全文获取类型
收费全文 | 125885篇 |
免费 | 9855篇 |
国内免费 | 3097篇 |
专业分类
耳鼻咽喉 | 1526篇 |
儿科学 | 7276篇 |
妇产科学 | 4943篇 |
基础医学 | 14079篇 |
口腔科学 | 1603篇 |
临床医学 | 13595篇 |
内科学 | 20904篇 |
皮肤病学 | 2420篇 |
神经病学 | 10887篇 |
特种医学 | 2777篇 |
外国民族医学 | 3篇 |
外科学 | 11830篇 |
综合类 | 17967篇 |
现状与发展 | 15篇 |
预防医学 | 7207篇 |
眼科学 | 2235篇 |
药学 | 6565篇 |
55篇 | |
中国医学 | 11039篇 |
肿瘤学 | 1911篇 |
出版年
2024年 | 236篇 |
2023年 | 2145篇 |
2022年 | 3432篇 |
2021年 | 6068篇 |
2020年 | 5549篇 |
2019年 | 4431篇 |
2018年 | 4456篇 |
2017年 | 4581篇 |
2016年 | 4683篇 |
2015年 | 4458篇 |
2014年 | 8740篇 |
2013年 | 9077篇 |
2012年 | 7135篇 |
2011年 | 8317篇 |
2010年 | 6452篇 |
2009年 | 6293篇 |
2008年 | 6118篇 |
2007年 | 6243篇 |
2006年 | 5633篇 |
2005年 | 4674篇 |
2004年 | 3966篇 |
2003年 | 3464篇 |
2002年 | 2385篇 |
2001年 | 2166篇 |
2000年 | 1865篇 |
1999年 | 1771篇 |
1998年 | 1441篇 |
1997年 | 1365篇 |
1996年 | 1303篇 |
1995年 | 1259篇 |
1994年 | 1071篇 |
1993年 | 957篇 |
1992年 | 873篇 |
1991年 | 673篇 |
1990年 | 625篇 |
1989年 | 525篇 |
1988年 | 533篇 |
1987年 | 470篇 |
1986年 | 417篇 |
1985年 | 545篇 |
1984年 | 458篇 |
1983年 | 290篇 |
1982年 | 365篇 |
1981年 | 325篇 |
1980年 | 273篇 |
1979年 | 216篇 |
1978年 | 137篇 |
1977年 | 107篇 |
1976年 | 86篇 |
1975年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Effects of androstenedione, insulin and luteinizing hormone on steroidogenesis in human granulosa luteal cells 总被引:5,自引:0,他引:5
BACKGROUND: The present study was conducted to investigate the effect of androstenedione, insulin and LH on human granulosa cell oestrogen and progesterone production. We postulated that elevated concentrations of androstenedione, insulin and LH may be important modulators of granulosa cell steroidogenesis. METHODS: Granulosa cells obtained in connection with IVF procedures were cultured for a total of 4 days in serum-free medium containing androstenedione (10(-6) mol/l). We tested the effect of androstenedione (10(-5) mol/l) on insulin (0-800 microIU/ml), LH (1-10 ng/ml) as well as on insulin + LH-stimulated oestrogen and progesterone production. RESULTS: Insulin increased the basal secretion of steroid hormones, and furthermore augmented LH-stimulated oestrogen and progesterone accumulation in granulosa cell cultures. Androstenedione (10(-5) mol/l) stimulated basal oestrogen production, but significantly reduced (32-58%) insulin + LH-stimulated oestrogen and progesterone secretion (P < 0.05). CONCLUSION: These results suggest that high androstenedione concentrations may act directly to impair insulin augmentation of LH-stimulated oestradiol and progesterone production in cultured human granulosa luteal cells. This is compatible with the hypothesis that high androgen levels may inhibit oestrogen production in polycystic ovary follicles, and as such may contribute to anovulation and infertility in women with polycystic ovary syndrome. 相似文献
992.
子宫阔韧带内静脉的解剖学研究及其临床意义 总被引:2,自引:0,他引:2
子宫底和体上部的静脉汇集于子宫角处浅出,应称子宫上静脉。该静脉续为卵巢静脉。子宫上静脉1条者占30%,2条者占56.7%,3条者占13.3%。子宫上静脉与输卵管峡部中点相对处的口径是3.7±0.2mm,卵巢丛与子宫上静脉汇合后的口径为5.0±0.4mm。输卵管峡部中点与子宫上静脉的间距为6.3±0.6mm。在输卵管系膜中见有输卵管静脉汇入子宫上静脉。本文研究结果认为盆腔静脉淤血症的发生,与结扎手术中损伤子宫上静脉和输卵管静脉有关。 相似文献
993.
目的 建立荧光定量PCR技术检测 2 1三体综合征。方法 采用PCR方法同时扩增位于 2 1号染色体上的人肝型磷酸果糖激酶基因 (humanliver typephosphofructokinasegene ,PFKL CH 2 1)和位于 1号染色体上的人肌型磷酸果糖激酶基因 (humanmuscle typephosphofructokinasegene ,PFKM CH1) ,使用SYBRGreenⅠ荧光染料处理产物、琼脂糖电泳后在凝胶成像系统进行分析 ,得出扩增产物的荧光强度对比值。用此方法检测 2 6例 2 1三体综合征患儿及 2 0名正常人。结果 2 6例 2 1三体综合征患儿PFKL CH2 1/PFKM CH 1扩增产物的荧光强度对比值为 1.5 8± 0 .17,而正常人为 1 0 0± 0 .0 5 ,两者差异有显著性。结论 SYBRGreenⅠ荧光定量PCR技术检测 2 1三体综合征具有准确、快速、安全、实用等特点 ,有较高的临床使用价值。 相似文献
994.
目的探讨产科多器功能障碍综合征(MODS)的诱因、临床诊断及处理。方法对16例MODS的临床资料进行回顾性分析。结果导致MODS的主要因素为妊娠期高血压疾病及产后出血,器官功能障碍以肾功能衰竭为最多见。结论及时处理MODS的诱发因素,积极治疗妊娠期高血压疾病及产后出血,早期诊断及治疗肾功能衰竭及凝血功能障碍,是减少产科MODS患者死亡的关键。 相似文献
995.
Nobuhiko Okamoto 《American journal of medical genetics. Part A》2019,179(5):822-826
Okamoto syndrome is characterized by severe intellectual disability, generalized hypotonia, stenosis of the ureteropelvic junction with hydronephrosis, cardiac anomalies, and characteristic facial gestalt. Several patients have been reported. The basic mechanism of Okamoto syndrome has not been clarified. Au–Kline syndrome is a new syndrome due to loss‐of‐function variants in the HNRNPK (heterogeneous nuclear ribonucleoprotein K) gene. A new patient with Okamoto syndrome visited our hospital. We noticed that the patient had features overlapping with Au–Kline syndrome. We studied the HNRNPK gene by Sanger sequencing, and identified a novel splicing variant. We suggest that Okamoto syndrome is identical to Au–Kline syndrome. 相似文献
996.
Roberts syndrome is a rare autosomal recessive condition characterized by growth retardation, cranio-facial abnormalities and symmetrical limb reduction of variable severity. Most patients with Roberts syndrome show a typical cytogenetic finding known as "Roberts syndrome effect". We describe a 4-month-old patient with a mild form of this syndrome, who presented with an asymmetrical reduction of the right upper limb. 相似文献
997.
Xiang F Buervenich S Nicolao P Bailey ME Zhang Z Anvret M 《Journal of medical genetics》2000,37(4):250-255
Rett syndrome (RTT) was first described in 1966. Its biological and genetic foundations were not clear until recently when Amir et al reported that mutations in the MECP2 gene were detected in around 50% of RTT patients. In this study, we have screened the MECP2 gene for mutations in our RTT material, including nine familial cases (19 Rett girls) and 59 sporadic cases. A total of 27 sporadic RTT patients were found to have mutations in the MECP2 gene, but no mutations were identified in our RTT families. In order to address the possibility of further X chromosomal or autosomal genetic factors in RTT, we evaluated six candidate genes for RTT selected on clinical, pathological, and genetic grounds: UBE1 (human ubiquitin activating enzyme E1, located in chromosome Xp11.23), UBE2I (ubiquitin conjugating enzyme E2I, homologous to yeast UBC9, chromosome 16p13.3), GdX (ubiquitin-like protein, chromosome Xq28), SOX3 (SRY related HMG box gene 3, chromosome Xq26-q27), GABRA3 (gamma-aminobutyric acid type A receptor alpha3 subunit, chromosome Xq28), and CDR2 (cerebellar degeneration related autoantigen 2, chromosome 16p12-p13.1). No mutations were detected in the coding regions of these six genes in 10 affected subjects and, therefore, alterations in the amino acid sequences of the encoded proteins can be excluded as having a causative role in RTT. Furthermore, gene expression of MECP2, GdX, GABRA3, and L1CAM (L1 cell adhesion molecule) was also investigated by in situ hybridisation. No gross differences were observed in neurones of several brain regions between normal controls and Rett patients. 相似文献
998.
The present report describes the cytogenetic findings in 357 cases referred for suspected chromosomal abnormalities because of abnormal clinical features. Chromosomal anomalies were found in 97 (27.2 %) of the cases studied. A significantly high rate of chromosomal abnormalities was found in a population with clinical abnormalities in comparison to an unselected population (0.48–0.55 %). 相似文献
999.
1000.
Yongchuan Chai Yu Wang Hua Qian Bo Yang Chao Wu Jiusheng Chu Tao Yang 《American journal of medical genetics. Part A》2019,179(2):243-248
Waardenburg syndrome (WS) is a genetic disorder characterized by hearing loss and pigmentary abnormalities with variable penetrance. Though heterozygous mutations in MITF are a major cause for Waardenburg syndrome type 2 (WS2), homozygous mutations in this gene and the associated phenotype have been rarely characterized. In this study, we identified a novel p.R223H mutation in MITF in a Chinese Han family with variable WS features. Both parents carried a heterozygous p.R223H mutation. They had normal hearing, and premature greying of the hair is their only pigmentary abnormality. In contrast, their two children both carried a homozygous p.R223H mutation and had classic WS features including profound hearing loss, heterochromia irides and marked pigmentary abnormalities in hair and skin. Interestingly, the two affected children also have persistent chronic constipation since the neonatal period, symptoms suggestive of Waardenburg syndrome type 4 (WS4). Our study revealed a likely association between homozygous mutations in MITF and WS4, which implies a dosage effect for the underlying pathogenesis mechanism. 相似文献