全文获取类型
收费全文 | 56505篇 |
免费 | 5600篇 |
国内免费 | 4110篇 |
专业分类
耳鼻咽喉 | 403篇 |
儿科学 | 1030篇 |
妇产科学 | 621篇 |
基础医学 | 6143篇 |
口腔科学 | 906篇 |
临床医学 | 8222篇 |
内科学 | 8040篇 |
皮肤病学 | 625篇 |
神经病学 | 2713篇 |
特种医学 | 1854篇 |
外国民族医学 | 27篇 |
外科学 | 4730篇 |
综合类 | 10429篇 |
现状与发展 | 15篇 |
一般理论 | 8篇 |
预防医学 | 4578篇 |
眼科学 | 1413篇 |
药学 | 6311篇 |
69篇 | |
中国医学 | 3336篇 |
肿瘤学 | 4742篇 |
出版年
2024年 | 187篇 |
2023年 | 862篇 |
2022年 | 2146篇 |
2021年 | 2755篇 |
2020年 | 2224篇 |
2019年 | 1788篇 |
2018年 | 1914篇 |
2017年 | 1788篇 |
2016年 | 1653篇 |
2015年 | 2616篇 |
2014年 | 3362篇 |
2013年 | 2966篇 |
2012年 | 4413篇 |
2011年 | 4830篇 |
2010年 | 3292篇 |
2009年 | 2712篇 |
2008年 | 3207篇 |
2007年 | 3303篇 |
2006年 | 3150篇 |
2005年 | 2972篇 |
2004年 | 2032篇 |
2003年 | 1917篇 |
2002年 | 1627篇 |
2001年 | 1365篇 |
2000年 | 1187篇 |
1999年 | 1119篇 |
1998年 | 764篇 |
1997年 | 710篇 |
1996年 | 556篇 |
1995年 | 486篇 |
1994年 | 404篇 |
1993年 | 225篇 |
1992年 | 302篇 |
1991年 | 213篇 |
1990年 | 183篇 |
1989年 | 177篇 |
1988年 | 179篇 |
1987年 | 130篇 |
1986年 | 117篇 |
1985年 | 94篇 |
1984年 | 53篇 |
1983年 | 41篇 |
1982年 | 35篇 |
1981年 | 36篇 |
1980年 | 17篇 |
1979年 | 26篇 |
1978年 | 10篇 |
1975年 | 11篇 |
1973年 | 10篇 |
1971年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Shengxuan Cao Chen Wang Xin Ma Xu Wang Jiazhang Huang Chao Zhang Li Chen Xiang Geng Kan Wang 《Journal of orthopaedic research》2019,37(8):1860-1867
Patients with mechanic ankle instability experience increased tibiotalar and subtalar joint laxity. However, in vivo joint kinematics in functional ankle instability (FAI) patients and lateral ankle sprain (LAS) copers, especially during dynamic activities, are poorly understood. Ten FAI patients, 10 LAS copers, and 10 healthy controls were included in this study. A dual fluoroscopic imaging system was used to analyze the tibiotalar and subtalar joint kinematics during stair descent. Five key poses of stair descent were analyzed. Kinematic data from six degrees of freedom were calculated utilizing a solid modeling software. The range of motion and joint positions in each degree of freedom were compared among the three groups. The tibiotalar joints of FAI patients and LAS copers were significantly more inverted than those of healthy controls during the foot strike (p = 0.016, = 0.264). The subtalar joints of FAI patients were significantly more anteriorly translated (pose 2, p = 0.003, = 0.352; pose 3, p < 0.001, = 0.454; pose 4, p = 0.004, = 0.334), inverted (pose 4, p = 0.027, = 0.234; pose 5,p = 0.034, = 0.221), and externally rotated (pose 4, p = 0.037, = 0.217; pose 5; p = 0.004, = 0.331) than those of healthy controls during the mid‐stance and the heel off. The FAI patients showed excessive tibiotalar inversion and subtalar joint hypermobility during stair descent. Meanwhile, the LAS copers maintained subtalar joint stability, and only showed excessive tibiotalar inversion in foot strike. These data provide insight into the mechanisms behind the development of FAI after initial LAS. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1860–1867, 2019 相似文献
2.
目的:分析鼻塞式同步间歇正压通气(NIPPV)联合布地奈德雾化治疗ARDS(新生儿急性呼吸窘迫综合征)疾病的临床应用效果。方法:纳入病例是2017年5月—2019年11月收治的104例ARDS新生儿,随机平均分为两组。参照组52例采纳CPAP(持续气道正压通气通气)治疗,实验组52例采纳NIPPV+布地奈德雾化治疗,对比两组呼吸机通气时间、用氧时间、住院时间、血气指标以及并发症发生情况。结果:实验组呼吸机通气时间、用氧时间、住院时间均明显短于参照组,差异有统计学意义P<0.05;实验组治疗3 d后PaCO2明显低于参照组,实验组治疗3 d后PH以及PaO2明显高于参照组,差异有统计学意义P<0.05;实验组并发症发生率(3.85%,2/52)明显低于参照组(21.15%,11/52),差异有统计学意义P<0.05。结论:NIPPV+布地奈德雾化可有效缩短ARDS患者机械通气时间,改善血气指标,降低并发症发生率,值得借鉴。 相似文献
3.
Xiaoqing Guo Ji-Eun Seo Xilin Li Nan Mei 《Journal of toxicology and environmental health. Part B, Critical reviews》2020,23(1):27-50
ABSTRACTGenotoxic compounds may be detoxified to non-genotoxic metabolites while many pro-carcinogens require metabolic activation to exert their genotoxicity in vivo. Standard genotoxicity assays were developed and utilized for risk assessment for over 40 years. Most of these assays are conducted in metabolically incompetent rodent or human cell lines. Deficient in normal metabolism and relying on exogenous metabolic activation systems, the current in vitro genotoxicity assays often have yielded high false positive rates, which trigger unnecessary and costly in vivo studies. Metabolically active cells such as hepatocytes have been recognized as a promising cell model in predicting genotoxicity of carcinogens in vivo. In recent years, significant advances in tissue culture and biological technologies provided new opportunities for using hepatocytes in genetic toxicology. This review encompasses published studies (both in vitro and in vivo) using hepatocytes for genotoxicity assessment. Findings from both standard and newly developed genotoxicity assays are summarized. Various liver cell models used for genotoxicity assessment are described, including the potential application of advanced liver cell models such as 3D spheroids, organoids, and engineered hepatocytes. An integrated strategy, that includes the use of human-based cells with enhanced biological relevance and throughput, and applying the quantitative analysis of data, may provide an approach for future genotoxicity risk assessment. 相似文献
4.
对医学院校伪贫困生的思考 总被引:1,自引:0,他引:1
目的 深入剖析医学院校出现伪贫困生的原因,提出一套治理伪贫困现象的方案。方法 从外部环境、学校、学生本身等3个方面分析出现伪贫困生现象的基本原因。结果 治理伪贫困现象的对策是:加强诚信教育、讲述贫困故事、建立监管机制、形成文化自觉。结论 只有治理高校里的伪贫困现象,才能使扶贫资金使用得当,体现公平的原则。 相似文献
5.
从土藿香根中得到两个二萜化合物,藿香酚(2)及异藿香酚(3)。经光谱解析(IR,UV,HRMS及NMR谱),确定它们的结构分别为11,14dihydroxy12methoxy19(4→3)abeoabieta4,(18),8,11,13tetraen7one(2)和11,14dihydroxy12methoxy19(4→3)abeoabieta3,8,11,13tetraen7one(3)藿香酚(2)为一新的化合物,而异藿香酚(3)系首次从天然界分离得到,二者为一对异构体。 相似文献
6.
Xin Mei Jiang Akio Ohnishi Tatsunori Yamamoto Yoshiyuki Murai Akira Awaya Masato Ikeda 《Acta neuropathologica》1995,90(2):130-134
One of the pyrimidine compounds, 2-piperadino-6-methyl-5-oxo-5,6-dihydro(7H)pyrrolo[3,4-d]pyrimidine (MS-818), has neurotropic effects in vitro. Therefore, we studied the effect of MS-818 on the regeneration of the peroneal nerve in C57BL/6J mice after a crush injury. Two test groups, which received a daily intraperitoneal injection of 5 mg/kg or 10 mg/kg MS-818, respectively, were compared with controls, which received daily intraperitoneal injections of physiological saline, over a 14-day period. The maximum foot-width ratio (crushed side/uncrushed side) was obtained on days 1, 8 and 14 after the crush injury, and the various morphometric parameters were evaluated at both 5 and 10 mm distal to the proximal portion of the crush site. The significant effects of MS-818 included a larger maximum foot width (P<0.04) and a greater number of unmyelinated axons per nerve at both levels (P<0.003) in both test groups than in controls. MS-818 had no significant effects on body weight, the increase of total transverse fascicular area after the crush injury, the total number of myelinated fibers with their size distributions, or the number of nuclei of Schwann cells and macrophages. Therefore, we conclude that MS-818 promotes axonal sprouting and elongation after a crush injury in mice. 相似文献
7.
Joseph M Dhahbi Shelley X Cao Patricia L Mote Brian C Rowley John E Wingo Stephen R Spindler 《The Journal of nutrition》2002,132(1):31-37
Molecular chaperones assist in the biosynthesis and processing of proteins. Most chaperones are induced by physiological stresses. We have shown that dietary energy restriction decreases the mRNA and protein levels of many endoplasmic reticulum chaperones in the livers of mice. Here, we have investigated the response of chaperone mRNA to feeding. Control and 50% energy-restricted C3B10RF1 mice were deprived of food for 24 h, fed, and killed 0, 1.5, 5 or 12 h after feeding. Chaperone mRNAs were strongly induced as early as 1.5 h after feeding in control and energy-restricted mice. The integrated levels of these mRNA over 24 h were significantly lower in energy-restricted mice. The mRNA response to energy intake was mirrored over the course of days in the level of chaperone protein. A similar but smaller response to feeding was found in kidney and muscle. Puromycin and cycloheximide failed to inhibit the feeding response, suggesting that feeding releases chaperone expression from an unstable inhibitor. Studies with dibutyryl-cAMP- and glucagon-supplemented, normal and streptozotocin-diabetic mice suggest that glucagon and insulin may be mediators of the feeding response. Adrenalectomy enhanced the feeding induction, but dexamethasone administration had no effect. Thus, postprandial changes in insulin and glucagon may link chaperone gene expression to feeding, possibly in several tissues including liver. 相似文献
8.
9.
10.
Lidong Zhang James E Littlejohn Yu Cui Xiaobo Cao Chander Peddaboina W Roy Smythe 《Molecular cancer》2010,9(1):110