全文获取类型
收费全文 | 24961篇 |
免费 | 2275篇 |
国内免费 | 2101篇 |
专业分类
耳鼻咽喉 | 170篇 |
儿科学 | 247篇 |
妇产科学 | 231篇 |
基础医学 | 2933篇 |
口腔科学 | 389篇 |
临床医学 | 3344篇 |
内科学 | 3570篇 |
皮肤病学 | 165篇 |
神经病学 | 1268篇 |
特种医学 | 860篇 |
外国民族医学 | 18篇 |
外科学 | 2891篇 |
综合类 | 4325篇 |
现状与发展 | 4篇 |
一般理论 | 1篇 |
预防医学 | 1752篇 |
眼科学 | 658篇 |
药学 | 2731篇 |
24篇 | |
中国医学 | 1377篇 |
肿瘤学 | 2379篇 |
出版年
2024年 | 108篇 |
2023年 | 405篇 |
2022年 | 1037篇 |
2021年 | 1205篇 |
2020年 | 955篇 |
2019年 | 826篇 |
2018年 | 857篇 |
2017年 | 745篇 |
2016年 | 777篇 |
2015年 | 1131篇 |
2014年 | 1389篇 |
2013年 | 1213篇 |
2012年 | 1697篇 |
2011年 | 1947篇 |
2010年 | 1245篇 |
2009年 | 990篇 |
2008年 | 1300篇 |
2007年 | 1360篇 |
2006年 | 1273篇 |
2005年 | 1310篇 |
2004年 | 811篇 |
2003年 | 913篇 |
2002年 | 689篇 |
2001年 | 574篇 |
2000年 | 636篇 |
1999年 | 744篇 |
1998年 | 460篇 |
1997年 | 462篇 |
1996年 | 323篇 |
1995年 | 302篇 |
1994年 | 307篇 |
1993年 | 169篇 |
1992年 | 216篇 |
1991年 | 179篇 |
1990年 | 150篇 |
1989年 | 150篇 |
1988年 | 126篇 |
1987年 | 103篇 |
1986年 | 75篇 |
1985年 | 82篇 |
1984年 | 28篇 |
1983年 | 17篇 |
1982年 | 13篇 |
1981年 | 11篇 |
1980年 | 6篇 |
1979年 | 19篇 |
1974年 | 1篇 |
1929年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Yihui Du Qiong Li Grigory Sidorenkov Marleen Vonder Jiali Cai Geertruida H. de Bock Yu Guan Yi Xia Xiuxiu Zhou Di Zhang Mieneke Rook Rozemarijn Vliegenthart Marjolein A. Heuvelmans Monique D. Dorrius P.M.A. van Ooijen Harry J.M. Groen Pim van der Harst Yi Xiao Shiyuan Liu 《Academic radiology》2021,28(1):36-45
992.
目的 采用三维有限元分析法研究新型动力化前路方形区钛板螺钉系统(DAPSQ)固定髋臼高位双柱骨折的生物力学特点,并比较其在不同方形区螺钉置钉方法 下的生物力学稳定性.方法 应用1例成年男性志愿者骨盆CT图像构建左侧髋臼高位双柱骨折的全骨盆有限元模型,并采用新型动力化前路方形区钛板螺钉系统固定.分别构建DAPSQ联合单方形区螺钉(A组)、双方形区螺钉(B组)、三方形区螺钉(C组)和四方形区螺钉(D组)固定模型,施加600 N垂直载荷或8N/m扭矩,模拟骨盆站位、坐位、站位+健侧旋转和站位+患侧旋转,比较各组内固定方法 下骨折线平均位移和内固定应力分布情况.结果 在站位、坐位、健侧旋转和患侧旋转4种工况下,方形区骨折线路径上各节点平均位移表现为A组>B组>C组>D组,组间比较显示D组位移显著低于A组和B组(P<0.05),C组和D组比较差异无统计学意义(P>0.05).应力分析结果 显示,站位和坐位下D组应力主要集中在钛板螺钉结合处,以近端第1枚方形区螺钉承担应力最大.结论 新型动力化前路方形区钛板螺钉系统固定髋臼高位双柱骨折的生物力学性能可靠,推荐在方形区应至少置入3或4枚螺钉进行固定,且靠近坐骨大切迹的方形区螺钉为关键钉. 相似文献
993.
目的 观察安罗替尼(anlotinib)对人肾癌细胞增殖和迁移能力的影响,探讨其抑制肾癌细胞生长、迁移能力的机制,以及在肾癌治疗领域的临床应用前景.方法 体外培养肾癌ACHN细胞,采用不同浓度(0、1.25、2.5、5和10 μmol/L)的安罗替尼处理ACHN细胞24、48和72h,MTT法检测安罗替尼对ACHN细胞增殖的影响,计算半数抑制浓度(IC50);划痕修复实验检测安罗替尼对ACHN细胞迁移能力的作用,计算迁移率;克隆形成实验检测细胞贴壁后细胞的成活能力,计算克隆数目;Western印迹法检测安罗替尼对PI3K/AKT信号通路相关蛋白表达和活性的影响,用灰度分析方法计算其灰度值.结果 安罗替尼能显著抑制ACHN细胞增殖,具有明显的浓度依赖性;与对照组相比,安罗替尼处理后,能明显抑制ACHN细胞的克隆形成、迁移和信号通路相关蛋白的活化(P<0.05).结论 安罗替尼能显著抑制人肾癌ACHN细胞的增殖、克隆形成和迁移能力,其机制与PI3K信号通路的抑制相关. 相似文献
994.
Purpose
In recent years, a variety of acute respiratory distress syndrome (ARDS) evaluation systems have been developed worldwide; however, they are not so convenient for the doctors clinically, we decided to establish and evaluate a simplified evaluation system of ARDS (SESARDS).Materials and Methods
Data from 140 ARDS patients (derivation data set) were collected to screen for prognostic factors affecting outcomes in ARDS patients. By logistic regression analysis, scores were allocated to corresponding intervals of the variables, respectively, by means of analysis of the frequency distribution to establish a preliminary scoring system. Based on this primary scoring system, a definitive evaluation scheme was created through consultation with a panel of experts. The scores for the validation data set (92 cases) were assigned and calculated by their predictive mortality with the SESARDS and acute physiology and chronic health evaluation II (APACHE II). The performance of SESARDS was compared with that of APACHE II by means of statistical analysis.Results
The factors of age, pH, Glasgow coma scale (GCS), oxygenation index (OI), and the lobes of lung were associated with prognosis of ARDS respectively. The sensitivity and specificity of SESARDS for the validation data set were 96.43% and 58.33%, respectively. On the AUC, no significant difference between APACHE II and SESARDS was detected. There were no significant differences between the prediction and the actuality obtained by SESARDS for the validation data set the SESARDS scores were positively correlated with the actual mortality.Conclusion
SESARDS was shown to be simple, accurate and effective in predicting ARDS progression. 相似文献995.
Yan-Feng Zou Jian-Hua Xu Jin-Hui Tao Sheng-Qian Xu Shuang Liu Shan-Yu Chen Jing Cai Li Lian Pei-Ling Chen De-Guang Wang Sheng-Xiu Liu Chun-Mei Liang Qian-Ling Ye Guo Tian Min Wu Hai-Feng Pan Fa-Ming Pan Hong Su Dong-Qing Ye 《Inflammation》2013,36(6):1424-1430
Although glucocorticoids (GCs) are effective in inducing remission in systemic lupus erythematosus (SLE) patients, there is a significant variation in response to therapeutic GCs, and some patients do not achieve full remission. The aim of this study was to explore the impact of environmental factors on the efficacy of GCs in a Chinese population with SLE. This was a prospective cohort study, and a total of 260 SLE patients treated with GCs (prednisone) were followed up for 12 weeks. The efficacy of GCs was measured with the scores on SLE disease activity index. Environmental factors were collected using a questionnaire. Single-variable analysis and multivariate logistic regression analysis were used to discriminate the impact of environmental factors on the efficacy of GCs. Two hundred forty-seven patients (95.00 %) completed the 12-week follow-up. Among these patients, 131 (53.04 %) were classified into sensitive group and 116 (46.96 %) were classified into insensitive group. Results from logistic analysis showed that the following environmental factors were significantly associated with decreased efficacy of GCs: high salt intake (OR?=?3.464, 95%CI?=?1.481–8.102, P?=?0.004), introverted personality (OR?=?3.550, 95%CI?=?1.901–6.628, P?<?0.0001), experience with negative life events (OR?=?5.526, 95%CI?=?1.612–18.946, P?=?0.007), and history of allergy (OR?=?2.966, 95%CI?=?1.312–6.704, P?=?0.009). These results indicate that environmental factors, including salt intake, personality, experience with negative life events, and history of allergy, may play an important role in the efficacy of GCs in the Chinese population with SLE. 相似文献
996.
Fan Zhen Sun Bing Lang Li-qin Hu Jie Hameed N. U. Farrukh Wei Zi-xuan Zhuang Qi-yuan Cai Jia-jun Liu Feng-tao Mao Yi-ting Feng Rui Pan Li 《Neurological sciences》2021,42(6):2353-2361
Neurological Sciences - Exploring the role of amygdala enlargement (AE) in temporal lobe epilepsy (TLE) without ipsilateral mesial temporal sclerosis (MTS) using comprehensive presurgical workup... 相似文献
997.
Meng Feng Junlong Cai Xiangyang Min Yongfeng Fu Qing Xu Hiroshi Tachibana Xunjia Cheng 《Parasitology research》2013,112(4):1529-1536
Many colonies of macaques (Macaca fascicularis and Macaca mulatta) are maintained in China, especially in Guangxi and Guizhou. A total of 803 fresh stool samples infected with Entamoeba were obtained from three big colonies of macaques located in southwest China. The samples were examined for the presence of five Entamoeba species using PCR. Entamoeba nuttalli, Entamoeba dispar, Entamoeba coli, and Entamoeba chattoni infections were detected, but Entamoeba histolytica infection was not. This study is the first to report on the prevalence of E. nuttalli in wild macaques from China. Eighteen E. nuttalli isolates and five E. dispar isolates were obtained by culturing the samples in Tanabe–Chiba medium. The serine-rich protein (SRP), ribosomal RNA (rRNA), hexokinase (HXK), glucose-6-phosphate isomerase (GPI), and phosphoglucomutase (PGM) genes of E. nuttalli isolates were compared with other reported isolates. The results showed clear differences among the Chinese E. nuttalli isolates and other isolates based on the SRP gene sequences. However, HXK, GPI, and PGM genes of these strains were similar to those of other isolates. The rRNA genes of E. coli and E. chattoni were also amplified and analyzed from these samples. The results suggested that host species might be a more important factor than geographic location in amebic genetic diversity. 相似文献
998.
Jing Zhang Bin Ye Jing Kong Hui Cai Yifeng Zhao Xiumin Han Faqi Li 《Parasitology research》2013,112(1):385-391
Echinococcus granulosus, the etiologic agent of cystic echinococcosis in humans and other animal hosts, is distributed worldwide. Echinococcosis is an increasing public health and socioeconomic concern. The present work evaluated whether or not a superabsorbent polymer (SAP) could enhance the damage efficacy of high-intensity focused ultrasound (HIFU) on the viability of E. granulosus protoscolices in vitro. HIFU of 100 W acoustic power and 0.01 g superabsorbent polymer were used to treat 5,000 protoscolices in 2-ml protoscolices suspension. After different HIFU exposure time (5, 10, 20, 30, 40, 50, and 60 s, respectively), the temperature of protoscolices suspension was taken, and the treated protoscolices were stained by trypan-blue exclusion assay, and their structures were observed by light microscopy. To better understand the biological mechanisms responsible for the deaths of protoscolices, the activity of succinate dehydrogenase (SDH) of the protoscolices treated with HIFU was examined. The temperature of protoscolices suspension treated with HIFU rose slowly, and the death rate of protoscolices was 73.7 % in the group of HIFU treatment time of 40 s; however, with the same HIFU treatment time of 40 s, the temperature of protoscolices suspension in the group of HIFU combined with SAP rose quickly, and the death rate of protoscolices was 100 %. The same protoscolicidal effect (100 %) of HIFU of 100 W acoustic power combined with SAP was also observed in the groups of HIFU treatment time of 50 and 60 s, respectively. The dead protoscolices were stained to blue, shrunken and black calcareous corpuscles, and disordered and decreasing hooks though of intact membrane, as well as some protoscolices lost hooks and tore open on membrane were observed. In the group of HIFU combined with SAP, it was found that the superabsorbent polymer was surrounded by the spoiled, and the destruction of protoscolices was much stronger than in the group of HIFU. The dead protoscolices exhibited the reduction or absence of SDH staining intensity in the parenchymal cell and calcareous corpuscles after HIFU irradiation, where a large number of necrotic cells were evident. These results suggested that HIFU could induce the damage and loss of viability of protoscolices; SAP could enhance the HIFU energy focused and cause more severe destruction efficacy on protoscolices; and mitochondrial energetic function is involved in the regulation of cell-death pathways of protoscolices. 相似文献
999.
目的:研究表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)对次声诱导的大鼠小胶质细胞过度激活的抑制作用,探讨EGCG潜在的次声对脑损伤的防护作用。方法:16 Hz,155 dB次声刺激原代培养的小胶质细胞,通过细胞因子表达量和免疫荧光染色,观察不同浓度(1μmol/L、10μmol/L、100μmol/L)的EGCG在不同时程(12 h和24 h)对次声激活的小胶质细胞的抑制作用。结果:1μmol/L或10μmol/L EGCG预孵可显著抑制次声后大鼠小胶质细胞IL-1β、IL-6、IL-18、TNF-α表达的上调,且10μmol/L组的作用最强(P<0.01)。10μmol/L EGCG可以减少次声诱导的小胶质细胞过度激活的形态变化。结论:EGCG对次声诱导的大鼠小胶质细胞过度激活具有显著的抑制作用。 相似文献
1000.