全文获取类型
收费全文 | 150272篇 |
免费 | 14364篇 |
国内免费 | 8539篇 |
专业分类
耳鼻咽喉 | 1155篇 |
儿科学 | 1897篇 |
妇产科学 | 1674篇 |
基础医学 | 22254篇 |
口腔科学 | 2826篇 |
临床医学 | 17691篇 |
内科学 | 21936篇 |
皮肤病学 | 1638篇 |
神经病学 | 7412篇 |
特种医学 | 5048篇 |
外国民族医学 | 65篇 |
外科学 | 14981篇 |
综合类 | 23463篇 |
现状与发展 | 29篇 |
一般理论 | 12篇 |
预防医学 | 10275篇 |
眼科学 | 3588篇 |
药学 | 17253篇 |
121篇 | |
中国医学 | 7855篇 |
肿瘤学 | 12002篇 |
出版年
2024年 | 573篇 |
2023年 | 2261篇 |
2022年 | 5797篇 |
2021年 | 7371篇 |
2020年 | 5361篇 |
2019年 | 4818篇 |
2018年 | 5074篇 |
2017年 | 4635篇 |
2016年 | 4434篇 |
2015年 | 6394篇 |
2014年 | 7935篇 |
2013年 | 7740篇 |
2012年 | 10903篇 |
2011年 | 11525篇 |
2010年 | 8056篇 |
2009年 | 6510篇 |
2008年 | 7935篇 |
2007年 | 7996篇 |
2006年 | 7270篇 |
2005年 | 6624篇 |
2004年 | 5219篇 |
2003年 | 5065篇 |
2002年 | 4402篇 |
2001年 | 3661篇 |
2000年 | 3209篇 |
1999年 | 2861篇 |
1998年 | 1744篇 |
1997年 | 1855篇 |
1996年 | 1321篇 |
1995年 | 1268篇 |
1994年 | 1132篇 |
1993年 | 811篇 |
1992年 | 1171篇 |
1991年 | 1053篇 |
1990年 | 948篇 |
1989年 | 914篇 |
1988年 | 813篇 |
1987年 | 717篇 |
1986年 | 678篇 |
1985年 | 569篇 |
1984年 | 473篇 |
1983年 | 396篇 |
1982年 | 327篇 |
1981年 | 272篇 |
1980年 | 228篇 |
1979年 | 274篇 |
1978年 | 254篇 |
1977年 | 266篇 |
1976年 | 248篇 |
1974年 | 213篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
11.
Post-induction hypotension is common and associated with postoperative complications. We hypothesised that pneumatic leg compression reduces post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy. In this double-blind randomised study, patients were allocated randomly to the pneumatic leg compression group (n = 50) or control (n = 50). In the intervention group, pneumatic leg compression was initiated before induction of anaesthesia. In the control group, pneumatic leg compression was initiated 20 min after anaesthesia induction. The primary outcome was the incidence of post-induction hypotension in these groups. Post-induction hypotension was defined as systolic blood pressure < 90 mmHg during the first 20 min after induction. Haemodynamic variables and area under the curve of post-induction systolic blood pressure over time were assessed. Complications associated with pneumatic leg compression were recorded, including: peripheral neuropathy; compartment syndrome; extensive bullae beneath the leg sleeves; and pulmonary thromboembolism. The incidence of post-induction hypotension decreased in the pneumatic leg compression group compared with that in the control group; 5 (10%) vs. 29 (58%), respectively, p < 0.001. In the pneumatic leg compression group, the lowest systolic, diastolic and mean blood pressures 20 min after induction of anaesthesia were significantly greater than the control group. Pneumatic leg compression resulted in an increased area under the curve of systolic blood pressure in the first 20 min after induction, p = 0.001. There were no pneumatic leg compression-related complications. Pneumatic leg compression reduced post-induction hypotension in elderly patients undergoing robot-assisted laparoscopic prostatectomy, suggesting that it is an effective and safe intervention to prevent post-induction hypotension among elderly patients undergoing general anaesthesia. 相似文献
12.
Byrne Emma Abel Stephen Yu Alexander Shepard Matthew Karlovits Stephen M. Wegner Rodney E. 《Journal of neuro-oncology》2022,157(1):197-205
Journal of Neuro-Oncology - Adjuvant radiation is often used in patients with low grade gliomas with high-risk characteristics with a recommended dose of 45–54 Gy. We used the... 相似文献
13.
14.
Stepanova E. S. Makarenkova L. M. Chistyakov V. V. Rybakov Yu. L. Gukasov V. M. Fedotcheva T. A. Parshin V. A. Votyakov V. A. Shimanovskii N. L. 《Pharmaceutical Chemistry Journal》2019,52(12):1016-1020
Pharmaceutical Chemistry Journal - An HPLC-MS method for simultaneous quantitative determination of a novel gestagenic pharmaceutical and two of its metabolites in rat and rabbit blood sera was... 相似文献
15.
背景 慢性阻塞性肺疾病(COPD)患者肺栓塞(PE)发生率显著高于常人,但目前不伴红细胞增多的COPD患者并发PE的机制尚不明确。目的 探讨不伴红细胞增多的COPD患者并发PE的影响因素。方法 本研究为回顾性病例对照研究。收集2017年1-12月在新疆医科大学第一附属医院呼吸与呼吸危重症中心住院治疗的血红蛋白(Hb)≤140 g/L的COPD患者。依据肺多层螺旋CT肺血管成像(CTPA)检查结果将患者分为并发PE组和单纯COPD组。记录患者的年龄、性别、合并症、服用抗血小板或抗凝药物史。采用倾向性评分匹配(PSM)方法,通过二元Logistic回归分析估计倾向性评分值,采用1∶1最邻近原则匹配,卡钳值为0.05,筛选出基线相同的两组病例。记录患者的D-二聚体、血常规检查结果,比较两组间差异;分析不伴红细胞增多的COPD患者并发PE的影响因素,红细胞分布宽度(RDW)与中性粒细胞/淋巴细胞比值(NLR)的相关性。结果 共纳入病例339例,其中单纯COPD组289例,并发PE组50例。采用PSM方法筛选两组患者,最终得到单纯COPD组、并发PE组各50例进行后续研究。并发PE组患者D-二聚体、中性粒细胞计数(N)、RDW、NLR高于单纯COPD组,淋巴细胞计数(L)低于单纯COPD组(P<0.05)。二元Logistic回归分析结果显示,RDW是不伴红细胞增多的COPD患者并发PE的影响因素〔OR=1.561,95%CI(1.096,2.225),P<0.05〕。Spearman秩相关分析结果显示,不伴红细胞增多的COPD患者RDW与NLR呈正相关(rs=0.225,P<0.05)。结论 RDW升高是Hb≤140 g/L的COPD患者并发PE的危险因素,且RDW与NLR呈正相关。 相似文献
16.
17.
Christopher Teng JiaDe Yu Jesse Taylor Adam I. Rubin James R. Treat 《Pediatric dermatology》2019,36(5):697-701
Erosive pustular dermatosis of the scalp (EPDS) is an uncommon chronic inflammatory response to scalp trauma that usually resolves with cicatricial alopecia. It most commonly affects elderly patients with a history of actinic damage. Herein, we describe a 16‐year‐old girl with acrofacial dysostosis type 1 presenting after surgery with crusting purulent scalp lesions, whose clinical presentation and histopathologic findings were consistent with EPDS. A review of the literature on EPDS in children is also detailed. 相似文献
18.
19.
20.
Zheng Xingming Ding Yanling Zhao Xiaowei Bai Yu Li Xiaofeng Zhao Kai 《Remote sensing letters.》2019,10(6):563-572
Vegetation water content (VWC) is the key input parameter for a soil moisture retrieval algorithm based on microwave remote sensing, and VWC uncertainty can limit the estimated accuracy of soil moisture. There has been little research on VWC algorithm development and validation in China, and the uncertainty of the VWC estimation method has not been well evaluated. Therefore, the aim of this study is to evaluate the uncertainty of the VWC estimation method used in the SMAP (Soil Moisture Active Passive) algorithm on three spatial scales (the point-scale, 30 m scale, and 1 km scale) for maize in northeast China. Results from three ground experimental datasets showed that the SMAP VWC estimation method was strongly biased with an average overestimation of 1.16 kg m?2,1.04 kg m?2, and 1.13 kg m?2 for the point-scale, 30 m scale, and 1 km scale respectively, and maximum bias occurred in the mid-stage of maize. Also, a new power relationship between NDVI (Normalized Difference Vegetation Index) and VWC was proposed for the 30 m scale based on Sentinel 2 NDVI and field VWC values from 2017 experiment, with respective R2 (coefficient of determination) and Root Mean Squared Error (RMSE) values of 0.80 and 0.67 kg m?2. The results confirmed that this power relationship was still suitable for VWC estimation at the 1 km scale, and it has smaller bias than the original SMAP VWC method. Future work will be carried out to evaluate the applicability of this VWC estimation method over a lager region. It is expected that it can improve the accuracy of soil moisture by providing high precision VWC input parameters. 相似文献