首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2560篇
  免费   161篇
  国内免费   28篇
耳鼻咽喉   28篇
儿科学   21篇
妇产科学   62篇
基础医学   136篇
口腔科学   330篇
临床医学   270篇
内科学   280篇
皮肤病学   132篇
神经病学   93篇
特种医学   93篇
外科学   527篇
综合类   264篇
预防医学   162篇
眼科学   114篇
药学   155篇
  2篇
中国医学   50篇
肿瘤学   30篇
  2024年   7篇
  2023年   63篇
  2022年   120篇
  2021年   156篇
  2020年   117篇
  2019年   92篇
  2018年   94篇
  2017年   86篇
  2016年   78篇
  2015年   85篇
  2014年   161篇
  2013年   168篇
  2012年   112篇
  2011年   140篇
  2010年   122篇
  2009年   100篇
  2008年   109篇
  2007年   106篇
  2006年   102篇
  2005年   96篇
  2004年   70篇
  2003年   66篇
  2002年   57篇
  2001年   42篇
  2000年   35篇
  1999年   33篇
  1998年   30篇
  1997年   24篇
  1996年   29篇
  1995年   24篇
  1994年   24篇
  1993年   24篇
  1992年   18篇
  1991年   13篇
  1990年   14篇
  1989年   15篇
  1988年   7篇
  1987年   12篇
  1986年   11篇
  1985年   15篇
  1984年   13篇
  1983年   5篇
  1982年   14篇
  1981年   6篇
  1980年   10篇
  1979年   4篇
  1978年   4篇
  1975年   3篇
  1974年   3篇
  1971年   2篇
排序方式: 共有2749条查询结果,搜索用时 0 毫秒
41.
New amendments to child welfare policy in New South Wales turn a spotlight on parents who use drugs and raise concerns about adequate provision of services for families facing issues with alcohol and other drug use. Sections of the new legislation are explicitly focused on parents who use illicit drugs, expanding the reach of child protection services over expectant parents during pregnancy. This targeting of women who are ‘addicted’ highlights the ambiguous scientific and moral attention to drug use in pregnancy. It also raises practical questions about the potential for the legislation to increase stigma towards drug use and disproportionately affect vulnerable and disadvantaged families. [Olsen A. Punishing parents: Child removal in the context of drug use. Drug Alcohol Rev 2015;34:27–30]  相似文献   
42.
比较2种方法在治疗良性前列腺增生(BPH)行经尿道前列腺等离子电切术中电切镜置入困难患者的临床疗效。选择2007年9月至2014年1月曲靖市第二人民医院泌尿外科收治的BPH患者行经尿道前列腺等离子电切术中发现电切镜进镜困难患者90例,随机分成观察组和对照组,每组45例。观察组采用去除外鞘电切术联合耻骨上膀胱微穿刺负压引流治疗,对照组采用扩张尿道和(或)尿道外口剖开,再置入电切镜行电切术治疗。2组手术均取得成功,平均手术时间、出血量无显著性差异(P>0。05),观察组术后平均住院时间、继发尿道狭窄的发生率均小于对照组(分别为P<0.05、P<0.01)。去除外鞘电切术联合耻骨上膀胱微穿刺负压引流在治疗BPH并电切镜进镜困难患者可降低术后继发尿道狭窄发生率,减少术后住院时间,临床疗效较好。  相似文献   
43.
Summary Clot removal at early surgery has been reported to be clinically effective for the prevention of cerebral vasospasm following subarachnoid hemorrhage (SAH) due to rupture of an intracranial aneurysm. We examined the most efficacious timing of mechanical clot removal on pharmacological responses in a monkey SAH model. Cynomolgus monkeys (Macaca fascicularis) were randomized into five groups: sham-operated, clot removal in which the clot was removed 48, 72, or 96h after SAH, and clot groups. An autologous blood clot was placed around the bilateral major cerebral arteries after craniectomy to mimic the hemorrhage. Seven days after the SAH, proximal and successively distal parts of the middle cerebral arteries were cut into rings for isometric tension measurement. The contractile responses to potassium chloride, 5-hydroxytryptamine, norepinephrine, adenosine triphosphate, prostaglandin F2, and hemoglobin were greater in the proximal parts than in the distal parts in each group. Compared with the sham-operated group, the responses of the clot-removal and clot groups to the drugs were progressively attenuated. The maximum responses to 5-hydroxytryptamine in the proximal parts and to adenosine triphosphate in the distal parts started to decrease, significantly, in the clot-removal group 48h after SAH, while most of the responses to the other agonists began to decrease in the clot-removal groups later than 72h after SAH. These results suggest that the attenuation of cerebrovascular contractile responses 7 days after SAH is pharmacologically inevitable, even if the clot is removed as early as 48h after the SAH. Clot removal may thus be recommended within 48h after SAH to ameliorate the severity of cerebral vasospasm following SAH.  相似文献   
44.
Lower extremity deep vein thrombosis (DVT) is a serious medical condition that can result in local pain and gait disturbance. DVT progression can also lead to death or major disability as a result of pulmonary embolism, postthrombotic syndrome, or limb amputation. However, early thrombus removal can rapidly relieve symptoms and prevent disease progression. Various endovascular procedures have been developed in the recent years to treat DVT, and endovascular treatment has been established as one of the major therapeutic methods to treat lower extremity DVT. However, the treatment of lower extremity DVT varies according to the disease duration, location of affected vessels, and the presence of symptoms. This article reviews and discusses effective endovascular treatment methods for lower extremity DVT.  相似文献   
45.
ObjectivesSelective caries removal (SCR) is recommended over non-selective removal for managing deep carious lesions to avoid pulp exposure and maintain pulp vitality. During SCR, residual carious dentin is left behind and sealed beneath the restoration. The biomechanical effects of such residual lesions on the restored tooth remain unclear and were assessed using finite element modeling (FEM).MethodsBased on μ-CT images of a healthy permanent human third molar, we developed five finite element models. Generic class I and II cavity restorations were modeled where residual lesions of variable sizes were either left or fully removed on occlusal and proximal surfaces. The cavities were restored with adhesive composite. All 3D-FE models were compared with a model of a healthy, non-treated molar. A vertical load of 100 N was applied onto the occlusal surface.ResultsRegardless of the lesion size, in molars with occlusal lesions higher mean stresses were predicted along the filling-lesion interface than in all other models. The smallest occlusal lesion (Ø1 = 1 mm) resulted in the highest maximum stresses at the filling-lesion interface with large stress concentrations at the filling walls indicating failure risk. In conclusion, lesion site and extent are influencing parameters affecting the filling-lesion interactions and thus the biomechanical behavior of the tooth after SCR.SignificanceRetaining carious lesions around the pulpal floor affects the deformation and stress states in tooth-filling complexes. The higher stresses observed in molars with occlusal lesions may affect restoration stability and longevity. Suprisingly, more extended occlusal lesions may provide a more favorable tooth performance than less extended ones. In contrast, in molars with proximal lesions the residual lesion had only limited effect on the tooth’s biomechanical condition.  相似文献   
46.
Abstract

Heavy metal contamination has become a worldwide environmental concern due to its toxicity, non-degradability and food-chain bioaccumulation. Conventional physical and chemical treatment methods for heavy metal removal have disadvantages such as cost-intensiveness, incomplete removal, secondary pollution and the lack of metal specificity. Microbial biomass-based biosorption is one of the approaches gaining increasing attention because it is effective, cheap, and environmental friendly and can work well at low concentrations. To enhance the adsorption properties of microbial cells to heavy metal ions, the cell surface display of various metal-binding proteins/peptides have been performed using a cell surface engineering approach. The surface engineering of Gram-negative bacteria, Gram-positive bacteria and yeast towards the adsorption of heavy metals are reviewed in this article. The problems and future perspectives of this technology are discussed.  相似文献   
47.
BACKGROUNDClinical femoral neck fracture is common. Based on patient age and fracture type, different surgical methods can be selected, including cannulated screw fixation of the femoral neck and artificial total hip joint or semi-hip joint replacement. When patients with femoral neck fracture are treated with cannulated screw fixation, a cannulated screw may be positioned too deep. The excessively deep-placed screw is difficult to remove and causes major trauma to the patient.CASE SUMMARYA patient with poliomyelitis and femoral neck fracture was treated with a cannulated screw that was placed too deep. A self-made auxiliary tool (made of a steel sternal wire) was used to remove the cannulated screw near the pelvic cavity.CONCLUSIONThe depth of the cannulated screw can be estimated before screw placement using an improved hollow screwdriver with a scale mark, thus improving the safety of screw placement and facilitating clinical use.  相似文献   
48.
This paper demonstrates the usefulness of endodontic guides for the removal of fibre posts. A 36‐year‐old man consulted for retreatment of a maxillary first molar presenting a periapical pathology. This tooth revealed a composite reconstruction together with a glass‐fibre post in the palatal root canal. To assist removal, use of an endodontic 3D‐printed guide was indicated. A cone beam computed tomography examination and an optical impression were made to produce a tooth‐supported guide by means of implant planning software (Blue Sky Plan, Blue Sky Bio®). The software enabled definition of a drilling pathway, which was transferred clinically using a resin template together with a sleeve and a 0.75‐mm drill. The drill was guided as far as the gutta‐percha situated in the apical third, limiting any risk of impairment or perforation.  相似文献   
49.
50.
目的探讨增殖性糖尿病视网膜病变(PDR)二期患者硅油填充术后行硅油取出联合白内障手术的临床疗效。方法回顾性分析2008—2012年于我院行硅油取出联合白内障超声乳化、人工晶体植入术的PDR患者55例(61眼),术后视力恢复情况。结果术后1个月最佳矫正视力好于术前最佳矫正视力的40眼(74.07%),与术前相同的10眼(18.52%),低于术前最佳矫正视力的4眼(7.41%)。所有患者均无角膜内皮失代偿、人工晶体移位、复发性视网膜脱离等并发症发生。结论 PDR行玻璃体切除术后合并白内障的患者,取出硅油时联合白内障超声乳化、人工晶体植入术是经济、安全、有效的治疗方法。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号