全文获取类型
收费全文 | 59388篇 |
免费 | 3760篇 |
国内免费 | 167篇 |
专业分类
耳鼻咽喉 | 734篇 |
儿科学 | 1392篇 |
妇产科学 | 854篇 |
基础医学 | 7904篇 |
口腔科学 | 1106篇 |
临床医学 | 5757篇 |
内科学 | 12631篇 |
皮肤病学 | 680篇 |
神经病学 | 6276篇 |
特种医学 | 2431篇 |
外国民族医学 | 55篇 |
外科学 | 9106篇 |
综合类 | 643篇 |
一般理论 | 82篇 |
预防医学 | 4381篇 |
眼科学 | 1194篇 |
药学 | 3854篇 |
中国医学 | 54篇 |
肿瘤学 | 4181篇 |
出版年
2023年 | 246篇 |
2022年 | 474篇 |
2021年 | 1105篇 |
2020年 | 638篇 |
2019年 | 1092篇 |
2018年 | 1285篇 |
2017年 | 940篇 |
2016年 | 1065篇 |
2015年 | 1308篇 |
2014年 | 1838篇 |
2013年 | 2489篇 |
2012年 | 3893篇 |
2011年 | 3993篇 |
2010年 | 2265篇 |
2009年 | 1951篇 |
2008年 | 3662篇 |
2007年 | 3873篇 |
2006年 | 3707篇 |
2005年 | 3739篇 |
2004年 | 3430篇 |
2003年 | 3252篇 |
2002年 | 3170篇 |
2001年 | 698篇 |
2000年 | 577篇 |
1999年 | 656篇 |
1998年 | 665篇 |
1997年 | 588篇 |
1996年 | 494篇 |
1995年 | 486篇 |
1994年 | 407篇 |
1993年 | 393篇 |
1992年 | 399篇 |
1991年 | 391篇 |
1990年 | 348篇 |
1989年 | 333篇 |
1988年 | 315篇 |
1987年 | 315篇 |
1986年 | 286篇 |
1985年 | 299篇 |
1984年 | 377篇 |
1983年 | 312篇 |
1982年 | 366篇 |
1981年 | 328篇 |
1980年 | 287篇 |
1979年 | 232篇 |
1978年 | 223篇 |
1977年 | 164篇 |
1976年 | 186篇 |
1975年 | 159篇 |
1974年 | 193篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Edward J. Holland Walter O. Whitley Kenneth Sall Stephen S. Lane Aparna Raychaudhuri Steven Y. Zhang 《Current medical research and opinion》2016,32(10):1759-1765
Objective: Report efficacy findings from three clinical trials (one phase 2 and two phase 3 [OPUS-1, OPUS-2]) of lifitegrast ophthalmic solution 5.0% for treatment of dry eye disease (DED).Research design and methods: Three 84-day, randomized, double-masked, placebo-controlled trials. Adults (≥18 years) with DED were randomized (1:1) to lifitegrast 5.0% or matching placebo. Changes from baseline to day 84 in signs and symptoms of DED were analyzed.Main outcome measures: Phase 2, pre-specified endpoint: inferior corneal staining score (ICSS; 0–4); OPUS-1, coprimary endpoints: ICSS and visual-related function subscale (0–4 scale); OPUS-2, coprimary endpoints: ICSS and eye dryness score (EDS, VAS; 0–100).Results: Fifty-eight participants were randomized to lifitegrast 5.0% and 58 to placebo in the phase 2 trial; 293 to lifitegrast and 295 to placebo in OPUS-1; 358 to lifitegrast and 360 to placebo in OPUS-2. In participants with mild-to-moderate baseline DED symptomatology, lifitegrast improved ICSS versus placebo in the phase 2 study (treatment effect, 0.35; 95% CI, 0.05–0.65; p?=?0.0209) and OPUS-1 (effect, 0.24; 95% CI, 0.10–0.38; p?=?0.0007). Among more symptomatic participants (baseline EDS ≥40, recent artificial tear use), lifitegrast improved EDS versus placebo in a post hoc analysis of OPUS-1 (effect, 13.34; 95% CI, 2.35–24.33; nominal p?=?0.0178) and in OPUS-2 (effect, 12.61; 95% CI, 8.51–16.70; p?<?0.0001).Limitations: Trials were conducted over 12 weeks; efficacy beyond this period was not assessed.Conclusions: Across three trials, lifitegrast improved ICSS in participants with mild-to-moderate baseline symptomatology in two studies, and EDS in participants with moderate-to-severe baseline symptomatology in two studies. Based on the overall findings from these trials, lifitegrast shows promise as a new treatment option for signs and symptoms of DED. 相似文献
2.
Andrea Stracciolini Jennifer Luz Gregory Walker Nicholas M. Edwards Avery D. Faigenbaum Gregory D. Myer 《The Physician and sportsmedicine》2020,48(2):199-207
ABSTRACT
Objective
To investigate primary care physician clinical practice patterns, barriers, and education surrounding pediatric physical activity (PA), and to compare practice patterns by discipline. 相似文献3.
Henry Havel Gregory Finch Pamela Strode Marc Wolfgang Stephen Zale Iulian Bobe Hagop Youssoufian Matthew Peterson Maggie Liu 《The AAPS journal》2016,18(6):1373-1378
Advancing nanomedicines from concept to clinic requires integration of new science with traditional pharmaceutical development. The medical and commercial success of nanomedicines is greatly facilitated when those charged with developing nanomedicines are cognizant of the unique opportunities and technical challenges that these products present. These individuals must also be knowledgeable about the processes of clinical and product development, including regulatory considerations, to maximize the odds for successful product registration. This article outlines these topics with a goal to accelerate the combination of academic innovation with collaborative industrial scientists who understand pharmaceutical development and regulatory approval requirements—only together can they realize the full potential of nanomedicines for patients. 相似文献
4.
5.
Implications for Practice
Breast cancer is far more curable than in the past but requires multimodality treatment. Great care must be taken to use the least leukemogenic treatment programs that do not sacrifice efficacy. Elimination of radiation and anthracycline/alkylating agent regimens will be helpful where possible, particularly in younger patients and possibly those with homologous repair deficiency (HRD). Use of colony-stimulating factors should be limited to those who truly require them for safe chemotherapy administration. Further study of a possible leukemogenic association with HRD and the various forms of colony-stimulating factors is badly needed.6.
7.
Rotary ventricular assist devices (VADs) are less sensitive to preload than the healthy heart, resulting in inadequate flow regulation in response to changes in patient cardiac demand. Starling‐like physiological controllers (SLCs) have been developed to automatically regulate VAD flow based on ventricular preload. An SLC consists of a cardiac response curve (CRC) which imposes a nonlinear relationship between VAD flow and ventricular preload, and a venous return line (VRL) which determines the return path of the controller. This study investigates the importance of a physiological VRL in SLC of dual rotary blood pumps for biventricular support. Two experiments were conducted on a physical mock circulation loop (MCL); the first compared an SLC with an angled physiological VRL (SLC‐P) against an SLC with a vertical VRL (SLC‐V). The second experiment quantified the benefit of a dynamic VRL, represented by a series of specific VRLs, which could adapt to different circulatory states including changes in pulmonary (PVR) and systemic (SVR) vascular resistance versus a fixed physiological VRL which was calculated at rest. In both sets of experiments, the transient controller responses were evaluated through reductions in preload caused by the removal of fluid from the MCL. The SLC‐P produced no overshoot or oscillations following step changes in preload, whereas SLC‐V produced 0.4 L/min (12.5%) overshoot for both left and right VADs. Additionally, the SLC‐V had increased settling time and reduced controller stability as evidenced by transient controller oscillations. The transient results comparing the specific and standard VRLs demonstrated that specific VRL rise times were improved by between 1.2 and 4.7 s ( = 3.05 s), while specific VRL settling times were improved by between 2.8 and 16.1 seconds ( = 8.38 s) over the standard VRL. This suggests only a minor improvement in controller response time from a dynamic VRL compared to the fixed VRL. These results indicate that the use of a fixed physiologically representative VRL is adequate over a wide variety of physiological conditions. 相似文献
8.
Gregory N. Gan 《Expert opinion on investigational drugs》2016,25(10):1153-1166
Introduction: Cancer treatment is moving away from conventional cytotoxic drugs and towards agents that target specific proteins and mechanisms important to cancer development or survival. The Hedgehog Pathway (HhP) is a signal transduction pathway and its constitutive activation is tumorigenic in basal cell carcinoma (BCC). The HhP enables phenotypic flexibility, and channels tumor-stroma interactions. As a result, it is over-expressed in numerous cancers as well as in the tumor microenvironment and may represent a promising therapeutic target.Areas covered: In this article, we review the rationale for targeting HhP and its role as an oncogenic driver, in tumor epithelial-to-mesenchymal transition (EMT), and in the tumor microenvironment and describe the results of preclinical and clinical studies involving HhP inhibitors.Expert opinion: HhP activation plays an important role in both the tumor microenvironment and tumor EMT which can lead to treatment resistance for a number of different malignancies. In addition to standard use in BCC, several HhP inhibitors are in preclinical, early, and mid-stage clinical development for other solid and hematologic malignancies. 相似文献
9.
Solid-state reactions between sodium hydride and sodium hydroxide are unusual among hydride-hydroxide systems since hydrogen can be stored reversibly. In order to understand the relationship between hydrogen uptake/release properties and phase/structure evolution, the dehydrogenation and hydrogenation behavior of the Na-O-H system has been investigated in detail both ex- and in-situ. Simultaneous thermogravimetric-differential thermal analysis coupled to mass spectrometry (TG-DTA-MS) experiments of NaH-NaOH composites reveal two principal features: Firstly, an H2 desorption event occurring between 240 and 380 °C and secondly an additional endothermic process at around 170 °C with no associated weight change. In-situ high-resolution synchrotron powder X-ray diffraction showed that NaOH appears to form a solid solution with NaH yielding a new cubic complex hydride phase below 200 °C. The Na-H-OH phase persists up to the maximum temperature of the in-situ diffraction experiment shortly before dehydrogenation occurs. The present work suggests that not only is the inter-phase synergic interaction of protic hydrogen (in NaOH) and hydridic hydrogen (in NaH) important in the dehydrogenation mechanism, but that also an intra-phase Hδ+… Hδ– interaction may be a crucial step in the desorption process. 相似文献
10.
Michelle Cleary Garry Walter Jan Sayers Violeta Lopez Catherine Hungerford 《Issues in mental health nursing》2015,36(4):266-271
Cultures of performativity may contribute to organizational and individual arrogance. Workplace organizations have individuals who at various times will display arrogance, which may manifest in behaviours, such as an exaggerated sense of self-importance, dismissiveness of others, condescending behaviors and an impatient manner. Arrogance is not a flattering label and irrespective of the reason or the position of power, in the context of organizational behaviors, may not be useful and may even be detrimental to the work environment. Thus, it is timely to reflect on the implications of arrogance in the workplace. Advocacy and empowerment can be undermined and relationships adversely impacted, including the achievement of positive consumer outcomes. This paper provides an introduction to arrogance, and then discusses arrogance to promote awareness of the potential consequences of arrogance and its constituent behaviors. 相似文献