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   33391篇
  免费   3451篇
  国内免费   64篇
耳鼻咽喉   436篇
儿科学   1251篇
妇产科学   996篇
基础医学   4662篇
口腔科学   709篇
临床医学   4661篇
内科学   6076篇
皮肤病学   407篇
神经病学   2607篇
特种医学   861篇
外科学   4114篇
综合类   733篇
一般理论   45篇
预防医学   4105篇
眼科学   553篇
药学   2316篇
中国医学   98篇
肿瘤学   2276篇
  2023年   192篇
  2022年   355篇
  2021年   752篇
  2020年   443篇
  2019年   716篇
  2018年   859篇
  2017年   633篇
  2016年   689篇
  2015年   713篇
  2014年   1057篇
  2013年   1437篇
  2012年   2137篇
  2011年   2262篇
  2010年   1148篇
  2009年   990篇
  2008年   1799篇
  2007年   1868篇
  2006年   1861篇
  2005年   1854篇
  2004年   1510篇
  2003年   1398篇
  2002年   1245篇
  2001年   737篇
  2000年   687篇
  1999年   673篇
  1998年   321篇
  1997年   293篇
  1996年   259篇
  1995年   237篇
  1994年   226篇
  1993年   182篇
  1992年   484篇
  1991年   455篇
  1990年   428篇
  1989年   403篇
  1988年   393篇
  1987年   373篇
  1986年   368篇
  1985年   372篇
  1984年   287篇
  1983年   254篇
  1982年   186篇
  1981年   187篇
  1979年   267篇
  1978年   219篇
  1977年   186篇
  1974年   201篇
  1973年   219篇
  1972年   180篇
  1971年   171篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Lateral orbitotomy--a review   总被引:2,自引:0,他引:2  
Lateral orbitotomy is the standard surgical approach to lesions in the middle third of the orbit, to many lesions in the posterior third of the orbit and to benign lacrimal gland tumours. The indications, surgical technique and complications are discussed.  相似文献   
92.
OBJECTIVES: to evaluate the Saville and Holdsworth Occupational Personality Questionnaire (OPQ) to assess its potential and validity as a tool in the recruitment of doctors. To determine the range of personality characteristics in a group of general practitioners. DESIGN: an administered commercially available questionnaire. SETTING: general practitioners in North and Mid. Stafftordshire. SUBJECTS: 133 general practitioners or trainees. RESULTS: 44% of general practitioners agreed to participate. The majority found it useful and recognised its potential to increase self-awareness, highlight weaknesses that might be improved and for future recruitment of others to their teams. Doctors' personality traits were similar to those of managerial/professional norms. The validity of the OPQ was supported by (a) significant associations with subjects' previously reported mental health problems and (b) 83% of respondents confirming that their reports correctly described their personalities at work. CONCLUSIONS: OPQs have a place in the recruitment of doctors by identifying appropriate people to strengthen the team.  相似文献   
93.
The Kasabach-Merritt syndrome is characterized by thrombocytopenia and localized coagulopathy associated with a hemangioma. Most techniques applied to eradicate the tumor or accelerate its involution (surgery, radiation therapy, embolization) are invasive and require transfusion of large amounts of blood products. In some cases, medical treatment is the only alternative. Efficacy of steroids and antifibronolytic agents has already been described, but even this approach is associated with the administration of blood products. We report two cases of infants with Kasabach-Merritt syndrome associated with cardiac and hepatic hemangiomas. At admission, both had signs of cardiac failure. They were successfully treated with prednisone and epsilon-aminocaproic acid (EACA). Blood products were not required once the diagnosis was made. These observations have important implications for the management of patients with Kasabach-Merritt syndrome because they show that even in severe cases blood transfusions can be avoided by the use of prednisone and EACA.  相似文献   
94.
Flow-independent angiography (FIA), an approach that isolates arterial blood using MR relaxation characteristics rather than flow effects, was evaluated for application in peripheral vascular disease (PVD). First, pilot studies were conducted in which FIA coronal projection images were obtained from controls and symptomatic patients with PVD to assess clinical utility. All control images corresponded to the expected leg arterial anatomy with little interference from deep veins (one of five) and muscle (zero of five). Superficial venous signal was less well suppressed in comparison to deep veins (four of five). Images of symptomatic patients were less consistent with difficulty suppressing muscle and deep venous signal in some cases and edema when present. We then compared T2 values for muscle (T2m, tibialis anterior), arterial blood (femoral and popliteal arteries), and venous blood (femoral, popliteal, and saphenous veins) in controls (n = 8) and symptomatic patients with intermittent claudication (n = 5) or ischemic rest pain (n = 7). Changes in T2 measurements of various tissues accounted for poorer contrast in symptomatic patients. Patients with ischemic rest pain had significantly higher T2m compared with controls (T2m = 39.3 ± 2.1 (1 standard error of the mean [SEM]) versus 30.9 ± .4, P < .01). For all measurements, other than saphenous vein, variances were greater in symptomatic patients. To realize the inherent advantages of FIA for this clinical application, additional work on suppression of signals from muscle, veins, and edema is required. One promising approach involves shifting from projection images to three-dimensional acquisitions for improved tissue suppression.  相似文献   
95.
96.
97.
The purpose of this investigation was to examine the morphologic and histochemical characteristics of paraspinal muscles in patients with scoliosis after long-term electrical stimulation. Thirty-six children with idiopathic scoliosis, who had been treated with implantable muscle stimulators, had paraspinal muscle biopsies at the time of implantable muscle stimulator removal. Group A patients whose curve did not progress, had 2.9 years of stimulation stopped at skeletal maturity, with a further 1.5 years of nonstimulation before implant removal and biopsy. In group B patients, who had an average of 2.3 years of stimulation, the curve progressed and stimulation was continued until fusion and biopsy. Neither group showed any increase in the frequency of pathologic changes of paraspinal muscles contrasted with values reported in the literature for scoliotic muscle. In group A patients there was an increased proportion of type 1 fibers on the convex side of the curve compared to the concavity. Despite this finding the curves did not require fusion, suggesting that the increased percentage of type 1 fibers was not the cause of the scoliosis. In group B patients there was an even higher type 1 concentration on the convex side contrasted to the convex side of group A patients.  相似文献   
98.
99.
OBJECTIVES: To determine the prevalence of mental illness in older adults and its effect on home care and personal care home (PCH) use. METHODS: Using nonidentifying administrative records (fiscal years 1997-1998 to 2001-2002) from the Population Health Research Data Repository housed at the Manitoba Centre for Health Policy, we determined the 5-year period prevalence for individuals aged 55 years and over (119 539 men and 145 752 women) for 3 mental illness categories: cumulative mental disorders (those having a diagnosis of depression, anxiety disorder, personality disorder, schizophrenia, and [or] substance abuse), any mental illness, and dementia. We calculated age-specific and age-adjusted rates of home care and PCH use and the prevalence of mental illness in PCH residents. RESULTS: From the group aged 55 to 59 years to the group aged 90 years or older, the prevalence of mental illness increased with the population's age. The prevalence of any mental illness rose from 32.4% to 45.0% in men and from 42.6% to 51.9% in women, and dementia prevalence rose from 2.0% to 33.6% in men and from 1.3% to 40.3% in women. The age-adjusted annual rates of open home care cases per 1000 population aged 55 and older varied by mental illness grouping (no mental disorder, 57 for men and 91 for women; cumulative mental disorders, 162 for men and 191 for women; dementia, 300 for men and 338 for women). The age-adjusted rates of PCH use per 1000 population aged 75 years and older also varied by mental illness grouping (no mental disorder, 53 for men and 78 for women; cumulative mental disorders, 305 for men and 373 for women; dementia, 542 for men and 669 for women). Among patients admitted to (or resident in) a PCH in 2002-2003, 74.6% (87.1%) had a mental illness, and 46.0% (69.0%) had dementia. CONCLUSIONS: Mental illness affects the use of home care and nursing homes profoundly. Individuals with dementia used home care at 3 times the rate of those having no mental illness diagnosis, and they used PCHs at 8 times the rate.  相似文献   
100.
BACKGROUND: Acute administration of different classes of antidepressants can enhance or reduce spontaneous locomotor activity in a novel environment, but the effects of chronic antidepressant treatment on spontaneous locomotor activity in novel and familiar environments are less well characterized. Because norepinephrine is an important regulator of spontaneous locomotor activity, we speculated that norepinephrine transporter blockade contributes to the effects of some antidepressants on spontaneous locomotor activity. METHODS: Antidepressant drugs (reboxetine, desipramine, imipramine, venlafaxine, bupropion) were administered acutely (intraperitoneal) or chronically (via osmotic minipump) to control and norepinephrine transporter knockout mice, and spontaneous locomotor activity in novel or familiar environments was recorded. RESULTS: Acute treatment with most norepinephrine transporter-blocking antidepressants decreased spontaneous locomotor activity in a novel environment, whereas chronic treatment decreased spontaneous locomotor activity in both novel and familiar environments. The exception was bupropion, a dual norepinephrine transporter/dopamine transporter blocker, which tended to increase spontaneous locomotor activity. Coadministration of reboxetine and the dopamine transporter blocker GBR 12909 also increased spontaneous locomotor activity. Norepinephrine transporter knockout mice had low basal spontaneous locomotor activity, which was increased by bupropion, whereas reboxetine had no effect in norepinephrine transporter knockout mice. CONCLUSIONS: Acute or chronic inactivation of the norepinephrine transporter decreases spontaneous locomotor activity in novel and familiar environments unless coupled with dopamine transporter blockade.  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