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   618篇
  免费   62篇
  国内免费   35篇
耳鼻咽喉   2篇
儿科学   30篇
妇产科学   34篇
基础医学   96篇
口腔科学   31篇
临床医学   73篇
内科学   123篇
皮肤病学   4篇
神经病学   81篇
特种医学   47篇
外科学   79篇
综合类   16篇
预防医学   22篇
眼科学   6篇
药学   33篇
中国医学   1篇
肿瘤学   37篇
  2023年   2篇
  2022年   5篇
  2021年   6篇
  2020年   9篇
  2019年   7篇
  2018年   10篇
  2017年   7篇
  2016年   8篇
  2015年   13篇
  2014年   15篇
  2013年   24篇
  2012年   19篇
  2011年   25篇
  2010年   32篇
  2009年   32篇
  2008年   20篇
  2007年   32篇
  2006年   29篇
  2005年   23篇
  2004年   32篇
  2003年   17篇
  2002年   16篇
  2001年   15篇
  2000年   21篇
  1999年   15篇
  1998年   38篇
  1997年   36篇
  1996年   26篇
  1995年   18篇
  1994年   18篇
  1993年   11篇
  1992年   10篇
  1991年   15篇
  1990年   6篇
  1989年   11篇
  1988年   15篇
  1987年   8篇
  1986年   11篇
  1985年   8篇
  1984年   8篇
  1983年   3篇
  1982年   12篇
  1981年   3篇
  1980年   5篇
  1978年   2篇
  1976年   2篇
  1975年   3篇
  1974年   2篇
  1973年   3篇
  1971年   2篇
排序方式: 共有715条查询结果,搜索用时 93 毫秒
1.
BACKGROUND: On December 26, 2004, the biggest earthquake for 40 years, measuring 9.0 on the Richter scale, triggered a tsunami that pounded the coastal areas of South Asia and East Africa. The effects of the tsunami on skin conditions have not been evaluated. OBJECTIVE: To determine the influence of the tsunami on skin conditions by evaluating the skin problems of patients presenting at hospitals after the tsunami. METHODS: Between 5 and 25 January 2005, two dermatologists evaluated patients who complained of skin problems at an outpatient clinic and emergency room of a general hospital in Banda Aceh, Aceh Province, Indonesia. RESULTS: The total number of patients that presented during the study period was 235 (131 males and 104 females), and they had a total of 265 skin problems. In terms of age distribution, most subjects were in their fourth decade (23.0%), followed by the third (22.6%) and fifth decade (16.6%). The most prevalent skin problems were infections-infestations (32.5%), followed by eczemas (29.8%) and traumatic skin disorders (29.4%). In males, traumatic skin disorders were most common. The great majority of infection-infestation cases involved superficial fungal infections. Contact dermatitis accounted for three-quarters of eczema cases, and mainly involved the arms (40.0%) and legs (27.1%). The majority of traumatic skin disorders were lacerations, punctures and penetrations, and the feet (44.7%) and hands (18.8%) were most frequently affected. CONCLUSIONS: Unhygienic conditions, exposure to a hazardous environment and contact with various objects during and after the tsunami probably increased the prevalence of infections-infestations, traumatic skin disorders and contact dermatitis. To prevent these problems and associated secondary bacterial infections, health-related education and early medical management are required.  相似文献   
2.
Abstract Perioscan requires a plaque sample to detect the presence of enzymes capable of degrading N-benzoyl-DL-arginine-2-naphthylamide (BANA) from relatively few anaerobic periodontal pathogens. Periocheck assays the presence of neutral proteases in crevicular fluid. The aim of this study was to compare these test kits with traditional clinical methods of detecting periodontal disease and to monitor the ability of the kits to reflect the response to initial therapy. 19 patients with moderately severe chronic periodontitis were seen before and after a course of oral hygiene and root instrumentation consisting of 4 appointments. Clinical measurements and test assays were collected at 5 diseased sites and 2 healthy sites in each subject. Complete data from 125 sites were available for statistical analysis. At baseline Periocheck had a sensitivity of 88% and a specificity of 61% whereas Perioscan had a sensitivity of 99% and a specificity of 55%, when related to the clinical diagnosis. A composite clinical assessment, based on improvement or deterioration of one whole unit change of the subjective clinical indices and 2mm changes or greater in probing depth or probing attachment level, revealed 75 sites which improved following treatment, whereas 45 sites did not change and 5 sites deteriorated. The probability that the tests agreed with the clinical outcome after treatment, was calculated as 50.4% for Periocheck and 52% for Perioscan. The diagnostic kits did not reliably reflect the clinical assessment of periodontal disease in the cross sectional study, or the outcome following treatment.  相似文献   
3.
Background: General anesthetics inhibit evoked release of classic neurotransmitters. However, their actions on neuropeptide release in the central nervous system have not been well characterized.

Methods: The effects of representative intravenous and volatile anesthetics were studied on the release of sulfated cholecystokinin 8 (CCK8s), a representative excitatory neuropeptide, from isolated rat cerebrocortical nerve terminals (synaptosomes). Basal, elevated KCl depolarization-evoked and veratridine-evoked release of CCK8s from synaptosomes purified from rat cerebral cortex was evaluated at 35[degrees]C in the absence or presence of extracellular Ca2+. CCK8s released into the incubation medium was determined by enzyme-linked immunoassay after filtration.

Results: Elevation of extracellular KCl concentration (to 15-30 mm) or veratridine (10-20 [mu]m) stimulated Ca2+-dependent CCK8s release. Basal, elevated KCl- or veratridine-evoked CCK8s release was not affected significantly by propofol (12.5-50 [mu]m), pentobarbital (50 and 100 [mu]m), thiopental (20 [mu]m), etomidate (20 [mu]m), ketamine (20 [mu]m), isoflurane (0.6-0.8 mm), or halothane (0.6-0.8 mm).  相似文献   

4.
5.
6.
7.
The present study was designed to detect three single nucleotide polymorphisms (SNPs) located on 22q11 that was thought as being of particularly importance for genetic research into schizophrenia. We recruited a total of 176 Chinese family trios of Han descent, consisting of mothers, fathers and affected offspring with schizophrenia for the genetic analysis. The transmission disequilibrium test (TDT) showed that of three SNPs, rs10314 in the 3'-untranslated region of the CLDN5 locus was associated with schizophrenia (chi(2) = 4.75, P = 0.029). The other two SNPs, rs1548359 present in the CDC45L locus centromeric of rs10314 and rs739371 in the 5'-flanking region of the CLDN5 locus, did not show such an association. The global chi-square (chi(2)) test showed that the 3-SNP haplotype system was not associated with schizophrenia although the 1-df test for individual haplotypes showed that the rs1548359(C)-rs10314(G)-rs739371(C) haplotype was excessively non-transmitted (chi(2) = 5.32, P = 0.02). Because the claudin proteins are a major component for barrier-forming tight junctions that could play a crucial role in response to changing natural, physiological and pathological conditions, the CLDN5 association with schizophrenia may be an important clue leading to look into a meeting point of genetic and environmental factors.  相似文献   
8.
Dopamine inhibits Na+,K(+)-ATPase activity in several renal tubule segments and thereby regulates urinary Na+ excretion. We now show that a phosphopeptide of 31 amino acids, corresponding to residues 8-38 of the protein phosphatase inhibitor DARPP-32 (dopamine- and cAMP-regulated phosphoprotein of Mr 32,000), mimics the inhibitory action of dopamine on Na+,K(+)-ATPase activity in renal tubule cells from the ascending limb of the loop of Henle. The dephosphorylated form of the peptide is ineffective. The results indicate that dopamine acts through a protein phosphorylation pathway to regulate the activity of an ion pump. In addition, the data suggest that inhibition of protein phosphatase 1 by phophorylated DARPP-32 is a component of the mechanism by which dopamine regulates urinary Na+ excretion.  相似文献   
9.
10.
Human chromosome 11p15.5 and distal mouse chromosome 7 include a megabase-scale chromosomal domain with multiple genes subject to parental imprinting. Here we describe mouse and human versions of a novel imprinted gene, IMPT1 , which lies between IPL and p57 KIP2 and which encodes a predicted multi-membrane-spanning protein similar to bacterial and eukaryotic polyspecific metabolite transporter and multi- drug resistance pumps. Mouse Impt1 and human IMPT1 mRNAs are highly expressed in tissues with metabolite transport functions, including liver, kidney, intestine, extra-embryonic membranes and placenta, and there is strongly preferential expression of the maternal allele in various mouse tissues at fetal stages. In post-natal tissues there is persistent expression, but the allelic bias attenuates. An allelic expression bias is also observed in human fetal and post-natal tissues, but there is significant interindividual variation and rare somatic allele switching. The fact that Impt1 is relatively repressed on the paternal allele, together with data from other imprinted genes, allows a statistical conclusion that the primary effect of human chromosome 11p15.5/mouse distal chromosome 7 imprinting is domain-wide relative repression of genes on the paternal homolog. Dosage regulation of the metabolite transporter gene(s) by imprinting might regulate placental and fetal growth.   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