全文获取类型
收费全文 | 14251篇 |
免费 | 1132篇 |
国内免费 | 630篇 |
专业分类
耳鼻咽喉 | 33篇 |
儿科学 | 47篇 |
妇产科学 | 19篇 |
基础医学 | 883篇 |
口腔科学 | 4535篇 |
临床医学 | 690篇 |
内科学 | 470篇 |
皮肤病学 | 96篇 |
神经病学 | 1263篇 |
特种医学 | 258篇 |
外国民族医学 | 1篇 |
外科学 | 796篇 |
综合类 | 2150篇 |
预防医学 | 258篇 |
眼科学 | 45篇 |
药学 | 2704篇 |
3篇 | |
中国医学 | 1676篇 |
肿瘤学 | 86篇 |
出版年
2024年 | 21篇 |
2023年 | 210篇 |
2022年 | 252篇 |
2021年 | 483篇 |
2020年 | 431篇 |
2019年 | 401篇 |
2018年 | 412篇 |
2017年 | 422篇 |
2016年 | 438篇 |
2015年 | 458篇 |
2014年 | 899篇 |
2013年 | 858篇 |
2012年 | 915篇 |
2011年 | 1048篇 |
2010年 | 737篇 |
2009年 | 638篇 |
2008年 | 732篇 |
2007年 | 814篇 |
2006年 | 691篇 |
2005年 | 643篇 |
2004年 | 520篇 |
2003年 | 516篇 |
2002年 | 446篇 |
2001年 | 404篇 |
2000年 | 324篇 |
1999年 | 269篇 |
1998年 | 270篇 |
1997年 | 210篇 |
1996年 | 187篇 |
1995年 | 139篇 |
1994年 | 151篇 |
1993年 | 157篇 |
1992年 | 125篇 |
1991年 | 105篇 |
1990年 | 97篇 |
1989年 | 72篇 |
1988年 | 76篇 |
1987年 | 52篇 |
1986年 | 73篇 |
1985年 | 78篇 |
1984年 | 51篇 |
1983年 | 37篇 |
1982年 | 38篇 |
1981年 | 30篇 |
1980年 | 36篇 |
1979年 | 13篇 |
1978年 | 9篇 |
1977年 | 7篇 |
1975年 | 4篇 |
1974年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
41.
牙根发育不良疾病的研究进展 总被引:2,自引:0,他引:2
牙根发育不良疾病是牙齿根部生理性发育出现障碍的疾病。其发病率为1%~10%,乳、恒牙列均可发生,其结果可导致牙根缺如或短根,严重者可造成牙齿过早脱落。国外学者将该疾病统称为短根异常疾病。其发病因素有遗传性疾病、全身性疾病、外源性因素和医源性因素等。 相似文献
42.
Abstract – A histometric method was applied for evaluation of root resorption in 57 experimentally replanted teeth and 22 controls. Representative axiobuccolingual sections were selected for measurement of resorptions at a magnification of × 40. The frequency of root resorption in the control teeth was low. In replanted teeth marked resorptive activity elicited by the trauma appeared after 2 wk. The extent of active resorptions increased until the third postoperative week. On an average 14% of the root periphery was affected at this stage. After the sixth postoperative week progressive cement deposition took place in the resorption lacunae. Incidental ankylosis of the periodontal membrane also occurred from this observation time but there was no increase among the long-term groups. 相似文献
43.
目的:评价泰勒宁片和科洛曲片对隆乳手术后疼痛的疗效和不良反应。方法:采用随机开放平行对照试验。共完成60例,其中A组30例予泰勒宁片,单次1片;B组30例予科洛曲片,单次1片。结果:泰勒宁片对隆乳手术后引起的中度或重度疼痛总有效率可达96.7%,科洛曲片的总有效率可达83.3%。服药后泰勒宁片组的疼痛强度差均高于科洛曲组,经统计学处理,有显著性差异(P<0.05)。不良反应发生率较科洛曲片组高。结论:泰勒宁片为中强度镇痛药,对于隆乳手术后引起的中重度疼痛有良好的镇痛效果。 相似文献
44.
The subthalamic nucleus (STN) is a major target for treatment of advanced Parkinson's disease patients undergoing deep brain stimulation surgery. Microelectrode recording (MER) is used in many cases to identify the target nucleus. A real-time procedure for identifying the entry and exit points of the STN would improve the outcome of this targeting procedure. We used the normalized root mean square (NRMS) of a short (5 seconds) MER sampled signal and the estimated anatomical distance to target (EDT) as the basis for this procedure. Electrode tip location was defined intraoperatively by an expert neurophysiologist to be before, within, or after the STN. Data from 46 trajectories of 27 patients were used to calculate the Bayesian posterior probability of being in each of these locations, given RMS-EDT pair values. We tested our predictions on each trajectory using a bootstrapping technique, with the rest of the trajectories serving as a training set and found the error in predicting the STN entry to be (mean +/- SD) 0.18 +/- 0.84, and 0.50 +/- 0.59 mm for STN exit point, which yields a 0.30 +/- 0.28 mm deviation from the expert's target center. The simplicity and computational ease of RMS calculation, its spike sorting-independent nature and tolerance to electrode parameters of this Bayesian predictor, can lead directly to the development of a fully automated intraoperative physiological procedure for the refinement of imaging estimates of STN borders. 相似文献
45.
46.
目的 从福参Angelica morii提取分离活性成分。方法 采用乙醇提取,溶剂萃取,大孔树脂、聚酰胺、硅胶柱层析,LH-20、重结晶等纯化,对福参饮片进行系统提取分离;运用波谱学方法及理化常数对照进行结构鉴定。结果 从正丁醇和水部分分离到6个苷类化合物,分别为升麻索苷(prim-O-glucosylcimifugin,Ⅰ)、紫花前胡苷(marmesinin,Ⅱ)、芹菜素7-O-β-D-葡萄糖苷(apigenin 7-O0-β-D-glucoside,Ⅲ)、木犀草素7-O-β-D-葡萄糖苷(1ute—olin 7-O-β-D-glucoside,Ⅳ),umbeliferone 7-apiosylglucoside(V)和胡萝卜苷(daucosterol,Ⅵ)。结论 6个化合物均为首次该植物中分得;化合物Ⅲ首次从当归属中分得。 相似文献
47.
Scott Lozanoff Barbara A. Long David L. Singer John J. Deptuch 《Journal of clinical periodontology》1992,19(8):553-559
Deposits of dental plaque or calculus are typically quantified using planimetric techniques. However, error is introduced into a quantitative analysis of plaque deposits using these methods, since they require a significant amount of human intervention. The purpose of this study is to describe and validate a computerized imaging routine which has the potential to objectively identify material on dental roots and measure the area covered by these deposits. Dentiform teeth with simulated plaque were videorecorded. A computer routine was developed based on a flood-fill algorithm which analyzed images of the dentiform teeth and determined the amount of simulated plaque on their root surfaces. Results showed that the dentiform teeth and their simulated plaque patterns are duplicated by the imaging routine in a rapid and reliable fashion. The system shows a high degree of accuracy with an average error factor of only 0.58%. As well, the system enables precise reproducibility with an average error factor of only 0.71%. 相似文献
48.
We present a case of a female patient suffering from type I complex regional pain syndrome (CRPS) who developed “mirror imaging” of her CRPS and was successfully treated with dual spinal cord stimulation (SCS) in the paraforaminal epidural space. This patient initially had unilateral pain that was unsuccessfully treated with midline SCS and single‐lead lateral epidural lead placement “paraforaminally.” One year later, because we believed that paraforaminal stimulation would preferentially stimulate primary sensitized afferents innervating the painful area, we reperformed SCS with two leads positioned laterally and paraforaminally close to the roots within the epidural space. After repositioning and after 1 year of paraforaminal stimulation, there was significant improvement in the patient's symptoms, resolving all unilateral and “mirrored” symptoms. We conclude that paraforaminal stimulation may be a valid therapeutic option for the treatment of CRPS. 相似文献
49.
50.
在8例健康志愿者中进行国产与进口氧氟沙星片药物动力学和生物利用度研究。随机交叉试验设计单剂量口服400mg,用HPLC测定血药浓度,按非室模型计算,求得2种制剂各项药物动力学参数,无显著性差异(P>0.05),以进口药片为标准(F=1)求得国产药片的相对生物利用度为92.2%。 相似文献