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   33077篇
  免费   3218篇
  国内免费   1009篇
耳鼻咽喉   223篇
儿科学   616篇
妇产科学   282篇
基础医学   3095篇
口腔科学   568篇
临床医学   3383篇
内科学   4576篇
皮肤病学   597篇
神经病学   2264篇
特种医学   2021篇
外国民族医学   5篇
外科学   1661篇
综合类   5136篇
现状与发展   4篇
一般理论   1篇
预防医学   3087篇
眼科学   2268篇
药学   4614篇
  20篇
中国医学   1400篇
肿瘤学   1483篇
  2024年   84篇
  2023年   421篇
  2022年   977篇
  2021年   1312篇
  2020年   1245篇
  2019年   1202篇
  2018年   1188篇
  2017年   1273篇
  2016年   1377篇
  2015年   1336篇
  2014年   2131篇
  2013年   2334篇
  2012年   2202篇
  2011年   2294篇
  2010年   1828篇
  2009年   1504篇
  2008年   1729篇
  2007年   1665篇
  2006年   1516篇
  2005年   1203篇
  2004年   1065篇
  2003年   894篇
  2002年   738篇
  2001年   679篇
  2000年   552篇
  1999年   469篇
  1998年   371篇
  1997年   354篇
  1996年   294篇
  1995年   314篇
  1994年   275篇
  1993年   246篇
  1992年   220篇
  1991年   174篇
  1990年   168篇
  1989年   153篇
  1988年   135篇
  1987年   145篇
  1986年   124篇
  1985年   218篇
  1984年   198篇
  1983年   145篇
  1982年   127篇
  1981年   104篇
  1980年   87篇
  1979年   68篇
  1978年   53篇
  1977年   30篇
  1976年   22篇
  1975年   24篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
目的:观察危重型肾功能衰竭合并高危出血患者选择抗凝药物进行血液透析治疗的效果。方法:应用吉派林(低分子肝素钠)作为抗凝剂进行血液透析。结果:129例病人进行血液透析386次,均没有出血发生。结论:吉派林在高危出血患者血液透析中使用方便,安全,效果良好。  相似文献   
32.
33.
34.
35.
本文对西宁地区新生儿缺氧缺血性脑病(HIE)颅脑超声诊断分析脑缺氧缺血产生的原因、脑实质损伤程度及预后评估。提出对围产期窒息导致脑缺血性损害的预防措施。  相似文献   
36.
A 10-year-old Persian girl has symptoms of congenital stationary night blindness and some drusen-like lesions in the region of the vascular arcades. Her electroretinogram shows no rod response to a weak stimulus, but a large (475 V) slow scotopic response to a strong stimulus that is unchanged by photopic conditions (15 F1 background illumination). However, the response to flicker had the typical (smaller) amplitude of a cone signal. This may represent a new form of night blindness in which rod sensitivity is reduced so that there is no vision under dim conditions but rod function still persists under photopic conditions.  相似文献   
37.
2,4,5-trimethylthiazoline (TMT) is a volatile component of the anal gland secretion of the red fox and elicits behavioral and physiological fear responses in the rat. Using instrumental conditioning paradigms, we determined olfactory detection thresholds for TMT in three rats, a natural prey species of the red fox, and compared their performance to that of three squirrel monkeys, three spider monkeys and four pigtail macaques, all non-prey species of the red fox. We found that the rats were able to discriminate concentrations between 0.04 and 0.10 ppt (parts per trillion) of TMT from the odorless solvent which is by far the lowest olfactory detection threshold for an odorant reported in rats so far. In contrast, the spider monkeys needed 0.14-1.38 ppb (parts per billion), the pigtail macaques 0.41-4.07 ppb, and the squirrel monkeys 4.07-13.80 ppb to detect TMT which does not rank among the lowest olfactory thresholds reported for these three primate species. Thus, these results support the assumption that the behavioral relevance of an odorant may be an important determinant of a species' olfactory sensitivity.  相似文献   
38.
Fear of bodily sensations has received extensive attention in relation to panic disorder, and more recently, other types of anxiety pathology and chronic pain problems. Extending this work, the present study examined fear of bodily sensations and its underlying dimensions in emergency room patients with Noncardiac Chest Pain (NCCP; n = 63). We posited a differential specificity hypothesis, expecting that specific cardiopulmonary fears would be more strongly associated with NCCP symptoms relative to other bodily fears. As hypothesized, participants reported cardiopulmonary sensations as significantly more fear-provoking than numbness, dissociation, and gastrointestinal sensations. Additionally, regression analysis indicated that after accounting for theoretically relevant demographic variables and health status, cardiopulmonary fear was the best predictor of a composite index of cardiac complaints intensity, even after removing variance related to the absolute number of cardiac complaints. We discuss these findings in relation to the specific role for the fear of cardiopulmonary sensations in chest pain complaints, with implications for better understanding the underlying psychological processes involved in NCCP.  相似文献   
39.
Peripheral deafferentation of the rodent olfactory bulb results in loss of dopamine content, tyrosine hydroxylase activity and immunocytochemical staining for tyrosine hydroxylase in juxtaglomerular dopamine neurons. Reinnervation of the bulb by afferent neurons results in the return of all parameters to control levels suggesting that the dopamine neurons did not degenerate but that the expression of tyrosine hydroxylase enzyme was transneuronally regulated in a static population of juxtaglomerular cells. To evaluate this possibility, we determined the activity and immunocytochemical localization of the second enzyme in the dopamine biosynthetic pathway, DOPA decar?ylase. At a time when tyrosine hydroxylase activity was reduced to 25% of control values, DOPA decar?ylase activity in the lesioned bulb was maintained at about 65% of that in the unlesioned bulb. Immunocytochemical staining with antibodies to both enzymes, performed sequentially in the same sections, demonstrated that in the unlesioned bulb tyrosine hydroxylase and DOPA decar?ylase are co-localized in the same population of juxtaglomerular neurons. Similar results were obtained in adjacent sections each stained with one of the two antibodies. In contrast, in the deafferented bulb, about three times as many neurons were stained with DOPA decar?ylase as with tyrosine hydroxylase antibodies. The DOPA decar?ylase activity measurements and immunocytochemistry argue for the continued presence, in the lesioned olfactory bulb, of a population of tyrosine hydroxylase deficient dopamine neurons.The data suggest that olfactory receptor cell innervation transneuronally regulates the expression of tyrosine hydroxylase by mechanisms separate from those controlling the levels of DOPA decar?ylase.  相似文献   
40.
A developmentally immature sleep pattern has been identified in infants with a recent history of an unexplained life-threatening episode of sleep apnoea who are considered at risk for SIDS. In these infants there is a persistence of Sleep Onset REM Periods (SOREMPS) after prolonged wakefulness when compared to controls matched for age, sex, birthweight and race. This sleep characteristic has not been previously reported.  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