全文获取类型
收费全文 | 106878篇 |
免费 | 11280篇 |
国内免费 | 3321篇 |
专业分类
耳鼻咽喉 | 749篇 |
儿科学 | 1697篇 |
妇产科学 | 1210篇 |
基础医学 | 20030篇 |
口腔科学 | 2848篇 |
临床医学 | 6702篇 |
内科学 | 16223篇 |
皮肤病学 | 1908篇 |
神经病学 | 11448篇 |
特种医学 | 2863篇 |
外国民族医学 | 27篇 |
外科学 | 8552篇 |
综合类 | 10588篇 |
现状与发展 | 14篇 |
预防医学 | 4371篇 |
眼科学 | 1092篇 |
药学 | 17097篇 |
34篇 | |
中国医学 | 4044篇 |
肿瘤学 | 9982篇 |
出版年
2024年 | 307篇 |
2023年 | 1941篇 |
2022年 | 4382篇 |
2021年 | 4943篇 |
2020年 | 4184篇 |
2019年 | 4432篇 |
2018年 | 4237篇 |
2017年 | 4196篇 |
2016年 | 3927篇 |
2015年 | 4449篇 |
2014年 | 6445篇 |
2013年 | 6679篇 |
2012年 | 5908篇 |
2011年 | 7037篇 |
2010年 | 5649篇 |
2009年 | 5676篇 |
2008年 | 5599篇 |
2007年 | 4765篇 |
2006年 | 4085篇 |
2005年 | 3771篇 |
2004年 | 3186篇 |
2003年 | 2831篇 |
2002年 | 2123篇 |
2001年 | 1795篇 |
2000年 | 1493篇 |
1999年 | 1408篇 |
1998年 | 1355篇 |
1997年 | 1317篇 |
1996年 | 1211篇 |
1995年 | 1107篇 |
1994年 | 1019篇 |
1993年 | 968篇 |
1992年 | 761篇 |
1991年 | 682篇 |
1990年 | 586篇 |
1989年 | 497篇 |
1988年 | 474篇 |
1987年 | 473篇 |
1986年 | 572篇 |
1985年 | 779篇 |
1984年 | 741篇 |
1983年 | 581篇 |
1982年 | 579篇 |
1981年 | 488篇 |
1980年 | 449篇 |
1979年 | 374篇 |
1978年 | 229篇 |
1977年 | 190篇 |
1976年 | 197篇 |
1975年 | 121篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
191.
刺梨酸的分离与结构研究 总被引:5,自引:0,他引:5
从刺梨中分离出一种新的五环三萜酸,命名为刺梨酸。通过光谱分析和衍生物的制备,确定其化学结构为2β,3α,7β,19α-四羟基乌苏-12-烯-28-羧酸。 相似文献
192.
越来越多的研究表明,维生素D除具有经典的调节钙磷平衡和维持骨骼健康的作用外,还具有其他更为广泛的骨外生物学效应,如调节免疫、抗肿瘤、保护中枢神经系统和防治代谢综合征等作用.本文就相关方面的研究进展进行综述. 相似文献
193.
194.
C Piérard-Franchimont P Paquet P Quatresooz GE Piérard 《Journal of the European Academy of Dermatology and Venereology》2007,21(5):657-661
BACKGROUND: The observation of photo-exposed skin under ultraviolet light reveals a mosaic pattern of varying intensity in epidermal melanization. Several patterns of mosaic subclinical melanoderma (MSM) have been described using a specially designed CCD camera and the ultraviolet light-enhanced visualization (ULEV) method. Vitamin D(3) and its analogues influence the biology of keratinocytes and melanocytes. OBJECTIVE: To assess the effect of calcipotriol on MSM. METHODS: This randomized split-face study was conducted in 27 men to compare the effect of once daily applications of 5% calcipotriol cream or a moisturizing cream on the heterogeneity of facial MSM. Computerized image analysis of video images was used at 1-month intervals before and during a 2-month treatment, as well as during a 3-month follow-up. RESULTS: At both sites, the average melanin content of the epidermis showed no significant change over time. However, the mottled appearance was smoothened at the calcipotriol site, whereas it was increased at the site receiving the moisturizer. CONCLUSION: The decreased heterogeneity in MSM after calcipotriol applications suggests a control of the epidermal melanocyte unit by the vitamin D(3) derivative. 相似文献
195.
Zhipan Zhang Gaoquan Shi 《Journal of electroanalytical chemistry (Lausanne, Switzerland)》2004,569(2):197-202
Poly (3-phenylthiophene) (P3PhT) films have been electrochemically synthesized by direct oxidation of 3-phenylthiophene in the electrolyte of pure boron trifluoride diethyl etherate (BFEE). The oxidation potential of the monomer was measured to be 1.29 V (vs. SCE), and about 0.15 V lower than that measured in a neutral medium of acetonitrile. Free-standing P3PhT film with tensile strength of 32–40 MPa has been obtained for the first time. The morphology and the structure of the polymer film have been studied by scanning electron microscopy, infrared and Raman spectroscopies. Raman spectral results demonstrated that the doping level of the P3PhT film increased with film thickness during electrochemical growth process. 相似文献
196.
螺旋CT三维重建影像在胫骨平台骨折诊疗中的价值 总被引:12,自引:0,他引:12
目的探讨螺旋CT三维重建影像在胫骨平台骨折诊断和治疗中的临床使用价值。方法2001年8月~2005年4月收集38例胫骨平台骨折分别行X线片和螺旋CT三维重建影像检查,对照术中所见,分析比较螺旋CT三维重建影像在临床诊断和治疗中的作用。结果X线片检查2例无法明确诊断,骨折分型错误6例;螺旋CT三维重建诊断、分型均正确。X线片与螺旋CT三维重建影像在确立诊断方面未见明显差异,但在分型和指导治疗方面,螺旋CT三维重建影像明显优于前者。结论螺旋CT三维重建影像能直观、立体地显示胫骨平台骨折的形态,有助于骨折的分型及治疗。 相似文献
197.
198.
雷公藤多甙对白细胞介素-1β诱导大鼠滑膜细胞株RSC-364基质金属蛋白酶-3、c-Jun基因表达的影响 总被引:1,自引:0,他引:1
目的 观察雷公藤多甙对白细胞介素(IL)-1β诱导大鼠滑膜细胞株RSC-364基质金属蛋白酶-3(MMP3)、c-Jun mRNA表达的影响.方法 选择不同浓度的雷公藤多甙作用IL-1β刺激的大鼠滑膜细胞株RSC-364,37℃,5%CO2的环境下培养48 h,运用酶联免疫吸附试验(ELISA)检测细胞上清的MMP3和实时聚合酶链反应(real-time PCR)检测分析细胞中的c-Jun mRNA表达.结果 不同浓度的雷公藤多甙(0、5、10、20 mg/L)对IL-1β刺激的大鼠滑膜细胞株RSC-364分泌MMP3的水平依次是198、176、140、115 μg/L,c-Jun mRNA表达分别是1.17×106、3.31×105、9.32 ×104、2.81 ×104copies/ml,即呈现明显地抑制.重要的是:c-Jun mRNA表达抑制呈现明显的剂量依赖性.结论 雷公藤多甙治疗类风湿性关节炎的有效的作用机制,可能与其抑制MMP3、c-Jun基因的表达相关. 相似文献
199.
K. Kim T. Mizunari N. Mizutani S. Kobayashi K. Takizawa H. Kamiyama Y. Murai A. Teramoto 《Acta neurochirurgica》2006,148(3):353-357
Summary We describe a giant aneurysm of the anterior communicating artery (ACoA) which was treated with a STA-RA graft-A3 bonnet bypass
and A3–A3 side-to-side anastomosis. A giant and partially thrombosed ACoA aneurysm was partially coated 3 years before his
current presentation, its gradual increase producing visual field disturbances. An A3–A3 side-to-side anastomosis and STA-RA
graft-A3 bonnet bypass were performed. The aneurysm was dissected, and the thrombus removed under transient parent-artery
occlusion. The aneurysmal neck was successfully clipped without encountering ischemic changes. This strategy may be useful
for treating giant or thrombosed aneurysms in the region of the ACoA. 相似文献
200.
AIMS: Diabetic ketoacidosis (DKA), a life-threatening acute complication of Type 1 diabetes, may be preventable with frequent monitoring of glycaemia and ketosis along with timely supplemental insulin. This prospective, two-centre study assessed sick day management using blood 3-hydroxybutyrate (3-OHB) monitoring compared with traditional urine ketone testing, aimed at averting emergency assessment and hospitalization. METHODS: One hundred and twenty-three children, adolescents and young adults, aged 3-22 years, and their families received sick day education. Participants were randomized to receive either a blood glucose monitor that also measures blood 3-OHB (blood ketone group, n = 62) or a monitor plus urine ketone strips (urine ketone group, n = 61). All were encouraged to check glucose levels > or = 3 times daily and to check ketones during acute illness or stress, when glucose levels were consistently elevated (> or = 13.9 mmol/l on two consecutive readings), or when symptoms of DKA were present. Frequency of sick days, hyperglycaemia, ketosis, and hospitalization/emergency assessment were ascertained prospectively for 6 months. RESULTS: There were 578 sick days during 21,548 days of follow-up. Participants in the blood ketone group checked ketones significantly more during sick days (276 of 304 episodes, 90.8%) than participants in the urine ketone group (168 of 274 episodes, 61.3%) (P < 0.001). The incidence of hospitalization/emergency assessment was significantly lower in the blood ketone group (38/100 patient-years) compared with the urine ketone group (75/100 patient-years) (P = 0.05). CONCLUSIONS: Blood ketone monitoring during sick days appears acceptable to and preferred by young people with Type 1 diabetes. Routine implementation of blood 3-OHB monitoring for the management of sick days and impending DKA can potentially reduce hospitalization/emergency assessment compared with urine ketone testing and offers potential cost savings. 相似文献