全文获取类型
收费全文 | 27060篇 |
免费 | 2673篇 |
国内免费 | 612篇 |
专业分类
耳鼻咽喉 | 124篇 |
儿科学 | 525篇 |
妇产科学 | 459篇 |
基础医学 | 3004篇 |
口腔科学 | 397篇 |
临床医学 | 3162篇 |
内科学 | 4828篇 |
皮肤病学 | 332篇 |
神经病学 | 4238篇 |
特种医学 | 1070篇 |
外国民族医学 | 5篇 |
外科学 | 1545篇 |
综合类 | 2802篇 |
预防医学 | 1534篇 |
眼科学 | 481篇 |
药学 | 2212篇 |
8篇 | |
中国医学 | 715篇 |
肿瘤学 | 2904篇 |
出版年
2024年 | 54篇 |
2023年 | 448篇 |
2022年 | 693篇 |
2021年 | 970篇 |
2020年 | 1058篇 |
2019年 | 1129篇 |
2018年 | 1109篇 |
2017年 | 1106篇 |
2016年 | 1020篇 |
2015年 | 1032篇 |
2014年 | 1538篇 |
2013年 | 2085篇 |
2012年 | 1381篇 |
2011年 | 1509篇 |
2010年 | 1204篇 |
2009年 | 1252篇 |
2008年 | 1208篇 |
2007年 | 1270篇 |
2006年 | 1076篇 |
2005年 | 1017篇 |
2004年 | 876篇 |
2003年 | 829篇 |
2002年 | 687篇 |
2001年 | 626篇 |
2000年 | 511篇 |
1999年 | 454篇 |
1998年 | 436篇 |
1997年 | 393篇 |
1996年 | 363篇 |
1995年 | 359篇 |
1994年 | 292篇 |
1993年 | 232篇 |
1992年 | 206篇 |
1991年 | 182篇 |
1990年 | 187篇 |
1989年 | 164篇 |
1988年 | 129篇 |
1987年 | 114篇 |
1986年 | 122篇 |
1985年 | 166篇 |
1984年 | 167篇 |
1983年 | 131篇 |
1982年 | 115篇 |
1981年 | 114篇 |
1980年 | 100篇 |
1979年 | 72篇 |
1978年 | 35篇 |
1977年 | 27篇 |
1976年 | 34篇 |
1975年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 421 毫秒
51.
17β-雌二醇对子宫内膜异位症患者在位子宫内膜间质细胞β-catenin mRNA和蛋白表达的影响 总被引:2,自引:0,他引:2
目的研究17β-雌二醇(17β-E2)对子宫内膜异位症(内异症)患者在位子宫内膜间质细胞β-catenin mRNA和蛋白表达的影响,探讨Wnt/β-catenin信号通路在介导雌激素促进内异症发生发展的作用。方法体外分离培养内异症患者在位子宫内膜间质细胞。用不同浓度17β-E2处理子宫内膜间质细胞48 h;此后选用10-10mol/L 17β-E2处理子宫内膜间质细胞12、24和48 h,逆转录聚合酶链反应(RT-PCR)和免疫印迹法(Western blotting)检测17β-E2处理前后子宫内膜间质细胞β-catenin mRNA和蛋白的表达水平。同法分析雌激素受体拮抗剂ICI182,780(10-6mol/L)对17β-E2促进β-catenin mRNA和蛋白表达的影响。免疫组织化学染色观察17β-E2作用后β-catenin在子宫内膜间质细胞中的定位。结果17β-E2能明显促进内异症患者在位子宫内膜间质细胞β-catenin mRNA和蛋白的表达,并呈剂量和时间依赖性,于10-10mol/L作用48 h最明显。雌激素受体拮抗剂ICI182,780能明显抑制17β-E2对子宫内膜间质细胞β-catenin mRNA和蛋白的表达。免疫组织化学染色发现17β-E2能促进β-catenin在子宫内膜间质细胞核内的表达。结论雌激素可能通过激活Wnt/β-catenin信号通路促进内异症在位子宫内膜的异位种植。 相似文献
52.
The case of a 75-year-old man with three synchronous carcinomas of the lung (large cell carcinoma, adenocarcinoma, and small cell carcinoma) is reported. This is the eighth well-documented case report in the literature; however, our case is the first to be reported with the newly described histological combination. 相似文献
53.
Dr. J. Tajti MD PhD ; Dr. K. Sas MD ; Dr. D. Szok MD ; Dr. E. Vörös MD ; Dr. L. Vécsei MD DSc 《Headache》1996,36(4):259-260
We report on a patient with clusterlike headache and multiple brain metastases of lung cancer. Initially, cluster headache was suggested clinically by characteristic symptoms without any focal central nervous system signs. However, magnetic resonance imaging demonstrated multiple brain metastases. It is possible that tumor necrosis factor may have played a role in initiating the clusterlike headache. 相似文献
54.
我院治疗66例心间隔缺损的病例中,有4例合并哑性动脉导管未闭(简称PDA),发生率6%。全组病例术前均无PDA临床体征,1例术前再次复查心脏彩超时发现,其余3例均漏诊。1例先处理PDA,3例在纠正心内畸形同时处理PDA。心间隔缺损合并哑性PDA容易漏诊,但有其临床特点,手术可先处理PDA,或在体外循环下处理PDA。 相似文献
55.
Autonomic dysfunction is frequent in patients with multiple sclerosis (MS). The sympathetic skin response (SSR) and the R-R interval variation (RRIV) are simple electrophysiologic tests for the assessment of central and peripheral autonomic disturbances. Both tests were performed in 60 patients with clinically definite MS and 30 controls. The SSR was recorded simultaneously from both upper and both lower limbs. In all volunteers normal responses were recorded from the four limbs, but 39 patients (65%) showed abnormal responses in at least one limb. The reduction in amplitude of the response was correlated with patients' EDSS. In individual limbs, the SSR amplitude correlated with weakness, spasticity and cerebellar dysfunction, but was not sufficiently related to the deep sensory loss. The RRIV was abnormal in 48 MS patients (80%), as compared to the controls, but showed no significant relationship either to the EDSS or to the SSR. The sensitivity of SSR and RRIV is high and comparable with that of visual and somatosensory evoked potentials. 相似文献
56.
本实验研究血液与非血液灌流条件下缺血预处理(IP)对心肌的保护作用。应用离体大鼠Langendorf灌流模型,分血液灌流IP组、非血液(KrebsHenseleit液,KH液)灌流IP组及相应的对照组。测量心肌电生理特性等指标。结果与KH液灌流心脏相似,用血液灌流的大鼠心脏经IP后,在随后的停灌和复灌期间,心室颤动阈升高,心律失常发生率明显降低。实验结论为在用血液灌流离体大鼠心脏模型上,IP对心肌的保护作用与用生理溶液灌流的模型基本相同。 相似文献
57.
The geographic distribution of multiple sclerosis within the 95 Départements and the 21 Régions of France was defined from a 1986 nationwide prevalence series derived from questionnaires. This indicated a significant clustering of high frequency regions in the northeastern part of the country with most significantly low areas in the south and west. Distributions were similar to those for MS death rates by Département and Région for 1968–1977, indicating geographic stability over time; but there was also evidence of diffusion over time. The 1986 prevalence distribution was also compared with all published prevalence rates for communities of France. From all these resources we conclude that all of France falls within the "high frequency zone" for MS, that the nationwide prevalence rate is at least 50 per 100000 population, and that there is evidence of geographic clustering of the disease with temporal spread of the cluster. 相似文献
58.
Brambati B.; Tului L.; Baldi M.; Guercilena S. 《Human reproduction (Oxford, England)》1995,10(4):818-825
Multiple pregnancies resulting from ovarian stimulation areat a higher risk of carrying at least one fetus affected byMendelian or chromosomal anomalies, the incidence of which isdirectly related to the order of multiples. Genetic analysisbefore fetal reduction was offered to both high-and low-riskpregnant women carrying two or more fetuses after ovulationinduction. Chorionic villus sampling (CVS) and fetal reductionwere achieved by transabdominal needling. The use of short-termculture, the polymerase chain reaction and fresh tissue enzymaticanalyses have made it possible for genetic diagnosis to be availablein a few days. A total of 100 patients had multifetal pregnancyreduction performed by a single operator; all of them completedpregnancy and none was lost at follow-up. The total fetal lossbefore 24 weeks was 7% and no statistically significant relationshipwas found with the final number of fetuses and CVS. Perinatallosses (3.9%) were only present in the series with a final numberof two fetuses. Pregnancy duration and birthweight were significantlyhigher in singletons than in twins, but were not related toCVS. The rate of chromosomal disorders was higher (7.2%) inthe study series than in singleton pregnancies not undergoingfetal reduction. Diagnostic error due to incorrect samplingwas reported in 1.5% of cases. These data support fetal reductionas a valuable strategy to improve the outcome of multiple pregnancy.The outcome of pregnancies reduced to singletons was significantlybetter than of those reduced to twins, and was not related toCVS. Therefore, prenatal genetic diagnosis should become anintegral part of counselling on multiple pregnancy, and is stronglyrecommended when reduction to singleton pregnancy is requested. 相似文献
59.
M. Filippi A. Campi V. Martinelli C. Pereira G. Scotti G. Comi 《Acta neurologica Scandinavica》1995,92(2):178-182
Transitional progressive multiple sclerosis (MS) is quite an unusual form of presentation and course of the disease. A case with this progressive form is presented and brain MRI and MTI findings are discussed in relation to the possible insight they may provide for understanding the mechanisms that determine progressive disability in MS. 相似文献
60.
肺脏在老龄大鼠多器官衰竭中的作用 总被引:3,自引:0,他引:3
目的:探讨肺脏在老龄大鼠多器官衰竭中的作用。方法:一次性静脉主射大肠杆菌内毒素,复制出老龄大鼠多器官衰竭(MOF)实验模型。动态观察了五个时相组(1、2,6、12,24h)的有关免疫,生化功能指标和病理变化。 相似文献