全文获取类型
收费全文 | 407348篇 |
免费 | 28255篇 |
国内免费 | 4918篇 |
专业分类
耳鼻咽喉 | 5407篇 |
儿科学 | 8518篇 |
妇产科学 | 10279篇 |
基础医学 | 56044篇 |
口腔科学 | 12236篇 |
临床医学 | 34003篇 |
内科学 | 82044篇 |
皮肤病学 | 8842篇 |
神经病学 | 28565篇 |
特种医学 | 15022篇 |
外国民族医学 | 97篇 |
外科学 | 63236篇 |
综合类 | 16216篇 |
现状与发展 | 14篇 |
一般理论 | 64篇 |
预防医学 | 19539篇 |
眼科学 | 10311篇 |
药学 | 34476篇 |
51篇 | |
中国医学 | 4389篇 |
肿瘤学 | 31168篇 |
出版年
2021年 | 4189篇 |
2020年 | 3061篇 |
2019年 | 3872篇 |
2018年 | 5785篇 |
2017年 | 4573篇 |
2016年 | 4542篇 |
2015年 | 5657篇 |
2014年 | 7708篇 |
2013年 | 9194篇 |
2012年 | 12692篇 |
2011年 | 12915篇 |
2010年 | 8075篇 |
2009年 | 7391篇 |
2008年 | 11104篇 |
2007年 | 11853篇 |
2006年 | 11726篇 |
2005年 | 10483篇 |
2004年 | 9787篇 |
2003年 | 9619篇 |
2002年 | 9013篇 |
2001年 | 28964篇 |
2000年 | 29298篇 |
1999年 | 24121篇 |
1998年 | 5287篇 |
1997年 | 4416篇 |
1996年 | 3905篇 |
1995年 | 3674篇 |
1994年 | 3264篇 |
1993年 | 2926篇 |
1992年 | 16137篇 |
1991年 | 14911篇 |
1990年 | 14228篇 |
1989年 | 14012篇 |
1988年 | 12637篇 |
1987年 | 12098篇 |
1986年 | 11132篇 |
1985年 | 10342篇 |
1984年 | 6920篇 |
1983年 | 5609篇 |
1982年 | 2719篇 |
1979年 | 5479篇 |
1978年 | 3345篇 |
1977年 | 2963篇 |
1975年 | 2636篇 |
1974年 | 3064篇 |
1973年 | 2863篇 |
1972年 | 2828篇 |
1971年 | 2773篇 |
1970年 | 2509篇 |
1969年 | 2543篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
82.
Fan Jia Dong-Xue Zheng Ru-Feng Chen Hong-Yu Zhao Jin-Yuan Liu Li-Li Zhang Lin-Hua Zhao Yong-Mei Liu Yun Zhang Xiao-Yun Zhu Jie Kan Xin-Min Liu 《海南医学院学报》2022,28(2):1-9
Objective: The differences of ovarian morphology, reproductive hormones, glucose and lipid metabolism and intestinal bacteria in rats with polycystic ovary syndrome (PCOS) induced by triazole were compared. Method: Eighteen 21 SPF female SD rats were randomly divided into group A (3-week group), group B (5-week group) and group D (control group) by random number table.Group A received letrozole + CMC-Na mixture by gavage in the first 3 weeks and CMC-Na solution by gavage in the last 2 weeks, group B received letrozole + CMC-Na mixture by gavage for 5 weeks, and group D received CMC-Na solution by gavage for 5 weeks, and all three groups of rats were fed with normal diet.At the end of gavage, the body weight of rats in each group was observed, the histological changes of ovaries were observed by hematoxylin-eosin (HE) staining, the serum levels of estradiol (E2), follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), total cholesterol (TC), triglyceride (TG), fasting blood glucose (Glu), fasting insulin (FINS) and lipopolysaccharide (LPS) were measured by enzyme-linked immunosorbent assay (ELISA), and the LH/FSH ratio and insulin resistance index (HOMA IR) were calculated; the intestinal bacteria of rats were detected by 16S rRNA technique. Result: 1. Comparison of ovary histomorphology: Under light microscope, multiple luteum and oocytes were observed in mature follicles in group D, and granulosa cells were orderly arranged and multilayered, without cystic dilated follicles. There were no mature follicles in the ovarian tissues of group A and GROUP B. The follicles were irregular in structure and more cystic dilated follicles were visible. The number of granular cells in some follicles decreased or even disappeared. 2. Comparison of sex hormone levels: compared with group D, T level in group B was significantly increased (P < 0.001), and T level in group A had an upward trend (P > 0.05); The LH/FSH levels in group A and B were significantly increased (P < 0.001; P < 0.001). Compared with group A, E2 in group B was significantly decreased (P < 0.05) and T was significantly increased (P < 0.01). 3. Comparison of glucose and lipid metabolism levels: Compared with group D, TC levels in groups A and B were significantly increased (P < 0.01; P < 0.01). Compared with group A, TG in group B was significantly increased (P < 0.05). There were no significant differences in Glu, FINS and HOMA-IR levels among all groups. 4. Comparison of LPS levels: Compared with group D, the serum LPS levels of rats in groups A and B were significantly increased (P < 0.001; P < 0.01). 5. Intestinal flora analysis and comparison: At the phylum level, compared with group D, the abundance of Firmicutes in group B increased (P < 0.01), Firmicutes in group A showed an upward trend (P > 0.05), and the abundance of Bacteroidetes in groups A and B decreased (P < 0.05). At the genus level, compared with group D, Lactobacillus in group B increased (P < 0.01). The results of LEfSe analysis showed that there were differences in the composition of various intestinal bacteria among the three groups (LDA > 3).Conclusion: The phenotype of PCOS rats was related to the length of modeling, and the phenotypic characteristics of PCOS in rats at 5 weeks of modeling were more typical than those in rats at 3 weeks of modeling; PCOS can cause changes in intestinal flora, and the changes in the structure of intestinal flora between groups are related to different modeling duration. 相似文献
83.
Prevention Science - This study aimed to evaluate the effectiveness of the drug and violence resistance educational program (PROERD) on short-term secondary outcomes, such as intentions to use... 相似文献
84.
85.
目的通过测量锁骨钩钢板内固定术后患者影像学资料,分析发生肩峰骨侵蚀的原因是否与钢板钩-肩峰匹配度相关。
方法回顾性分析2015年8月1日至2018年8月31日期间在上海市浦东医院骨科就诊的210例患者的影像学资料,210例患者均因肩锁关节脱位或锁骨远端骨折行锁骨钩钢板内固定治疗,其中男110例、女100例;年龄24~76岁,平均(44.60±8.75)岁;肩锁关节脱位70例,锁骨远端骨折140例。测量术后及终末随访患者肩锁关节正位X线片相关数据,按锁骨钩钢板术后是否发生肩峰骨侵蚀,将纳入患者分为3组:无骨侵蚀组(A组)、伴钢板钩移位骨侵蚀组(B组)、不伴移位的骨侵蚀组(C组),分别测量钢板钩-肩峰的匹配度(β),统计分析术后发生肩峰骨侵蚀与钢板钩-肩峰匹配度之间的关系。
结果纳入研究的210例患者术后随访24~64周,平均(32.0±6.5)周。A组患者115例,B组患者54例,C组患者41例。A组匹配度β(3.72±0.48)mm与B组β1(6.91±0.84)mm比较差异有统计学意义(P<0.05);A组匹配度β(3.72±0.48)mm与C组β2(5.88±0.65)mm比较差异有统计学意义(P<0.05);B组匹配度β1(6.91±0.84)mm与C组β2(5.88±0.65)mm比较差异有统计学意义(P<0.05)。
结论锁骨钩钢板内固定术后是否发生肩峰骨侵蚀与钢板钩-肩峰匹配度β存在明显相关性,钢板钩与肩峰之间的匹配度越好,β值越小,发生肩峰骨侵蚀的可能性更小。 相似文献
86.
87.
88.
89.