全文获取类型
收费全文 | 2351951篇 |
免费 | 171805篇 |
国内免费 | 3335篇 |
专业分类
耳鼻咽喉 | 32083篇 |
儿科学 | 75954篇 |
妇产科学 | 62711篇 |
基础医学 | 348426篇 |
口腔科学 | 63704篇 |
临床医学 | 211598篇 |
内科学 | 457683篇 |
皮肤病学 | 51740篇 |
神经病学 | 185544篇 |
特种医学 | 88091篇 |
外国民族医学 | 489篇 |
外科学 | 354097篇 |
综合类 | 47569篇 |
现状与发展 | 12篇 |
一般理论 | 849篇 |
预防医学 | 183005篇 |
眼科学 | 54348篇 |
药学 | 175242篇 |
11篇 | |
中国医学 | 4575篇 |
肿瘤学 | 129360篇 |
出版年
2021年 | 19027篇 |
2019年 | 19589篇 |
2018年 | 27126篇 |
2017年 | 20413篇 |
2016年 | 22784篇 |
2015年 | 25670篇 |
2014年 | 36155篇 |
2013年 | 54080篇 |
2012年 | 74804篇 |
2011年 | 79524篇 |
2010年 | 47127篇 |
2009年 | 44646篇 |
2008年 | 74750篇 |
2007年 | 79603篇 |
2006年 | 80423篇 |
2005年 | 77893篇 |
2004年 | 74464篇 |
2003年 | 71813篇 |
2002年 | 69439篇 |
2001年 | 108784篇 |
2000年 | 111479篇 |
1999年 | 93540篇 |
1998年 | 27007篇 |
1997年 | 23676篇 |
1996年 | 24070篇 |
1995年 | 22728篇 |
1994年 | 20911篇 |
1993年 | 19722篇 |
1992年 | 72022篇 |
1991年 | 70089篇 |
1990年 | 68421篇 |
1989年 | 65688篇 |
1988年 | 60339篇 |
1987年 | 59146篇 |
1986年 | 55243篇 |
1985年 | 53047篇 |
1984年 | 39328篇 |
1983年 | 33413篇 |
1982年 | 19870篇 |
1979年 | 35877篇 |
1978年 | 25665篇 |
1977年 | 21238篇 |
1976年 | 20340篇 |
1975年 | 21825篇 |
1974年 | 26160篇 |
1973年 | 24812篇 |
1972年 | 23205篇 |
1971年 | 22041篇 |
1970年 | 20250篇 |
1969年 | 19323篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
J H Newcorn J M Halperin J M Healey J D O'Brien D M Pascualvaca L E Wolf A Morganstein V Sharma J G Young 《Journal of the American Academy of Child and Adolescent Psychiatry》1989,28(5):734-738
To assess the relationship between the DSM-III criteria for attention deficit disorder with hyperactivity (ADDH) and the DSM-III-R criteria for attention-deficit hyperactivity disorder (ADHD), children from an inner city parochial school were evaluated using a 30-item teacher questionnaire consisting of the DMS-III and DSM-III-R criteria for these disorders, the revised Conners Parent and Teacher Questionnaires, and a continuous performance test. Diagnostic groups were established based on teacher ratings of the DSM items and evaluated in relation to the rating scale data and continuous performance test. While children who were identified by teachers as having ADDH almost always satisfied the criteria for ADHD, a new group of children who were hyperactive and impulsive but less clearly inattentive also met the criteria for ADHD. Implications of the change in diagnostic criteria are discussed. 相似文献
952.
953.
954.
M M Pedrotti A L Basso 《Metabolic, pediatric, and systemic ophthalmology (New York, N.Y. : 1985)》1986,9(2-4):94-97
The authors describe a case of retrobulbar optic neuropathy in a patient with type 1 Diabetes mellitus. In spite of good metabolic control, there has been a slow but progressive functional visual decline. Worthy of note is the abnormal precocity of the appearance of the functional damage of the optic nerve compared to the involvement of the peripheral system. 相似文献
955.
956.
A case of Bonnet syndrome associated with blindness due to bilateral eye disease and a posterior parasagittal meningioma is reported. It is assumed that visual afferent deprivation alone is not enough to produce the syndrome and that, in most instances, a 'cerebral factor' must be operative if hallucinoses are to occur. The distinction between hallucinosis and hallucinations is favored and a common neural circuit for the mediation of hallucinotic imageries in general is suggested. One should not immediately put the blame on obvious eye or visual pathways affections when facing cases of Bonnet syndrome, as they are not likely to explain the complex array of images perceived by any given patient. On the contrary, the possibility of a clinically covert intracranial disease should be always raised and intensively looked for. 相似文献
957.
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
958.
959.
960.
S. Tsagarakis Feng Ge L. H. Rees G. M. Besser A. Grossman 《Journal of neuroendocrinology》1989,1(2):129-133
While extensive evidence suggests that adrenoceptors play an important role in the control of growth hormone in the rat, there are few studies involving the direct measurement of growth hormone-releasing hormone (GHRH). We have therefore developed a radioimmunoassay for rat GHRH, and used it to investigate the modulation of GHRH release by noradrenaline from incubated rat hypothalamus in vitro. The GHRH radioimmunoassay had no significant cross-reactivity with other hypothalamic or GHRH-related peptides, and was sensitive to 4 pg/tube; intra- and interassay coefficients of variation were 6% and 12% respectively. Single incubated rat hypothalami produced a stable and readily measurable output of GHRH in successive 20 min incubations after an initial 60 min preincubation; the release of GHRH was increased in the presence of 56 mM KCI, but did not respond to KCI-depolarization when calcium was excluded from the medium. Stimulated GHRH release was identical to synthetic rat GHRH(1–43) on high-performance liquid chromatography and Sephadex G-75 chromatography.
Noradrenaline stimulated GHRH secretion in a dose-dependent manner in the concentration range 10−10 — 10−6 M, with a plateau in response at 10−7 M. Stimulation with noradrenaline 10−7 M was blocked by idazoxan 10−5 M and attenuated by thymoxamine 10−5 M, but was unaffected by timolol 10−5 M. Both the α2 -adrenoceptor agonist guanfacine, and the α1 -adrenoceptor agonist methoxamine, specifically stimulated GHRH secretion.
It is concluded that noradrenaline stimulates the release of GHRH at both α1 and α2 -adrenoceptors. 相似文献
Noradrenaline stimulated GHRH secretion in a dose-dependent manner in the concentration range 10
It is concluded that noradrenaline stimulates the release of GHRH at both α