全文获取类型
收费全文 | 119778篇 |
免费 | 10743篇 |
国内免费 | 4488篇 |
专业分类
耳鼻咽喉 | 1482篇 |
儿科学 | 2237篇 |
妇产科学 | 1668篇 |
基础医学 | 14580篇 |
口腔科学 | 2171篇 |
临床医学 | 13911篇 |
内科学 | 19164篇 |
皮肤病学 | 2894篇 |
神经病学 | 6930篇 |
特种医学 | 5456篇 |
外国民族医学 | 22篇 |
外科学 | 11975篇 |
综合类 | 14183篇 |
现状与发展 | 18篇 |
一般理论 | 19篇 |
预防医学 | 9816篇 |
眼科学 | 2820篇 |
药学 | 12312篇 |
80篇 | |
中国医学 | 5169篇 |
肿瘤学 | 8102篇 |
出版年
2024年 | 271篇 |
2023年 | 1270篇 |
2022年 | 3220篇 |
2021年 | 4589篇 |
2020年 | 3300篇 |
2019年 | 3129篇 |
2018年 | 3303篇 |
2017年 | 3217篇 |
2016年 | 3460篇 |
2015年 | 5163篇 |
2014年 | 6440篇 |
2013年 | 7104篇 |
2012年 | 10177篇 |
2011年 | 10256篇 |
2010年 | 7205篇 |
2009年 | 6040篇 |
2008年 | 7317篇 |
2007年 | 6981篇 |
2006年 | 6571篇 |
2005年 | 5772篇 |
2004年 | 4383篇 |
2003年 | 3868篇 |
2002年 | 3374篇 |
2001年 | 2178篇 |
2000年 | 1892篇 |
1999年 | 1513篇 |
1998年 | 732篇 |
1997年 | 756篇 |
1996年 | 568篇 |
1995年 | 540篇 |
1994年 | 471篇 |
1993年 | 393篇 |
1992年 | 744篇 |
1991年 | 756篇 |
1990年 | 631篇 |
1989年 | 656篇 |
1988年 | 640篇 |
1987年 | 616篇 |
1986年 | 525篇 |
1985年 | 513篇 |
1984年 | 416篇 |
1983年 | 339篇 |
1982年 | 250篇 |
1981年 | 231篇 |
1980年 | 206篇 |
1979年 | 305篇 |
1978年 | 261篇 |
1977年 | 186篇 |
1974年 | 209篇 |
1973年 | 222篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
目的通过是否进行腭咽肌肉重建的两组腭裂修复术后患者鼻咽内窥镜的比较观察,了解腭咽部肌肉重建术后腭咽闭合状况的改变。方法将41例腭裂术后患者,按照在腭裂修复时是否进行腭咽肌肉重建分为重建组(22例)和非重建组(19例),以鼻咽纤维内窥镜记录静态和发音时腭咽闭合运动状况,对两组患者腭咽闭合运动类型和状况进行比较。结果重建组静态腭咽腔形态较非重建组明显缩小,各壁光滑丰满,未见软腭鼻腔面V型缺损畸形;动态时以环状闭合为主。非重建组静态腭咽腔形态较大,可见软腭鼻腔面V型缺损畸形;动态时以冠状闭合为主。经比较重建组腭咽闭合良好率(90.91%)明显优于非重建组(37.31%)。结论鼻咽内窥镜观察证实腭咽肌肉重建腭裂修复术后腭咽闭合功能恢复明显优于非重建组。腭裂修复术时重建腭咽肌肉有助于缩小腭咽腔和更易于达到良好的腭咽闭合状态。 相似文献
22.
目的应用显微手术夹闭、血管内栓塞和栓塞后手术夹闭3种治疗方法,探讨治疗颅内破裂动脉瘤的安全有效方案。方法显微手术瘤颈夹闭30个动脉瘤,栓塞34个动脉瘤,栓塞后夹闭15个动脉瘤。结果夹闭组30个完全夹闭,无复发,死亡率6%(2/30)。栓塞组完全闭塞率70.6%(24/34),复发率17.6%(6/34),死亡率11.8%(4/34)。栓塞后手术组15个完全夹闭,无复发,死亡率6.7%(1/15)。治疗结束用GOS评价,1个月后3组良好率分别为80.0%、79.4%和80.0%;半年后良好率分别为90.0%、88.2%和86.7%。结论显微手术瘤颈夹闭术仍然是治疗破裂动脉瘤的有效方法,具有1次治疗彻底和复发率低的优势,并可作为栓塞失败的补救手段。 相似文献
23.
Taylor Moran-Gates Christopher Grady Young Shik Park Ross J Baldessarini Frank I Tarazi 《European neuropsychopharmacology》2007,17(6-7):448-455
The atypical antipsychotic risperidone is often prescribed to pediatric patients with neuropsychiatric disorders, though its effects on the developing brain remain unclear. Accordingly, we studied the effects of repeated treatment of risperidone on dopamine receptors in brain regions of juvenile rat. Levels of dopamine receptors (D(1), D(2), D(3), D(4)) in forebrain regions of juvenile rats were quantified after 3 weeks of treatment with three different doses of risperidone (0.3, 1.0 and 3.0 mg/kg) and compared findings to those in adult rats treated with risperidone (3.0 mg/kg/day) previously. Risperidone (at 1.0 and 3.0 mg/kg/day) increased levels of D(1) receptors in nucleus accumbens and caudate-putamen of juvenile, but not adult rats. Conversely, all three doses of risperidone dose-dependently increased D(2) labeling in medial prefrontal cortex and hippocampus, and D(4) receptor in nucleus accumbens, caudate-putamen and hippocampus of juvenile animals as well as in adults. Only the high dose of risperidone (3.0 mg/kg) increased D(2) receptors in caudate-putamen in both juvenile and adult brain. D(3) receptors were not altered by risperidone in any brain region at any dose or age. The findings indicate dose-dependent effects of risperidone on dopamine receptors in developing animals, and that juvenile animals are more sensitive than adults to the cerebral effects of risperidone. 相似文献
24.
25.
26.
抽动障碍中医证型与血清单胺类物质的相关性研究 总被引:1,自引:0,他引:1
目的 观察抽动障碍不同中医证型患者血清多巴胺、去甲肾上腺素等单胺类神经递质的水平,并探讨各证型之间血清神经递质的水平是否存在差别.方法 采用化学荧光法测定46例抽动障碍患者(病例组)血清多巴胺、去甲肾上腺素水平,并与40例正常儿童(对照组)进行比较.结果 病例组血清多巴胺为0.449μg/ml,对照组为0.210μg/ml;病例组血清去甲肾上腺素为0.227μg/ml,对照组为0.127μg/ml,两组各均值比较,病例组血清多巴胺和去甲肾上腺素均显著高于对照组.病例组外风侵袭、肝风内动型,或兼气郁化火型,或兼脾虚痰聚型,或兼阴虚风动型血清多巴胺水平分别为0.316、0.400、0.235、0.247μg/ml,四者比较有显著性差异;病例组符证型血清去甲.肾上腺素水平分别为0.203、0.224、0.144、0.154μg/ml,四者比较差异有显著性.结论 抽动障碍患者存在多巴胺和去甲肾上腺素水平异常,且各证型血清多巴胺、去甲肾上腺素水平有明显差异,而尤其以外风侵袭、肝风内动兼气郁化火型水平最高. 相似文献
27.
Man Bok Jeong Kristina Narfström Shin Ae Park Je Min Chae Kang Moon Seo 《Documenta ophthalmologica. Advances in ophthalmology》2009,119(2):79-88
The objective of this study is to compare the effects of three different anesthetic combinations on the electroretinogram
in the same animals under similar laboratory conditions. Thiopental–isoflurane (TI), medetomidine–ketamine (MK), and xylazine–ketamine
(XK) were used on each of 12 healthy miniature schnauzer dogs (MS) with a period of at least 3 weeks in between subsequent
anesthesia protocols, using the Dog Standard Protocol. The scotopic ERGs consisted of scotopic low stimulus strength (S) responses
designated S1, S2, S3, S4, and S5, at 1, 5, 10, 15, and 20 min after dark adaptation, respectively, and scotopic standard
stimulus strength (S-ST) responses. The photopic ERGs consisted of a photopic single flash (P) response and 31 Hz flicker
(P-FL) responses. For S-ST (2.5 cd s/m2), the amplitude of the a-wave using TI was significantly lower than that using MK (adjusted P = 0.05) and XK (adjusted P = 0.03), and the implicit time of the a-wave was significantly shorter than that using MK (adjusted P = 0.04). For P (2.5 cd s/m2), the amplitude of the b-wave using XK was significantly higher than that using MK (adjusted P = 0.01). The implicit times of the b-wave using TI was significantly longer and shorter than that of MK for S1, S2 and P-FL
and for S4 and S-ST, respectively, and than that of XK for S2 and P-FL and for S5 and S-ST, respectively. The results of the
present study showed that TI affected both the amplitude and the implicit time of the a-wave for S-ST and the implicit time
of the b-wave relatively more so than was the case when using XK or MK. Therefore, it appears that either XK or MK could be
advantageous to use rather than TI for clinical studies. 相似文献
28.
Su Jin Lee Young Keun On Eun Jeong Lee Joon Young Choi Byung-Tae Kim Kyung-Han Lee 《Journal of nuclear medicine》2008,49(8):1277-1282
Vascular 18F-FDG uptake marker represents inflammation in atherosclerotic lesions, but whether inflammation can be reversed by risk-modifying interventions has not, to our knowledge, been demonstrated. In this study, we evaluated the change of vascular 18F-FDG uptake in response to lifestyle intervention on serial PET/CT scans and further assessed how the findings relate to atherogenic risk reduction. METHODS: A total of 60 healthy adults underwent 18F-FDG PET/CT scans and atherogenic risk-factor assessment at baseline and again after 17.1 +/- 8.3 mo of practicing lifestyle modification. The PET/CT images were evaluated for the presence of vascular 18F-FDG lesions, and vessel-to-blood-pool 18F-FDG ratios were measured. Indices from summed ratios of positive lesions were compared and correlated to atherogenic risk factors. RESULTS: At follow-up, significant reductions in diastolic blood pressure (P < 0.05), total cholesterol (P < 0.05), and low-density lipoprotein level (P < 0.05) and an increase in high-density lipoprotein (HDL) level (P < 0.0001) were demonstrated. On the initial PET/CT scan, 50 of 60 subjects showed 1 or more 18F-FDG-positive lesions (5.9 +/- 5.0/subject), leading to a total of 352 vascular sites. On follow-up, 18F-FDG-positive lesions were significantly reduced to 2.1 +/- 2.2 sites per subject (P < 0.0001) and a total of 124 sites (64.8% reduction). Follow-up 18F-FDG-positive rates were significantly reduced for the aorta and iliac arteries. In addition, significant reductions in the whole-body 18F-FDG index from 1.39 +/- 1.23 to 0.53 +/- 0.59 (P < 0.0001) and carotid 18F-FDG index from 0.08 +/- 0.16 to 0.03 +/- 0.06 (P = 0.01) were shown. The whole-body 18F-FDG index correlated with total cholesterol (P < 0.05) and HDL level (P < 0.05), and the magnitude of reduction in the 18F-FDG index closely correlated to the amount of increase in plasma HDL level (P = 0.005). CONCLUSION: Our study demonstrated that vascular 18F-FDG uptake is reversed in response to atherogenic risk reduction by lifestyle intervention and that the magnitude of improvement correlates to increases in plasma HDL levels. Thus, serial 18F-FDG PET/CT may be useful for monitoring improvements in the inflammatory component of atherosclerotic lesions in response to risk modification. 相似文献
29.
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
30.