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   136806篇
  免费   10520篇
  国内免费   3350篇
耳鼻咽喉   1485篇
儿科学   7644篇
妇产科学   4166篇
基础医学   14985篇
口腔科学   1669篇
临床医学   14896篇
内科学   24093篇
皮肤病学   2500篇
神经病学   12273篇
特种医学   3220篇
外国民族医学   4篇
外科学   12459篇
综合类   18693篇
现状与发展   16篇
一般理论   6篇
预防医学   8992篇
眼科学   2323篇
药学   7147篇
  59篇
中国医学   11191篇
肿瘤学   2855篇
  2024年   397篇
  2023年   2494篇
  2022年   4983篇
  2021年   6608篇
  2020年   6075篇
  2019年   4860篇
  2018年   4854篇
  2017年   4976篇
  2016年   5023篇
  2015年   4822篇
  2014年   9305篇
  2013年   9683篇
  2012年   7560篇
  2011年   8737篇
  2010年   6808篇
  2009年   6625篇
  2008年   6492篇
  2007年   6547篇
  2006年   5944篇
  2005年   4922篇
  2004年   4189篇
  2003年   3770篇
  2002年   2670篇
  2001年   2397篇
  2000年   2086篇
  1999年   1940篇
  1998年   1626篇
  1997年   1533篇
  1996年   1444篇
  1995年   1408篇
  1994年   1194篇
  1993年   1062篇
  1992年   981篇
  1991年   756篇
  1990年   702篇
  1989年   591篇
  1988年   585篇
  1987年   508篇
  1986年   445篇
  1985年   578篇
  1984年   473篇
  1983年   293篇
  1982年   365篇
  1981年   326篇
  1980年   260篇
  1979年   218篇
  1978年   141篇
  1977年   115篇
  1976年   97篇
  1975年   47篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Oral allergy syndrome induced by spinach   总被引:1,自引:1,他引:0  
  相似文献   
82.
Using hierarchical cluster analysis, applied to 47 cases of Guillain-Barre Syndrome (GBS) incident in South-West Stockholm (SWS) during the period from January 1973 to June 1992, we identified three major clinicoepidemiological subgroups. The first subgroup, 25.5% of the cases (26.7 ± 6.7 years), recorded a peak incidence at ages 20–29 years and presented significant differences from other subgroups, a high proportion of cases with onset at low age preceded by respiratory infection (83.3%) and with normal motor conduction velocity (50.0%). Also found, were less affected biological parameters, a rapidly progressive course and independence in gait at one month after onset. A second subgroup, 27.7% of cases, was severely affected, clinically and functionally. It consisted predominantly of young individuals (22.7 ± 11.1 years), with a high incidence (69.2% of cases) in autumn. A third subgroup, comprising 40.47; of cases, was older (61.1 ± 11.0 years) and, in general, also severely affected. The incidence of this form appeared to be invariant with time.  相似文献   
83.
During the development of motor vagal nuclei (MVN), the neuroblasts of the myeloencephalic basal plate migrate in the dorsolateral direction to form the dorsal motor vagal nucleus (DMVN) and ventrolaterally to form the ventral motor vagal nucleus (VMVN). Those neuroblasts that remain close to the median sulcus will form the hypoglossal nucleus. In support of the congenital origin of the alteration of the MVN in sudden infant death syndrome (SIDS), we report the case of an 8‐month‐old female child who was found dead in her cot. The neuropathological assessment revealed that the medullary triangle of the 4th ventricle floor was asymmetric, owing to the presence of three prominences to the left side of the median sulcus. The medial prominence corresponded to the hypoglossal nucleus, which showed a marked increase in the number of large neurons; the intermediate prominence corresponded to the DMVN whose large neurons were reduced and were recognizable mainly at the level of the medial fringe; the lateral prominence corresponded to the solitary nucleus. The left solitary tract showed a reduction of the transverse diameter. Also, the left VMVN showed marked reduction in the number of neurons. Inflammatory and astrocytic reactions were absent. We suggest that in SIDS cases the hypocellularity of the MVN and the increased number of neurons of the hypoglossal nucleus are intimately related, indicating a congenital alteration due to incomplete migration of the vagal neuroblasts with abnormality of the autonomic cardio‐respiratory control.  相似文献   
84.
We report on a Thai family with dominantly inherited malformation syndrome with upper limb anomalies, short stature, quadricuspid aortic valve, and minor craniofacial anomalies. The affected individuals comprised a mildly affected mother, a moderately affected daughter, and a most severely affected son. The daughter and son had short stature. The craniofacial abnormalities comprised frontal bossing, hypoplastic nasal bones, depressed nasal bridge, and broad nasal alae. The upper limb defects varies among the patients, ranging from radial ray defects in the mother through radial and ulnar ray defects with unilateral humeral hypoplasia in the daughter to radial ray defects with severe oligodactyly and bilateral humeral hypoplasia in the son. All patients in this family had hypoplasia of the shoulder girdle and resembled what is observed in many families with Holt‐Oram syndrome. Moreover, the son showed quadricuspid aortic valve with mild aortic regurgitation. However, the present family did not show any mutation of the TBX5 gene, a disease‐causing gene of Holt‐Oram syndrome. The present family deserves further investigation on other genes that play a role in the development of the upper limbs, particularly of radial rays. © 2002 Wiley‐Liss, Inc.  相似文献   
85.
Summary A patient who developed a unilateral opercular syndrome following a cerebrovascular accident is described. Computed tomography showed that the lesion did not affect the opercular cortex, but involved deep white matter and the head of the caudate nucleus of the left hemisphere. Persistent hypophonia and transient aphasia were associated. Comparison with previous cases is discussed.  相似文献   
86.
X chromosome instability associated with familial Turner syndrome   总被引:1,自引:0,他引:1  
A family with two members (two generations) exhibiting Turner syndrome is described. Cytogenetic studies on these individuals showed the presence of multiple X chromosome changes. Evidence is presented to show that the maternally inherited X chromosome is the chromosome involved in the structural alterations observed. The effect of a tendency of the maternal X chromosome to break at specific sites on the development of the Turner phenotype and abnormal karyology is discussed.  相似文献   
87.
S.P. Sivam   《Brain research》1989,500(1-2):119-130
The present study examined the influences of dopamine (DA) receptor stimulation on enkephalin (Met5-enkephalin; ME) and tachykinin (substance P; SP) systems of basal ganglia of Sprague-Dawley rats, lesioned as neonates with 6-hydroxydopamine (6-OHDA). It has been proposed that the neonatal 6-OHDA-lesioned rat could serve as a model for the DA deficiency and self-injurious behavior (SIB) observed in the childhood neurological disorder. Lesch-Nyhan syndrome. In agreement with earlier work, the present study found that the neonatal 6-OHDA treatment at 3 days of age, reduced DA and caused an increase in ME and a decrease in SP content in the striatum and substantia nigra, when tested as adults. Administration of the DA precursor, L-dihydroxyphenylalanine (L-DOPA), to lesioned animals, induced SIB; increased DA and DOPAC levels; produced a greater decrease (-64%) in SP levels in the striatum and substantia nigra than was observed with lesion alone (-28%). The L-DOPA-induced decrease in SP levels and the SIB observed in the lesioned animals were blocked by pretreatment with the D1 receptor antagonist, SCH-23390. Moreover, administration of the D1 receptor agonist, SKF-38393, but not the D2 agonist, LY-171555, to lesioned animals mimicked the L-DOPA responses in all respects, except that the agonists did not alter DA or DOPAC levels. None of the DA agonists or antagonists treatments affected lesion-induced increase in ME levels in the striatum. These results indicate for the first time, that SIB precipitated by DA agonists in neonatal dopaminergic denervated animals, is associated with a marked and selective decrease in SP in the striatonigral SP neurons. This process has two components: (a) a retarded development of the SP system due to neonatal dopaminergic denervation: and (b) a depletion of the remaining SP, presumably by enhanced release due to D1 DA receptor-mediated activation of striatonigral SP neurons.  相似文献   
88.
Anorectal function in the solitary rectal ulcer syndrome   总被引:8,自引:6,他引:2  
The anorectal function of nine patients with solitary rectal ulcer syndrome (SRUS) (5 F: 4 M, median age, 27 (range, 19–41 years) and nine control subjects (5 F: 4 M, median age, 47 (35–66)P<0.01) has been investigated by a new technique that radiologically visualizes the anorectum during voiding of a semisolid contrast medium, while simultaneously measuring intrarectal pressure and anal sphincter EMG activity. A degree of rectal prolapse was demonstrated in eight of the SRUS patients; six of these lesions were clinically occult. Abnormal failure of the anal sphincter to relax on voiding was present in seven of the SRUS patients. These abnormalities resulted in the SRUS patients requiring a greater increase in intrarectal pressure (median, 100 cm water) to void than the control subjects (median, 65 cm water,P<0.01). This combination of high intrarectal pressure and rectal prolapse during straining seems to be the cause of SRUS This work was supported by a grant from the Medical Research Council.  相似文献   
89.
阻塞性睡眠呼吸暂停综合征相关高血压病的临床特点   总被引:4,自引:0,他引:4  
探讨阻塞性睡眠呼吸暂停综合征相关性高血压病 (obstructive sleep apnea associated hypertension,OSAAHT)的临床特点。对照分析 2 4例 OSAAHT和年龄及病期相匹配的 2 2例原发性高血压病患者 ,比较症状、体重指数、治疗前睡眠前后血压变化及 2 4h血压动态监测等指标。结果发现 OSAAHT患者白天明显过度困倦 ,睡眠监测呼吸紊乱指数 (AHI)为 (4 5 .1± 15 .3)次 / h,体重指数高于对照组 [(2 7.9± 2 .5 ) kg/ m2比 (2 3.9± 1.7) kg/ m2 ,P<0 .0 1]。OSAAHT睡前血压 (137.1± 10 .5 ) / (88.4± 6 .6 ) mm Hg,清晨血压 (15 5 .9± 14.4) / (10 1.8± 4.9) m m Hg;原发性高血压病组睡前血压 (149.2± 12 .5 ) / (91.7± 6 .2 ) mm Hg,清晨血压 (140 .7± 9.4) / (83.4± 5 .9) mm Hg;两组睡前收缩压及清晨收缩压和舒张压均有差异 ,P<0 .0 1。OSAAHT夜间血压下降率明显小于原发性高血压病对照组[(13.3± 4.9) %比 (4 .5± 1.6 ) % ,P<0 .0 1]。提示 OSAAHT除了睡眠呼吸障碍外 ,还具有以下临床特点 :清晨睡醒时血压较高 ,夜间血压下降幅度变小 ,白天过度困倦以及肥胖等  相似文献   
90.
Advanced malignant melanomas of the uvea unsuited for an eye salvaging approach require enucleation of the tumor containing eye. A series of 68 patients is reported who underwent enucleation combined with insertion of a spherical dura-encased implant after 30 Gray pre-irridiation therapy of the orbit. Postoperative results with special attention to cosmetic outcome and motility of the prosthesis suggest that the insertion of an orbital implant should be preferred to the enucleation with no implant.  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