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   861篇
  免费   68篇
  国内免费   2篇
耳鼻咽喉   13篇
儿科学   23篇
妇产科学   4篇
基础医学   97篇
口腔科学   114篇
临床医学   76篇
内科学   144篇
皮肤病学   12篇
神经病学   40篇
特种医学   101篇
外科学   120篇
综合类   44篇
预防医学   44篇
眼科学   6篇
药学   44篇
肿瘤学   49篇
  2019年   16篇
  2018年   12篇
  2016年   16篇
  2015年   14篇
  2014年   18篇
  2013年   18篇
  2012年   22篇
  2011年   21篇
  2010年   23篇
  2009年   18篇
  2008年   19篇
  2007年   30篇
  2006年   26篇
  2005年   23篇
  2004年   31篇
  2003年   18篇
  2002年   21篇
  2001年   26篇
  2000年   27篇
  1999年   31篇
  1998年   28篇
  1997年   22篇
  1996年   24篇
  1995年   15篇
  1994年   16篇
  1993年   13篇
  1992年   22篇
  1991年   15篇
  1990年   11篇
  1989年   27篇
  1988年   16篇
  1987年   15篇
  1986年   19篇
  1985年   16篇
  1984年   16篇
  1983年   12篇
  1982年   10篇
  1981年   15篇
  1980年   15篇
  1979年   11篇
  1978年   15篇
  1977年   14篇
  1976年   17篇
  1974年   9篇
  1973年   10篇
  1972年   10篇
  1971年   8篇
  1970年   8篇
  1969年   8篇
  1968年   13篇
排序方式: 共有931条查询结果,搜索用时 15 毫秒
61.
This study compares the effects of atypical and conventional antipsychotic medications on treatment continuation and outcomes in a first admission sample of patients with schizophrenia treated in usual practice settings. In a sample of 189 participants with a research diagnosis of DSM-IV schizophrenia drawn from the Suffolk County Mental Health Project, we compared the effects of atypical and conventional agents on change of medication, medication gaps, and rehospitalization. For these analyses we used the method of survival analysis for recurrent events, in which the episodes of treatment rather than individual subjects are the units of analysis. In addition, we compared improvement in positive and negative symptoms from intake to 24- or 48-month followups for subjects who stayed on one type of medication or changed to atypicals from conventional antipsychotics. Atypical agents were associated with lower risk of medication change, medication gaps, and rehospitalization. Both conventional and atypical agents were associated with improvement of positive symptoms at followup, but only subjects on atypical agents at followup experienced a significant improvement in negative symptoms. We conclude that in usual practice settings, as in randomized clinical trials, atypical agents are associated with improved treatment continuation and outcomes.  相似文献   
62.
63.
MR imaging of the pancreas   总被引:2,自引:0,他引:2  
Current MR imaging technology offers the surgeon diagnostic information about pancreatic diseases. This article reviews the basics of MR imaging formation and the rationale for the different types of imaging sequences that comprise a comprehensive pancreaticobiliary examination. Clinical examples include evaluation of pancreatic neoplasms, acute and chronic pancreatitis, and congenital abnormalities.  相似文献   
64.
OBJECTIVE: The authors examined the duration of untreated psychosis, defined as the interval from first psychotic symptom to first psychiatric hospitalization, in a county-wide sample of first-admission inpatients who had received no previous antipsychotic medication. Differences between diagnostic groups in 24-month illness course and clinical outcomes as well as relationships between outcomes and duration of untreated psychosis were evaluated. METHOD: The data were derived from subjects in the Suffolk County Psychosis Project who were diagnosed at 24-month follow-up according to DSM-IV as having schizophrenia or schizoaffective disorder (N=155), bipolar disorder with psychotic features (N=119), or major depressive disorder with psychotic features (N=75). Duration of untreated psychosis was derived from the Structured Clinical Interview for DSM-III-R, medical records, and information from significant others. Measures at 24-month follow-up included consensus ratings of illness course, Global Assessment of Functioning Scale scores for the worst week in the month before interview, and current affective and psychotic symptoms. RESULTS: The median duration of untreated psychosis was 98 days for schizophrenia, 9 days for psychotic bipolar disorder, and 22 days for psychotic depression. Duration of untreated psychosis was not significantly associated with 24-month illness course or clinical outcomes in any of the diagnostic subgroups. CONCLUSIONS: Although these findings require replication in other epidemiologically based first-admission samples, at face value they do not support the suggestion of a psychotoxic effect of prolonged exposure to untreated psychosis.  相似文献   
65.
The recent commercial success of intraoral sensor systems largely reflects the quest to improve the quality assurances for endodontic services. The many advantages of these systems include reduced radiation exposures, real-time images, resolution improvements after initial image capture and archival benefits, although their diagnostic benefits over conventional film based radiographs remain a concern. For instance, the images from either charge-coupled device or storage phosphor sensors have yet to exceed the potential 50 microns spatial and 12-bit contrast resolutions obtained from the 1.75-6.40 microns silver grain emulsions of conventional films or the potential improvements derived from smaller (1 micron) grains. Intraoral sensor systems alone are therefore unlikely to improve the quality assurances for endodontic services.  相似文献   
66.
67.
68.
69.
Sarcoma arises extremely rarely on foreign bodies in man, but is aggressive and often lethal. A coating for implants which would further reduce the risk in man is desirable. The incidence in mice is much greater, and responds to chemical treatment of the implant surface. Coating with histones increases tumour yield. Accordingly, related substances, foreign DNA, DNase and a mixture of the two, were tested for anticancer activity by application to 25 mm nitrocellulose filters in groups of 30-45 BALB/c mice, in comparison with untreated filters. Other substances reported to influence neoplasia, paprika, beta-carotene, rhodamine and tuftsin; and substances expected to be neutral, oxyprenolol, liquid paraffin, iodine, and adenosine diphosphate were similarly tested against concurrent untreated controls for comparison. Bovine DNA (p = 0.01) and DNA/DNase mixture (p = 0.04) and DNase fomented tumour growth by 55, 45 and 59% respectively. Paprika and beta-carotene did so by 70% (p = 0.05). The other substances were inert. None were candidates for an anti-sarcoma coating.  相似文献   
70.
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