全文获取类型
收费全文 | 184998篇 |
免费 | 15980篇 |
国内免费 | 10987篇 |
专业分类
耳鼻咽喉 | 1514篇 |
儿科学 | 2653篇 |
妇产科学 | 2165篇 |
基础医学 | 20208篇 |
口腔科学 | 3396篇 |
临床医学 | 23383篇 |
内科学 | 26113篇 |
皮肤病学 | 2428篇 |
神经病学 | 8801篇 |
特种医学 | 6823篇 |
外国民族医学 | 56篇 |
外科学 | 16840篇 |
综合类 | 33868篇 |
现状与发展 | 37篇 |
一般理论 | 19篇 |
预防医学 | 15297篇 |
眼科学 | 4389篇 |
药学 | 19885篇 |
163篇 | |
中国医学 | 10417篇 |
肿瘤学 | 13510篇 |
出版年
2024年 | 533篇 |
2023年 | 2185篇 |
2022年 | 5585篇 |
2021年 | 7391篇 |
2020年 | 5670篇 |
2019年 | 4841篇 |
2018年 | 5159篇 |
2017年 | 5029篇 |
2016年 | 4939篇 |
2015年 | 7677篇 |
2014年 | 9732篇 |
2013年 | 10018篇 |
2012年 | 14749篇 |
2011年 | 15626篇 |
2010年 | 11382篇 |
2009年 | 9575篇 |
2008年 | 11691篇 |
2007年 | 11479篇 |
2006年 | 10551篇 |
2005年 | 9735篇 |
2004年 | 7444篇 |
2003年 | 7312篇 |
2002年 | 6043篇 |
2001年 | 4874篇 |
2000年 | 4262篇 |
1999年 | 3552篇 |
1998年 | 2111篇 |
1997年 | 2147篇 |
1996年 | 1568篇 |
1995年 | 1470篇 |
1994年 | 1213篇 |
1993年 | 781篇 |
1992年 | 902篇 |
1991年 | 785篇 |
1990年 | 683篇 |
1989年 | 590篇 |
1988年 | 474篇 |
1987年 | 462篇 |
1986年 | 351篇 |
1985年 | 305篇 |
1984年 | 193篇 |
1983年 | 137篇 |
1982年 | 100篇 |
1981年 | 77篇 |
1980年 | 53篇 |
1979年 | 81篇 |
1978年 | 52篇 |
1976年 | 36篇 |
1973年 | 44篇 |
1970年 | 35篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
John Jenn-Yenn Lu Chi-Chia Cheng Shieu-Ming Chou Chang-Bor Hor Yi-Chen Yang Hsiang-Ling Wang 《Vaccine》2009
The first universal hepatitis B vaccination program for newborns in the world was launched in Taiwan in July 1984. Most studies on the effectiveness of hepatitis B vaccination focused on the seroprevalence of HBs Ag among children under 14 years old. Only few studies focused on the seropositivity of anti-HBs among adolescents aged 15–18 years old. The present study aimed to evaluate the impact of the nationwide hepatitis B vaccination program on the immunity to HBV infection and the necessity of boost among adolescents. In this study including eight annual seroprevalence surveys from 2000 to 2007, 2342 college entrants (1589 15-year-olds in group I and 753 18-year-olds in group II) and 1851 university freshmen (18-year-olds in group III) participated. Subjects identified anti-HBs, HBs Ag and anti-HBc negative were given boost three doses of HBV vaccine. The HBs Ag seroprevalence was 11.6%, 3.5% and 1.0% for participants who were born before 1984, 1984–1986 and after 1986. The anti-HBs-seropositive rates were significantly higher in group II (83.1%) than in group I (53.0%) and group III (53.5%). All 572 participants who were seronegative for anti-HBs, HBs Ag and anti-HBc became anti-HBs-seropositive after catch-up vaccination. It is concluded that the anti-HBs-seropositive rate decreased to 50% in 15 years after vaccination, and boost vaccination was 100% effective. The necessity and age for boost among anti-HBs negative adolescents and the timing of the first immunization should be further evaluated. 相似文献
22.
Eun Young Jung Hyung Joo Suh Wan Soo Hong Dong Geon Kim Yang Hee Hong In Sun Hong Un Jae Chang 《Nutrition Research》2009,29(7):457-461
Cooking processes that gelatinize granules or disrupt structure might increase the glucose and insulin responses because a disruption of the structure of starch by gelatinization increases its availability for digestion and absorption in the small intestine. We hypothesized that the uncooked form of rice, which has a relatively low degree of gelatinization even though in powder form, would result in lower metabolic glucose and insulin responses compared with cooked rice (CR). To assess the effects of the gelatinization of rice on metabolic response of glucose and insulin, we investigated the glucose and insulin responses to 3 rice meals of different gelatinization degree in female college students (n = 12): CR (76.9% gelatinized), uncooked rice powder (UP; 3.5% gelatinized), and uncooked freeze-dried rice powder (UFP; 5.4% gelatinized). Uncooked rice powders (UP and UFP) induced lower glucose and insulin responses compared with CR. The relatively low gelatinization degree of UPs resulted in low metabolic responses in terms of the glycemic index (CR: 72.4% vs UP: 49.7%, UFP: 59.8%) and insulin index (CR: 94.8% vs UP: 74.4%, UFP: 68.0%). In summary, UPs that were less gelatinized than CR induced low postprandial glucose and insulin responses. 相似文献
23.
目的 探讨实时双平面超声心动图的临床应用价值。方法 对 83例受检者进行实时双平面超声 (BP)检查 ,其中男 46例 ,女 3 7例 ,平均年龄 2 0 92± 19 16岁。正常人 10例 ,先天性心脏病 44例 ,心瓣膜病 2 6例 ,其他心脏病变3例。结果 实时双平面超声有助于理解心脏立体解剖 ;能通过有限的声窗获得更多的切面 ,并可显示常规经胸超声不易得到的切面 ;多切面显示心脏瓣膜及其病变 ,有利于获得瓣膜狭窄或关闭不全的最佳观察平面 ;多切面显示房、室间隔缺损 ,便于寻找缺损的最佳显示切面以及与毗邻结构的关系。房、室间隔缺损BP、2DE测值与手术测值均有良好相关性 ;室间隔缺损BP测值与手术测值无显著性差异 ;BP、2DE均有低估房间隔缺损大小的倾向。实时双平面超声能同时显示复杂先心病的多种解剖畸形 ,有利于确定房室连接 ;辨认主、肺动脉。结论 实时双平面超声有其独特的优势 ,可为心血管疾病的准确诊断提供更多的信息。 相似文献
24.
在深静脉血栓—肺栓塞病程中腔静脉滤器的应用价值分析 总被引:1,自引:1,他引:0
目的:探讨腔静脉滤器(Vena cava filter VCF)在深静脉血栓(Deep venous thrombosis DVT)—肺栓塞(Pulmonary embolism PE)病程中的应用价值。方法:结合本组25例高危深静脉血栓一肺栓塞患者,对其中24例置放5种构型的永久型或临时型下腔静脉滤器(IVCF)26枚的临床疗效、影响病程与预后因素及病生理改变,复习文献分析讨论。结果:DVT有可能脱落导致PE或致死性肺栓塞;置放IVCF可有效预防肺栓塞,早期进行溶栓治疗,改变预后。结论:严格按适应证植入IVCF,对DVT—PE的早期治疗和预防致死性肺栓塞有重要意义,但其应用价值需进行综合评价和进一步探讨。 相似文献
25.
26.
随着医疗设备的不断增加 ,对其进行科学的管理显得愈加重要.为次,我们设备处管理人员引进了 EASY医院固定资产信息管理系统. 相似文献
27.
对28例严重脊柱侧凸患者行矫形手术,结果手术均获成功,松解术后1周行后路矫形内固定加植骨融合术,术后Cobb角平均为40.8°,侧弯矫正率平均为52.0%。术后随访6~30个月,均无并发症发生。提出在做好脊柱侧凸矫形手术常规护理的同时,加强患者心理、体位、呼吸、镇痛、排便等方面的舒适护理,可增强患者舒适感,为手术获得成功和患者顺利康复提供有力保障。 相似文献
28.
Repeated administration of the antimanic drug lithium (4 mEq/kg/day for 2, 4 or 6 days, i.p.) to rats produced a progressive decline and eventual depletion of dynorphin-A (1-8) (DYN) concentration whereas Met5-enkephalin (ENK) was only marginally decreased in the neurointermediate lobe of the pituitary (NIL). Administration of a neuroleptic haloperidol neither affected ENK and DYN levels nor influenced lithium-induced changes. The study reveals that lithium produces a preferential perturbation in the dynorphin system relative to the enkephalin system. These results taken together with other evidence, indicate that dynorphin is possibly coreleased with vasopressin following lithium administration and provide a pharmacological support to the previously described colocalization and corelease of these endogenous peptides in the NIL. 相似文献
29.
Glutamate acts at NMDA receptors on fresh bovine and on cultured human retinal pigment epithelial cells to trigger release of ATP 总被引:3,自引:0,他引:3
Efficient vesicle membrane recycling at presynaptic terminals is pivotal for preventing depletion and maintaining high firing rates in neuronal networks. We used a new approach, based on the combination of spectrally different optical probes, to investigate how stimulation determines the fate of synaptic vesicles after endocytosis. We found that in the small central synapses of rat hippocampal neurones low frequency stimulation (40 action potentials at 2 Hz) targets vesicles preferentially to vesicle pools that were kinetically faster. Vesicles taken up during endocytosis triggered by high frequency stimulation (400 action potentials, 20 Hz) were also placed in the back of the release queue. We performed a spatial analysis of the recycled vesicles in living hippocampal boutons using two spectrally different FM-dyes (FM1-43 and FM5-95). By using these consecutively, vesicles endocytosed by either stimulation protocol were labelled with a different colour. This revealed that the kinetic arrangement was also reflected in the spatial organization of vesicles within the bouton. Next, we identified the postsynaptic site of the active zone by transfecting the neurones with postsynaptic density protein PSD-95-CFP. The data from these triple colour experiments suggest that retrieval after low frequency stimulation keeps vesicles in a more confined region closer to the active zone as identified by PSD-95-CFP expression at the postsynaptic site. 相似文献
30.
Lei Wang Moyi Sun Yuegui Jiang Lianjia Yang Delin Lei Chao Lu Yinghua Zhao Pu Zhang Yaowu Yang Jianhu Li 《Journal of oral and maxillofacial surgery》2006,64(4):636-641
PURPOSE: Perineural invasion is a frequent occurrence in salivary adenoid cystic carcinoma (ACC) and may prevent complete surgical resection. Studies have indicated that nerve growth factor (NGF) and its high-affinity receptor tyrosine kinase A (TrkA) may play a role in perineural invasion in several malignancies in which perineural invasion is observed. The present study was conducted to investigate the expression of NGF and TrkA in salivary ACC and to examine the effects of NGF on adhesion, migration and invasion capacities of a salivary ACC cell line (SACC-83) in vitro. PATIENTS AND METHODS: Expression of NGF and TrkA was explored using immunohistochemistry in paraffin-embedded tissues of 32 cases of salivary ACC. The effects of NGF on in vitro adhesion, migration, and invasion capacities of the SACC-83 cell line were examined using an MTT assay and a modified Boyden chamber assay respectively. RESULTS: In ACC specimens, 31 (96.9%) and 32 (100%) tumors showed immunoreactivity for NGF and TrkA respectively. Significant correlations were found between NGF/TrkA expression levels and perineural invasion (P < .05). In cell adhesion assay, the percent adherences of SACC-83 cells co-cultured with 25 ng/ml NGF at 1.5 hours and 5, 25 ng/ml NGF at 6 hours were significantly higher than that co-cultured with 0 ng/ml NGF (P < .05). However, high concentration of NGF (500 ng/ml) resulted in a significant inhibition of invasion (P < .05). CONCLUSION: Overexpression of NGF and TrkA in human salivary ACC tissues may constitute a reason for perineural invasion in salivary ACC. 相似文献