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   30679篇
  免费   2584篇
  国内免费   1484篇
耳鼻咽喉   298篇
儿科学   532篇
妇产科学   685篇
基础医学   3590篇
口腔科学   421篇
临床医学   3536篇
内科学   5845篇
皮肤病学   414篇
神经病学   2082篇
特种医学   1069篇
外国民族医学   11篇
外科学   3805篇
综合类   3380篇
一般理论   5篇
预防医学   1832篇
眼科学   748篇
药学   2886篇
  15篇
中国医学   1047篇
肿瘤学   2546篇
  2024年   65篇
  2023年   388篇
  2022年   872篇
  2021年   1238篇
  2020年   831篇
  2019年   911篇
  2018年   1032篇
  2017年   797篇
  2016年   867篇
  2015年   1195篇
  2014年   1463篇
  2013年   1421篇
  2012年   2114篇
  2011年   2334篇
  2010年   1343篇
  2009年   1188篇
  2008年   1700篇
  2007年   1644篇
  2006年   1645篇
  2005年   1580篇
  2004年   1220篇
  2003年   1034篇
  2002年   935篇
  2001年   789篇
  2000年   773篇
  1999年   722篇
  1998年   426篇
  1997年   380篇
  1996年   352篇
  1995年   310篇
  1994年   229篇
  1993年   194篇
  1992年   315篇
  1991年   302篇
  1990年   274篇
  1989年   259篇
  1988年   224篇
  1987年   208篇
  1986年   193篇
  1985年   159篇
  1984年   121篇
  1983年   78篇
  1982年   44篇
  1981年   58篇
  1980年   48篇
  1979年   71篇
  1978年   58篇
  1977年   36篇
  1976年   36篇
  1974年   44篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Though distressing and potentially dangerous, sleep apnea may be an under-recognized disease in many countries. The obstructive type, which usually presents with loud snoring and excessive daytime sleepiness, is by far the commonest form. It causes a great deal of medical, social and psychological morbidity as well as an increased mortality. Doctors of different specialties have an important role in detecting and referring suspected patients for early assessment and treatment. Multidisciplinary management in a general hospital and accurate assessment with polysomnography are essential as modern and sometimes effective methods of treatment are becoming available.  相似文献   
12.
13.
This study evaluated the effectiveness of early orthodontic treatment with the Twin-block appliance for the developing Class II Division 1 malocclusion. This multicenter trial was carried out in the United Kingdom. A total of 174 children, aged 8 to 10 years old, with Class II Division 1 malocclusion were randomly allocated to receive treatment with a Twin-block appliance or to an untreated, control group. Data were collected at the start of the study and 15 months later. Results showed that early treatment with Twin-block appliances resulted in reduction of overjet, correction of molar relationships, and reduction in severity of malocclusion. Most of this correction was due to dentoalveolar change, but some was due to favorable skeletal change. Early treatment with the Twin-block appliance is effective in reducing overjet and severity of malocclusion. The small change in the skeletal relationship might not be considered clinically significant.  相似文献   
14.
15.
BACKGROUND AND PURPOSE: The Doppler waveform patterns of loss of diastolic flow, appearance of retrograde diastolic flow, or no detectable flow in the cerebral arteries suggest significantly abnormal cerebral blood flow (CBF). A retrospective study was performed to show that significantly abnormal CBF alone, without clinical criteria, is not necessarily specific to brain death in the young pediatric population. PATIENTS AND METHODS: Forty-seven pediatric patients, from newborn to 4 years of age, were found to have significantly abnormal CBF, including 7 patients with loss of diastolic flow, 28 with retrograde diastolic flow, and 23 with no detectable cerebral flow on serial Doppler sonographic examinations. Their clinical data and sonographic results were collected and analyzed. RESULTS: Forty-two patients died, a few of whom had only transient improvement of cerebral flow. All of the patients with no detectable cerebral flow expired. Five patients survived with or without sequelae. Their underlying conditions that caused increased intracranial pressure were treated by medical and/or surgical intervention, and diastolic reversal of CBF corrected within 1 day in all 5. CONCLUSIONS: Although no detectable flow is a lethal sign, pediatric patients with loss or reversal of diastolic flow may survive with prompt and effective treatment. Using Doppler ultrasound to diagnose cerebral circulatory arrest should be done with caution in pediatric patients.  相似文献   
16.
Extracellular phospholipase A2 (PLA2) is a proinflammatory enzyme found especially in the inflammatory exudate to modulate blood flow to areas of antigen stimulation. In this study we found that PLA2 exerted a biphasic effect on the proliferation of phytohemagglutinin (PHA)-stimulated human mononuclear cells (PHA MNC). At low concentrations range from 0.001 to 1 U/ml, PLA2 enhanced the proliferation of PHA MNC (maximal increase was 37.0 +/- 5.67%). Conversely, at concentrations over 10 U/ml, PLA2 markedly suppressed the PHA-induced MNC proliferation (maximal decrease was 88.86 +/- 2.89%). PLA2 was non-toxic to lymphocytes after three days culture, unless the concentration was higher than 100 U/ml. The membrane polarization of PHA-stimulated lymphocytes was also increased by PLA2 at a low concentration. In addition, PLA2 displayed a similar effect on the proliferation of streptokinase-streptodornase (SK/SD) or allogeneic cell stimulated lymphocytes. The change of lymphocyte proliferation by PLA2, was parallel to the change of percentage of helper T cells. Furthermore--a CD4-rich population was proved more susceptible to PLA2 effect than a CD8-rich population. Para-bromophenacyl bromide (pBPB), an irreversible inhibitor of PLA2, abrogated the biphasic effect of PLA2 on PHA MNC proliferation. These results suggest that PLA2 plays a regulatory role on immune reactions by modulating the percentage of helper T cells.  相似文献   
17.
Abstract Traditional Native American people are experiencing serious health, economic, and social problems resulting from alcoholism. Native Americans maintain a worldview of health and illness that conflicts with the dominant culture's approach to treatment. The purposes of this study were to describe the health beliefs of traditional Muscogee (Creek) Indians concerning the causes of illness and learn how these beliefs relate to alcoholism. The researchers conducted in-depth interviews of 55 traditional Muscogee (Creek) participants to learn traditional beliefs about illness and alcoholism. Data were analyzed using content analysis. Results indicate that both illness and alcoholism are perceived as having natural and unnatural (supernatural) causes. A challenge facing nurses is how to provide culturally sensitive care when clients' and nurses' beliefs about the cause of alcoholism may be in conflict. The authors discuss preservation, accommodation, and repatterning of health care beliefs as a basis for planning culturally sensitive nursing care.  相似文献   
18.
Vasculitis in many forms has been reported rarely in association with ulcerative colitis. We report the occurrence of necrotizing vasculitis in a 48-year-old man 19 years after the onset of ulcerative colitis and 5 years after total colectomy with rectal preservation. The disease was limited to small arteries of skin and muscle consistent with the syndrome of cutaneous polyarteritis nodosa that has been reported with regional enteritis but not previously with ulcerative colitis.  相似文献   
19.
Quality of life in adult survivors of lung,colon and prostate cancer   总被引:22,自引:0,他引:22  
In a cross-sectional study design, a disease free sample of 57 lung, 117 colon, and 104 prostate cancer survivors who represented short, intermediate and long-term survivors completed a detailed assessment of quality of life (QOL) and rehabilitation needs using the CAncer Rehabilitation Evaluation System (CARES). Demographic and medical data, social support, and a global QOL rating were also assessed. Lung cancer patients showed no differences in QOL with respect to their period of survival. QOL improved for survivors of colon cancer as they lived for longer periods, but declined with time for survivors of prostate cancer. The best predictor of QOL for all groups was KPS, although other variables such as type of hospital, gender, and work status were predictive for survivors of colon cancer. For survivors of prostate cancer comorbidity with other medical illnesses, time since diagnosis and comorbidity due to psychiatric difficulties were predictive of QOL. All groups had significant rehabilitation problems in the domains of physical, psychosocial, sexual, medical interaction, and marital relationships. Lung cancer survivors had more problems than the other cancer survivors. We conclude that patients who survive cancer do not return to a state of normal health. They demonstrate a variety of difficulties with which they must cope as they continue to survive. Greater efforts need to be made early in diagnosis and treatment to understand rehabilitation problems and target interventions in the hope of reducing later sequelae.Currently in private practice, Glendale, CaliforniaC. A. C. Schag was supported in part by Veterans Administration Health Research and Development Grant 83-002 and in part by Cares Consultants, 2210 Wilshire Blvd., Suite 359, Santa Monica, CA 90403.Address requests for Information about CARES to: CARES Consultants, 2210 Wilshire Blvd., Suite 359, Santa Monica, CA 90403, USA. Tel: (+1) 310-450-7410; Fax: (+1) 310-399-0016  相似文献   
20.
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