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   1807篇
  免费   125篇
  国内免费   7篇
耳鼻咽喉   21篇
儿科学   75篇
妇产科学   53篇
基础医学   257篇
口腔科学   130篇
临床医学   129篇
内科学   378篇
皮肤病学   41篇
神经病学   166篇
特种医学   92篇
外科学   215篇
综合类   6篇
预防医学   175篇
眼科学   39篇
药学   75篇
中国医学   8篇
肿瘤学   79篇
  2023年   9篇
  2022年   31篇
  2021年   44篇
  2020年   20篇
  2019年   44篇
  2018年   50篇
  2017年   35篇
  2016年   43篇
  2015年   61篇
  2014年   75篇
  2013年   87篇
  2012年   120篇
  2011年   151篇
  2010年   81篇
  2009年   58篇
  2008年   89篇
  2007年   78篇
  2006年   89篇
  2005年   61篇
  2004年   66篇
  2003年   46篇
  2002年   51篇
  2001年   41篇
  2000年   42篇
  1999年   31篇
  1998年   11篇
  1997年   20篇
  1996年   23篇
  1995年   17篇
  1994年   22篇
  1993年   18篇
  1992年   16篇
  1991年   22篇
  1990年   12篇
  1989年   27篇
  1988年   21篇
  1987年   24篇
  1986年   21篇
  1985年   19篇
  1984年   13篇
  1983年   13篇
  1982年   8篇
  1980年   12篇
  1979年   13篇
  1978年   13篇
  1977年   11篇
  1976年   9篇
  1972年   8篇
  1969年   7篇
  1966年   9篇
排序方式: 共有1939条查询结果,搜索用时 0 毫秒
41.
Isolated growth hormone (GH) deficiency (IGHD) is a rare cause of short stature. The same mutation of the gene encoding the growth hormone-releasing hormone receptor (GHRHR) has been identified as the basis for IGHD in three families from the Indian subcontinent. The prevalence and heterogeneity of defects in the GHRHR gene are not known. Twenty-two dwarf members of a large, extended kindred containing at least 105 affected members with autosomal recessive short stature underwent extensive endocrine evaluation, which confirmed markedly reduced or undetectable serum concentrations of GH that did not increase in response to different stimuli. DNA sequences of the 13 exons and intron-exon boundaries of the GHRHR gene were determined in an index patient. A novel homozygous 5' splice site mutation (G-->A at position +1) in IVS1 was found. Thirty of the affected subjects tested were homozygous for this mutation, and 64 clinically unaffected patients were either heterozygous for the mutation (n = 41, including 9 obligate carriers) or homozygous for the wild-type sequence (n = 23). We describe a novel mutation in the GHRHR gene as cause of dwarfism in the largest kindred with familial IGHD described to date.  相似文献   
42.
Diabetic cardiomyopathy is associated with cardiac muscle remodeling, resulting in myocardial dysfunction, whereas exercise training (ET) is a useful nonpharmacological strategy for the therapy of cardiac diseases. This study tested the effects of low-intensity swimming-training on the structural remodeling of the left ventricle (LV) in growing rats with unmanaged experimental diabetes. Thirty-day-old male Wistar rats were divided into four groups (n = 5/group): sedentary-control (SC), exercised-control (EC), sedentary-diabetic (SD), and exercised-diabetic (ED). Swimming-training rats exercised 5 days/week, 90 min/day, with a load of 5% BW during 8 weeks. Sections of LV were stained with Periodic acid-Schiff, Sirius Red, and Gomori's reticulin. Seven days and 8 weeks after streptozotocin (STZ) induction (60 mg kg−1 BW), blood glucose (BG) in the diabetic groups (SD = 581.40 ± 40.48; ED = 558.00 ± 48.89) was greater (p < 0.05) than in their controls (SC = 88.80 ± 21.70; EC = 85.60 ± 11.55). Swimming-training reduced BG by 23 mg/dL in the diabetics (p > 0.05). The LV of diabetic rats had increased interstitial collagen and reticular fibers on the extracellular matrix and presented glycogen accumulation. More importantly, all these adverse tissue changes induced by STZ were attenuated by ET. Together, these findings support the idea of a beneficial role of exercise in the LV remodeling in rats with unmanaged type-1 diabetes mellitus.  相似文献   
43.
ObjectiveTo assess the utility of self-reported symptoms in identifying positive coronavirus disease 2019 (COVID-19) cases among predominantly healthy young adults in a military setting.MethodsA questionnaire regarding COVID-19 symptoms and exposure history was administered to all individuals contacting the Israeli Defence Forces Corona call-centre, before PCR testing. Surveyed symptoms included cough, fever, sore throat, rhinorrhoea, loss of taste or smell, chest pain and gastrointestinal symptoms. Factors were compared between positive and negative cases based on confirmatory test results, and positive likelihood ratios (LR) were calculated. Results were stratified by sex, body mass index, previous medical history and dates of questioning, and a multivariable analysis for association with positive test was conducted.ResultsOf 24 362 respondents, 59.1% were men with a median age of 20.5 years (interquartile range 19.6–22.4 years). Significant positive LRs were associated with loss of taste or smell (LR 3.38, 95% CI 3.01–3.79), suspected exposure (LR 1.33, 95% CI 1.28–1.39) and fever (LR 1.26, 95% CI 1.17–1.36). Those factors were also associated with positive PCR result in a multivariable analysis (OR 3.51, 95% CI 3.04–4.06; OR 1.86, 95% CI 1.65–2.09; and OR 1.34, 95% CI 1.19–1.51, respectively). Reports of loss of taste or smell increased gradually over time and were significantly more frequent during the late period of the study (63/5231, 1.21%; 156/7941, 1.96%; and 1505/11 190, 13.45%: p < 0.001).ConclusionLoss of taste or smell, report of a suspicious exposure and fever (>37.5°C) were consistently associated with positive LRs for a positive SARS-CoV-2 PCR test result, in a population of predominantly young and healthy adults.  相似文献   
44.
45.
The pathological evaluation of rectal biopsies for the diagnosis of Hirschsprung disease has been a challenging issue. We analyzed prospectively the usefulness of calretinin immunostaining and acetylcholinesterase (AChE) histochesmistry in rectal biopsies for the diagnosis of Hirschsprung disease. Frozen tissue samples from 43 patients were used for AChE histochemistry and paraffin-embedded sections for calretinin immunohistochemistry and conventional histology (hematoxylin and eosin [H&E]). Activity for AChE, was demonstrated in 13 of 43 cases, and the absence of immunoreactivity for calretinin was observed in 14 of 43 cases. Conventional histology (H&E) did not reveal ganglion cells in 24 of 43 cases. The results on calretinin were in good agreement with AChE according to the κ index (0.946; P < .001) and presented significantly higher specificity (96.7 × 63.3; P < .002) and accuracy (97.6 × 74.4; P < .003) when compared with conventional histology (H&E). The final diagnosis of Hirschsprung disease was confirmed in 13 of 43 patients who were submitted to surgical treatment. The results of the present study indicate that calretinin can be a good tool in ruling out the diagnosis of Hirschsprung disease, by showing positive staining in ganglion cells and intrinsic nerve fibers, whereas AChE is useful in confirming the diagnosis of Hirschsprung disease, by revealing activity of this enzyme in hypertrophied nerve fibers. The association between calretinin and AChE can be a useful panel for the histopathologic evaluation of rectal biopsies for the diagnosis of Hirschsprung disease.  相似文献   
46.
Clinical Oral Investigations - To evaluate therapeutic effects of laser therapy on patients with recurrent aphthous stomatitis assessing evidences from previously published systematic reviews. An...  相似文献   
47.
The postoperative course of 100 pts. that underwent aorto-coronary bypass surgery was studied at the Instituto Nacional de Cardiología "Ignacio Chávez": 84 were men and 16 women between 37 and 74 years. 56 had previous history of myocardial infarction, while in 16 of them occurred within 30 days of the surgical procedure. 88 had symptomatic angina and 8 were in cardiac failure. The coronariography showed trivascular lesions in 73% and 8 pts. had stenosis of the left main coronary artery. Two pts. had 5 coronary grafts, 4 had 17, 3 had 37, two 35 and one 9 pts. All anterior descending coronary arteries were grafted. 61 of them and the 8 main left damaged were grafted with internal mammary artery Afert surgery; 15 pts had AMI, 4 profuse bleeding, one cardiac failure and shock. CPK enzyme levels of 500 were found in the majority of the pts with AMI with 81.2 positive predictive value and negative of 97.6. Three pts died, two at the OR with cardiac failure one of them had ventricular rupture, and the last at the ICU also with cardiac failure. We emphasize that CPK values of 500 UI or more in the postoperative course may be diagnostic of AMI.  相似文献   
48.
49.
50.
AIM: To optimize diagnosis and treatment guidelines for this geographic region, a panel of gastroenterologists, epidemiologists, and basic scientists carried out a structured evaluation of available literature.METHODS: Relevant questions were distributed among the experts, who generated draft statements for consideration by the entire panel. A modified three-round Delphi technique method was used to reach consensus. Critical input was also obtained from representatives of the concerned medical community. The quality of the evidence and level of recommendation supporting each statement was graded according to United States Preventive Services Task Force criteria.RESULTS: A group of ten experts was established. The survey included 15 open-ended questions that were distributed among the experts, who assessed the articles associated with each question. The levels of agreement achieved by the panel were 50% in the first round, 73.3% in the second round and 100% in the third round. Main consensus recommendations included: (1) when available, urea breath and stool antigen test (HpSA) should be used for non-invasive diagnosis; (2) detect and eradicate Helicobacter pylori (H. pylori) in all gastroscopy patients to decrease risk of peptic ulcer disease, prevent o retard progression in patients with preneoplastic lesions, and to prevent recurrence in patients treated for gastric cancer; (3) further investigate implementation issues and health outcomes of H. pylori eradication for primary prevention of gastric cancer in high-risk populations; (4) prescribe standard 14-d triple therapy or sequential therapy for first-line treatment; (5) routinely assess eradication success post-treatment in clinical settings; and (6) select second- and third-line therapies according to antibiotic susceptibility testing.CONCLUSION: These achievable steps toward better region-specific management can be expected to improve clinical health outcomes.  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