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   1310篇
  免费   120篇
  国内免费   7篇
耳鼻咽喉   21篇
儿科学   84篇
妇产科学   68篇
基础医学   160篇
口腔科学   69篇
临床医学   101篇
内科学   277篇
皮肤病学   54篇
神经病学   162篇
特种医学   29篇
外科学   139篇
综合类   7篇
一般理论   1篇
预防医学   107篇
眼科学   14篇
药学   61篇
中国医学   3篇
肿瘤学   80篇
  2023年   6篇
  2022年   12篇
  2021年   32篇
  2020年   24篇
  2019年   37篇
  2018年   57篇
  2017年   45篇
  2016年   37篇
  2015年   31篇
  2014年   32篇
  2013年   54篇
  2012年   75篇
  2011年   91篇
  2010年   56篇
  2009年   49篇
  2008年   72篇
  2007年   70篇
  2006年   68篇
  2005年   56篇
  2004年   51篇
  2003年   51篇
  2002年   44篇
  2001年   17篇
  2000年   25篇
  1999年   15篇
  1998年   15篇
  1997年   11篇
  1996年   7篇
  1995年   8篇
  1992年   14篇
  1991年   23篇
  1990年   20篇
  1989年   23篇
  1988年   16篇
  1987年   23篇
  1986年   10篇
  1985年   15篇
  1984年   8篇
  1983年   6篇
  1982年   6篇
  1981年   8篇
  1980年   8篇
  1979年   14篇
  1978年   9篇
  1977年   10篇
  1976年   6篇
  1975年   8篇
  1974年   7篇
  1971年   6篇
  1970年   9篇
排序方式: 共有1437条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
For more than two decades, the International Narcotic Control Board (INCB) has tried to stop harm reduction and its HIV prevention programs. This posture is based on a fundamental misunderstanding of their responsibilities and of drug addiction itself – i.e. as a public health and clinical care matter made criminal by decree. A recent focal point for the Board's action has been rejecting the use of supervised injection facilities to reduce morbidity and mortality of drug injectors. They single out individual countries and attempt to bully them into rejecting such programs under the banner of the United Nations (falsely) and in the name of international treaties. Their unrelenting and unjustified badgering of signatories to the international treaties that established the INCB is not only unjustified; it is an affront to one of the core purposes of the Board itself: to ensure adequate medical supplies and safe use of controlled substances. The INCB's ill-conceived obsession with intravenousaddiction as a crime flies in the face of the medical view and policies of the World Health Organization and the universally endorsed principles of the General Assembly of the United Nations.  相似文献   
5.
Although membrane sites from brain, labelled with [3H]glutamate (Glu) under sodium-free conditions, are thought to represent excitatory receptors, certain anomalous characteristics of the kinetics of apparent binding raised the question of whether transport might contribute to this process, prompting a closer examination of it. Hyperosmolar media and low incubation temperatures (4 degrees C) both led to decreases in the apparent specific binding of [3H]glutamate to membranes from the brain of the rat in the presence of chloride. Furthermore, only 15% of the [3H]glutamate, bound at 37 degrees C, was dissociable when the membranes were then cooled to 4 degrees C. The binding of [3H]glutamate was increased in the presence of certain dipeptides such as L-phenylalanyl-L-glutamate (Phe-Glu); and the binding augmented by the presence of Phe-Glu, was also sensitive to temperature and osmolarity of the incubation buffer. Sonication of membranes in 5 mM glutamate increased the apparent binding of [3H]glutamate and abolished the stimulatory effect of Phe-Glu. These findings are consistent with the hypothesis that chloride-dependent association of [3H]glutamate with membranes from brain reflects, in part, a sequestration process, which may be driven by glutamate exchange.  相似文献   
6.
Background and objective The classification of hydrocephalus in newborns and in infants is different from the classification in adulthood. This difference exists due to disparity in the source pathologies that produce the hydrocephalus, and the practical distinctions in prognosis and treatment choices. The objective of this paper is to present the spectrum of obstructive-communicating hydrocephalus, which is more complex in the pediatric group, and to propose the relevance of this particular classification to treatment options. Materials and methods The authors categorized infants with active hydrocephalus at time of presentation into the following four groups along the spectrum of communicating vs obstructive HCP. Group 1: patients with a purely absorptive (communicating) HCP. In these patients, tetraventricular dilatation is usually observed with occasional extraaxial fluid accumulation. An extracranial CSF diversion (shunt) is the treatment of choice. Group 2: patients with an obstructive component together with a persistent absorptive component. In these patients, a technically successful endoscopic procedure will not prevent progression of clinical symptoms of HCP. An extracranial CSF diversion (shunt) should be the treatment of choice even though some of these patients are currently treated by endoscopy. Group 3: patients with an obstructive component together with a temporary absorptive component. In these patients, a technically successful ETV should be followed by temporary CSF drainage [via LP, continuous spinal drainage (CLD), or ventriculostomy] with or without supplemental medical treatment (i.e., Diamox) for several days. Such temporary drainage may decrease failure rate in this subgroup. Group 4: patients with a purely obstructive HCP. In these patients, an endoscopic procedure (ETV) is the treatment of choice. According to this spectrum classification, the authors classify different entities with representative cases and discuss relevancy to treatment options and prognosis. Results The data suggest that obstructive hydrocephalus in the very young population may be rather a combination of obstructive and absorptive problem. The outcome of the patient depends mainly not only on the basic pathology causing the hydrocephalus but also on the treatment that is chosen and its complications. While bleeding and infection represent the major causes for communicating hydrocephalus, patients with complex pathologies of congenital type and intra- or interventricular obstructions may reflect obstructive hydrocephalus. Treatment of these patients may be successful by shuntless procedures if the absorptive problem is not the major component. In transient absorptive hydrocephalus, temporary measures were effective in many cases leading to successful procedures of ETV and/or posterior-fossa decompression in selected cases. Conclusions Shuntless procedures are the dream of a pediatric neurosurgeon provided it solves the problem and does not imply unacceptable risk. However, the benefit has to be evaluated years after the procedure is performed, as only prospective multicenter studies will truly show which procedure may have the best overall results in the developing child. Until such studies are available, understanding the basic pathology or the combination of pathologies leading to hydrocephalus in a given child may open the window of opportunities for other than shunt surgery in many hydrocephalic children with major obstructive component.  相似文献   
7.
OBJECTIVE: This analysis examined whether patients with Alzheimer disease (AD) tolerate continuous positive airway pressure (CPAP). METHOD: Thirty patients with AD were randomized to CPAP or sham CPAP and completed sleep, depression, and quality-of-life questionnaires. Participants could choose to continue treatment after the trial. RESULTS: Patients wore CPAP for 4.8 hours per night. More depressive symptoms were associated with worse adherence (rS=-0.37; N=30, p<0.04). Patients who continued using CPAP had fewer depressive symptoms (t [19]=2.45, p=0.02) and better adherence (t [19]=2.32, p=0.03) during the trial. CONCLUSION: Patients with AD with obstructive sleep apnea can tolerate CPAP. Adherence and long-term use may be more difficult among those patients with more depressive symptoms.  相似文献   
8.
Oral rehydration therapy (ORT) was hailed 10 years ago as potentially the most significant medical advance of the century. ORT is a simple and inexpensive means of treating diarrheal dehydration, which killed approximately 5 million children each year in the late 1970s. Today 25% of the world's children have access to ORT, and it is estimated that every year it saves 500,000 lives. Where ORT is not widely available, diarrheal dehydration remains the leading killer of children. It is still responsible for 25% of the 250,000 worldwide child deaths each week. Because there have been problems with acceptance of the ORT formula of salt, sugar, and water, researchers have been experimenting with cereal-based oral rehydration formulas that are much like traditional home remedies for diarrhea. In addition to relieving dehydration, these cereal-based formulas lessen severity and duration of diarrheal illness. Critics, however, claim that they fail to provide a child with sufficient calories, and call for a combination of ORT with early feeding--4-8 hours after completion of rehydration. Even with growing evidence of the benefits of early feeding, the practice of withholding food from children with diarrhea persists in the developing world and in the U.S. Problems in developing countries are greater, but each year 14 of every 1,000 American infants are hospitalized because of acute diarrhea. The major hurdle that ORT faces in the U.S. is that it is a simple form of therapy attempting to displace a higher technology. As long the U.S. health care system serves as a model for developing countries, distrust of ORT by American doctors will hamper efforts to spread ORT in the developing world.  相似文献   
9.
The study examined differences in division of household tasks and spousal support among a sample of educated dual‐earner families from two national groups in Israel: Jews (n = 116), and Arabs (n = 163). The contribution of the spousal interaction variables (household roles and spousal support) toward explaining two dimensions of psychological well‐being (burnout and life satisfaction) was also examined. The research findings indicate that in general, the Arabs maintain a more traditional orientation toward gender roles than their Jewish counterparts. Arab men showed a greater tendency to perform outside tasks than their Jewish counterparts who participate more in domestic chores. By contrast, no differences were found between the two groups with regard to the mutual support provided by spouses. Gender role attitudes were found to be a key predictor of the two psychological well‐being dimensions in both national groups. Regarding sex differences, men of both nationalities were more likely than women to report that they perform all types of household tasks. Concomitantly, the women reported higher levels of burnout, while no differences between the sexes were found with respect to life satisfaction. © 2003 Wiley Periodicals, Inc.  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