全文获取类型
收费全文 | 13390篇 |
免费 | 852篇 |
国内免费 | 295篇 |
专业分类
耳鼻咽喉 | 54篇 |
儿科学 | 183篇 |
妇产科学 | 65篇 |
基础医学 | 1815篇 |
口腔科学 | 1015篇 |
临床医学 | 1593篇 |
内科学 | 3634篇 |
皮肤病学 | 147篇 |
神经病学 | 611篇 |
特种医学 | 290篇 |
外国民族医学 | 1篇 |
外科学 | 1570篇 |
综合类 | 1303篇 |
预防医学 | 492篇 |
眼科学 | 108篇 |
药学 | 1061篇 |
3篇 | |
中国医学 | 484篇 |
肿瘤学 | 108篇 |
出版年
2024年 | 43篇 |
2023年 | 307篇 |
2022年 | 1351篇 |
2021年 | 1433篇 |
2020年 | 627篇 |
2019年 | 477篇 |
2018年 | 496篇 |
2017年 | 447篇 |
2016年 | 391篇 |
2015年 | 482篇 |
2014年 | 723篇 |
2013年 | 963篇 |
2012年 | 550篇 |
2011年 | 634篇 |
2010年 | 502篇 |
2009年 | 515篇 |
2008年 | 501篇 |
2007年 | 483篇 |
2006年 | 431篇 |
2005年 | 364篇 |
2004年 | 328篇 |
2003年 | 294篇 |
2002年 | 262篇 |
2001年 | 202篇 |
2000年 | 146篇 |
1999年 | 136篇 |
1998年 | 132篇 |
1997年 | 136篇 |
1996年 | 116篇 |
1995年 | 99篇 |
1994年 | 86篇 |
1993年 | 59篇 |
1992年 | 89篇 |
1991年 | 73篇 |
1990年 | 69篇 |
1989年 | 66篇 |
1988年 | 37篇 |
1987年 | 51篇 |
1986年 | 42篇 |
1985年 | 58篇 |
1984年 | 53篇 |
1983年 | 46篇 |
1982年 | 65篇 |
1981年 | 32篇 |
1980年 | 33篇 |
1979年 | 25篇 |
1978年 | 23篇 |
1977年 | 11篇 |
1976年 | 21篇 |
1975年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Paulo N. Rocha Ana T. Rocha Scott M. Palmer R. Duane Davis Stephen R. Smith 《American journal of transplantation》2005,5(6):1469-1476
The incidence, predictors and clinical significance of acute renal failure (ARF) after lung transplantation are not well described. We retrospectively collected data on 296 patients transplanted at our center between April 1992 and December 2000; follow-up was extended until December 2002. Patients were initially divided into two groups: ARF (doubling of baseline creatinine within 2 weeks after surgery) and NoARF. The ARF group was subdivided into ARFD (dialyzed) and ARFnD (not dialyzed). The incidence of ARF was 56% (166/296), but most cases were ARFnD (n = 143). Independent predictors of ARFD (n = 23) were: baseline GFR (OR 0.98, CI 0.96-0.99, p = 0.012), pulmonary diagnosis other than COPD (OR 6.80, CI 1.5-30.89, p = 0.013), mechanical ventilation > 1 d (OR 6.16, CI 1.70-22.24, p = 0.006) and parenteral amphotericin B use (OR 3.04, CI 1.03-8.98, p = 0.045). Both ARFnD and ARFD were associated with longer duration of mechanical ventilation, increased hospital stay and increased early mortality. One-year patient survival was 92.3%, 81.8% and 21.7% in the NoARF, ARFnD and ARFD groups, respectively (p < 0.0001). After controlling for important covariates, ARFD remained associated with an increased hazard of dying (HR 6.77, CI 4.00-11.44, p < 0.0001). In conclusion, ARF occurs commonly after lung transplantation and affects important clinical outcomes, especially when dialysis is required. 相似文献
42.
由聚酯二元醇、异佛尔酮二异氰酸酯和二羟甲基丙酸合成聚氨酯预聚体,以氨乙基氨丙基聚二甲基硅氧(AEAPS)为扩链剂,制备了AEAPS改性聚氨酯水分散液。与未改性的聚氨酯水分散液相比,AEAPS改性聚氨酯水分散液的粒径增大,但粒径分布和表面张力基本不变,说明疏水的聚二甲基硅氧烷侧链被包裹于分散颗粒的内部;此外,改性聚氨酯水分散液的冻融稳定性显著增强。AEAPS改性聚氨酯水分散液成膜后,吸水率明显下降,水在膜表面的接触角增加,400℃时热失重下降,具有良好的疏水性和耐热性。 相似文献
43.
Clinically, phenol is used often as a neurolytic agent to treat pain and spasticity. The purpose of this study was to examine the time course of denervation and recovery in several hindlimb muscles following application of a 5% aqueous solution of phenol to the sciatic nerve. Phenol was applied to the sciatic nerve of adult female rats either by intraneural or perineural injection. Axonal degeneration was evident within the sciatic nerve 2 days following phenol application, although variable amounts of damage were observed. By 2 weeks, the soleus and tibialis anterior had atrophied to 63% and 51% of control. Reinnervation of hindlimb muscles occurred between 2 and 4 weeks following the nerve block. Following denervation, the soleus became slower in that all of the fibers expressed the slow myosin heavy chain (MHC). At 5 months, maximum tension of the soleus was 74% of control and the muscle consisted of more fast fibers on average, some of which expressed IIx MHC. These data suggest that 5% phenol causes an injury to the nerve that is more severe than a crush injury, and that reinnervation of denervated muscles may be by motoneurons other than those that originally innervated the muscles. © 1996 John Wiley & Sons, Inc. 相似文献
44.
This paper considers a pole assignment problem to cluster all poles of a closed-loop system into some specified regions by introducing the complex state for systems having an isotropic property and by using the Riccati equation. The algebraic relations for the distribution of the eigenvalues of a complex matrix are used in order to cluster the poles into specified regions, which guarantees the relative stability margin, e.g. uniform damping or uniform damping ratio. The proposed scheme is essentially a combination of the pole assignment approach and linear quadratic design, taking the advantages of both. A block modal control method—an extension of recursive pole assignment—is also developed for the vibration control of rotating systems by clustering the forward and backward modes in order. Vibration control simulations with an isotropic rotor—bearing system, a magnetic bearing system and a rotating circular disc are treated in order to demonstrate the advantages of the proposed method. 相似文献
45.
46.
47.
48.
应用双相气道内正压呼吸机(BiPAP)对9例慢性阻塞性肺疾病(COPD)康复期和呼吸衰竭稳定期进行临床观察发现,治疗后动脉血氧分压与治疗前相比显著升高(P<0.01);肺活量及用力肺活量轻度升高;1例3次发生急性左心衰、急性肺水肿致急性呼衰患者治疗后,病情很快改善;1例阻塞性夜间睡眠呼吸暂停综合征者应用效果满意。该机应用简便、安全,对心率血压无明显影响,为COPD康复期、急性左心衰兼肺水肿的治疗提供了新途径。 相似文献
49.
人正常下颌升支区应力分布的三维有限元法分析 总被引:3,自引:0,他引:3
目的:对正常人下颌升支在不同咀嚼力作用时应力分布情况进行三维有限元分析。方法:采用三维有限元应力分析的方法,对正常离体人下颌升支在不同加载条件下的应力分布特征进行对比定量分析。结果:(1)所有载荷形式的各种应力值,随着单元距加载点的距离的增大,其应力值相对减小。(2)下颌骨下颌角、升支后缘的应力梯度变化较大。结论:下颌骨下颌角、升支后缘是应力相对集中的区域,也是临床上常见的下颌骨骨折区,同时还是下颌升支矢状骨劈开术后加强固定以及防止骨段移位的区域。 相似文献
50.