全文获取类型
收费全文 | 60635篇 |
免费 | 4691篇 |
国内免费 | 3478篇 |
专业分类
耳鼻咽喉 | 355篇 |
儿科学 | 871篇 |
妇产科学 | 577篇 |
基础医学 | 5130篇 |
口腔科学 | 1062篇 |
临床医学 | 7350篇 |
内科学 | 6887篇 |
皮肤病学 | 475篇 |
神经病学 | 1964篇 |
特种医学 | 2367篇 |
外国民族医学 | 13篇 |
外科学 | 5484篇 |
综合类 | 13861篇 |
现状与发展 | 7篇 |
一般理论 | 4篇 |
预防医学 | 6907篇 |
眼科学 | 982篇 |
药学 | 6456篇 |
52篇 | |
中国医学 | 3786篇 |
肿瘤学 | 4214篇 |
出版年
2024年 | 156篇 |
2023年 | 606篇 |
2022年 | 1515篇 |
2021年 | 2129篇 |
2020年 | 1662篇 |
2019年 | 1300篇 |
2018年 | 1348篇 |
2017年 | 1434篇 |
2016年 | 1338篇 |
2015年 | 2053篇 |
2014年 | 2926篇 |
2013年 | 3028篇 |
2012年 | 3765篇 |
2011年 | 4160篇 |
2010年 | 3216篇 |
2009年 | 2779篇 |
2008年 | 3321篇 |
2007年 | 6378篇 |
2006年 | 5912篇 |
2005年 | 3859篇 |
2004年 | 2460篇 |
2003年 | 2567篇 |
2002年 | 1989篇 |
2001年 | 1600篇 |
2000年 | 1340篇 |
1999年 | 1045篇 |
1998年 | 628篇 |
1997年 | 708篇 |
1996年 | 532篇 |
1995年 | 437篇 |
1994年 | 379篇 |
1993年 | 232篇 |
1992年 | 263篇 |
1991年 | 316篇 |
1990年 | 228篇 |
1989年 | 187篇 |
1988年 | 157篇 |
1987年 | 155篇 |
1986年 | 140篇 |
1985年 | 88篇 |
1984年 | 60篇 |
1983年 | 36篇 |
1982年 | 28篇 |
1981年 | 19篇 |
1980年 | 28篇 |
1979年 | 49篇 |
1978年 | 25篇 |
1976年 | 14篇 |
1975年 | 21篇 |
1974年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Amy Y. Zhang Christopher Burant Alex Z. Fu Gerald Strauss Donald R. Bodner Lee Ponsky 《Journal of psychosocial oncology》2020,38(2):210-227
AbstractPurpose: We examined underlying psychosocial processes of a behavioral treatment for urinary incontinence (UI) of prostate cancer survivors.Design: Secondary analysis of data collected from a clinical trial.Sample: Two hundred forty-four prostate cancer survivors who participated in a clinical trial of behavioral intervention to UI as intervention or control subjects.Methods: The participants had a 3-month behavioral intervention or usual care and were followed up for an additional 3?months. They were assessed at baseline, 3, and 6?months. Latent growth curve models were performed to examine trajectories of each study variable and relationships among the variables.Findings: Increasing self-efficacy and social support were significantly and independently associated with more reduction of urinary leakage frequency over time.Implications for psychosocial oncology: Providing problem-solving skills and social support, including peer support, are essential for empowering patients to reduce UI. 相似文献
32.
33.
目的观察认知行为干预在冠心病患者护理中的应用效果。方法选取本院2016年12月~2018年2月期间收治的53例冠心病患者,根据住院号奇偶性情况将其随机分为观察组(n=27)和对照组(n=26),对照组予以常规护理,观察组予以认知行为干预。比较两组患者控制态度评分、心理状况评分、生活质量改善情况及依从性。结果观察组控制态度评分、心理状况评分、生活质量改善情况及依从性与对照组比较,差异有统计学意义(P0.05)。结论在冠心病患者护理中给予认知行为干预应用效果极佳,可作为临床干预首选措施。 相似文献
34.
A Stable Q Compensated Reverse Time Migration Method Based on Excitation Amplitude Imaging Condition
下载免费PDF全文
![点击此处可从《Communications In Computational Physics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Qingqing Li Li-Yun Fu Weijia Sun Wei Wei & Wanting Hou 《Communications In Computational Physics》2020,28(1):141-166
The stability and efficiency, especially the stability, are generally concerned
issues in Q compensated reverse time migration (Q-RTM). The instability occurs because of the exponentially boosted high frequency ambient noise during the forward
or backward seismic wavefield propagation. The regularization and low-pass filtering
methods are two effective strategies to control the instability of the wave propagation in Q-RTM. However, the regularization parameters are determined experimentally, and the wavefield cannot be recovered accurately. The low-pass filtering method
cannot balance the selection of cutoff frequency for varying Q values, and may damage
the effective signals, especially when the signal-to-noise ratio (SNR) of the seismic data
is low, the Q-RTM will be a highly unstable process. In order to achieve the purpose
of stability, the selection of cutoff frequency will be small enough, which can cause
great damage to the effective high frequency signals. In this paper, we present a stable Q-RTM algorithm based on the excitation amplitude imaging condition, which can
compensate both the amplitude attenuation and phase dispersion. Unlike the existing Q-RTM algorithms enlarging the amplitude, the exponentially attenuated seismic
wavefield will be used during both the forward and backward wavefield propagation
of Q-RTM. Therefore, the new Q-RTM algorithm is relative stable, even for the low
SNR seismic data. In order to show the accuracy and stability of our stable Q-RTM
algorithm clearly, an example based on Graben model will be illustrated. Then, a realistic BP gas chimney model further demonstrates that the proposed method enjoys
good stability and anti-noise performance compared with the traditional Q-RTM with
amplitude amplification. Compare the Q-RTM images of these two models to the reference images obtained by the acoustic RTM with acoustic seismic data, the new Q-RTM
results match the reference images quite well. The proposed method is also tested
using a field seismic data, the result shows the effectiveness of our proposed method. 相似文献
35.
顺铂(DDP)作为第一个被发现的金属抗癌药物,是目前最有潜力和应用最广泛的抗肿瘤药物。顺铂在宫颈癌的治疗中尤为重要,目前已被推荐为同步放化疗的首选药物。但随着广泛的使用,顺铂的耐药性逐渐显露出来,并成为限制临床疗效和部分患者肿瘤治疗进展的主要原因之一。顺铂的耐药机制复杂,发生环节较多,但具体耐药机制尚不明确,目前按照顺铂耐药发生的环节可分为:①顺铂在血液循环过程中产生耐药;②顺铂通过细胞膜的流入或流出产生耐药;③顺铂在胞质中产生耐药;④顺铂与DNA结合后产生耐药。本文综述了宫颈癌顺铂耐药可能发生的四个环节及克服耐药常用的手段,为提高顺铂对宫颈癌的疗效提供依据。 相似文献
36.
37.
OBJECTIVES: To assess the effectiveness and safety of additional bedtime H2‐receptor antagonists (H2RAs) in suppressing nocturnal gastric acid breakthrough (NAB) via a systematic review. METHODS: Eligible trials were identified by searching the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 2, 2004), MEDLINE (January 1966–June 2004), EMBASE (January 1980–June 2004) and CINAHL (January 1982–June 2004). Additional hand‐searching was conducted on the proceedings of correlated conferences, eight important Chinese journals and references of all included trials. All randomized controlled trials evaluating H2RAs for the control of NAB were eligible for inclusion. The systematic review was conducted using methods recommended by The Cochrane Collaboration. RESULTS: Only two randomized crossover studies, comprising 32 participants, met the inclusion criteria. Because the design, dosage and duration of the treatments were different between the studies, it was not possible to conduct meta‐analysis. There were no consistent conclusions found between the two included studies in evaluating H2RAs for the control of NAB. CONCLUSIONS: No implications for practice at this stage can be concluded. Appropriately designed large‐scale randomized controlled trials with long‐term follow up are needed to determine the effects of additional bedtime H2RAs in suppressing NAB. 相似文献
38.
陶瑞卿 《四川生殖卫生学院学报》2006,(5):13-16,23
生殖健康是当今国际社会关注的重要问题,也为我国政府重视。本文通过对攀枝花市人口与计划生育技术服务工作分析,总结出该市生殖健康服务模式的主要内容,对正确认识和提高我国西部地区人口生殖健康会水平,稳定我国低生育率水平,实现优生优育,具有十分重要的现实意义。 相似文献
39.
Deng H. Le W. - D. Hunter C. B. 《世界核心医学期刊文摘》2006,2(6):17-18
背景:Parkin基因(PRKN)突变可导致常染色体隐性遗传性早发帕金森病(EOPD)。目的:探讨EOPD白人家族PRKN突变的表现和基因型-表型关系。设计:对EOPD家族的3代20例成员进行基因分析,该家族有4例患者。应用直接基因组DNA测序、半定量聚合酶链反应、实时定量聚合酶链反应以及逆转录酶聚合酶链反应分析以确定PRKN突变。结果:4例早发患者(年龄30—38岁)被确定有PRKN复合杂合突变(T240M和EX5_6缺失),虽然PRKN的杂合T240M和纯合EX5_6缺失突变已有描述,但是据悉,本文为上述复合杂合突变的首次报道。患者的表型为典型常染色体隐性遗传性EOPD的表现,其特征是对左旋多巴治疗有效、相对缓慢的进展和运动障碍。所有杂合突变的基因携带者(T240M或EX5_6缺失)和1例56岁的复合杂合突变女性携带者(T240M和EX5_6缺失)无任何神经系统症状。结论:研究发现,PRKN基因复合杂合突变(T240M和EX5_6缺失)导致一个大的白人家族中4例成员发生常染色体隐性遗传性EOPD。另外1例成员具有相同的突变,比4例患者的平均发病年龄大10岁,并且无本病的临床表现。不完全的外显率对遗传咨询具有暗示作用,并且提示复杂的基因一环境交互作用在PRKN相关EOPD的发病机制中发挥作用。 相似文献
40.
目的比较劳累性心绞痛患者抑郁障碍与冠状动脉粥样硬化程度的相关性,以进一步明确两者之间关系。方法将146名劳累性心绞痛患者根据汉密尔顿抑郁量表评分分为无抑郁症状组、可疑抑郁症状组、明确抑郁症状组。比较三组冠脉Gensini积分。结果3组之间Germini积分值存在统计学差异(P〈0.05)。HAMD量表评分与Gensimi评分成正相关(r=0.244,P〈0.01)。结论劳累性心绞痛患者冠脉粥样硬化程度与抑郁障碍程度成正相关,抑郁障碍对冠脉粥样硬化的发展可产生不良影响。 相似文献