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   1055533篇
  免费   80279篇
  国内免费   2710篇
耳鼻咽喉   13806篇
儿科学   36261篇
妇产科学   29878篇
基础医学   154014篇
口腔科学   29828篇
临床医学   95967篇
内科学   204572篇
皮肤病学   24515篇
神经病学   85348篇
特种医学   40979篇
外国民族医学   305篇
外科学   157152篇
综合类   23949篇
现状与发展   1篇
一般理论   415篇
预防医学   82403篇
眼科学   23796篇
药学   75967篇
  3篇
中国医学   2148篇
肿瘤学   57215篇
  2019年   8230篇
  2018年   12168篇
  2017年   9486篇
  2016年   10896篇
  2015年   11892篇
  2014年   16026篇
  2013年   24706篇
  2012年   32550篇
  2011年   34735篇
  2010年   20580篇
  2009年   18857篇
  2008年   32510篇
  2007年   34335篇
  2006年   34443篇
  2005年   33099篇
  2004年   32239篇
  2003年   31091篇
  2002年   29970篇
  2001年   48928篇
  2000年   50619篇
  1999年   41646篇
  1998年   11686篇
  1997年   10546篇
  1996年   10492篇
  1995年   10060篇
  1994年   9364篇
  1993年   8744篇
  1992年   32477篇
  1991年   31640篇
  1990年   31174篇
  1989年   30094篇
  1988年   27337篇
  1987年   27494篇
  1986年   25616篇
  1985年   24816篇
  1984年   18674篇
  1983年   15740篇
  1982年   9507篇
  1981年   8564篇
  1979年   17056篇
  1978年   12365篇
  1977年   10479篇
  1976年   9906篇
  1975年   10316篇
  1974年   12444篇
  1973年   11985篇
  1972年   10958篇
  1971年   10181篇
  1970年   9447篇
  1969年   8803篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Out of 24 patients with laryngeal papillomatosis 6 (5 female, 1 male) suffered from repeated relapses and underwent long-term treatment with alpha-IFN-therapy. Age at onset of the disease: 1 5/12-16 2/12 years. Duration of illness: 1-7 years, with several relapses were treated surgically and with laser-coagulation. Three out of 6 patients had a tracheal cannula and were cauterized by podophylline at 2-4 week intervals. IFN was given in dosages of 5-20 X 10(4) U/kg 2 or 3 times a week. IFN-dosage for each patient was determined using the induction kinetics of (2'-5')-oligo(A)synthetase (OAS) in the mononuclear cells of the circulating blood of patients with laryngeal papillomatosis. A continuous effect could be achieved by the dose of IFN determined in the described way always before OAS activity decreased to its initial level. All 6 patients responded favorably to the alpha-IFN-therapy. Two patients treated only with IFN showed remission without relapses. In 2 cases IFN was successfully used to prevent relapses after surgical treatment and laser-coagulation. In 2 patients with papillomatosis extending into the main bronchi the disease could only be brought to a standstill, i.e. it was not necessary to remove the papillomas. Two out of 3 patients with laryngeal papillomatosis could be decannulated. Long-term therapy following the above described principles is efficient and without significant side-effects. Three patients are in treatment for more than 3 10/12 years.  相似文献   
993.
994.
995.
996.
Dawn and dusk simulation as a therapeutic intervention   总被引:1,自引:0,他引:1  
  相似文献   
997.
Scopolamine (SCOP) (3.0 mu/kg and 6.0 micrograms/kg) and saline were administered intramuscularly at 11:00 PM to eight normal male volunteers in a randomized design, and the effects on the sleep electroencephalogram (EEG) and nocturnal cortisol secretion (via blood sampling every 15 min) were evaluated. Compared to saline, SCOP produced a significant dose-related delay in rapid eye movement (REM) latency. In contrast, neither dose of SCOP significantly affected nocturnal plasma cortisol concentrations. These results suggest that the central cholinergic system that regulates the onset of REM sleep is more sensitive to dysregulation than the cholinergic system that controls the degree of nocturnal cortisol secretion. If central cholinergic overactivity is responsible for both the REM sleep latency and cortisol abnormalities in depressed patients, then our findings with SCOP might help explain why the incidences of these abnormalities are different.  相似文献   
998.
999.
Y Smith  B Lavoie  J Dumas  A Parent 《Brain research》1989,482(2):381-386
Injections of the retrograde fluorescent tracer fast blue in the striatum (STR) and nuclear yellow in the internal segment of the globus pallidus (GPi) in the squirrel monkey (Saimiri sciureus) revealed a nigropallidal projection whose cellular origin was largely distinct from that of the nigrostriatal pathway. Neurons containing the tracer injected in GPi were scattered throughout the substantia nigra-ventral tegmental area complex where they formed approximately 20-25% of the total number of retrogradely labeled cells. Only about 5-10% of all positive neurons were double-labeled after STR-GPi injections. In experiments combining the use of the fluorescent tracer propidium iodide with immunofluorescence, the majority of neurons projecting to GPi displayed tyrosine hydroxylase immunoreactivity. Hence, in addition to their important role at striatal level, midbrain dopaminergic neurons may influence directly the output neurons of the basal ganglia at pallidal level in primates.  相似文献   
1000.
Pharmacological studies suggest that beta-adrenergic receptors (beta AR) in the medial nuclei of the solitary tracts (m-NTS) facilitate presynaptic release of catecholamines and also function at postsynaptic sites. We have localized the antigenic sites for a monoclonal antibody against a peptide corresponding to amino acids 226-239 of beta AR in the m-NTS of rat brain. By light microscopy, immunoperoxidase labeling for this antibody was detected in somata and proximal processes of many small cells that were distributed throughout the rostrocaudal extent of the m-NTS. Electron microscopy confirmed the cytoplasmic localization of beta AR in perikarya and proximal dendrites of neurons. Immunoreactivity occurred as discrete patches associated with cytoplasmic surfaces of plasma membrane and with irregularly-shaped saccules with clear lumen in the immediate vicinity. Select regions of nuclear envelopes, mitochondrial membranes, and rough endoplasmic reticulum were also immunoreactive along their cytoplasmic surfaces. In contrast, the Golgi apparatus was labeled, but infrequently. Immunoreactivity was also detected at numerous post- and occasional presynaptic membrane specializations of select axodendritic junctions. Dual labeling for the beta AR-antibody by the immunoperoxidase method and for a rabbit antiserum against the catecholamine-synthesizing enzyme, tyrosine hydroxylase (TH), by the immunoautoradiographic method within the same sections, further established the precise cellular relations between beta AR and catecholaminergic neurons. Immunoreactivity for beta AR was detected in numerous perikarya and proximal dendrites that did not show detectable levels of TH. However, a few cells were dually labeled for both antigens, as seen by both light and electron microscopy. The TH-labeled terminals formed synapses at junctions both with and without beta AR-like immunoreactivity. These results from the single and dual labeling studies: (1) confirm biochemical predictions that amino acids 226-239 of beta AR protein reside intracellularly; (2) provide the first ultrastructural evidence for beta AR localization within both pre- and postsynaptic membrane specializations of a subset of catecholaminergic synapses; and (3) suggest select intracellular sites that may be involved with synthesis and/or internalization and degradation of the receptor protein.  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