patients and arterial hypertension in 23 patients. Blood was drawn before, every hour during, and after a single HD session in each patient. Low-flux cuprophane dialyzers (GFS 12, Gambro, Lund, Sweden) were used in 22 and high-flux polysulfone dialyzers (Hemoflow F 60S, Fresenius, Oberursel, Germany) in 13 cases. At 30 min into the HD session (n=31, 20 low-flux HD, 11 high-flux HD) blood was drawn simultaneously from the entrance and the exit line of the dialyzer. From all these samples, serum concentrations of sICAM-1 and sVCAM-1 were determined by commercially available enzyme immunoassays (ELISA, R&D Systems, Minneapolis, USA). Results were corrected according to hemoconcentration, where appropriate. Plasma levels of sVCAM-1 were elevated in patients with end stage renal disease before the beginning of the dialysis session when compared to healthy controls (1449 +/- 497 ng/mL vs. 691 +/- 118 ng/mL). On the contrary, such an elevation was not found in the case of sICAM-1 (231 +/- 58.5 ng/mL vs. 236.4 +/- 96.8 ng/mL in healthy controls). These levels remained stable in all measurements throughout the dialysis procedure. Furthermore, serum sICAM-1 and sVCAM-1 levels remained unaltered after the passage of the dialyzer. The levels of sICAM-1 and sVCAM-1 were not influenced by the existence of diabetes mellitus, hypertension, or by the utilization of biocompatible, high flux dialyzers. Our study confirms that in chronic HD patients serum levels for sVCAM-1 are elevated. The levels of adhesion molecules are not affected by the HD procedure. These findings probably can be attributed to a decreased renal clearance or catabolism of sICAM-1 and sVCAM-1 and to the different sources of the two molecules. Neither coexisting diabetes mellitus nor arterial hypertension influences the circulating levels of these adhesion molecules. The functional role of sVCAM-1 and sICAM-1, the exact renal contribution to their metabolism, and their role as markers of atherosclerosis in chronic renal disease need further evaluation.  相似文献   
68.
Dorsal epidural migration of an extruded disc fragment is an infrequent event, especially in the thoracic spine. An uncommon case involving a 55-year-old man is presented, with a 1-month history of paraparesis and thoracolumbar pain. Magnetic resonance imaging demonstrated a dorsally located, extramedullary mass at the T10-T11 intervertebral level. The lesion was suspected to be a tumor. The patient underwent a T10-T11 laminectomy. Intraoperatively, an encapsulated mass of soft tissue adherent to the dural sac was found. The pathologic diagnosis was inflammatory tissue and disc material. Six months after the operation, the patient remained asymptomatic, and radiologic control showed no residual mass. Although rare, a sequestered disc fragment should be included in the differential diagnosis of an enhancing posterior extramedullary thoracic mass. Preoperative diagnosis of such pathology is difficult because the clinical signs and radiologic images may not entirely exclude other more common thoracic spinal lesions, especially tumors.  相似文献   
69.
The surgical management of patients with neglected developmental dysplasia of the hip (DDH) after the age of 6 years has been the subject of controversy. We present 11 cases (16 hips) of neglected DDH that were treated operatively by means of open reduction and derotational subtrochanteric osteotomy. Patient age ranged between 10 and 17 years (mean, 12 years). Follow-up ranged from 5 to 13 years (mean, 8.7 years). The results have been satisfactory both clinically (evaluated using the modified Harris hip score) and radiographically (evaluated using Severins classification). Our data suggest that neglected DDH cases, not only during early childhood, but also in the periadolescent period, should be considered for surgical treatment.  相似文献   
70.
The authors report on the unusual case of a patient with intracranial hypotension following an incidental durotomy complicated by an extensive but reversible cerebral vasospasm. Despite the dural tear repair and correction of the intracranial hypotension, the vasospasm ran its course. The precise mechanism of the cerebral vasospasm in this patient is unclear.  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