全文获取类型
收费全文 | 96970篇 |
免费 | 30179篇 |
国内免费 | 1089篇 |
专业分类
耳鼻咽喉 | 2522篇 |
儿科学 | 2546篇 |
妇产科学 | 2476篇 |
基础医学 | 2500篇 |
口腔科学 | 5026篇 |
临床医学 | 25854篇 |
内科学 | 25008篇 |
皮肤病学 | 3232篇 |
神经病学 | 12160篇 |
特种医学 | 3536篇 |
外科学 | 17847篇 |
综合类 | 127篇 |
现状与发展 | 40篇 |
一般理论 | 1篇 |
预防医学 | 13100篇 |
眼科学 | 2123篇 |
药学 | 1201篇 |
中国医学 | 9篇 |
肿瘤学 | 8930篇 |
出版年
2024年 | 541篇 |
2023年 | 5020篇 |
2022年 | 1234篇 |
2021年 | 2966篇 |
2020年 | 5321篇 |
2019年 | 2008篇 |
2018年 | 6879篇 |
2017年 | 7324篇 |
2016年 | 7913篇 |
2015年 | 8023篇 |
2014年 | 10419篇 |
2013年 | 12127篇 |
2012年 | 3762篇 |
2011年 | 3518篇 |
2010年 | 6783篇 |
2009年 | 9037篇 |
2008年 | 3482篇 |
2007年 | 2439篇 |
2006年 | 3581篇 |
2005年 | 2123篇 |
2004年 | 1556篇 |
2003年 | 1232篇 |
2002年 | 1079篇 |
2001年 | 1795篇 |
2000年 | 1122篇 |
1999年 | 1665篇 |
1998年 | 2056篇 |
1997年 | 1884篇 |
1996年 | 1935篇 |
1995年 | 1676篇 |
1994年 | 1073篇 |
1993年 | 903篇 |
1992年 | 739篇 |
1991年 | 622篇 |
1990年 | 502篇 |
1989年 | 512篇 |
1988年 | 495篇 |
1987年 | 370篇 |
1986年 | 358篇 |
1985年 | 290篇 |
1984年 | 244篇 |
1983年 | 295篇 |
1982年 | 224篇 |
1981年 | 200篇 |
1980年 | 121篇 |
1978年 | 123篇 |
1977年 | 117篇 |
1976年 | 86篇 |
1974年 | 71篇 |
1972年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 115 毫秒
991.
992.
Chung H. Kim MD Alan R. Zinsmeister PhD Juan-R. Malagelada MD 《Digestive diseases and sciences》1988,33(2):193-199
The effect of electrical dysrhythmias on the mechanical activity of the fed stomach was investigated in 5 conscious dogs implanted with Ag-AgCl electrodes and strain gauge force transducers. Each dog was fed 1 can of ALPO® and electromechanical activities of the stomach were recorded for the next 120 min. The results show that intraarterial boluses of met-enkephalin (75 g/kg), PGE2 (36 g/kg), and epinephrine (36 g/kg) induced episodes of antral dysrhythmias whereas saline (1 cc) did not. The postcibal antrat motility index for the test period was not altered following saline injection, but it was reduced by 61%, 70%, and 81% following the administration of met-enkephalin, epinephrine, and PGE2, respectively (p<0.01 vs. baseline period). During periods of normal electrical rhythm, PGE2 and epinephrine significantly reduced the antral motility index (2.07±0.93 and 3.24±0.79, respectively) vs. saline (7.92±0.44) (p<0.05 for both drugs) whereas met-enkephalin (4.98±0.56) did not. In contrast, during episodes of dysrhythmia, met-enkephalin significantly depressed antral motility (1.70±0.74) (p<0.05 vs. periods with normal electrical rhythm) whereas neither epinephrine nor PGE2 caused a further reduction in antral motility from what was seen during periods of normal electrical rhythm (1.84±0.72 and 1.34±0.37, respectively). We thus conclude that intraarterial administration of met-enkephalin, PGE2, or epinephrine induce gastric dysrhythmias postcibally and depress antral contractile activity. The relaxatory effect of met-enkephalin on antral contractions is primarily due to its dysrhythmic effect whereas PGE2 and epinephrine inhibit antral motility even when the electrical rhythm is undisturbed.This work was supported in part by the USPHS, NIH grants AM26428, AM07198, and AM34988 and the Mayo Foundation. 相似文献
993.
Mario Perez-Reyes MD Robert E. Hicks PhD Jean Bumberry BS A. Robert Jeffcoat PhD C. Edgar Cook PhD 《Alcoholism, clinical and experimental research》1988,12(2):268-276
This is a report of the results of a placebo-controlled study in which the effects of the interaction between ethanol and marihuana on drug plasma concentrations, subjective ratings of intoxication, heart rate acceleration, and psychomotor performance were investigated. Six healthy, male, paid volunteers, moderate users of ethanol and marihuana, participated in the study. Ethanol (0.42 g/kg, 0.85 g/kg, or placebo) was administered over a 30-min interval. Fifteen minutes later the subjects smoked, in their customary manner, NIDA cigarettes containing 2.4% or 0.0004% (placebo) delta-9-tetrahydrocannabinol (THC). Each subject was tested in a single-blind, latin-square crossover design with the following six conditions: placebo ethanol/placebo marihuana; low dose ethanol/placebo marihuana; high dose ethanol/placebo marihuana; placebo ethanol/marihuana; low dose ethanol/marihuana; and high dose ethanol/marihuana. The variables measured in the study were: (a) subjective rating of ethanol and/or marihuana intoxication; (b) heart rate; (c) accuracy and latency of response in the Simulator Evaluation of Drug Impairment (SEDI) task; (d) blood ethanol concentration by gas chromatography; and (e) plasma concentration of THC by radioimmunoassay. The results indicate that the decrements due to ethanol in performance of skills necessary to drive an automobile were significantly enhanced by marihuana in an additive and perhaps synergistic manner. The administration of ethanol prior to marihuana smoking did not produce significant effects on the subjective rating of "high," heart rate acceleration, or THC plasma concentration. 相似文献
994.
Tai-Chan Peng MD Robert P. Kusy PhD Philip F. Hirsch PhD John R. Hagaman BA 《Alcoholism, clinical and experimental research》1988,12(5):655-659
Chronic ingestion of ethanol resulted in ultrastructural and mechanical changes in rat femurs. Scanning electron microscopy of the distal end of the femur revealed that the trabeculae of bones from ethanol-fed rats were thinner, more columnar, and more extensive than those from control rats. Three-point bending tests of the rat femurs showed that the maximum force or so-called "strength" required to break the bone was less in ethanol- than in control-fed animals. A significant inverse correlation was observed between the strength required to break the femur and the dose of ethanol calculated on a body weight basis. For the first time our study presents quantitative proof that a relationship exists between bone strength and the consumption of ethanol in rats. The study revealed that ethanol consumption resulted in a weaker femur compared to controls. We suggest that a common mechanism may be responsible for the decreased bone strength of ethanol-fed rats and the increased incidence of fractures in human alcoholics. 相似文献
995.
J. J. M. Askenasy MD. PhD. M. D. Yahr 《Journal of neural transmission (Vienna, Austria : 1996)》1988,72(1):67-76
Summary In the present study a single case observation of myoclonus during sleep-wave transition was monitored in a depressed patient treated with the monoamine oxidase inhibitor, phenelzine. The myoclonus had a rhythm of 1 c/second and lasted for two years, the duration of phenelzine treatment. Myoclonus appeared neither during wakefulness nor during sleep, but at wake-sleep-wake transitions. This switch myoclonus was associated with phasic muscle hyperactivity during REM sleep.Methysergide a 5-HT suppressor, decreased the switch myoclonus frequency and the REM muscle hyperactivity, indicating serotoninergic involvement in the mechanism of phenelzine induced myoclonus. 相似文献
996.
Tomasz Trojanowski Jerzy P ceszyński Krzysztof Turowski Stanisław Kamiński Igor Gościński Marian Reinfus Tadeusz Krzyszkowski Marek Pyrich Adam Bielawski Czesława Leszczyk Barbara Bendarzewska Andrzej Staszczak Halina Koźniewska 《Journal of neuro-oncology》1988,6(3):285-291
A prospective, randomized trial evaluates the effects of two postoperative treatment regimens on survival in 198 adult patients with supratentorial gliomas. All patients were irradiated with 6 000 rads after possibly radical removal of tumors. CCNU administration in the dosis of 100 mg/sq m of body surface every 6–8 weeks following surgery proved to have no significant effect on the survival of patients. The median survival time in patients receiving radiation therapy alone was 61±7 weeks, while in those receiving additional chemotherapy was 56±4 weeks. Tumor histological malignancy and patients age were found to be the only important prognostic factors, irrespective of the treatment modality.
Address for offprints: T Trojanowski, Department of Neurosurgery, Medical School, Jaczewskiego 8, 20-950 Lublin, Poland 相似文献
997.
Albert Kingman PhD 《Journal of public health dentistry》1992,52(6):353-360
Statistical issues associated with demonstrating significance between treatment groups (efficacy or superiority) and nonsignificance (equivalence) are presented and discussed. Methodologies for demonstrating efficacy of a product are proposed and contrasted, incorporating clinical and statistical criteria, with emphasis on situations in which placebo groups are precluded from the study design. Distinctions are drawn between study designs for demonstrating superiority and those for equivalence, including the determination of sample sizes needed for the different approaches. The "at least as good as" criterion is proposed as a reasonable alternative to that of equivalence in active control equivalence studies for demonstrating that dental product modifications or new products are efficacious. 相似文献
998.
Conway F. Saylor PhD Cynthia Cupit Swenson Ph.D. Paige Powell Ph.D. 《Child psychiatry and human development》1992,22(3):139-149
This article reports highlights from over 200 parents' observations of their preschoolers' play and verbalizations in the year following Hurricane Hugo. Commonly reported activities included reenactment and discussion of the event in multiple mediums, personification of Hugo, and expression of fears related to storms. Precocious concern for others, insight, and vocabulary were also noted. In these intact, relatively high functioning families, parents seemed able to facilitate their youngsters' adjustment without outside intervention.Portions of this report were presented in earlier form at the 1991 Society for Research in Child Development meeting in Seattle, Washington. 相似文献
999.
R. Langevin PhD P. Wright MA L. Handy 《Sexual abuse : a journal of research and treatment》1989,2(3):227-253
From a data bank of 479 sex offenders, a comparison was undertaken of those reporting any childhood sexual abuse versus those reporting none. A total of 201 men (42.0%) reported abuse, 261 (54.5%) did not and for 17 (3.5%), information was unavailable. The Abused and Nonabused Groups were compared on demographic information, the MMPI, Clarke Sex History Questionnaire and the Clarke Parent Child Relations Questionnaire. The Abused and Nonabused groups were similar in age, marital status, income, and criminal history, but the Abused Group had significantly less education. The Abused Group showed sexualization of their childhood, not only in the number of contacts with adults but also with age peers and siblings of both sexes. They tended to have wider ranging and more frequent sexual experiences as adults both with men and women. They more often raped. The Abused Group tended to show more emotional instability than the Nonabused Group in more frequent suicidal ideation and suicide attempts, as well as in elevated Mania Scale Scores on the MMPI. The family background of the Abused Group was more disturbed than the Nonabused Group's; especially father-son relations. They reported more alcohol use and abuse in their parents and more parent-child aggression than nonabused offenders did. Although it is unlikely that child sexual abuse causes sexual anomalies, the results of the present study suggest that childhood sexual victimization in the lives of adult sex offenders merits further investigation and has implications for treatment. 相似文献
1000.
Mazur G Bogunia-Kubik K Wróbel T Karabon L Polak M Kuliczkowski K Lange A 《Immunology letters》2005,96(2):241-246
Multiple myeloma (MM) is a plasma cell malignancy characterised by bone marrow infiltration and the presence of a monoclonal protein in serum and/or urine. Interleukin-6 (IL-6) has been identified as one of the most important cytokines that contributes to myeloma cell survival and proliferation. Recent investigations suggest involvement of another cytokine, IL-10, in the activation of MM cells. The present study aimed to determine whether there is an association between the polymorphic features located within the promoter regions of IL-6 and IL-10 genes and progression the disease. IL-6 (-174 G/C) and IL-10 (-1082 A/G, -819 C/T, -592 A/C) promoter single nucleotide polymorphisms (SNPs) were determined by PCR-SSP technique using commercial primers. Our single centre results were compared with the data from literature and combined in cumulative analysis employing the Mantel-Haenszel method. In univariate analysis, only IL-10 ACC genotype tended to prevail in our (Polish) group of patients. None of IL-6 genotypes or IL-10 (-1082) alleles was found to associate with MM disease either in our single centre or in cumulative study. Among patients who died within 36 months of diagnosis, a significant prevalence (P < 0.05) of IL-6 heterozygous cases as opposed to IL-6 homozygotes was observed. IL-6 and IL-10 promoter gene polymorphisms were not found to associate with the susceptibility to the development of MM. However, the IL-6 polymorphic features appeared as factors that might affect the survival of MM patients. The latter observation warrants further study. 相似文献