全文获取类型
收费全文 | 48540篇 |
免费 | 3208篇 |
国内免费 | 1782篇 |
专业分类
耳鼻咽喉 | 196篇 |
儿科学 | 1765篇 |
妇产科学 | 323篇 |
基础医学 | 4753篇 |
口腔科学 | 79篇 |
临床医学 | 4712篇 |
内科学 | 3048篇 |
皮肤病学 | 52篇 |
神经病学 | 14159篇 |
特种医学 | 2885篇 |
外国民族医学 | 5篇 |
外科学 | 6136篇 |
综合类 | 6231篇 |
现状与发展 | 1篇 |
预防医学 | 1553篇 |
眼科学 | 93篇 |
药学 | 3846篇 |
25篇 | |
中国医学 | 1164篇 |
肿瘤学 | 2504篇 |
出版年
2024年 | 127篇 |
2023年 | 724篇 |
2022年 | 1211篇 |
2021年 | 1709篇 |
2020年 | 1665篇 |
2019年 | 1510篇 |
2018年 | 1444篇 |
2017年 | 1504篇 |
2016年 | 1551篇 |
2015年 | 1664篇 |
2014年 | 2708篇 |
2013年 | 3350篇 |
2012年 | 2509篇 |
2011年 | 2688篇 |
2010年 | 2365篇 |
2009年 | 2204篇 |
2008年 | 2413篇 |
2007年 | 2469篇 |
2006年 | 2366篇 |
2005年 | 2081篇 |
2004年 | 1606篇 |
2003年 | 1518篇 |
2002年 | 1259篇 |
2001年 | 1094篇 |
2000年 | 874篇 |
1999年 | 818篇 |
1998年 | 721篇 |
1997年 | 795篇 |
1996年 | 628篇 |
1995年 | 524篇 |
1994年 | 539篇 |
1993年 | 398篇 |
1992年 | 396篇 |
1991年 | 328篇 |
1990年 | 295篇 |
1989年 | 287篇 |
1988年 | 284篇 |
1987年 | 246篇 |
1986年 | 293篇 |
1985年 | 370篇 |
1984年 | 387篇 |
1983年 | 243篇 |
1982年 | 312篇 |
1981年 | 270篇 |
1980年 | 247篇 |
1979年 | 146篇 |
1978年 | 92篇 |
1977年 | 87篇 |
1976年 | 70篇 |
1975年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
BACKGROUND AND PURPOSE: The Doppler waveform patterns of loss of diastolic flow, appearance of retrograde diastolic flow, or no detectable flow in the cerebral arteries suggest significantly abnormal cerebral blood flow (CBF). A retrospective study was performed to show that significantly abnormal CBF alone, without clinical criteria, is not necessarily specific to brain death in the young pediatric population. PATIENTS AND METHODS: Forty-seven pediatric patients, from newborn to 4 years of age, were found to have significantly abnormal CBF, including 7 patients with loss of diastolic flow, 28 with retrograde diastolic flow, and 23 with no detectable cerebral flow on serial Doppler sonographic examinations. Their clinical data and sonographic results were collected and analyzed. RESULTS: Forty-two patients died, a few of whom had only transient improvement of cerebral flow. All of the patients with no detectable cerebral flow expired. Five patients survived with or without sequelae. Their underlying conditions that caused increased intracranial pressure were treated by medical and/or surgical intervention, and diastolic reversal of CBF corrected within 1 day in all 5. CONCLUSIONS: Although no detectable flow is a lethal sign, pediatric patients with loss or reversal of diastolic flow may survive with prompt and effective treatment. Using Doppler ultrasound to diagnose cerebral circulatory arrest should be done with caution in pediatric patients. 相似文献
72.
目的 探讨CT检查对判断新生儿缺氧缺血性脑病 (HIE)预后的价值。方法 对 85例HIE患儿分别在生后 1周内、2周~ 2个月、3~ 6个月、1~ 1 5岁进行CT检查 ;同时在生后12~ 14d进行新生儿行为神经测定 ;在 1~ 1 5岁测定发育商判断预后。结果 生后 1周内CT结果分度为重度者预后不良率为 4 0 9% (9/ 2 2 ) ,为中度者预后不良率为 5 7% (3/ 5 2 ) ;2个月时CT随访结果异常者预后不良率为 6 0 0 % (6 / 10 ) ;CT结果中度且 12~ 14d的NBNA评分≥ 35分与 <35分者的预后差异无显著性 ,CT结果重度且 12~ 14d的NBNA评分 <35分者有 72 7% (8/ 11)预后不良。结论 生后 1周内CT分度及生后 1个月左右随访结果 ,同时结合临床、生后 12~ 14dNBNA评分对判断HIE患儿的预后、制定治疗方案及疗程有重要意义。 相似文献
73.
Protein kinase C (PKC) activity was measured in rat brain with 2 h of middle cerebral artery (MCA) and common carotid artery (CCA) occlusion, using dual autoradiography of [14C]iodoantipyrine (IAP) and [3H]phorbol-12,13-dibutyrate (PDBu). In the ischemic brain, it required more than 120 min of incubation to obtain a plateau in PDBu binding. In contrast, the binding of PDBu in non-ischemic brain reached a plateau with incubation for 60 min. This delay of PDBu binding in the ischemic brain suggests that the affinity of this ligand is reduced due to a change in structure of the cell membrane caused by ischemia. PDBu binding in the ischemic brain increased significantly compared to the non-ischemic brain. This finding provides further evidence that excessive activation of PKC in the ischemic brain may play an important role in ischemic neuronal damage. ©1997 Elsevier Science B.V. All rights reserved. 相似文献
74.
MASATO FUKUDA MD AKINOBU HATA MD SHIN-ICHI NIWA MD KEN-ICHI HIRAMATSU MD MASAFUMI YOKOKOJI MD SEIKI HAYASHIDA AM KENJI ITOH DENG KAZUYUKI NAKAGOME MD AKIRA IWANAMI MD 《Psychiatry and clinical neurosciences》1996,50(2):85-88
Abstract A female patient exhibiting functional hearing loss in her left ear demonstrated reduced amplitude of P3 component in event-related potentials (ERP) to left monaural stimulation, with preserved N1 and N2 components to stimulation of either ear. This result suggested that stimuli in the affected ear were conducted successfully up to the auditory cortex but that further processing in higher brain regions was 'repressed'. Event-related potential examination for such hysterical disorders could be useful in clarifying their brain mechanism and offer a useful diagnostic clue to its nature. 相似文献
75.
烟碱对脑M胆碱能受体信息跨膜转导的调节 总被引:1,自引:1,他引:0
采用体外实验研究烟碱对大鼠脑M受体信息跨膜转导的调节作用.脑突触体以烟碱1.0μmol·L-1预处理后,[3H]l-二苯羟乙酸奎宁酯与M受体结合及解离动力学过程减慢.在溶脱的大脑皮层M受体与G蛋白复合体上,烟碱1.0μmol·L-1可减慢[35S]-腺苷5'-[γ-硫]三磷酸与G蛋白的结合,并增强M受体与G蛋白之间的偶联关系.烟碱0.1~1000μmol·L-1既不影响纹状体腺苷酸环化酶的基础活性,也不影响氟化钠激活腺苷酸环化酶的作用.烟碱0.1~30μmol·L-1浓度依赖性地提高脑细胞内Ca2+浓度.据此提出烟碱对脑M受体信息跨膜转导系统有多点调节作用. 相似文献
76.
Harwant S. Gill Michael W. O'Boyle Julie Hathaway 《Cortex; a journal devoted to the study of the nervous system and behavior》1998,34(5):707-718
Alpha power (8–12 Hz) was monitored over the frontal, temporal, parietal and occipital lobes of the left and right cerebral hemispheres while participants mentally rotated three-dimensional shapes to match a specified target. By comparing the activational patterns generated during three experimental conditions, each designed to systematically isolate the involvement of the various subcomponents comprising this mental rotation task, it was suggested that the right frontal lobe mediates encoding and comparison/decision processes, while the left parietal and the left temporal region appear most involved in the generation of images and their mental rotation. A preliminary model describing the cooperative interaction of these cortical regions during mental rotation tasks is proposed. 相似文献
77.
VIM thalamic stimulation for tremor in a patient with IgM paraproteinaemic demyelinating neuropathy. 总被引:1,自引:0,他引:1
Evzen R?zicka Robert Jech Katerina Zárubová Jan Roth Dusan Urgosík 《Movement disorders》2003,18(10):1192-1195
We demonstrate the effect of deep brain stimulation of the ventral intermediate thalamic nucleus on intractable action tremor, in a 72-year-old man suffering from neuropathy associated with monoclonal gammopathy. 相似文献
78.
M. M. Moneer 《Surgery today》1997,27(11):1022-1025
This study consists of a preliminary report of 94 cases with various types of inguinal hernias. All cases were repaired by
a new technique, in which the herniotomy is performed via a preperitoneal approach and the repair is achieved by using a bipedicled
flap from the external oblique aponeurosis, which is transpositioned into the preperitoneal space and sutured to the iliopubic
tract. The details of this technique are herein described. After a follow-up ranging from 15 to 48 months, both the early
and late complications are presented. They were minimal and of minor significance, apart from a hernial recurrence in one
case. 相似文献
79.
Yoshimasa Mori Masakazu Takayasu Yoshio Suzuki Masato Shibuya Jun Yoshida Hiroyoshi Hidaka 《European journal of pharmacology》1997,320(2-3):183-186
The vasodilator effects of C-type natriuretic peptide (CNP) were investigated in isolated rat cerebral arterioles. CNP caused dose-dependent vasodilation, maximally by 10.0±2.2% at 10−6 M. The median effective concentration (EC50) was 5.2×10−10 M. In contrast, atrial natriuretic peptide and B-type natriuretic peptide, other members of the natriuretic peptide family, produced little or no vasodilation. Pretreatment with methylene blue (10−4 M) abolished CNP-induced vasodilation, whereas pretreatment with NG-monomethyl--arginine or indomethacin did not inhibit vasodilation. Thus, CNP is suggested to cause significant vasodilation in cerebral arterioles via a cyclic guanosine monophosphate-dependent mechanism. © 1997 Elsevier Science B.V. All rights reserved. 相似文献
80.
无张力疝修补术后顽固性疼痛原因和对策 总被引:1,自引:0,他引:1
目的 探讨无张力疝修补术后的顽固性疼痛病因及预防治疗。方法 将同期无张力疝修补术与传统的腹股沟疝修补方法进行比较。结果 无张力疝修补术后的顽固性疼痛率为9.02%(12/133),传统的腹股沟疝修补方法疼痛率为8.61%(18/209)。无张力疝修补与传统的腹股沟疝修补相比,术后顽固性疼痛的发生率差异无显著性(P>0.05)。结论 无张力疝修补并不一定减少传统的腹股沟疝修补术后顽固性疼痛,手术规范操作是预防的关键,治疗应先保守治疗,无效再考虑手术治疗。 相似文献