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   27139篇
  免费   1261篇
  国内免费   164篇
耳鼻咽喉   302篇
儿科学   774篇
妇产科学   547篇
基础医学   3238篇
口腔科学   1012篇
临床医学   1943篇
内科学   6836篇
皮肤病学   381篇
神经病学   2372篇
特种医学   1000篇
外科学   4285篇
综合类   97篇
一般理论   11篇
预防医学   1790篇
眼科学   326篇
药学   1619篇
中国医学   90篇
肿瘤学   1941篇
  2023年   228篇
  2022年   525篇
  2021年   939篇
  2020年   524篇
  2019年   759篇
  2018年   981篇
  2017年   634篇
  2016年   722篇
  2015年   851篇
  2014年   1142篇
  2013年   1324篇
  2012年   2184篇
  2011年   2123篇
  2010年   1299篇
  2009年   1067篇
  2008年   1793篇
  2007年   1749篇
  2006年   1668篇
  2005年   1537篇
  2004年   1344篇
  2003年   1228篇
  2002年   1172篇
  2001年   232篇
  2000年   169篇
  1999年   214篇
  1998年   196篇
  1997年   164篇
  1996年   158篇
  1995年   158篇
  1994年   117篇
  1993年   109篇
  1992年   93篇
  1991年   77篇
  1990年   110篇
  1989年   73篇
  1988年   70篇
  1987年   58篇
  1986年   75篇
  1985年   57篇
  1984年   70篇
  1983年   50篇
  1982年   56篇
  1981年   41篇
  1980年   49篇
  1979年   36篇
  1978年   47篇
  1977年   25篇
  1975年   23篇
  1973年   25篇
  1972年   23篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
We examined the effectiveness of self-operated auditory prompts when used to decrease the off-task and aberrant behaviors of two students with moderate mental retardation. Its purpose was to determine if self-operated auditory prompts could be effectively used by these individuals to decrease their off-task and aberrant behaviors in work settings and during transitional times between settings. A multiple-probe across settings design with a reversal and replication was used to evaluate the effectiveness of the self-operated auditory prompting system on aberrant student behaviors in school and community settings. Previous findings were replicated in this study that demonstrate that stimulus control can be achieved through the use of self-operated auditory prompts, and demonstrates that these prompts can serve to occasion a decrease in aberrant behaviors when used by individuals with moderate mental retardation in school and community settings.  相似文献   
103.
104.
105.
PURPOSE: Loss of a certain amount of cutaneous tissue of the perineal region may be remedied by first intention with creation of cutaneous flaps, thus preventing second intention healing. METHODS: We present three emblematic cases in which the posterior perineal region was reconstructed by means of vertical subcutaneous pedicle flaps, subsequent to cutaneous tissue loss after surgery for extensive condilomas or neoplastic pathologies. RESULTS: Tissue loss was repaired by means of a V-Y type vertical subcutaneous pedicle flap, constructed laterally of the extirpation zone and advanced in a median direction. In all cases, no ischemia or infection of flaps occurred; sphincteral continence and long-term aesthetic results have proved to be satisfactory. CONCLUSIONS: Vertical pedicle subcutaneous flaps are well vascularized, extremely mobile, and easy to perform and have no serious postoperative complications.  相似文献   
106.
Socioeconomic and family characteristics of two cohorts of babies born in 1982 and 1993 in Pelotas (Southern Brazil) were compared. There were 6,011 births in 1982 and 5,304 in 1993. In relation to family income, there were fewer poor babies in 1993; 60.8 % of the families earned less than 3 times the monthly minimum wage in 1993, as compared to 69.5% in 1982. Sanitary conditions also improved over the decade, and the proportion of families with running water and flush toilets increased by 10%. On the other hand, there were no changes in the proportion of single-parent families or availability of home appliances like radios, stoves, and refrigerators. The mean number of persons per household increased from 3.0 in 1982 to 3.2 in 1993. In general, comparison of the two birth cohorts in this city suggests an improvement in quality of living over the time period for families with newborns. This finding should be taken into account when studying the evolution of health indicators over the course of the decade.  相似文献   
107.
108.
Spontaneous portosystemic shunts are commonly found in cirrhotic patients. Not yet established is their role after orthotopic liver transplantation (OLTx), especially when an increase in portal pressure develops, as during early acute rejection. In this study, 34 cirrhotic patients in a series of 70 OLTx are considered. Each patient had preoperative angiographic assessment, and, in 21 (62%), large spontaneous portosystemic shunts were evident. In 12 cases the shunts were not affected by the surgical procedure and were present during the postoperative period; in 9 the hepatectomy itself involved interruption of the shunts. The patient population was divided into two groups: patients with postoperative shunts (n=12) and those without (n=22). The two groups were similar in age, sex, Child's stage, transplantation variables, and number and grade of rejection episodes. However, mean transaminases (AST) values in the first 2 weeks were significantly higher levels in shunt versus nonshunt patients (421±335 vs 183±126; P<0.025), and this was even more evident when rejection occurred (626±375 vs 195±129; P<0.001). Furthermore, during an acute rejection reaction, three cases showed a true steal phenomenon through the large reopened shunts with ischemic damage to the grafts. The data indicate a possible detrimental effect of the spontaneous shunts on graft perfusion and suggest the prophylactic surgical interruption of the residual shunts during the transplantation.  相似文献   
109.
The locomotor activity of C57B1/6J and DBA/2J mice was studied, under the influences of heroin, amphetamine, strychnine, or ethanol, and of combinations of the opiate with each one of the other drugs. Heroin treatment was followed by the typical running fit in the C57 mice, while the DBA strain was unaffected. Amphetamine enhanced the activity in the C57 strain only. The combination of heroin with amphetamine or ethanol increased the locomotor activity only in the DBA strain, while heroin + strychnine exerted a clear stimulating effect on the activity of the C57 mice. The strychnine + heroin mixture was more toxic than heroin alone when the lethal doses (LD50) were determined in the 2 strains.  相似文献   
110.
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