全文获取类型
收费全文 | 6317篇 |
免费 | 626篇 |
国内免费 | 333篇 |
专业分类
耳鼻咽喉 | 74篇 |
儿科学 | 90篇 |
妇产科学 | 120篇 |
基础医学 | 831篇 |
口腔科学 | 125篇 |
临床医学 | 774篇 |
内科学 | 1065篇 |
皮肤病学 | 81篇 |
神经病学 | 351篇 |
特种医学 | 224篇 |
外科学 | 826篇 |
综合类 | 896篇 |
现状与发展 | 2篇 |
一般理论 | 1篇 |
预防医学 | 352篇 |
眼科学 | 133篇 |
药学 | 584篇 |
4篇 | |
中国医学 | 270篇 |
肿瘤学 | 473篇 |
出版年
2024年 | 20篇 |
2023年 | 110篇 |
2022年 | 252篇 |
2021年 | 290篇 |
2020年 | 235篇 |
2019年 | 180篇 |
2018年 | 231篇 |
2017年 | 202篇 |
2016年 | 202篇 |
2015年 | 283篇 |
2014年 | 359篇 |
2013年 | 306篇 |
2012年 | 459篇 |
2011年 | 508篇 |
2010年 | 283篇 |
2009年 | 272篇 |
2008年 | 334篇 |
2007年 | 332篇 |
2006年 | 294篇 |
2005年 | 299篇 |
2004年 | 233篇 |
2003年 | 210篇 |
2002年 | 176篇 |
2001年 | 156篇 |
2000年 | 158篇 |
1999年 | 173篇 |
1998年 | 99篇 |
1997年 | 77篇 |
1996年 | 80篇 |
1995年 | 63篇 |
1994年 | 52篇 |
1993年 | 36篇 |
1992年 | 47篇 |
1991年 | 37篇 |
1990年 | 37篇 |
1989年 | 28篇 |
1988年 | 24篇 |
1987年 | 22篇 |
1986年 | 23篇 |
1985年 | 14篇 |
1984年 | 14篇 |
1983年 | 11篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1979年 | 10篇 |
1973年 | 2篇 |
1972年 | 4篇 |
1971年 | 3篇 |
1970年 | 6篇 |
1969年 | 6篇 |
排序方式: 共有7276条查询结果,搜索用时 31 毫秒
991.
Tao W 《Expert opinion on biological therapy》2006,6(7):717-726
Ophthalmic disorders represent a rapidly growing disease area that is associated with the ageing population. Their sight is threatened by age-related macular degeneration, diabetic retinopathy, glaucoma and/or retinitis pigmentosa (RP). Few effective treatments for these disorders are available at present, in part due to lack of effective delivery of therapeutic molecules to the retina. Encapsulated cell technology (ECT) allows the controlled, continuous and long-term administration of protein drugs in the eye, where therapeutic agents are needed, and does not subject the host to the systemic exposure. Furthermore, the implants can be retrieved, providing an added level of safety. Ciliary neurotrophic factor (CNTF) has been shown to protect the retina from degeneration in 13 animal models, and ECT-based delivery of CNTF protected photoreceptors in the rcd1 dog model of RP. 相似文献
992.
Ecologists studying microbial life in the environment have recognized the enormous complexity of microbial diversity for many years, and the development of a variety of culture-independent methods, many of them coupled with high-throughput DNA sequencing, has allowed this diversity to be explored in ever-greater detail. Despite the widespread application of these new techniques to the characterization of uncultivated microbes and microbial communities in the environment, their application to human health and disease has lagged. Because DNA-based techniques for defining uncultured microbes allow not only cataloging of microbial diversity but also insight into microbial functions, investigators are beginning to apply these tools to the microbial communities that abound on and within us, in what has aptly been called "the second Human Genome Project." In this review we discuss the sequence-based methods for microbial analysis that are currently available and their application to identify novel human pathogens, improve diagnosis of known infectious diseases, and advance understanding of our relationship with microbial communities that normally reside in and on the human body. 相似文献
993.
Sheau-Chung Tang Gwo-Tarng Sheu Ruey-Hong Wong Chia-Ying Huang Mao-Wen Weng Li-Wen Lee Chung-Ping Hsu Jiunn-Liang Ko 《Toxicology letters》2010
Glutathione S-transferases (GSTs) are a family of inducible enzymes that are important in carcinogen detoxification. GST-Mu class is showing the high activity towards most polycyclic aromatic hydrocarbon (PAH) epoxide. Our objective is to clarify the expression of GST-M2 in non-small-cell lung carcinoma (NSCLC) patients and to determine the role of GST-M2 in protecting against DNA damage. We detected changes in GST-M2 expression at mRNA levels with a panel of lung cell lines and clinical samples of malignant and paired adjacent non-malignant tissues from 50 patients with stage I or II non-small-cell lung carcinoma using real-time RT-PCR. Comet assay and γ-H2AX were used to clarify whether DNA damaged was protected by GST-M2. Our data demonstrate that the expression of GST-M2 in tumor tissues is significantly lower than in paired adjacent non-malignant tissues (p = 0.016). Loss of GST-M2 is closely associated with age, gender, T value, N value and cell differentiation (p < 0.05) in early stage I/II patients. Downregulation of GST-M2 is mediated through aberrant hypermethylation in lung cancer cell lines. Protection against B[a]P-induced DNA damage by GST-M2 in lung cancer cells was detected by Comet assay and γ-H2AX. In conclusion, DNA hypermethylation altered and reduced GST-M2 expression that resulted in susceptible to benzo[a]pyrene (B[a]P) induced DNA damage. It implies that GST-M2 reduction occurs prior to tumorigenesis. 相似文献
994.
De-Kun Li Bei Yan Zheng Li Ersheng Gao Maohua Miao Dongming Gong XiaoPing Weng Jeannette R. Ferber Wei Yuan 《Reproductive toxicology (Elmsford, N.Y.)》2010,29(1):86-92
We conducted a population-based case–control study among healthy sperm donors to study exposure to magnetic fields (MFs) and poor sperm quality. All participants wore a meter to capture daily MF exposure. After controlling for confounders, compared to those with lower MF exposure, those whose 90th percentile MF level ≥1.6 mG had a two-fold increased risk of abnormal sperm motility and morphology (odds ratio (OR): 2.0, 95% confidence interval (CI): 1.0–3.9). Increasing duration of MF exposure above 1.6 mG further increased the risk (p = 0.03 for trend test). Importantly, the association and dose–response relationship were strengthened when restricted to those whose measurement day reflected their typical day of the previous 3 months (a likely period of spermatogenesis). Age-adjusted Spearman Rank Order Correlations showed an inverse correlation between MF exposure and all semen parameters. Our study provides some evidence for the first time that MF exposure may have an adverse effect on sperm quality. 相似文献
995.
Yu-I Weng Sandya Liyanarachchi Daniel E. Deatherage Tao Zuo Ching-Hung Lin Tim H.-M. Huang 《Toxicology and applied pharmacology》2010,248(2):111-121
Substantial evidence indicates that exposure to bisphenol A (BPA) during early development may increase breast cancer risk later in life. The changes may persist into puberty and adulthood, suggesting an epigenetic process being imposed in differentiated breast epithelial cells. The molecular mechanisms by which early memory of BPA exposure is imprinted in breast progenitor cells and then passed onto their epithelial progeny are not well understood. The aim of this study was to examine epigenetic changes in breast epithelial cells treated with low-dose BPA. We also investigated the effect of BPA on the ERα signaling pathway and global gene expression profiles. Compared to control cells, nuclear internalization of ERα was observed in epithelial cells preexposed to BPA. We identified 170 genes with similar expression changes in response to BPA. Functional analysis confirms that gene suppression was mediated in part through an ERα-dependent pathway. As a result of exposure to BPA or other estrogen-like chemicals, the expression of lysosomal-associated membrane protein 3 (LAMP3) became epigenetically silenced in breast epithelial cells. Furthermore, increased DNA methylation in the LAMP3 CpG island was this repressive mark preferentially occurred in ERα-positive breast tumors. These results suggest that the in vitro system developed in our laboratory is a valuable tool for exposure studies of BPA and other xenoestrogens in human cells. Individual and geographical differences may contribute to altered patterns of gene expression and DNA methylation in susceptible loci. Combination of our exposure model with epigenetic analysis and other biochemical assays can give insight into the heritable effect of low-dose BPA in human cells. 相似文献
996.
云南省丘北县麻风菌株基因分型研究 总被引:1,自引:0,他引:1
目的:验证云南省丘北县麻风菌株与流行病学间的关联性。方法:对2003-2007年发现的106例新麻风患者菌株进行了6个VNTR位点分型,以系统发育树分析与流行病学的关联性。结果:丘北菌株依据(GTA)9等位基因型可分为两大菌群。第一枝由(GTA)9位点从9到13个重复数组成的A、B和C聚集株,主要分布在该县北部和西北部;第二枝由(GTA)9重复数高达20以上的D、E菌株组成,主要分布在中部和东南部。A至F聚集株内,至少有两个或以上有多个患者的家庭。第一菌群内患者间有明显的流行病学关联,但第二菌群内患者则缺乏关联性。结论:(GTA)9等位基因高度多态菌群来源与异质性的原因不清楚。以家庭和邻居关联的麻风病传播在丘北县很常见,有多个患者的家庭,感染菌株可能来自相同的传播链。 相似文献
997.
骨质疏松症是抗精神病药物的常见不良反应,其症状是以低骨密度为特征,导致骨脆性增加、畸形和骨折的全身性进行性骨骼疾病.以利培酮为代表的抗精神病药物使用会导致高泌乳素血症,高水平催乳素能够通过刺激骨吸收、降低性激素水平影响骨代谢.然而高乳素血症学说存在一定的局限性.现通过探讨人骨代谢指标的变化、动物体内骨量变化和对成骨细胞... 相似文献
998.
目的 探讨盐酸氟哌噻吨美西辛(黛力新)辅助治疗对肠易激综合征患者心理和临床疗效的作用.方法 回顾性分析66例肠易激综合征患者的临床资料,对照组按常规治疗,观察组在治疗组的基础上给于黛力新辅助治疗,观察两组疗效.结果 132例患者中,确诊存在焦虑的患者98例,抑郁患者9例,发病率为81%;观察组治疗前后SAS、SDS评分差异有统计学意义(均P<0.05),对照组治疗前后SAS、SDS评分差异无统计学意义(均P>0.05);与对照组相比,观察组治疗显效率和总有效率均明显升高(均P<0.05).结论 黛力新辅助治疗肠易激综合征能显著改善患者焦虑/抑郁水平,提高临床疗效. 相似文献
999.
Symptomatic hemorrhagic transformation is common in supratentorial and cerebellar infarction, but is rare in brainstem infarction. It is seldom reported in basilar artery occlusion. Although early arterial recanalization by thrombolytic agent has became the new trend of treatment, for some neurologists anticoagulant is still a conventional alternative treatment of basilar artery occlusion, especially in longer-existing ischemic deficits. We report a case of massive pontine hemorrhage associated with enoxaparin (low-molecular-weight heparin) treatment for basilar artery occlusion. On the basis of the clinical information and neuroimaging, an embolism was the most likely cause of stroke. The case presented herein adds massive pontine hemorrhagic transformation to the list of possible complications of anticoagulants for basilar artery occlusion. Apart from no evidence-based benefit in treatment of basilar artery occlusion, anticoagulant may contribute to devastating hemorrhagic transformation. 相似文献
1000.
Haoqing Li Chuanshun Wang Jiandong Wang Kai Wu Donghua Hang 《European journal of medical research》2013,18(1):42