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   12212篇
  免费   809篇
  国内免费   23篇
耳鼻咽喉   159篇
儿科学   344篇
妇产科学   236篇
基础医学   1588篇
口腔科学   140篇
临床医学   2127篇
内科学   2394篇
皮肤病学   152篇
神经病学   987篇
特种医学   336篇
外国民族医学   9篇
外科学   1213篇
综合类   120篇
一般理论   10篇
预防医学   1160篇
眼科学   342篇
药学   644篇
  1篇
中国医学   6篇
肿瘤学   1076篇
  2023年   55篇
  2022年   93篇
  2021年   185篇
  2020年   130篇
  2019年   157篇
  2018年   226篇
  2017年   177篇
  2016年   183篇
  2015年   221篇
  2014年   339篇
  2013年   472篇
  2012年   718篇
  2011年   832篇
  2010年   456篇
  2009年   384篇
  2008年   720篇
  2007年   820篇
  2006年   715篇
  2005年   781篇
  2004年   712篇
  2003年   665篇
  2002年   667篇
  2001年   230篇
  2000年   224篇
  1999年   222篇
  1998年   125篇
  1997年   102篇
  1996年   103篇
  1995年   100篇
  1994年   96篇
  1993年   49篇
  1992年   155篇
  1991年   146篇
  1990年   131篇
  1989年   112篇
  1988年   120篇
  1987年   104篇
  1986年   98篇
  1985年   78篇
  1984年   85篇
  1983年   82篇
  1982年   70篇
  1981年   61篇
  1980年   58篇
  1979年   73篇
  1978年   43篇
  1977年   40篇
  1976年   49篇
  1975年   38篇
  1974年   38篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
The effectiveness of an antiarrhythmic drug is judged by the degree of ventricular arrhythmia (VA) suppression. We evaluated the relationship between the degree of VA suppression and survival in a dose-adjusted trial of 110 symptomatic patients treated with amiodarone. Cohorts had left-ventricular ejection fraction (LVEF) of 41 plus minus 18%, ventricular premature contractions (VPCs) of 445 plus minus 571 h, couplets (C) of 733 plus minus 1498 24 h and nonsustained (N) ventricular tachycardia (VT) of 65 plus minus 217 24 h; these conditions were followed for 15 plus minus 11.5 months. Amiodarone was initiated with an oral loading of 670 plus minus 111.7 mg per day for 10 days and continued on maintenance of 274.9 plus minus 102 mg per day. Survival rates of responders and nonresponders with VPCs <70%, 70--89%, greater-than-or-equal90%; C greater-than-or-equal 90%; NVT (100%); and the response to all 3 criteria (suppresion of VPCs greater-than-or-equal70%, C greater-than-or-equal 90% and complete abolition of NVT) were not statistically significant. Survival rates as a function of LVEF <40% (51 patients) or greater-than-or-equal40% (59 patients), as well as responders or nonresponders to all three criteria, were not significant (p = NS). We conclude that, in patients treated with low-dose amiodarone, the degree of VA suppression of PVCs, C and NVT does not predict survival; the survival of patients with LVEF <40% improved irrespective of VA suppression; and criteria for VA suppression should be reassessed at lower levels of suppression for the improvement of the drug risk:benefit ratio. More improvement is not necessarily better.  相似文献   
72.
Development and validation of the Diabetes Care Profile   总被引:7,自引:0,他引:7  
To determine the reliability and the validity of the Diabetes Care Profile (DCP), an instrument that assesses the social and psychological factors related to diabetes and its treatment, two studies with separate populations and methodologies were conducted. In the first study, the DCP was administered to, and physiologic measures collected from, individuals with diabetes being cared for in a community setting (n = 440). In the second study, the DCP and several previously validated scales were administered to individuals with diabetes receiving care at a university medical center (n = 352). Cronbach's alphas of individual DCP scales ranged from .60 to .95 (Study 1) and from .66 to .94 (Study 2). Glycohemoglobin levels correlated with three DCP scales (Study 1). Several DCP scales discriminated among patients with different levels of disease severity. The results of the studies indicate that the DCP is a reliable and valid instrument for measuring the psychosocial factors related to diabetes and its treatment.  相似文献   
73.
Most of us agree that people are our most important resource. Yet we spend a minimal amount of time learning more about human behavior, communication, and how our attitudes and behavior impact employee performance. Instead we rely on traditional methods of negative reinforcement in an attempt to control our areas of responsibility. While these methods can render some short-term success, managers and organizations that succeed during these times of change and fierce competition will be those that take the time to understand and capture the power of a committed workforce. The committed workforce is energized, not simply compliant, as a result of having basic human needs for achievement satisfied, belonging to a group, and receiving recognition for its contributions. Committed workers typically describe the manager as one who has the ability to give them a great degree of control over their area of influence. We all know that we don't change our leadership style like we change clothes. Old habits die hard. it takes a personal commitment and lots of practice to rid outselves of habits and behavior that no longer serve our departments and facilities. This commitment, however, is crucial to survival. As managers, we must cope with increasing ambiguity and uncertainty in the workplace. To survive these challenges, we must improve our interpersonal skills and ability to successfully bring out the best in others. I believe that success will continue for managers who not only increase their knowledge and technical ability, but who also inspire their workers to move forward with a collective sense of enthusiasm and purpose.  相似文献   
74.
Vision through cataracts   总被引:11,自引:0,他引:11  
Contrast thresholds for a range of different spatial frequencies were compared with "acuity" tests for 10 subjects with uniocular senile cataract. The results indicate that the magnitude and extent of the intra-resolution limit abnormality vary dramatically in cataract subjects and that, for some subjects, vision is abnormal for objects of all sizes. This finding indicates that the present acuity evaluation of vision with cataracts is inadequate because, in some cases, it grossly overestimates the nature of the visual world of the cataract patient.  相似文献   
75.
The effect of increasing temporal frequency on contrast sensitivity anomalies in unilateral optic neuritis has been investigated. For 4 c/deg gratings no change in the deficit was observed at any temporal frequency whereas there was a tendency for the deficit to decrease with increase in temporal frequency for 0-5 c/deg gratings. The latter effect was not observed in a case of optic neuritis with severe deficit and not in two cases of other optic nerve pathology. An explanation based on the assumption that "threshold scotomata" might be present in cases of demyelinating optic nerve disease is proposed.  相似文献   
76.
D Allen  R F Hess 《Vision research》1992,32(6):1075-1084
We asked the question "is the visual field temporally homogeneous when the well known spatial inhomogeneity is taken into account?" Our results show that the visual field exhibits inhomogeneity for stimuli of low spatial frequency for which the spatial inhomogeneity is minimal. This inhomogeneity takes the form of a reduction in sensitivity for stimuli of low temporal frequency in the periphery and an enhancement of sensitivity for stimuli of high temporal frequency in the periphery. The low temporal frequency loss in the periphery is post-receptoral and must involve a selective loss of sensitivity of the low pass filter. The enhanced high frequency sensitivity may be post-receptoral or purely receptoral. The consequence of such an inhomogeneity for subsequent stages of visual processing is discussed.  相似文献   
77.
In summary, let's review the result of the Joneses' coordinated retirement income and estate planning strategy: 1. The Joneses maximized their estate assets, converting an inefficient estate asset to an efficient estate asset, without jeopardizing their current or future standard of living. 2. They committed to a gifting program for only 10 years, after which they have the flexibility to continue gifting the trust or to retain all the current IRA income. 3. They are free to "consume" their other taxable assets during their lifetimes without worrying about saving something for their three children. The Wealth Replacement Trust will leave approximately $1 million for each child. This strategy is obviously not available to everyone, nor is it applicable to everyone. While this solution worked extremely well for these clients, everyone's situation is different. Every situation needs a professional and personalized plan based upon individual objectives. Only after objectives have been clearly identified and alternatives thoroughly explored can a suitable solution be identified. It is important that a thorough review of the entire financial picture be performed by a competent financial planning team before you attempt to correct a potential problem. Make certain your advisers are familiar with solving this type of problem so as not to create additional problems.  相似文献   
78.
79.
Hess DC  Demchuk AM  Brass LM  Yatsu FM 《Neurology》2000,54(4):790-796
Statins represent a promising class of agents to prevent stroke. In randomized trials of middle-aged patients with coronary artery disease, statins reduce the incidence of stroke. The reduction in stroke may not be solely related to cholesterol or low-density lipoprotein reduction but may involve nonsterol mechanisms effects on endothelial cells, macrophages, platelets, and smooth muscle cells. Statins also reduce the size of cerebral infarction in a murine stroke model, suggesting a neuroprotective effect. The best current evidence for stroke prevention is with pravastatin and simvastatin. Pravastatin reduces the risk of stroke in patients with coronary artery disease and average cholesterol levels; simvastatin reduces the risk of the combined endpoint of stroke and transient ischemic attack in hypercholesterolemic patients with coronary artery disease. Future studies of statins are needed in stroke populations, particularly the elderly.  相似文献   
80.
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