全文获取类型
收费全文 | 443133篇 |
免费 | 42361篇 |
国内免费 | 23374篇 |
专业分类
耳鼻咽喉 | 4255篇 |
儿科学 | 7675篇 |
妇产科学 | 3515篇 |
基础医学 | 28570篇 |
口腔科学 | 7743篇 |
临床医学 | 51534篇 |
内科学 | 43343篇 |
皮肤病学 | 5395篇 |
神经病学 | 11560篇 |
特种医学 | 17085篇 |
外国民族医学 | 2篇 |
外科学 | 39623篇 |
综合类 | 115191篇 |
现状与发展 | 94篇 |
一般理论 | 1篇 |
预防医学 | 49619篇 |
眼科学 | 5306篇 |
药学 | 53790篇 |
674篇 | |
中国医学 | 43189篇 |
肿瘤学 | 20704篇 |
出版年
2024年 | 2186篇 |
2023年 | 5618篇 |
2022年 | 13883篇 |
2021年 | 17748篇 |
2020年 | 15458篇 |
2019年 | 8694篇 |
2018年 | 9148篇 |
2017年 | 12243篇 |
2016年 | 9378篇 |
2015年 | 17044篇 |
2014年 | 21900篇 |
2013年 | 27859篇 |
2012年 | 39824篇 |
2011年 | 42411篇 |
2010年 | 37597篇 |
2009年 | 32983篇 |
2008年 | 34656篇 |
2007年 | 33448篇 |
2006年 | 29466篇 |
2005年 | 23469篇 |
2004年 | 17011篇 |
2003年 | 13796篇 |
2002年 | 10742篇 |
2001年 | 9789篇 |
2000年 | 7606篇 |
1999年 | 3484篇 |
1998年 | 947篇 |
1997年 | 725篇 |
1996年 | 732篇 |
1995年 | 592篇 |
1994年 | 571篇 |
1993年 | 389篇 |
1992年 | 821篇 |
1991年 | 689篇 |
1990年 | 632篇 |
1989年 | 620篇 |
1988年 | 519篇 |
1987年 | 518篇 |
1986年 | 500篇 |
1985年 | 378篇 |
1984年 | 304篇 |
1983年 | 257篇 |
1982年 | 167篇 |
1979年 | 222篇 |
1978年 | 130篇 |
1977年 | 113篇 |
1974年 | 123篇 |
1973年 | 127篇 |
1972年 | 122篇 |
1971年 | 110篇 |
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
81.
82.
C C Naus M Cimino G R Wood M Di Luca F Cattabeni 《Brain research. Developmental brain research》1992,70(1):39-46
Methylazoxymethanol acetate (MAM) is a mitotic inhibitor that has been used to selectively destroy neuroblasts at specific times during gestation. The administration of MAM results in a dose-dependent microencephaly. Following MAM treatment at 15 days of gestation, we have noted an increase in the level of SS immunoreactivity in the neocortex, as determined by radioimmunoassay. Northern blot analysis for preproSS mRNA revealed an increase in MAM-treated cortex. The cellular distribution of SS has been determined using in situ hybridization and immunocytochemistry. There was a 30% increase in the density of SS-immunoreactive neurons in the cortex of the MAM-treated animals. These data suggest that SS neurons in the cortex are spared following MAM treatment at GD 15. 相似文献
83.
A. Di Stefano M. Wittner B. Corman 《Pflügers Archiv : European journal of physiology》1991,419(3-4):327-331
The maximal urinary osmolality that can be reached by the kidney is reduced with age. This may be due to impaired NaCl transport by the medullary thick ascending limb of Henle's loop, which is part of the renal concentrating mechanism and is modulated by antidiuretic hormone (ADH). We therefore tested in vitro a possible age-related change in the transport capacity and in the response of this nephron segment to ADH in young (1–2 months) and old (20–24 months) mice. The transepithelial potential difference (V
te) was significantly higher in young mice (+8.5±0.4 mV, n=13) than in old ones (+6.6±0.5 mV, n=17). Addition of 0.1 nmol.l–1 ADH to the bath solution significantly increased V
te by 5.2±0.5 mV in the young and by 3.1±0.6 mV in the old animals. Application of dibutyryl-cAMP (0.1 mmol.1–1) did not further increase the hormonal response in both groups. The ADH-mediated increase in the corresponding equivalent short-circuit current (I
SC = V
te/Rte) was twice as great in young mice as in old, indicating that the stimulation of NaCl transport by ADH across the medullary thick ascending limb is significantly reduced with age. These results suggest that the previously reported age-related defect in the urinary concentrating ability of the kidney is partly due to a decreased response of the medullary thick ascending limb to ADH. 相似文献
84.
Total agenesia of the left pericardium is an uncommon congenital anomaly. The case of a 20-year-old male patient practising sports and complaining of atypical chest pain is described. The Authors point out the importance of the particular ECG and Rx findings obtained varying the patient's supine position. The fundamental role of chest CAT scanning as a non-invasive diagnosis technique is confirmed. 相似文献
85.
Luciano Baresi Fabrizio Consorti Manuele Di Paola Antonio Gargiulo Mauro Pezzè 《Journal of medical systems》1997,21(6):369-388
The quality of health care systems and processes is becoming a prominent problem and more and more efforts are devoted to define methodologies and tools to measure and assure quality of care. New methods are required to optimize health care processes to guarantee high quality standards within (limited) available resources. Resource optimizations able to preserve the quality of treatments require good models of medical processes. This paper presents LEMMA, a new notation to model medical processes. LEMMA provides physicians with intuitive graphical elements to design their models. At the same time a high level timed Petri net corresponding to the designed model is built automatically. In this way, LEMMA models are ascribed formal semantics and can be executed and analyzed automatically. The dual language approach followed in this paper allows physicians to gain all the benefits of formal methods without being proficient in them. Medical users manage simple graphical elements, while Petri nets ensure formality and validation capabilities. In this way LEMMA mixes formal and informal notations, overcoming the problems of both the approaches. The definition of the notation has been supported by the development of an environment to design LEMMA models. The environment, besides letting us experiment with the notation, has been employed to define and analyze real case studies. 相似文献
86.
上颌阻生尖牙的临床诊断与治疗 总被引:2,自引:0,他引:2
目的:对阻生上颌尖牙的病因、临床检查、诊断及其相应的治疗进行了临床研究。方法:选取57例上颌尖牙阻生患者,通过病史询问、临床检查、X线片和模型测量的综合分析,从临床角度对阻生牙进行了诊断分类,采用不同的方法进行了矫治,并对矫治效果进行了评估。结果:采取适宜有效的治疗办法,均取得了满意的治疗效果,牙周膜愈合成功率达100%,活髓牙成功率达93.6%,牙龈形态良好者达89.4%。结论:尖牙阻生情况各异,治疗方法多样,根据临床分类选择合适的治疗方法,是矫治成功的关键。 相似文献
87.
Alberto Falchetti Marco Di Stefano Francesca Marini Francesca Del Monte Carmelo Mavilia Debora Strigoli Maria L De Feo Giovan Isaia Laura Masi Antonietta Amedei Federica Cioppi Valentina Ghinoi Susanna Maddali Bongi Giuseppina Di Fede Carmela Sferrazza Giovan B Rini Daniela Melchiorre Marco Matucci-Cerinic Maria L Brandi 《Journal of bone and mineral research》2004,19(6):1013-1017
PDB is genetically heterogeneous. Mutations of the sequestosome1 gene have been reported in sporadic and familial forms of Paget's in patients of French Canadian and British descent. Mutational analyses in different ethnic groups are needed to accurately investigate hereditary diseases. We describe two novel mutations of sequestosome1 in 62 Italian sporadic patients, confirming the role of the encoded protein in this disorder. INTRODUCTION: Paget's disease of bone (PDB) is a relatively common disease of bone metabolism reported to affect up to 3% of whites over 55 years of age. The disorder is genetically heterogeneous, and at present, there is scientific evidence that at least eight different human chromosomal loci are correlated with its pathogenesis. Mutations of the sequestosome1 (SQSTM1) gene were identified as responsible for most of the sporadic and familial forms of Paget in patients of French Canadian and British descent. Such mutations were located at exon 7 and 8 levels, encoding for the ubiquitin protein-binding domain (UBA) and representing a mutational hot spot area. MATERIALS AND METHODS: To verify the involvement of this gene in Italian subjects affected by PDB, we performed mutational analysis in 62 sporadic PDB cases. RESULTS: We described three different mutations at exon 8 level: P392L, already described in the French Canadian population and families predominantly of British descendent, and two novel mutations consisting of the amino acid substitutions M404V and G425R. No significant differences in the clinical history of PDB have been observed in patients with SQSTM1 mutations in respect to those without. CONCLUSIONS: Even though our findings suggest a minor involvement of the SQSTM1 gene in the pathogenesis of sporadic Italian Paget's cases, the identification of different significant mutations within the SQSTM1 gene in unrelated, but clinically similar individuals, offers extremely convincing evidence for a causal relationship between this gene and PDB. Longitudinal studies are needed to assess the penetrance of genotype/phenotype correlations. Our findings confirm the evidence of a clustered mutation area at this level in this disorder. 相似文献
88.
89.
90.