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   119751篇
  免费   6400篇
  国内免费   146篇
耳鼻咽喉   1826篇
儿科学   5351篇
妇产科学   4080篇
基础医学   16634篇
口腔科学   2927篇
临床医学   8621篇
内科学   22543篇
皮肤病学   3406篇
神经病学   9271篇
特种医学   5292篇
外国民族医学   32篇
外科学   19567篇
综合类   1641篇
一般理论   35篇
预防医学   6165篇
眼科学   3639篇
药学   8338篇
中国医学   328篇
肿瘤学   6601篇
  2018年   935篇
  2017年   816篇
  2016年   1137篇
  2015年   1284篇
  2014年   1689篇
  2013年   2488篇
  2012年   3254篇
  2011年   3321篇
  2010年   2060篇
  2009年   2023篇
  2008年   3414篇
  2007年   3663篇
  2006年   3783篇
  2005年   3910篇
  2004年   3815篇
  2003年   3696篇
  2002年   3616篇
  2001年   7137篇
  2000年   7095篇
  1999年   5943篇
  1998年   1665篇
  1997年   1597篇
  1996年   1370篇
  1995年   1236篇
  1994年   1131篇
  1993年   1147篇
  1992年   3844篇
  1991年   3658篇
  1990年   3659篇
  1989年   3437篇
  1988年   3064篇
  1987年   2992篇
  1986年   2872篇
  1985年   2723篇
  1984年   2017篇
  1983年   1659篇
  1982年   964篇
  1981年   959篇
  1980年   796篇
  1979年   1875篇
  1978年   1396篇
  1977年   1160篇
  1976年   960篇
  1975年   1214篇
  1974年   1244篇
  1973年   1241篇
  1972年   1081篇
  1971年   999篇
  1970年   910篇
  1969年   815篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
101.
102.
The article examines the question whether and – if – under which conditions physicians should perform purely esthetic interventions. Starting point of the considerations is the special character of the medical profession and the necessity of the anticipated confidence in the system of medicine. The medical measures for aesthetic improvement are systematized. Medical measures to increase the wanted, positively felt attention of others are not compellingly required according to the medical ethic. Nevertheless they do not offend the ethos if high quality standards are insured: The measures must be presumably helpful for the patient; a thorough informed consent and avoidance of damage must be insured. Esthetic measures, in particular operations which are totally cosmetic, should be limited strictly if performed with children and adolescents. Nevertheless convincing arguments support medical-esthetic measures with children and adolescents to avoid stigmatization.  相似文献   
103.
104.
105.
106.
A mutant form of ammodytoxin A, a neurotoxic phospholipase A2 from the venom of the long nosed viper Vipera ammodytes ammodytes, was prepared by site-directed mutagenesis, conjugated to a nanogold particle and inoculated into the antero-lateral aspect of one hind limb of female mice. Eight hours later the mice were killed, the soleus muscles of both ipsi- and contra-lateral hind limbs were removed, exposed to a silver enhancing medium and then prepared for transmission electron microscopy. Silver-enhanced particles were subsequently found concentrated in the peri-synaptic area, particularly within the synaptic gutter and the deep synaptic folds, and in many cases had been taken up into the cytoplasm of the terminal boutons of the motor axon. The results suggest that the presynaptic neurotoxicity of snake venom phospholipases A2 involves several components of the neuromuscular apparatus, including intracellular organelles of the motor nerve terminal.  相似文献   
107.
Background Diagnosis of brainstem lesions in children based on magnetic resonance imaging alone is a challenging problem. Magnetic resonance spectroscopy (MRS) is a noninvasive technique for spatial characterization of biochemical markers in tissues and gives information regarding cell membrane proliferation, neuronal damage, and energy metabolism. Methods We measured the concentrations of biochemical markers in five children with brainstem lesions and evaluated their potential diagnostic significance. Images and spectra were acquired on a 1.5-T imager. The concentrations of N-acetylaspartate, tetramethylamines (e.g., choline), creatine, phosphocreatine, lactate, and lipids were measured within lesions located at the brainstem using Point-resolved spectroscopy sequences. Results Diagnosis based on localized proton spectroscopy included brainstem glioma, brainstem encephalitis, demyelination, dysmyelination secondary to neurofibromatosis type 1 (NF 1), and possible infection or radiation necrosis. In all but one patient, diagnosis was confirmed by biopsy or by clinical follow-up. Conclusions This small sample of patients suggests that MRS is important in the differential diagnosis between proliferative and nonproliferative lesions in patients without neurofibromatosis. Unfortunately, in cases of NF 1, MRS can have a rather misdiagnosis role.  相似文献   
108.
Precise knowledge of the undesirable effects of chloroquine and hydroxychloroquine allows better exploitation of their therapeutic effects. Retinopathy can be avoided by observing a maximum daily dosage of 3.5-4 mg/kg ideal body weight for chloroquine and 6-6.5 mg/kg for hydroxychloroquine. In this way, both can be used for long-term therapy. The pharmacokinetics of chloroquine (storage in deep compartments with long plasma half-life) means that it can cumulate, especially with higher dosages and in the presence of renal or hepatic insufficiency. A high plasma concentration reinforces the side-effects without reinforcing the therapeutic effects. Besides subjective symptoms (e.g. anorexia, diarrhoea, nausea), the following undesirable reactions are significant. On the skin exanthema, hyperpigmentation and photodynamic reactions can develop. The hair can become white in blonde and red-haired men. In the eye, chloroquine deposits in the cornea and disturbances of accommodation can occur, besides retinopathy. Neuromyopathy and central nervous system disturbances (e.g. psychosis) are rare, as is impairment of auditory function or blood cells. During pregnancy there is a risk of potential fetal damage (hearing loss, abortion). An acute overdose is extremely dangerous: the lethal dose is 1 g for children and 4 g for adults. As death occurs rapidly, chloroquine has to be stored where it is absolutely inaccessible to children.  相似文献   
109.
For various amine transmitters (noradrenaline, dopamine, 5-HT) re-uptake into the releasing varicosity limits the transmitter's life span in the biophase. In the second TiPS Lecture, given at this year's FASEB meeting in Atlanta, Georgia, Ullrich Trendelenburg summarized the evidence relating to the function of the neuronal noradrenaline carrier (uptake1), why it is absolutely dependent on Na+ and Cl- and how it functions as a metabolizing system, hand in hand with intraneuronal monoamine oxidase and vesicular storage. This carrier clears noradrenaline from the extracellular space very efficiently. Hence, loading of incubated organs with exogenous substrates of uptake1 results in a very heterogeneous distribution of the amine. Moreover, under certain experimental and pathophysiological conditions the carrier is able to transport axoplasmic noradrenaline out of the varicosity, a 'release' mechanism operating, for instance, in cardiac ischaemia.  相似文献   
110.
The present study revealed that the majority of nurses had adequate knowledge about dietary practices during the antenatal and post-natal period. However, their knowledge about nutritive value of foods and nutrition advice during disease conditions was inadequate. It is recommended that to make the training more meaningful, the identification of the incorrect dietary beliefs of trainees should be done at the beginning of the training course. Each incorrect belief should be explained in detail for better comprehension of the correct knowledge in nutrition.  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