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   3027篇
  免费   190篇
  国内免费   17篇
耳鼻咽喉   36篇
儿科学   75篇
妇产科学   75篇
基础医学   409篇
口腔科学   101篇
临床医学   214篇
内科学   806篇
皮肤病学   31篇
神经病学   329篇
特种医学   117篇
外科学   454篇
综合类   13篇
一般理论   1篇
预防医学   181篇
眼科学   58篇
药学   159篇
中国医学   17篇
肿瘤学   158篇
  2023年   21篇
  2022年   56篇
  2021年   95篇
  2020年   60篇
  2019年   76篇
  2018年   108篇
  2017年   82篇
  2016年   86篇
  2015年   76篇
  2014年   126篇
  2013年   139篇
  2012年   242篇
  2011年   250篇
  2010年   135篇
  2009年   105篇
  2008年   166篇
  2007年   166篇
  2006年   177篇
  2005年   186篇
  2004年   144篇
  2003年   137篇
  2002年   115篇
  2001年   68篇
  2000年   43篇
  1999年   44篇
  1998年   20篇
  1997年   12篇
  1996年   13篇
  1995年   8篇
  1994年   12篇
  1993年   17篇
  1992年   26篇
  1991年   17篇
  1990年   19篇
  1989年   17篇
  1988年   19篇
  1987年   17篇
  1986年   14篇
  1985年   22篇
  1984年   11篇
  1983年   7篇
  1981年   8篇
  1979年   13篇
  1978年   7篇
  1977年   6篇
  1975年   4篇
  1974年   6篇
  1973年   4篇
  1968年   4篇
  1965年   6篇
排序方式: 共有3234条查询结果,搜索用时 62 毫秒
1.
ABSTRACT

Purpose

New instrument-based techniques for anterior chamber (AC) cell counting can offer automation and objectivity above clinician assessment. This review aims to identify such instruments and its correlation with clinician estimates.  相似文献   
2.
Objectives. Traditional deep brain stimulation (DBS) at the subthalamic nucleus (STN) has proved to be efficacious on core Parkinsonian symptoms. However, very disabling l ‐dopa–induced abnormal involuntary movements (AIMs) and axial signs are slightly affected, suggesting that we target less conventional targets. Our candidates for DBS were the globus pallidus internus (GPi) plus the intralaminar thalamic complex (Pf or CM), given its extensive functional links with basal ganglia nuclei. Materials and Methods. The routine utilization of our innovative stereotactic apparatus allows us to implant, at the same time, both the CM‐Pf complex together with the GPi in six Parkinson disease patients. Both intraoperative and postoperative neurophysiologic assessments helped us recognize functional subregions while optimizing implantation of electrodes. Unified Parkinson disease rating scale (UPDRS) motor scores, AIMs, and freezing were carefully blindly evaluated for each condition. Results. A significant amelioration of UPDRS scores was achieved by simultaneous activation of both targets. CM‐Pf activation was only slightly effective in reducing rigidity and akinesia, but more efficacious on freezing. Not surprisingly, AIMs were peculiarly decreased by the activation of the permanent electro‐catheter in the posteroventral GPi. Conclusions. These findings confirm that, in selected patients, it is conceivable to target structures other than the conventional STN in order to maximize clinical benefit.  相似文献   
3.
HYPOTHESIS: Based on recent findings on the association between vascular risk factors and hippocampal atrophy, we hypothesized that hypertension and diabetes mellitus (DM) are associated with medial temporal lobe atrophy (MTA) in subjects without disability, independent of the severity of white matter hyperintensities. METHODS: In the Leukoaraiosis And DISability in the elderly (LADIS) study, we investigated the relationships between DM, hypertension, blood pressure and MTA in 582 subjects, stratified by white matter hyperintensity severity, using multinomial logistic regression. MTA was visually scored for the left and right medial temporal lobe (score 0-4), and meaned. RESULTS: Mean age was 73.5 years (sd 5.1), 54% was female. Of the subjects, 15% had DM, and 70% had a history of hypertension. The likelihood of having MTA score 3 was significantly higher in subjects with DM (OR 2.9; 95% CI: 1.1-7.8) compared with an MTA score of 0 (no atrophy). The odds ratio for MTA score 2 was not significantly increased (OR 1.8; CI: 0.9-4). Systolic and diastolic blood pressure and a history of hypertension were not associated with MTA. There was no interaction between DM and hypertension. Stratification on white matter hyperintensities (WMH) did not alter the associations. CONCLUSION: Our study strengthens the observation that MTA is associated with DM, independently of the amount of small vessel disease as reflected by WMH.  相似文献   
4.
5.
6.
OBJECTIVES: To determine what treatment decisions physicians will make when faced with a hypothetical incompetent elderly patient with life-threatening gastrointestinal bleeding and to examine the relative importance of physician characteristics and factors (legal and ethical concerns, hospital costs, level of dementia, patient's age, physician's religion, patient's wishes and family's wishes) in making those decisions. DESIGN: Survey. SETTING: Family practice, medical and geriatrics rounds in academic medical centres and community hospitals in seven countries. PARTICIPANTS: Physicians who regularly cared for incompetent elderly patients. MAIN OUTCOME MEASURES: A self-administered questionnaire describing the elderly patient. Respondents were asked to choose one of four levels of care and to identify the level of importance factors had in making that decision. Older physicians, those less concerned about litigation, those for whom the level of dementia was important and those for whom the patient's age was important were expected to give less aggressive care than the other physicians. MAIN RESULTS: Supportive care was chosen by 8.1% of the respondents, limited therapeutic care by 41.5%, maximum therapeutic care without admission to the intensive care unit (ICU) by 32.2% and maximum care with admission to the ICU by 18.2%. The patient's wishes were reported by 91.0% as being extremely or very important in choosing the treatment. Stepwise logistic regression analysis revealed that the following variables independently predicted the level of treatment: level of dementia, country of residence, duration of practice, legal concerns, patient's age and ethical concerns. These factors were significantly correlated with the physicians' treatment choices (p less than 0.05). CONCLUSIONS: The importance that the physicians placed on the level of dementia was the strongest predictor of the level of care that would be provided. A societal consensus on the influence of cognitive function on the appropriate level of care as well as training of physicians in ethical issues are required.  相似文献   
7.
8.
The ability of cations to modulate the binding of the sigma 1 receptor-selective ligand (+)-[3H]pentazocine to guinea pig cerebellum was investigated. Di- and trivalent cations biphasically inhibited (+)-[3H]pentazocine binding, revealing multiple affinity states. The rank order of potency of these cations (based on the high affinity component of inhibition) was Zn2+ > Co2+ > La3+ = Ni2+ = Cd2+ = Mn2+ = Gd2+ > Ba2+ = Sr2+ > Mg2+ > Ca2+. The inhibition of 1,3-[3H]di(2-tolyl)guanidine binding to the sigma 2 receptor by these cations differed qualitatively and quantitatively from their effects on (+)-[3H]pentazocine binding. Although monovalent cations decreased the Kd for (+)-[3H]pentazocine binding, divalent cations split (+)-[3H]pentazocine binding into low and high affinity components. The Bmax of the high affinity component decreased with increasing divalent cation concentrations. Both mono- and divalent cations significantly reduced the rate of association of (+)-[3H]pentazocine with the sigma 1 receptor without altering the dissociation rate. (+)-[3H]Pentazocine binding was not altered by guanine nucleotides or by treatment with cholera or pertussis toxins. However, nonselective cation channel blockers (cinnarizine, hydroxyzine, prenylamine, amiodarone, and proadifen) potently inhibited (+)-[3H]pentazocine binding. These results indicate that physiologically relevant concentrations of divalent cations allosterically modulate (+)-[3H]pentazocine binding to the sigma 1 receptor, to reveal multiple affinity states. These sites do not represent sigma 1 to sigma 2 subtype interconversion or ternary complex formation with guanine nucleotide-binding proteins. However, the rank order of cation potency and the inhibition of binding by cation channel blockers is consistent with a potential role for sigma receptors as constituents of cation channels.  相似文献   
9.
A case of severe anaphylactic reaction provoked by suxamethonium during the induction of general anaesthesia is reported. Diagnosis of reaction and the trigger effect of suxamethonium was identified by intradermal testing. Diagnosis of anaphylactic reaction was confirmed on serial blood estimations of IgE and C3-C4 of complement fractions.  相似文献   
10.
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