全文获取类型
收费全文 | 96360篇 |
免费 | 9380篇 |
国内免费 | 5303篇 |
专业分类
耳鼻咽喉 | 1105篇 |
儿科学 | 1287篇 |
妇产科学 | 707篇 |
基础医学 | 7504篇 |
口腔科学 | 1599篇 |
临床医学 | 11309篇 |
内科学 | 10050篇 |
皮肤病学 | 964篇 |
神经病学 | 3392篇 |
特种医学 | 3827篇 |
外国民族医学 | 12篇 |
外科学 | 9877篇 |
综合类 | 23021篇 |
现状与发展 | 27篇 |
一般理论 | 4篇 |
预防医学 | 9986篇 |
眼科学 | 1419篇 |
药学 | 11042篇 |
125篇 | |
中国医学 | 8571篇 |
肿瘤学 | 5215篇 |
出版年
2024年 | 1289篇 |
2023年 | 1641篇 |
2022年 | 3345篇 |
2021年 | 4217篇 |
2020年 | 3599篇 |
2019年 | 2361篇 |
2018年 | 2374篇 |
2017年 | 2775篇 |
2016年 | 2330篇 |
2015年 | 4069篇 |
2014年 | 5095篇 |
2013年 | 6271篇 |
2012年 | 8914篇 |
2011年 | 9157篇 |
2010年 | 7670篇 |
2009年 | 6563篇 |
2008年 | 6989篇 |
2007年 | 6533篇 |
2006年 | 5825篇 |
2005年 | 4709篇 |
2004年 | 3619篇 |
2003年 | 2911篇 |
2002年 | 2171篇 |
2001年 | 1687篇 |
2000年 | 1242篇 |
1999年 | 674篇 |
1998年 | 284篇 |
1997年 | 259篇 |
1996年 | 238篇 |
1995年 | 236篇 |
1994年 | 174篇 |
1993年 | 125篇 |
1992年 | 136篇 |
1991年 | 142篇 |
1990年 | 118篇 |
1989年 | 104篇 |
1988年 | 82篇 |
1987年 | 84篇 |
1986年 | 86篇 |
1985年 | 87篇 |
1984年 | 86篇 |
1983年 | 59篇 |
1982年 | 59篇 |
1981年 | 51篇 |
1980年 | 48篇 |
1979年 | 45篇 |
1978年 | 47篇 |
1975年 | 39篇 |
1974年 | 39篇 |
1973年 | 36篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Human transmissible spongiform encephalopathies (TSE) encompass a group of rare neurodegenerative diseases. In April 2004, a group of international experts and regulators met in Buenos Aires, Argentina, to review the safety and to reach consensus on the use of urinary-derived gonadotrophins with respect to TSE. Iatrogenic transmission of Creutzfeldt-Jakob Disease (CJD) from pituitary-derived gonadotrophins has been reported, no infectivity in urine has been demonstrated, and no definite cases of transmission via urine have been reported. It is currently not possible to monitor donor urine or finished product for the presence of prions. Therefore the assessment of risk has to be based on the likelihood of infection in urine, the source of the urine, and the capacity of the manufacturing process to remove any adventitious infection. Urine for the production of medicinal products should be obtained from sources that minimize the possible presence of materials derived from subjects suffering from human TSE. As no strong evidence for TSE infectivity in urine exists, it can be concluded that the risk of disease-generating prions and TSE infectivity being present in donor urine is low. Current evidence indicates that, with respect to the risk of TSE infection, urinary-derived gonadotrophins appear to be safe. 相似文献
62.
广东汉族人蛋氨酸合成酶基因多态性 总被引:7,自引:2,他引:7
目的了解广东汉族人蛋氨酸合成酶基因的分布特点.方法应用聚合酶链反应技术对211例正常人蛋氨酸合成酶基因进行扩增,进行图谱分析.并结合文献进行了不同种族间的分析比较.结果广东汉族人群中MS基因型以AA最多见,AG次之.AA基因型频率为0.8009、AG为0.1802、GG为0.0189.A基因型频率为0.8910、G为0.1090.与其他种族相比较,MS基因型在中国正常人群中的分布与白种人群中的分布差异显著.结论蛋氨酸合成酶基因因多态性在不同种族间分布存在着明显的差异. 相似文献
63.
We report on the antileukemia effect of interleukin 2 (IL2) on different immune cells from 22 patients with chronic myeloid leukemia (CML). Bone marrow cells from these patients were first cultured in modified long-term bone marrow culture medium for several days, then separately cultured with lymphokine activated killer cells (LAK), cytokine-induced killer cells (CIK), and dendritic cell cocultured CIK (DC-CIK) for another 1-2 days. They were then detected for presence of the Philadelphia chromosome (Ph) by cytogenetic analysis and fluorescence in situ hybridization (FISH). The percentage of Ph-chromosome-positive cells in the bone marrow mononuclear cells after culturing with CIK and DC-CIK was significantly lower than that after culturing with IL2 or LAK. Our results demonstrate that cytogenetics and FISH are useful techniques for the evaluation of the anti-CML effect of immune cells and that CIK or DC-CIK can be appropriate candidates for adoptive immune cell therapy in vivo or for leukemia cell purging ex vivo. 相似文献
64.
65.
目的 探讨经舟骨月骨周围脱位的诊断和治疗。方法 回顾性分析17例经舟骨月骨周围脱位病例,背侧型13例,掌侧型4例;新鲜损伤组10例中8例行撬拨复位成功,仅2例因舟骨对位不良接受手术治疗;陈旧性组7例中均接受手术,4例行开放复位内固定,3例行近排腕骨切除术。结果 采用Cooney评价标准,优11例,良3例,可1例,差2例,优良率82.35%。结论 经舟骨月骨周围脱位的早期治疗简单且疗效较好,而一旦误诊,则多数需手术治疗,且残留不同程度的功能障碍。提高对本病损伤机制、腕部体征和影像学特点的认识和了解,减少误诊。是提高本病预后的关键因素之一。 相似文献
66.
67.
A study of the x-ray sensitivity of amorphous selenium (a-Se) for digital mammography has been performed. A uniform layer of a-Se was deposited on a glass substrate with electrodes on both surfaces. The deposition procedure was identical to that used for a-Se flat-panel detectors. A high voltage was applied to the top surface of the a-Se layer in order to establish an electric field E(Se). Then the sample was exposed to x rays with 27 kVp spectra generated from an x-ray tube with a molybdenum (Mo) target. The mean x-ray energy of the spectrum used was approximately 16.6 keV. The x-ray current generated by the a-Se layer was measured as a function of E(Se). From the current measurement and the estimation of total x-ray energy absorbed in the a-Se, the energy required to create one electron-hole pair (EHP), W, was determined as a function of E(Se). It was found that at the most commonly used E(Se) of 10 V/microm, W was measured as 64 eV. This is considerably higher than the widely accepted typical value of W = 50 eV measured at higher x-ray photon energies (e.g., 50 keV). The dependence of W as a function of E(Se) can be best fitted using the empirical expression of E(Se)-gamma. This relationship is consistent with the results obtained at higher x-ray energies. This article provides an accurate measurement of x-ray sensitivity of a-Se at mammographic energies independent of detector operation, such as the most recently developed flat-panel detectors. The results will be a useful tool for investigation and optimization of a-Se-based x-ray imaging detectors, such as determination of pixel fill-factor and optimal E(Se) during operation. 相似文献
68.
用Millicell底膜培养皿研究Tourmaline对ECV-304细胞增殖的影响 总被引:2,自引:0,他引:2
目的 用联合培养的方法研究Tourmaline对体外培养的人血管内皮细胞(ECV-304)增殖作用的影响。方法 用放置Tourmaline微球的Millicell底膜培养皿与人血管内皮细胞ECV304联合培养。通过细胞形态、细胞融合面积、细胞计数及增殖细胞核抗原(PCNA)的免疫细胞化学等方法观察培养细胞增殖的变化。结果 联合培养24h后Tourmaline组(与对照组比)细胞形态正常,呈铺路石样生长,贴壁细胞覆盖率从(79.50±5.92)%长到(90.17±3.49)%(P<0.05),细胞数增加(16.62±4.14)%(P<0.05),PCNA阳性细胞为(43.50±3.19)%,与对照组比,差异均有非常显著意义(P<0.01)。结论 Tourmaline可通过加强DNA合成,促进体外培养的ECV-304细胞增殖。 相似文献
69.
人缺血脑组织中IP-10和IFN-γ的表达 总被引:1,自引:0,他引:1
目的:探讨趋化因子IP-10和细胞因子IFN-γ是否参与人缺血脑损伤过程。方法:将21例脑梗死死亡病例按发病持续时间分为〈7天、7~14天和15~21天3组,以非缺血侧半球做对照,用HE染色法观察炎性细胞浸润情况;通过免疫组织化学方法检测缺血半球脑组织与非缺血半球脑组织中趋化因子IP-10和细胞因子IFN-γ的表达。结果:在〈7天组和7~14天组中,缺血脑组织可见大量炎性细胞浸润。在〈7天组、7~14天组和15~2l天组中,趋化因子IP-10在缺血半球脑组织中的表达高于非缺血半球(分别是1.74倍增高,P〈0.01;1.41倍增高,P〈0.05和1.52倍增高,P〈0.01)。在对细胞因子IFN-γ的检测中发现〈7天和7~14天组中,IFN-γ在缺血半球脑组织中的表达高于非缺血半球(分别是1.65倍增高,P〈0.05和1.32倍增高,P〈0.05);在15~21天组中,IFN-γ在缺血半球与非缺血半球中的表达没有显著差异(P〉0.05)。结论:在人缺血脑组织中观察到IP-10和IFN-γ的表达,提示IP-10和IFN-γ参与了炎症反应对脑组织的损伤过程。同时也提示IP-10可能参与后期对损伤脑组织的修复。 相似文献
70.
Yanping Tang Ying Wang Ping Yang Yuan Liu Bo Wang Robert Podolsky Richard McIndoe Cong-Yi Wang 《American journal of medical genetics. Part B, Neuropsychiatric genetics》2006,(3):242-244
The prevalence of juvenile-onset Huntington's disease (HD) is about ten times lower than adult HD. Here we report a Chinese HD family showing both intergeneration CAG expansion and contraction. The expansion resulted from a paternal transmission which leads to juvenile-onset HD for a 17-year-old Chinese boy (III-5). More interestingly, a contraction was noticed in a maternal transmission (III-3), which changed the CAG repeat from an expanded, disease-causing allele (48 repeats) to a normal or intermediate allele (34 repeats). Of note, the contraction resulted in a deletion of 14 CAG repeats, which is much larger than previously reported contractions. Our results are consistent with previous observations in Western Caucasians that juvenile-onset HD is more likely inherited through the male germline. 相似文献