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   455325篇
  免费   28414篇
  国内免费   21051篇
耳鼻咽喉   4758篇
儿科学   9673篇
妇产科学   8809篇
基础医学   57321篇
口腔科学   9989篇
临床医学   52889篇
内科学   72771篇
皮肤病学   6861篇
神经病学   26234篇
特种医学   20045篇
外国民族医学   297篇
外科学   53929篇
综合类   45335篇
现状与发展   75篇
一般理论   28篇
预防医学   31992篇
眼科学   12427篇
药学   41585篇
  307篇
中国医学   15762篇
肿瘤学   33703篇
  2023年   4429篇
  2022年   11460篇
  2021年   14199篇
  2020年   10801篇
  2019年   9305篇
  2018年   13067篇
  2017年   12266篇
  2016年   11140篇
  2015年   16941篇
  2014年   19156篇
  2013年   15799篇
  2012年   28289篇
  2011年   26035篇
  2010年   15139篇
  2009年   13838篇
  2008年   15234篇
  2007年   15996篇
  2006年   16487篇
  2005年   24774篇
  2004年   20625篇
  2003年   15622篇
  2002年   9683篇
  2001年   9994篇
  2000年   8090篇
  1999年   12981篇
  1998年   5237篇
  1997年   5010篇
  1996年   4033篇
  1995年   3884篇
  1994年   3232篇
  1992年   9061篇
  1991年   8928篇
  1990年   8897篇
  1989年   8266篇
  1988年   7592篇
  1987年   7216篇
  1986年   6695篇
  1985年   5843篇
  1984年   3933篇
  1983年   3122篇
  1979年   3917篇
  1978年   2361篇
  1975年   2473篇
  1974年   3105篇
  1973年   2738篇
  1972年   2756篇
  1971年   2742篇
  1970年   2555篇
  1969年   2464篇
  1968年   2237篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
The New Zealand obese mouse (NZO/Hl) is characterised by hereditary obesity and type-2 diabetes, including insulin resistance, hyperinsulinaemia, and glucose intolerance. In other diabetic models, it has been revealed that the proper functioning of the glucose transporter isoform 2 (GLUT2) is essential for adequate secretion of insulin. The aim of this study was to compare the distribution of islet cells and GLUT2, as well as the expression of GLUT2-mRNA, in the pancreas of NZO mice and metabolically unimpaired NMRI (Naval Medical Research Institute) mice. Pancreas tissue was obtained from different stages of development. For molecular determination of the expression level of GLUT2-mRNA, total-RNA was extracted from the pancreas and analysed by quantitative real-time RT-PCR. All investigated NZO mice displayed increased weight, elevated hyperinsulinaemia, and slightly enhanced blood glucose levels compared with the NMRI control mice. By means of immunofluorescence microscopy drastically reduced insulin levels were detected, which might be compensated by the observed islet cell hyperplasia and hypertrophy. Furthermore, the normally peripheral localisation of the alpha-cells within islets was disturbed. By contrast, there were no changes in somatostatin cell distribution. However, considerable differences appeared with regard to GLUT2: whereas the beta-cells of NMRI mice showed dense immunostaining of the GLUT2 transporter on the cell surface, in all age groups of NZO mice, GLUT2 on the plasma membranes was reduced and dispersed in the cytoplasm. These findings agree with the molecular biological results, which displayed decreased mRNA-expression of GLUT2. In summary, the observed alteration of islet morphology and of GLUT2 expression in diabetic mice complements our previous results from a superfusion protocol and further clarifies the mechanisms of diabetogenesis in NZO mice.  相似文献   
22.
Levels of the soluble form of the triggering receptor expressed on myeloid cells (sTREM)-1 are elevated in severe sepsis. However, it is not known whether sTREM-1 measurements can distinguish milder bacterial infections from noninfectious inflammation. The present authors studied whether serum sTREM-1 levels differ in community-acquired pneumonia, exacerbations of chronic obstructive pulmonary disease (COPD), asthma and controls, and whether sTREM-1 may be used as a surrogate marker for the need for antibiotics. Serum sTREM-1 levels in 150 patients with pneumonia, COPD and asthma exacerbations and 62 healthy controls were measured. Serum sTREM-1 levels were significantly elevated in pneumonia (median 295.2 ng x mL(-1)), COPD (280.3 ng x mL(-1)) and asthma exacerbations (184.0 ng x mL(-1)) compared with controls (83.1 ng x mL(-1)). Levels were higher in pneumonia and Anthonisen type 1 COPD exacerbations than in type 2 and 3 COPD and asthma exacerbations. The area under the receiver operating characteristics curve for sTREM-1 as a surrogate marker for the need for antibiotics was 0.77. Serum levels of the soluble form of the triggering receptor expressed on myeloid cells-1 were elevated predominantly in pneumonia and Anthonisen type 1 COPD exacerbations versus type 2 and 3 chronic obstructive pulmonary disease exacerbations, asthma and controls. Serum levels of the soluble form of the triggering receptor expressed on myeloid cells-1 has moderate but insufficient accuracy as a surrogate marker for the need for antibiotics in lower respiratory tract infections.  相似文献   
23.
张良圣 《中医药导报》2006,12(7):27-28,73
目的:观察中医益气补血活血法治疗阳痿病的临床疗效。方法:将符合诊断的114例阳痿病患者随机分为治疗组和对照组各57例,患者入院后分别进行阴茎硬度测试和FSH(促滤泡激素)、HCG(人绒毛膜促性腺激素)、PRL(泌乳素)测定。对照组予温肾壮阳中药加常规西药治疗;治疗组予自拟益气补血活血法方药加减治疗,并辅以精神疏导。对两组病例的疗效进行总结和随访。结果:114例病例全部得到随访,治疗组治愈率63.12%,总有效率91.23%;对照组分别为50.87%;68.41%。两组比较,治疗组优于对照组(P<0.05)。结论:采用中医益气补血活血法治疗阳痿病疗效显著,尤对血管性阳痿病显效。  相似文献   
24.
针对老年高血压病人的治疗,要积极采取药物和非药物治疗措施,既要保持血压稳定在正常或接近正常水平,又要最大限度地降低心脑血管病的并发率、病残率和死亡率。在临床工作中,除采取必要的药物控制血压外,帮助老年高血压患者安排好日常生活,树立正确地防治观念,养成按时作息和定时排便的习惯;合理的饮食,限制食盐量,戒烟戒酒,控制热量摄入;以及根据老年高血压病人的身体情况,选择有规律的适当运动,坚持循序渐进的锻炼:同时,要保持乐观开朗的心怀和积极健康的心态,生活要安排张弛有度,又多姿多彩,努力营造一个感情融洽,和睦相处的温馨美好的家庭环境。这些非药物治疗措施,都能取得了令人满意的效果,是治疗老年高血压病的最佳保健良方。  相似文献   
25.
The increased number of lymphocytes in airways during an asthmatic response is believed to be the result of increased recruitment of these cells. However, it is possible that a decreased apoptotic rate could also contribute to the increased number. The aim of the present study was to investigate whether allergen airway provocation influences the apoptotic phenotype of lung and peripheral blood lymphocytes (PBL) in subjects with atopic asthma. Bronchoalveolar lavage (BAL) lymphocytes and PBL from 12 asthmatic subjects previously challenged with allergen (n = 7) or saline (n = 5) were exposed to the apoptotic stimulus tributyltin (TBT) in vitro and assayed for apoptosis. Airway allergen provocation resulted in decreased sensitivity of BAL lymphocytes to TBT-induced apoptosis, with 42.2% (range 33.9-62.5%) apoptotic cells before challenge versus 23.5% (range 15.3-42.4%) after challenge, while PBL were unaffected. The increased apoptosis resistance correlated with higher numbers of Bcl-2-expressing lymphocytes. Interestingly, baseline caspase-3-like activity was significantly elevated in viable BAL lymphocytes compared with viable PBL, and was unaltered by allergen exposure. In conclusion, allergen inhalation renders bronchoalveolar lavage lymphocytes more resistant to apoptosis while peripheral blood lymphocytes were not influenced at all, indicating that the apoptotic phenotype of airway lymphocytes may play a role in asthmatic inflammation.  相似文献   
26.
Aggressive behavior linked to corticotropin-reactive autoantibodies.   总被引:3,自引:0,他引:3  
BACKGROUND: Altered stress response is characteristic for subjects with abnormal aggressive and antisocial behavior, but the underlying biological mechanisms are unclear. We hypothesized that autoantibodies (autoAbs) directed against several stress-related neurohormones may exist in aggressive subjects. METHODS: Using enzyme-linked immunosorbent assay, we studied whether autoAbs directed against corticotropin (ACTH), alpha-melanocyte-stimulating hormone (alpha-MSH), oxytocin, and vasopressin are present in serum of male subjects with conduct disorder and prisoners with history of violence. Healthy blood donors served as control subjects. RESULTS: Both conduct disorder and prisoners groups displayed strongly increased levels of ACTH-reactive immunoglobulin G (IgG) and immunoglobulin M (IgM) autoAbs compared with control subjects. Levels of oxytocin-reactive IgM autoAbs were slightly increased in both groups of aggressive subjects, whereas levels of vasopressin-reactive IgG and IgM autoAbs were lower only in conduct disorder. No differences in the levels of alpha-MSH-reactive autoAbs were found between aggressive and control subjects. CONCLUSIONS: High levels of ACTH-reactive autoAbs as well as altered levels of oxytocin- and vasopressin-reactive autoAbs found in aggressive subjects may interfere with the neuroendocrine mechanisms of stress and motivated behavior. Our data suggest a new biological mechanism of human aggressive behavior that involves autoAbs directed against several stress-related neurohormones.  相似文献   
27.
医科院校学生心理危机管理浅探   总被引:2,自引:0,他引:2  
结合医科院校学生心理危机管理的实践,阐述大学生心理危机的内涵、类型、特征及心理危机管理的特性,并从建立预警系统、增设心理委员、危机处理的专业化及危机干预策略等方面探讨在医科院校加强学生心理危机管理的对策。  相似文献   
28.
PURPOSE: In children with locally advanced or recurrent malignant tumours, prognosis can be improved by regional deep hyperthermia (RHT) in combination with platin-based chemotherapy. However, because of the increasing number of patients that achieve long-time remission with this therapy, it is necessary to evaluate long-term sequelae of thermochemotherapy. During the years 1993-2004 one has observed avascular osteonecrosis (AON) of the femoral head after RHT in seven children with pelvic germ cell tumours or rhabdomyosarcomas. METHODS: Although AON may develop in patients with malignancies treated with chemo- or radiotherapy alone, RHT might nevertheless contribute to the occurrence of AON. In order to determine potential risk factors for AON after RHT, this study analysed the relationship of AON to the patient's age, medical history and treatment parameters such as thermal dose equivalent and power output. RESULTS AND CONCLUSIONS: In the present study AON was associated with young age as well as intensity of hyperthermia indicated by high power levels that exceed 20 W per kg body weight and/or application of eight or more heat sessions as well as additional radiotherapy. Based on this observation, it was assumed that an optimized three dimensional thermal field modelling may be helpful to avoid hazardous temperatures in the femoral heads during RHT treatment and to reduce AON of the femoral heads.  相似文献   
29.
目的治疗顽固性下颌磨牙根尖周炎。并尽量减少对牙周膜的机械性损伤。方法采用下牙槽神经阻滞麻醉,并配合局部麻醉。拔牙钳的尖置放于釉牙骨质界以上,采用颊舌向摆动的方式将患牙拔下。在不断滴有生理盐水的条件下,立即用高速车针磨除患牙根尖2 ̄3mm的牙体组织,根管内3 ̄5mm深的充填物要用圆钻将其清除,再用牙胶尖和氢氧化钙糊剂充填。将患牙再植入牙槽窝之前,务必用生理盐水将牙槽窝冲洗干净,要求严格控制在15分钟内完成再植,并尽量减少对牙周膜的机械性损伤。再植牙齿一般不需要夹板固定,必要时可采用缝线缝合固定。结果我们选择的5例患者,术后随访1 ̄2年,1例患者再植失败,4例患者再植成功。结论特异性再植术治疗顽固性下颌磨牙根尖周炎疗效理想,而且较易掌握。  相似文献   
30.
Bifid mandibular canal.   总被引:1,自引:0,他引:1  
PURPOSE: To determine the incidence and characteristics of bifid mandibular canals. METHODS: A retrospective study was performed using panoramic radiographs of 2012 patients subjected to dental treatment in the Dental Clinic of the Valencia University Dental School (Valencia, Spain) between 1996 and 1999. The goal was to investigate the presence of double mandibular canals. RESULTS: The extraoral panoramic radiographs revealed a total of 7 images suggestive of bifid canals. Mandibular computed tomography revealed the existence of this anatomic variant in 2 of 3 patients. An analysis was performed on the incidence of this type of image in extraoral panoramic radiography, its possible interpretations, and the clinical implications of bifid mandibular canals. CONCLUSIONS: In this study, 0.35% of canals were bifid. All cases were in women.  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