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   39407篇
  免费   2563篇
  国内免费   791篇
耳鼻咽喉   108篇
儿科学   490篇
妇产科学   477篇
基础医学   2533篇
口腔科学   644篇
临床医学   6949篇
内科学   5238篇
皮肤病学   281篇
神经病学   997篇
特种医学   1240篇
外国民族医学   4篇
外科学   9589篇
综合类   5863篇
现状与发展   3篇
预防医学   2755篇
眼科学   142篇
药学   3127篇
  82篇
中国医学   760篇
肿瘤学   1479篇
  2024年   49篇
  2023年   715篇
  2022年   1117篇
  2021年   1947篇
  2020年   2059篇
  2019年   1701篇
  2018年   1718篇
  2017年   1413篇
  2016年   1557篇
  2015年   1489篇
  2014年   3276篇
  2013年   3194篇
  2012年   2638篇
  2011年   2638篇
  2010年   2055篇
  2009年   1958篇
  2008年   1784篇
  2007年   1700篇
  2006年   1407篇
  2005年   1271篇
  2004年   1054篇
  2003年   906篇
  2002年   738篇
  2001年   583篇
  2000年   493篇
  1999年   372篇
  1998年   345篇
  1997年   294篇
  1996年   270篇
  1995年   271篇
  1994年   242篇
  1993年   182篇
  1992年   160篇
  1991年   99篇
  1990年   112篇
  1989年   100篇
  1988年   108篇
  1987年   104篇
  1986年   81篇
  1985年   100篇
  1984年   88篇
  1983年   47篇
  1982年   74篇
  1981年   46篇
  1980年   46篇
  1979年   33篇
  1978年   28篇
  1977年   34篇
  1976年   18篇
  1975年   17篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
Background Despite improving surgical techniques, treatment of heart valve disease in children remains controversial. Somatic growth and adequate anticoagulation are of concern when children undergo valve replacement. We conducted this study to evaluate the performance of valves in this age group. Methods 42 children under the age of 13 years who underwent valve replacement were included in this study. Totally, 50 valves were implanted in 42 patients: 48 were mechanical prostheses, two were bioprosthetic both in pulmonary position. 37 (74%) valves were implanted in mitral position, 10 (20%) in aortic position, 1 (2%) in tricuspid position and 2 (4%) in pulmonary position. Preoperatively, 14 (33,3%) patients were in New York Heart Association (NYHA) class IV, while 27 (64.2%) were in NYHA class III. Results There were 2 (4.7%) hospital deaths and 2 (4.7%) late deaths while 2 (4.7%) patients were lost to follow up. The mean follow up period was 9.4 yrs. 35 (83.3%) patients are in NYHA Class I and free of all medications except warfarin. 3 (7.1%) patients have undergone 5 successful pregnancies. The median INR was 2.23. Major thrombo-embolic episode occurred in 1 (2.3%) patient. Conclusions In view of the problems of sizing, anticoagulation and need for re-operation at an early age, there is a reluctance to replace valves in children. This study shows that despite these problems, valve replacement can be undertaken safely and successfully in children, when repair has failed or not technically feasible.  相似文献   
82.
上海市闵行区性病门诊本地和外来病人的比较研究   总被引:1,自引:0,他引:1  
目的分析和比较上海市闵行区性病门诊本地与外来病人的流行病学特征。方法对2001~2004年上海市闵行区3家设有标准化性病门诊的公立医院进行门诊病历的回顾性分析。结果外来人口约占全部性病门诊病人的50%,其中女性病例占18.2%,未婚者占23.8%,均高于本地同类人员的比例;外来病人年龄偏低,多重感染者比例较高;男女外来病人与本地病人的首诊原因和症状排位相同,均以淋病感染为主;外来病人随访率(81.2%)较本地病人低(86.0%)。结论性病门诊本地和外来病人在人口学特征、诊疗行为上存在差异,防制措施应有所不同和侧重。  相似文献   
83.
This study examined the interface between acute hospital care and return to home in relation to elderly patients' perceived ability and preparedness to cope at home. Seventy-six (n = 76) elderly patients aged 60 years and over were randomly recruited from a large Queensland hospital and interviewed prior to discharge about their perceived health, functional status and their ‘readiness’ to cope at home. They were followed up at home 7–10 days post-discharge. Comparisons were made between a number of measures at discharge and post-discharge. Although the majority of patients indicated that they would cope very well upon discharge, a large number of patients reported experiencing considerable difficulty with activities of daily living, particularly instrumental activities of daily living prior to and especially after discharge. The self-reported health status of patients similarly deteriorated between discharge and follow-up. Despite a large number of patients experiencing functional limitations, few were referred to hospital or community-based therapy services. Some policy implications are explored.  相似文献   
84.
Thirty-seven children and adolescents on renal replacement therapy (11 on haemodialysis, 14 on continuous ambulatory peritoneal dialysis and 12 after renal transplantation) were studied by echocardiography, echo-Doppler and phonocardiography. Right and left ventricular (R/L V) diastolic functions were measured by transmitral and transtricuspid flow velocities and by LV isovolumic relaxation time (LVIRT). Thirty-seven age- and sex-matched healthy subjects served as controls. R/L V diastolic dysfunction was only observed in the dialysis patients. In these patients LVIRT was prolonged. LV and RV peak inflow velocities were increased both in early (E) and late (A) diastole with a reduction in the E/A ratios. This pattern of diastolic dysfunction is compatible with the combined effects of a hypercirculatory state (volume overload, anaemia, arteriovenous fistula) and an abnormality of cardiac relaxation. The transplant patients showed no major cardiac abnormalities.  相似文献   
85.
The present study evaluates the response comparability between 361 elderly hip fracture patients admitted from the community to seven Baltimore area hospitals between 1984 and 1986 and interviewer selected proxies on items pertaining to patients' pre-fracture health and functional status. Agreement across items ranges from very poor to good and varies with respect to the health or functional area assessed. Proxies tend to overestimate patient disability relative to the patients themselves, especially with regard to capacity to perform instrumental activities of daily living. Although proxies who report the greatest contact with patients respond most comparably to the patients, when they do disagree, proxies with the greatest patient contact tend to overestimate patient disability. The authors suggest that attention to item construction and phrasing may improve response comparability.  相似文献   
86.
Immediate reconstruction of more than 1000 breasts was performed on high-risk patients on whom a prophylactic mastectomy was done. The mastectomy removes as much breast tissue as possible while leaving sufficient skin, and possibly the nipple-areola complex, to enable immediate reconstruction. The creation of symmetrical, well-balanced muscle pockets for the implant is the most important factor in producing satisfactory results in these cases.  相似文献   
87.
The incidence of lower urinary tract dysfunction increases during the climacteric, and there is embryological, biochemical and epidemiologic evidence to suggest that depleted estrogen status is at least partially responsible. Twelve climacteric women underwent full assessment before and 1 year after treatment with a 50 mg subcutaneous estradiol implant +5 mg norethisterone for 7 days per month. Assessment consisted of a symptoms questionnaire, midstream urine sample, uroflowmetry, videocystourethrography with pressure flow studies, and urethral pressure profilometry. Subjectively, only the symptom of nocturia significantly improved. There was no change in flow variables but there was a significant decrease in residual urine and the degree of bladder base descent. Cystometric capacity was slightly but significantly decreased, and two patients developed genuine stress incontinence whilst on treatment. Nonetheless, there was a significant improvement in urethral pressures at rest but not under stress. This effect was predominantly in the proximal urethra. These data do not support the contention that estrogen replacement therapy is beneficial for lower urinary tract dysfunction during the climacteric.  相似文献   
88.
目的:探讨两种剂量的7-甲异炔诺酮(OrgOD14,利维爱)对绝经症状控制的比较。方法:60例绝经后妇女随机分为两组:①A组30例,每日口服7-甲异炔诺酮2.5mg。②B组30例,隔日口服7-甲异炔诺酮2.5mg,共6个月。观察服药前后的Kupperman评分变化及血雌二醇、促卵泡激素水平的改变。结果:两组服药后绝经症状明显改善,Kupperman评分明显降低(P<0.01),雌二醇水平显著上升(P<0.01),促卵泡激素水平明显下降(P<0.05),而两组之间差异无显著性。结论:7-甲异炔诺酮可有效地控制绝经症状,每日口服2.5mg并不比隔日口服2.5mg有较好的控制效果(除控制失眠外),故推荐隔日口服2.5mg7-甲异炔诺酮。  相似文献   
89.
The majority of patients being treated for acute renal failure in intensive care units have multiple medical problems. Accordingly, the withdrawal of renal replacement therapies should be considered as part of a general decision about whether to initiate or continue with treatment per se. Several guidelines on withdrawing and withholding therapy have been produced and some common themes emerge: concerns to avoid euthanasia, potential for benefit, patient consent (shared decision‐making), team consensus/decision‐making, and the provision of appropriate palliative care and resource implications. Each of these is considered in turn, although the word limit for this paper does not permit detailed exposition.  相似文献   
90.
目的 探讨血流动力学检测在老年性牙周病患者中的价值。方法 采用R8Oa锥板旋转式血粘度测试仪 ,测定老年性牙周病患者的血流动力学指标。结果 老年性牙周病患者的血流动力学指标与正常对照组差异有显著性 (P <0 .0 5 ~ 0 .0 0 1)。全血低切粘度、全血低切还原粘度、全血低切相对粘度极显著高于正常对照组 ;全血中切粘度、卡松粘度、红细胞刚性指数、红细胞聚集指数 ,差异有高度显著性 ;红细胞压积、纤维蛋白原、全血高切粘度差异也存在着显著性。然而 ,全血高切还原粘度、血浆粘度、红细胞变形指数虽也增高 ,但无统计学差异 (P>0 .0 5 )。结论 老年性牙周病患者的病程中存在着严重的血流动力学改变。  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