首页 | 官方网站   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   2591篇
  免费   111篇
  国内免费   15篇
医药卫生   2717篇
  2021年   30篇
  2020年   15篇
  2019年   15篇
  2018年   18篇
  2017年   29篇
  2016年   27篇
  2015年   50篇
  2014年   68篇
  2013年   67篇
  2012年   99篇
  2011年   93篇
  2010年   83篇
  2009年   72篇
  2008年   98篇
  2007年   80篇
  2006年   85篇
  2005年   59篇
  2004年   67篇
  2003年   70篇
  2002年   54篇
  2001年   53篇
  2000年   55篇
  1999年   70篇
  1998年   61篇
  1997年   76篇
  1996年   63篇
  1995年   57篇
  1994年   66篇
  1993年   46篇
  1992年   37篇
  1991年   38篇
  1990年   32篇
  1989年   43篇
  1988年   42篇
  1987年   48篇
  1986年   47篇
  1985年   32篇
  1984年   24篇
  1983年   23篇
  1982年   17篇
  1981年   27篇
  1980年   20篇
  1975年   15篇
  1971年   13篇
  1959年   37篇
  1958年   58篇
  1957年   87篇
  1956年   45篇
  1955年   75篇
  1954年   67篇
排序方式: 共有2717条查询结果,搜索用时 15 毫秒
1.
2.
3.
目的:采用核磁共振氢谱(~1H-NMR)植物代谢组学技术比较青海产区枸杞子与其他产区(宁夏、甘肃、新疆、内蒙古)枸杞子的化学成分差异。方法:收集5个产区共97份枸杞子样本,其中青海61个样本,采用50%甲醇提取,检测~1H-NMR图谱,结合多元统计分析,对比青海产区枸杞子与其他产区枸杞子的化学差异性,并对各产区样本的枸杞多糖进行含量测定(以无水葡萄糖计),检测波长490 nm。结果:枸杞子的~1H-NMR图谱共检测到32个化学成分,多元统计分析表明青海产区枸杞子与其他产区样本相比,无明显分离趋势;青海产区枸杞子与宁夏产区相比,以及青海省6个不同地区的枸杞子相比,重叠样品较多,均不能显著分开。相似度结果表明,大多数样品的相似度0.85;化合物的单变量分析结果显示,除了蔗糖、葡萄糖、脯氨酸等个别代谢物在各产区样本中存在显著差异外,其余代谢物在各产区样品中的含量分布基本一致。青海与其他产区样本中枸杞多糖含量无显著性差异,且枸杞多糖含量与~1H-NMR指认的小分子化合物的相关系数处于-0.2~0.4。结论:采用~1HNMR植物代谢组学技术从整体化学组成上分析了青海产区枸杞子的化学特征,并结合枸杞多糖含量测定,显示青海产区枸杞子与其他产区枸杞子的化学差异较小。建立的基于~1H-NMR的枸杞子质量评价方法可为其质控水平提升及种植产区选择提供科学依据。  相似文献   
4.
宫腹腔镜联合手术诊治不孕症150例分析   总被引:14,自引:0,他引:14  
目的:探讨宫腹腔镜联合手术在诊治不孕症中的应用。方法:对150例不孕症患者行宫腹腔镜联合手术,对不孕症病因进行诊断,同时行治疗。结果:盆腔粘连和输卵管阻塞是不孕症的主要原因。子宫内膜息肉和正常盆腔占次要比例。子宫内膜异位症和多囊卵巢也是主要病因。150例同时行宫腹腔镜输卵管通液和各种疾病的治疗。联合手术后妊娠率为48.8%。结论:腹腔镜联合手术,在一次麻醉下,可以对不孕的原因全面评价和明确诊断,在诊断同时进行治疗,对不孕症的诊断和治疗有重大的意义,值得推广。  相似文献   
5.
6.
7.
The authors measured the comorbid effect of alcohol and other drug (AOD) problems on medical, surgical, and psychiatric inpatient charges and length of stay (LOS) in an urban hospital by use of retrospective study of hospital clinical computer data comparing AOD-affected patients with non-AOD-affected patients in terms of cost, diagnostic, demographic, and utilization variables (N = 14,768). Patients were men and women with and without comorbid history of AOD problems, admitted for medical, surgical, and psychiatric reasons. For 10 of the 20 most frequent Diagnosis-Related Groups (DRGs), total hospital charges and LOS were significantly lower in patients with comorbid AOD problems (P < 0.001). Overall, for the most frequent 20 DRGs, total charges and LOS remained significantly lower for the AOD group. Most physicians believed that AOD-affected patients were often less ill than non-AOD patients within the same DRG. Alcohol/drug-affected patients had robustly lower costs and LOS. Fragmentation of psychosocial costs and addiction treatment from general health care and the fee-for-service DRG system appear to financially reward acute-care hospitals to repeatedly treat secondary AOD sequelae without providing any apparent incentives for the treatment of the primary alcohol/drug condition itself.  相似文献   
8.
This paper reviews evidence from clinical, epidemiologic, and family studies regarding the association between social phobia and other syndromes. Social phobia is strongly associated with other anxiety disorders, substance abuse, and affective disorders in both clinical and community samples. An average of 80% of social phobics identified in community samples meet diagnostic criteria for another lifetime condition. Social phobia is most strongly associated with other subtypes of anxiety disorders, with an average of 50% of social phobics in the community reporting a concomitant anxiety disorder including another phobic disorder, generalized anciety, or panic disorder. Approximately 20% of subjects in the community meet lifetime criteria for a major depressive disorder. The onset of social phobia generally precedes that of all other disorders, with the exception of simple phobia. Both clinical severity and treated prevalence are consistently greater among social phobics with comorbid disorders The results of family and twin studies reveal that shared etiologic factors explain a substantial proportion of the comorbidity between social phobia and depression, whereas the association between social phobia and alcoholism derives from a nonfamilial causal relationship between the two conditions. Clinical and phenomenologic implications of these findings are discussed.  相似文献   
9.
Summary Linkage analysis has been successful in identifying the genetic basis of numerous Mendelian diseases. These successes were due in part to the rapid developments in molecular biology, which have yielded a plethora of informative genetic markers. Although there is strong evidence that the manifestation of schizophrenia and bipolar affective disorders is controlled by genes, no evidence for linkage has been established. For psychiatric disorders, the most important limiting factor is likely to be the lack of single loci with very large effects that occur with any relevant frequency. The difficulties of linkage studies in psychiatric disorders are discussed with reference to non-psychiatric genetic diseases for which linkage to genetic markers has been successful. Recommendations for collecting information to clarify the patterns of transmission of the psychiatric disorders are described.  相似文献   
10.
A case of life-threatening respiratory distress during a Caesarean section under spinal anaesthesia is reported. Possible causes of the event including anaphylactoid reactions and the methods of their diagnosis are discussed. The most likely cause of the episode was felt to be an anaphylactoid reaction to Syntocinon.  相似文献   
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-23

京公网安备 11010802026262号