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   4098篇
  免费   304篇
  国内免费   11篇
耳鼻咽喉   50篇
儿科学   136篇
妇产科学   118篇
基础医学   556篇
口腔科学   243篇
临床医学   289篇
内科学   919篇
皮肤病学   140篇
神经病学   215篇
特种医学   282篇
外科学   613篇
综合类   98篇
一般理论   2篇
预防医学   313篇
眼科学   24篇
药学   197篇
中国医学   45篇
肿瘤学   173篇
  2022年   33篇
  2021年   85篇
  2020年   71篇
  2019年   89篇
  2018年   104篇
  2017年   85篇
  2016年   90篇
  2015年   87篇
  2014年   110篇
  2013年   172篇
  2012年   184篇
  2011年   209篇
  2010年   152篇
  2009年   128篇
  2008年   193篇
  2007年   218篇
  2006年   178篇
  2005年   145篇
  2004年   161篇
  2003年   131篇
  2002年   137篇
  2001年   123篇
  2000年   131篇
  1999年   109篇
  1998年   95篇
  1997年   69篇
  1996年   62篇
  1995年   43篇
  1994年   48篇
  1993年   38篇
  1992年   81篇
  1991年   61篇
  1990年   69篇
  1989年   75篇
  1988年   91篇
  1987年   66篇
  1986年   66篇
  1985年   75篇
  1984年   44篇
  1983年   43篇
  1982年   27篇
  1981年   19篇
  1980年   17篇
  1979年   15篇
  1978年   20篇
  1977年   13篇
  1976年   13篇
  1972年   20篇
  1971年   18篇
  1967年   12篇
排序方式: 共有4413条查询结果,搜索用时 31 毫秒
11.
Background: In familial adenomatous polyposis and juvenile polyposis, polyps can occur throughout the gastrointestinal tract.Methods: We report seven patients with familial adenomatous polyposis and two patients with juvenile polyposis who underwent small bowel enteroscopy at the time of exploratory celiotomy either for colectomy or other pathology.Results: Polyps in the jejunum and/or ileum were noted in five of nine (56%) patients at enteroscopy. In three of nine (33%) patients these polyps were adenomatous. Two of these patients had polyps in the jejunum and in the ileum, whereas one patient had jejunal adenomas alone. These polyps were from 3 mm to 30 mm in size. The remaining two patients with polyps had lymphoid hyperplasia in the ileum. All three patients who had adenomas at intraoperative small bowel enteroscopy had duodenal adenomas at esophagogastroduodenoscopy. At the age of 14 years, one patient had an intramucosal carcinoma in a small bowel juvenile polyp.Conclusion: Baseline small bowel enteroscopy should be considered at the time of surgical exploration in patients with asymptomatic familial adenomatous polyposis and juvenile polyposis. In patients with duodenal polyps, enteroscopy should be performed at the time of surgery. Biopsy and/or excision of larger polyps should be performed because these polyps may harbor a carcinoma. (Gastrointest Endosc 1995;42:560-4.)  相似文献   
12.
BACKGROUND: In general practice, acute sinusitis is frequently diagnosed and treated with antibiotics. OBJECTIVE: This study aimed to determine the evidence for the effectiveness of antibiotic treatment in acute maxillary sinusitis in adults by assessing the methodological quality of placebo-controlled double-blind randomized trials. METHOD: An evaluation by four raters through a 35-item scoring-scale for internal and external validity of all placebo-controlled double-blind randomized trials on acute sinusitis found between January 1966 and July 1996. RESULTS: Eighty-five trials were excluded because they were not placebo-controlled, double-blind, randomized, or were carried out in patients with chronic sinusitis or in children. The three remaining trials were performed in different populations (one in general practice) between 1973 and 1978. Only one study claimed superiority of antibiotic treatment. Different inclusion criteria and major outcome measures were used by the authors. The reliability of major outcome events was reported poorly or not at all and in two studies outcome measures were clinically inappropriate. The studies scored 30-62% of the maximum attainable score for internal validity and 10-20% for external validity. CONCLUSION: The effectiveness of antibiotic treatment in acute maxillary sinusitis in a general practice population is not based sufficiently on evidence.   相似文献   
13.
Orthotopic liver transplantation was performed in 20 pigs. Serum total bile acids (STBA) were determined and their profile compared with standard early function parameters: total bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactic acid. In phase I, the STBA level was 32.89 +/- 1.29 mumol/l. In phase II, STBA accumulated to 84.46 +/- 15.25 mumol/l (p less than 0.01), followed by hepatic clearance in phase III (63.61 +/- 9.71 mumol/1; NS). Between phase III and 6- and 12-hour samples, STBA decreased progressively, reaching values of 33.63 +/- 7.05 mumol/l at 24 h. AST was elevated in phases I, II, III, and at 6, 12 and 24 h (p less than 0.001), as was ALT (but with insignificant differences). Thus, STBA and their profile appear to be earlier and more specific indicators of early graft function than conventional parameters.  相似文献   
14.
A closed femur fracture pain model was developed in the C57BL/6J mouse. One day after fracture, a monoclonal antibody raised against nerve growth factor (anti-NGF) was delivered intraperitoneally and resulted in a reduction in fracture pain-related behaviors of approximately 50%. Anti-NGF therapy did not interfere with bone healing as assessed by mechanical testing and histomorphometric analysis. INTRODUCTION: Current therapies to treat skeletal fracture pain are limited. This is because of the side effect profile of available analgesics and the scarcity of animal models that can be used to understand the mechanisms that drive this pain. Whereas previous studies have shown that mineralized bone, marrow, and periosteum are innervated by sensory and sympathetic fibers, it is not understood how skeletal pain is generated and maintained even in common conditions such as osteoarthritis, low back pain, or fracture. MATERIALS AND METHODS: In this study, we characterized the pain-related behaviors after a closed femur fracture in the C57BL/6J mouse. Additionally, we assessed the effect of a monoclonal antibody that binds to and sequesters nerve growth factor (anti-NGF) on pain-related behaviors and bone healing (mechanical properties and histomorphometric analysis) after fracture. RESULTS: Administration of anti-NGF therapy (10 mg/kg, days 1, 6, and 11 after fracture) resulted in a reduction of fracture pain-related behaviors of approximately 50%. Attenuation of fracture pain was evident as early as 24 h after the initial dosing and remained efficacious throughout the course of fracture pain. Anti-NGF therapy did not modify biomechanical properties of the femur or histomorphometric indices of bone healing. CONCLUSIONS: These findings suggest that therapies that target NGF or its cognate receptor(s) may be effective in attenuating nonmalignant fracture pain without interfering with bone healing.  相似文献   
15.
16.
Focal abnormalities of gyration (FAG) are developmental disorders that may occur in isolated patients or, as in the case being reported, as part of a familial disorder. Analysis of individuals in a family spanning three generations was carried out using MRI. Abnormalities, present in all members of generations II and III, included focal cortical dysplasia (three patients), focal cortical infolding (two patients) and schizencephaly (one patient); associated minor anomalies, such as white matter abnormalities, were seen in the remaining three members of generations II and III. MRI recognition of FAG in the family being reported proved useful in defining their phenotypical expression and providing proper counselling for individual family members. Received: 22 August 1996 Accepted: 7 October 1996  相似文献   
17.
Plasma zinc and pituitary and testicular hormone concentrations were measured in two groups of male adolescents. One group comprised insulin-dependent diabetes mellitus patients, aged 14-19 years; the other, as control, included 12 healthy youngsters aged 13-19 years. Plasma concentration of zinc, prolactin, testosterone, and dihydrotestosterone were lower in diabetics than in controls, whereas the ratios of androstenedione and androstenedione to testosterone + dihydrotestosterone were higher. Plasma FSH and LH were normal. These results suggest a diminished conversion of androstenedione to testosterone and relate zinc with the 17-beta-hydroxysteroid dehydrogenase enzyme activity.  相似文献   
18.
Summary Levels of dopamine (DA), noradrenaline (NA) and 5-hydroxytryptamine (serotonin, 5-HT) and their metabolites, and the activities of tyrosine hydroxylase (TH), tryptophan hydroxylase (TPH) and monoamine oxidase A and B (MAO-A and MAO-B) have been determined in the rat posterior thalamus after enucleation during postnatal development. DA and 5-HT turnover rate have been measured as 3,4-dihydroxyphenylalanine (DOPA) and 5-hydroxytryptophan (5-HTP) accumulation rates after central decarboxylase inhibition by 3-hydroxybenzylhydrazine (NSD-1015). The major changes were an increase in noradrenergic and serotoninergic metabolism in enucleated animals compared with control animals. A decrease of the MAO-A to MAO-B ratio during postnatal development was found.Abbreviations DA dopamine - DOPAC 3,4-dihydroxyphenylacetic acid - HVA homovanillic acid - DOPA 3,4-dihydroxyphenylalanine - NA noradrenaline - MHPG 3-methoxy-4-hydroxyphenylgly-col - NMN normetanephrine - TRP tryptophan - 5-HTP 5-hydroxytryptophan - 5-HT serotonin - 5-HIAA 5-hydroxy-3-indolacetic acid - TH tyrosine hydroxylase - TPH tryptophan hydroxylase - MAO-A monoamine oxidase-A - MAO-B monoamine oxidase-B Recipients of fellowships from I.I.E. del FISS Reincorporación de doctores y tecnólogos del M.E.C., and Perfeccionamiento de doctores y tecnólogos del MEC, Spain  相似文献   
19.
Six treatment-resistant schizophrenic patients were given a ten-week single-blind trial of carbamazepine. Treatment resistance was determined on the basis of documented failure to respond to treatment with at least three neuroleptic drugs from two different chemical classes. The adjunctive use of carbamazepine resulted in a significant improvement of the negative symptoms of schizophrenia. These symptoms are often poorly responsive to conventional antipsychotic drugs. Therefore, controlled studies should be performed to further assess the possible efficacy of carbamazepine in schizophrenia.  相似文献   
20.
Co-existence of facial and occipital pain may occur in occipital neuralgia, migraine and cluster headache; suggesting convergence of trigeminal and cervical afferents. Such convergence has been shown in humans and other animals, but the site and extent of this are uncertain. In anaesthetized adult cats, the superior sagittal sinus and occipital nerve were stimulated electrically, and extracellular recordings made in the dorsolateral area of the upper cervical cord using glass-coated tungsten electrodes. Of 49 units in 10 cats, 33 (67%) had input from the superior sagittal sinus and the occipital nerve. Thirteen (27%) had superior sagittal sinus input and 3 (6%) had occipital nerve input. Convergent receptive fields were identified mechanically in 7 units. These experiments in cats show convergent input from occipital nerve and superior sagittal sinus on dorsolateral area units in two-thirds of cases studied. This experimental site of trigeminocervical convergence may relate to referral of pain in occipital neuralgia and other headaches.  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