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   11361篇
  免费   1229篇
  国内免费   25篇
耳鼻咽喉   98篇
儿科学   383篇
妇产科学   213篇
基础医学   1491篇
口腔科学   195篇
临床医学   1428篇
内科学   2205篇
皮肤病学   122篇
神经病学   1114篇
特种医学   427篇
外科学   1346篇
综合类   725篇
一般理论   13篇
预防医学   1144篇
眼科学   336篇
药学   739篇
中国医学   3篇
肿瘤学   633篇
  2023年   57篇
  2022年   102篇
  2021年   215篇
  2020年   133篇
  2019年   181篇
  2018年   283篇
  2017年   168篇
  2016年   175篇
  2015年   161篇
  2014年   255篇
  2013年   451篇
  2012年   501篇
  2011年   500篇
  2010年   322篇
  2009年   276篇
  2008年   462篇
  2007年   535篇
  2006年   543篇
  2005年   524篇
  2004年   474篇
  2003年   442篇
  2002年   441篇
  2001年   417篇
  2000年   408篇
  1999年   374篇
  1998年   153篇
  1997年   137篇
  1996年   150篇
  1995年   142篇
  1994年   105篇
  1993年   125篇
  1992年   279篇
  1991年   269篇
  1990年   282篇
  1989年   240篇
  1988年   222篇
  1987年   238篇
  1986年   190篇
  1985年   152篇
  1984年   152篇
  1983年   131篇
  1982年   97篇
  1981年   63篇
  1980年   73篇
  1979年   110篇
  1978年   102篇
  1977年   88篇
  1976年   71篇
  1975年   75篇
  1970年   56篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The synovial fluid aspirated from patients with symptomatic arthritis was analyzed for the presence of tumor necrosis factor (TNF), interleukin 6 (IL-6) and interleukin 8 (IL-8). All three cytokines were found in both inflammatory and non-inflammatory arthritides: IL-8 levels ranged from less than 20 to 38,990 pg/ml, IL-6 from less than 10 to 72,300 pg/ml and TNF from less than 4 to 61 pg/ml. No inhibitors of cytokine activity were found. IL-8 and IL-6 were present in significantly higher levels in patients with inflammatory arthritis compared to patients with osteoarthritis, and there was significant correlation between the IL-6 and IL-8 levels. These findings document the presence of multiple cytokines in the synovial fluid specimens of patients with arthritis, and demonstrate that higher cytokine levels accompany inflammatory arthritis.  相似文献   
82.
Although survival of older burn victims has improved significantly in recent years, controversy remains over the care that should be given to this group and the functional recovery of survivors. To assess the impact of burn injury on lifestyle in the elderly, we conducted a mail-in survey among surviving patients ages 45 years or older who were treated in our burn center from 1978 to the middle of 1987. The survey asked questions about living arrangements, personal care, family relations, social life, work status, and outlook on the future. Of 168 surveys mailed, 109 were completed and returned (64.9%). Responders consisted of 82 men and 27 women with a mean age of 57.8 years (range, 45 to 92 years). Ninety-seven percent of patients were able to return home after discharge, but 27% of the oldest patients (ages greater than 75 years) required permanent placement in extended care facilities. With increased age there was an increased tendency toward dependence and the need for assistance in daily living; half of the oldest patients required assistance in daily living. Even so, most of the patients in this survey remained independent and maintained a positive outlook on the future. These results appear to justify a policy of aggressive treatment for elderly burn victims.  相似文献   
83.
Nitrous acid, a component of photochemical smog and a common indoor air pollutant, may reach levels of 100 ppb where gas stoves and unvented portable kerosene heaters are used. Nitrous acid is a primary product of combustion and may also be a secondary product by reaction of nitrogen dioxide with water. Because the usual assays for nitrogen dioxide measure several oxides of nitrogen (including nitrous acid) together, previous studies of indoor nitrogen dioxide may have included exposure to and health effects of nitrous acid. To assess the respiratory effects of nitrous acid exposure alone, we carried out a double-blinded crossover chamber exposure study with 11 mildly asthmatic adult subjects. Each underwent 3-hr exposures to 650 ppb nitrous acid and to filtered room air with three 20-min periods of moderate cycle exercise. Symptoms, respiratory parameters during exercise, and spirometry after exercise were measured. A statistically significant decrease in forced vital capacity was seen on days when subjects were exposed to nitrous acid. This effect was most marked at 25 min and 85 min after exposure began. Aggregate respiratory and mucous membrane symptoms were also significantly higher with nitrous acid. We conclude that this concentration and duration of exposure to nitrous acid alters lung mechanics slightly, does not induce significant airflow obstruction, and produces mild irritant symptoms in asthmatics.  相似文献   
84.
85.
86.
87.
Acquired immunodeficiency syndrome (AIDS) is a serious disease that has special concern for the health care provider. AIDS has continued to grow despite control efforts. As the disease infectivity period remains lengthy, and the heterosexual population is affected to a greater degree, the level of anxiety has also risen despite educational endeavours. Many fears and anxieties have been associated with AIDS patients by health care workers. The reduction of stress, perceived risk and discomfort following educational efforts have been supported in past research. Educational programmes will need to be given for current health care workers at all levels as well as nursing students. Future nurses must be prepared to meet this challenge. This study was conducted using a convenience sample of nursing students at a university in western United States. Its purpose was to assess any changes that occurred in state anxiety following an educational presentation. Spielberge's State-Trait Anxiety Inventory was used as the measurement instrument. Some anxiety levels were significantly reduced.  相似文献   
88.
A father and his two sons each presented with atrial tachycardia in the newborn period. The father went on to develop dilated cardiomyopathy. The first son (who also had transposition of the great arteries) died from the arrhythmia after surgery. The second son is currently successfully managed pharmacologically.  相似文献   
89.
90.
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