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   70517篇
  免费   6423篇
  国内免费   2956篇
耳鼻咽喉   732篇
儿科学   840篇
妇产科学   1277篇
基础医学   9949篇
口腔科学   1818篇
临床医学   6711篇
内科学   12259篇
皮肤病学   1159篇
神经病学   4584篇
特种医学   2550篇
外国民族医学   11篇
外科学   9218篇
综合类   7918篇
现状与发展   6篇
一般理论   6篇
预防医学   4348篇
眼科学   1966篇
药学   6599篇
  21篇
中国医学   2071篇
肿瘤学   5853篇
  2024年   85篇
  2023年   483篇
  2022年   934篇
  2021年   1635篇
  2020年   1144篇
  2019年   1241篇
  2018年   1715篇
  2017年   1501篇
  2016年   1379篇
  2015年   1780篇
  2014年   2341篇
  2013年   2672篇
  2012年   3870篇
  2011年   3809篇
  2010年   2459篇
  2009年   2290篇
  2008年   3026篇
  2007年   2994篇
  2006年   2776篇
  2005年   2376篇
  2004年   2015篇
  2003年   2023篇
  2002年   1835篇
  2001年   5058篇
  2000年   4867篇
  1999年   4091篇
  1998年   1510篇
  1997年   1113篇
  1996年   682篇
  1995年   584篇
  1994年   519篇
  1993年   463篇
  1992年   1981篇
  1991年   1724篇
  1990年   1568篇
  1989年   1521篇
  1988年   1315篇
  1987年   1206篇
  1986年   1082篇
  1985年   911篇
  1984年   597篇
  1983年   474篇
  1982年   252篇
  1981年   182篇
  1980年   146篇
  1979年   287篇
  1978年   84篇
  1976年   74篇
  1974年   80篇
  1973年   101篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A strain (named BJ-1) of hepatitis A virus (HAV) causing cytopathic effects (CPE) has been isolated in A549 cell cultures from a fecal specimen of an infant with hepatitis A. Hepatitis A antigen (HAAg) w3s detectable in about 50To of the cells by immunofluo- rescence (IF) assay. The viral antigenicity was spe- cifically identified by monoclonal anti-HAV and chim- panzee reference antiserum to HAV (NIH). HAV particles in crystal arraDgement were observed in cell cytoplasm by electron microscopy in ultrathin sec tions. The particles appeared both "empty" and "full". It was observed that many 27-30 nm virtts particles were aggregated by convalescent human he- patitis A sera and chimpanzee HAV antisera observ- ed by immune electron microscopic (IEM) ex- amination. BJ-1 HAAg could be detected on day 34 after inoculation at the initial passage. The virus titers increased and the virus replication cycle short- ened with serial passages. The highest TCID 50 was 10-5/0.1 ml and the shortest replication cycle 2-3 days. IF kit consisting of BJ-1 HAV infected A549 coverslip culture and sheep fluorescence antibody to human IgM were made to detect anti-HAV IgM. Comparing the BJ-t IF with the Abbott EIA HAVAB- M kit. the coincidence rate was 98.4% (246/250).  相似文献   
992.
"Spontaneous" remission of leukemia has been observed in both humans and animals. Bierman et al2 in 1953 reported 11 cases of remis- sion in acute lymphoblastic leukemia (ALL) of childhood following acute infectious disease. In 1979 we saw a case of ALL remission in a child following a severe attack of respiratory infection.  相似文献   
993.
994.
The molecular heterogeneity of serum alpha-fe- toprotein (AFP) in 36 patients was studied by lectin affinity-radioimmunoelectrophoresis. Two variants of AFP, concanavalin-A (Con-A) reactive and the Con-A nonreactive, were obtained. AFP in all 13 patients with hepatoma consisted of the two va- riants, but the Con-A reactive variant was the ma jor one. In 8 patients with benign liver disorder, however, only the Con-A reactive variant of AFP was detected. Over 50"70 0f AFP in 5 patients with yolk sac tumor was Con-A nonreactive. Thus, there were three different patterns of AFP variants. The clinical implications are discussed.  相似文献   
995.
In order to evaluate the significance of the sinus node function test by transvenous atrial pacing in the diagno,sis of sick sinus syndrome (SSS), sinus node recovery time (SRT), co]rrected sinus node recovery time (CSRT) and total atrio- sinus and sino-atrial conduction time (SACT) are observed in 69 patients including non-SSS group 39 cases and SSS group 30 cases. According to our data, we suggest criteria for sinus node dysfunction as follows. SRT>1,400 ms and/or A-V junctional esca.pe before sinus recovery and;or secondary pause, CSRT>560 ms. total SACT>300 ms. With l item abnormal, the false positive rat.e in the non-SSS group is 7.7c7。 and the false negative rate in the S.SS group 3.30i" with 2 items abnormal, the false positive rate in the non-SSS group Oi and the false negative rate in the SSS grOiup 6.7'70. Atropine test results are compared with that of atrial pacing, 95.8To and 84.2% are compatible with each other in these 2 groups. In order to cut the use of invasive technic to the minimum, we propose performing the atropine test first. Only in those with unexplainable test results should the trial pacing test. be resorted to..  相似文献   
996.
AT1727 is a derivative of ICRF 154. The purpose of this study was to evaluate its "radiosensitizer" properties. From October 1979 until the end of December 1980, 89 patients with radiation resistant cancers such as soft tissue sarcoma, squamous lung cancer (with large lesion, 6-8 cm diameter) and other cancers had been included in trial. Radiation therapy was carried out using CO60 or 8 Mev Linac. Fifty-five patients had a remarkable objective remission rate of 61.8% (55/89). Eighteen of 30 patients with soft tissue sarcomas obtained obvious remission (60%), and 26 of 38 patients with lung cancer had remission (68.4%). Patients with esophageal cancer (5/6) and nasopharyngeal cancer (5/5) also had good remission rates. The side-effects of this treatment were very mild: anorexia and vomiting were noted in 50% and no significant changes were noted in liver and kidney function tests and blood platelet count. Leucopenia was slight in all but one patient. No difference in the lung fibrosis rate was noted between the two randomized groups. From the results of this study we concluded that AT1727 had some effect as a "radiosensitizer" but much more work is needed to confirm this.  相似文献   
997.
目的 调查河南省儿童青少年遗尿症的情绪和行为问题的现况及其影响因素。 方法 从2019年10月—2020年3月,采用分层随机整群抽样方法抽取河南某县5所中小学校,采用一般资料调查表、长处和困难问卷及儿童睡眠调查表进行调查,对影响遗尿患儿情绪和行为的因素进行单因素、多因素分析。 结果 实际发放问卷4 500份,回收4 120份,有效问卷3 912份,有效回收率为94.95%。调查结果显示有7.82%儿童患有遗尿症。遗尿组的情绪症状、多动和困难总分得分明显高于正常组(P<0.001),两组品行问题、同伴交往和社会行为得分的比较差异无统计学意义(P>0.05)。Pearson相关分析结果显示,遗尿儿童和青少年的困难总分与打鼾、夜间呼吸问题、嗜睡、注意力缺陷、睡眠总分均存在正相关关系(P<0.05)。多元线性回归结果显示睡眠呼吸紊乱、照顾者文化程度低、便秘、学习成绩较差是遗尿患儿情绪和行为问题的影响因素。 结论 遗尿患儿情绪和行为问题的检出率高,影响因素是睡眠呼吸紊乱、照顾者文化程度低、孩子学习成绩差、便秘,应引起关注。  相似文献   
998.
Quality of Life Research - To develop two item content-matched, precise, score-level targeted inpatient physical function (PF) short form (SF) measures: one clinician-reported, one...  相似文献   
999.
Advances in Health Sciences Education - Background: Despite being a mandated, foundational value in healthcare, research on compassion remains limited. Studying the individual, patient, clinical,...  相似文献   
1000.
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