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   3456450篇
  免费   243487篇
  国内免费   9408篇
耳鼻咽喉   48771篇
儿科学   112163篇
妇产科学   97982篇
基础医学   485356篇
口腔科学   97924篇
临床医学   312007篇
内科学   673829篇
皮肤病学   81967篇
神经病学   282060篇
特种医学   133777篇
外国民族医学   1123篇
外科学   519685篇
综合类   73279篇
现状与发展   11篇
一般理论   1316篇
预防医学   260207篇
眼科学   79695篇
药学   254438篇
  14篇
中国医学   7163篇
肿瘤学   186578篇
  2018年   36454篇
  2017年   28317篇
  2016年   32503篇
  2015年   36582篇
  2014年   50595篇
  2013年   76491篇
  2012年   101032篇
  2011年   106960篇
  2010年   64464篇
  2009年   61717篇
  2008年   100476篇
  2007年   107512篇
  2006年   109067篇
  2005年   104938篇
  2004年   101312篇
  2003年   98061篇
  2002年   95035篇
  2001年   161557篇
  2000年   165713篇
  1999年   140121篇
  1998年   40515篇
  1997年   36081篇
  1996年   35749篇
  1995年   34465篇
  1994年   31772篇
  1993年   29829篇
  1992年   109587篇
  1991年   105826篇
  1990年   102847篇
  1989年   99744篇
  1988年   92001篇
  1987年   90265篇
  1986年   85261篇
  1985年   81486篇
  1984年   61112篇
  1983年   51923篇
  1982年   31154篇
  1981年   27935篇
  1979年   55575篇
  1978年   39508篇
  1977年   34063篇
  1976年   31257篇
  1975年   34214篇
  1974年   40339篇
  1973年   38721篇
  1972年   36636篇
  1971年   34182篇
  1970年   31866篇
  1969年   30717篇
  1968年   28499篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
A new approach to the activation of reactants during the condensation of aromatic aldehydes with N-aroylglycines (acting as CH-acids) is described. The condensation reaction carried out on heating in phosphorus oxychloride leads to a high yield of 4-benzylideneoxazol-5-one derivatives. The hydrolysis of these intermediate products yields the target α-benzoylaminocinnamic acids. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 39, No. 7, pp. 41 – 42, July, 2005.  相似文献   
992.
A reply     
M. Harmer 《Anaesthesia》1991,46(9):790-790
  相似文献   
993.
Using Syva EMIT reagents and a Cobas Bio centrifugal analyser we have developed a cost-effective assay for the detection of cannabinoids in urine. With this method, up to 1500 samples can be assayed with a single 100 test kit while maintaining acceptable precision. A mean CV of 6.1% was obtained for the concentration range 80-130 micrograms/l. The method is suitable for high-risk urines since heart treatment may be performed prior to analysis. There was no significant change in the measured concentration of cannabinoids in urine samples on storage in plastic containers, refrigerated or frozen, for up to seven weeks.  相似文献   
994.
The sudden appearance of multiple keratoacanthomas in a patient who has sustained a thermal burn is extremely uncommon. This case report describes a sixty-four-year-old man who noted multiple keratoacanthomas within three weeks after being involved in a gasoline explosion. Multiple keratoacanthomas appear to be a rare complication of thermal cutaneous injury in predisposed persons.  相似文献   
995.
996.
We examined binding to excitatory amino acid and inhibitory amino acid receptors in frozen hippocampal sections prepared from surgical specimens resected from 8 individuals with medically refractory temporal lobe epilepsy. The excitatory receptors studied included N-methyl-D-aspartate (NMDA), strychnine-insensitive glycine, phencyclidine, and quisqualate. The inhibitory receptors studied were gamma-aminobutyric acid type A (GABAA) and benzodiazepine. Excitatory and inhibitory amino acid receptor binding were differentially altered in the patients with temporal lobe epilepsy in comparison to 8 age-comparable autopsy control subjects, and changes in receptor binding were regionally selective in four areas. Binding to phencyclidine receptors associated with the NMDA channel was reduced by 35 to 70% in all regions in the hippocampi of the patients. In contrast, binding to the NMDA recognition site and its associated glycine modulatory site was elevated by 20 to 110% in the cornu ammonis (CA) 1 area and dentate gyrus of the hippocampus of the patients. Binding to these sites was unaffected in area CA4. Binding to the quisqualate-type excitatory amino acid receptor was unchanged in all regions except the stratum lacunosum moleculare CA1, where it was increased by 63%. GABAA and benzodiazepine receptor binding was reduced by 20 to 60% in CA1 and CA4, but unchanged in dentate gyrus. The data indicate that excitatory and inhibitory amino acid receptors are altered in the hippocampus of patients with temporal lobe epilepsy.  相似文献   
997.
Artificial dopamine agonists are widely employed for the treatment of idiopathic parkinsonism. Pleuropulmonary disease has previously been reported to occur with the use of bromocriptine and mesulergine. We report similar adverse effects induced by the newer agonists lisuride and cabergoline. All these agents are tetracyclic ergot derivatives. This suggests a causal link between ergot-derived dopamine agonists and pleuropulmonary disease.  相似文献   
998.
Reports on individual nonbehavioral child and adolescent psychotherapy since 1963 are reviewed. Inclusion criteria required some minimal contrasting group. Forty-three studies were assessed for basic methodological adequacy and main findings. The authors conclude that summary impressions from this body of literature cannot be made due to the magnitude of the flaws in basic psychotherapy research methodology. Suggestions are made regarding the future of child and adolescent psychotherapy research.  相似文献   
999.
Postencephalitic acquired Tourette-like syndrome in a child.   总被引:1,自引:0,他引:1  
R S Northam  H S Singer 《Neurology》1991,41(4):592-593
We report a 6-year-old girl who developed a Tourette-like syndrome following presumed herpes encephalitis. This case suggests that tics can be acquired in childhood and may be associated with lesions involving basal ganglia or limbic circuitry.  相似文献   
1000.
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