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   489220篇
  免费   47820篇
  国内免费   2299篇
耳鼻咽喉   7694篇
儿科学   14700篇
妇产科学   10928篇
基础医学   54812篇
口腔科学   13808篇
临床医学   60576篇
内科学   101304篇
皮肤病学   10825篇
神经病学   49503篇
特种医学   21477篇
外国民族医学   37篇
外科学   80768篇
综合类   3692篇
现状与发展   41篇
一般理论   219篇
预防医学   37279篇
眼科学   11970篇
药学   27789篇
  1篇
中国医学   656篇
肿瘤学   31260篇
  2023年   6648篇
  2022年   3627篇
  2021年   8901篇
  2020年   8917篇
  2019年   7999篇
  2018年   14983篇
  2017年   13404篇
  2016年   15169篇
  2015年   16481篇
  2014年   21488篇
  2013年   27497篇
  2012年   28229篇
  2011年   28246篇
  2010年   20504篇
  2009年   21124篇
  2008年   26088篇
  2007年   26714篇
  2006年   27429篇
  2005年   26385篇
  2004年   24488篇
  2003年   22817篇
  2002年   21979篇
  2001年   9879篇
  2000年   8836篇
  1999年   9058篇
  1998年   6312篇
  1997年   5302篇
  1996年   4755篇
  1995年   4158篇
  1994年   3285篇
  1993年   3045篇
  1992年   4106篇
  1991年   3861篇
  1990年   3596篇
  1989年   3396篇
  1988年   3042篇
  1987年   2859篇
  1986年   2717篇
  1985年   2634篇
  1984年   2450篇
  1983年   2128篇
  1982年   1955篇
  1981年   1812篇
  1980年   1589篇
  1979年   1930篇
  1978年   1659篇
  1977年   1439篇
  1975年   1467篇
  1974年   1509篇
  1973年   1346篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Introduction: Pharmacological options to address the imbalance between bone resorption and accrual in osteoporosis include anti-resorptive and osteoanabolic agents. Unique biologic pathways such as the Wnt/β-catenin pathway have been targeted in the quest for new emerging therapeutic strategies.

Areas covered: This review provides an overview of existing pharmacotherapy for osteoporosis in women and explore state-of–the-art and emerging therapies to prevent bone loss, with an emphasis on the mechanism of action, indications and side effects.

Expert opinion: Bisphosphonates appear to be a reliable and cost-effective option, whereas denosumab has introduced a simpler dosing regimen and may achieve a linear increase in bone mineral density (BMD) with no plateau being observed, along with continuous anti-fracture efficacy. Abaloparatide, a parathyroid-hormone-related peptide (PTHrP)-analogue, approved by the FDA in April 2017, constitutes the first new anabolic osteoporosis drug in the US for nearly 15 years and has also proven its anti-fracture efficacy. Romosozumab, a sclerostin inhibitor, which induces bone formation and suppresses bone resorption, has also been developed and shown a significant reduction in fracture incidence; however, concerns have arisen with regard to increased cardiovascular risk.  相似文献   

13.
ABSTRACT

Purpose

To investigate the effect of 1% tropicamide on anterior chamber aqueous flare (ACAF) measurements acquired with laser flare meter in patients with pseudoexfoliation.  相似文献   
14.
BACKGROUND AND PURPOSE: There is concern about the increase of radiation-induced malignancies with the application of modern radiation treatment techniques such as intensity-modulated radiotherapy (IMRT) and proton radiotherapy. Therefore, X-ray scatter and neutron radiation as well as the impact of the primary dose distribution on secondary cancer incidence are analyzed. MATERIAL AND METHODS: The organ equivalent dose (OED) concept with a linear-exponential and a plateau dose-response curve was applied to dose distributions of 30 patients who received radiation therapy of prostate cancer. Three-dimensional conformal radiotherapy was used in eleven patients, another eleven patients received IMRT with 6-MV photons, and eight patients were treated with spot-scanned protons. The treatment plans were recalculated with 15-MV and 18-MV photons. Secondary cancer risk was estimated based on the OED for the different treatment techniques. RESULTS: A modest increase of 15% radiation-induced cancer results from IMRT using low energies (6 MV), compared to conventional four-field planning with 15-MV photons (plateau dose-response: 1%). The probability to develop a secondary cancer increases with IMRT of higher energies by 20% and 60% for 15 MV and 18 MV, respectively (plateau dose-response: 2% and 30%). The use of spot-scanned protons can reduce secondary cancer incidence as much as 50% (independent of dose-response). CONCLUSION: By including the primary dose distribution into the analysis of radiation-induced cancer incidence, the resulting increase in risk for secondary cancer using modern treatment techniques such as IMRT is not as dramatic as expected from earlier studies. By using 6-MV photons, only a moderate risk increase is expected. Spot-scanned protons are the treatment of choice in regard to secondary cancer incidence.  相似文献   
15.
16.
OBJECTIVE: A series of nasopharyngeal appliance designs is presented that represents our evolving experience over a 20-year period in the adjunctive use of prosthetic stents in the surgical correction of nasopharyngeal stenosis. DESIGN: Retrospective assessment of effectiveness of two nasopharyngeal stenosis hollow stent designs in a consecutive series of patients for relief of nasal obstructive symptoms. SETTING: Tertiary academic medical center, Craniofacial Program at Children's Hospital. PATIENTS: Four patients with nasopharyngeal stenosis were treated with a preoperatively fabricated stent made from a clasped palatal appliance onto which hollow acrylic conduits were extended through surgically re-created pharyngeal ports. A subsequent set of four patients with nasopharyngeal stenosis were treated with intraoperatively-fashioned silastic grommets, as opposed to palatal appliances. INTERVENTIONS: Postoperative intraoral stenting of nasopharyngeal ports. MAIN OUTCOME MEASURES: Maintenance of pharyngeal port opening after 1 year, improvement in nasal airway obstructive symptoms. RESULTS: The palatal appliance stents were less well tolerated and had a lower maintenance of port patency after device removal (4 of 8, 50%). The silastic grommets provided better retention into the ports and increased patient tolerance, as well as better 1-year port maintenance (6 of 8, 75%). CONCLUSIONS: The grommet stent appliance offers numerous advantages over a conventional dental-clasped appliance for prosthetic nasopharyngeal stenting, including obviation of extensive preoperative preparation, ease of insertion and removal, and exchange of air during the stenting period. Improved nasopharyngeal patency with this device may be due to greater patient tolerance and subsequent longer use.  相似文献   
17.
18.
Although psychoanalysis was the first-choice treatment for premature ejaculation (PE) between 1920 and 1960, hardly any reports on its efficacy have been published. Moreover, a scientific debate about its findings has never been fully developed. The recent progress that has been made in the classification of three different PE syndromes creates a new opportunity for psychoanalytic investigations of men with complaints of PE, distinguished by the actual duration of their intravaginal ejaculation latency time (IELT). The term premature-like ejaculatory dysfunction has been introduced to distinguish men with self-perceived PE at normal and long IELT durations from those men with lifelong, acquired and normal variable PE. Psychoanalytic research may contribute to a better understanding of the consequences of objective early ejaculations on the unconscious mental life of men with the four forms of PE. By integrating neurobiological, clinical and epidemiological data of ejaculatory performance, a revival of psychoanalytic research of PE in the four distinct, classified PE groups, will probably contribute to a deeper insight in to the unconscious mental life of men affected by PE.  相似文献   
19.
20.
Low molecular weight heparins are widely used in the prophylaxis and treatment of thrombotic disorders. The effect of low molecular weight heparins on coagulation was examined ultrastructurally in an animal model. A test and a control group was formed, each consisting of five rabbits. Nadroparine (225 Institute of Chaoy Unit/kg twice daily) was applied to the test group for 10 days. The control group received 1 ml saline solution subcutaneously. Blood and vascular tissue samples collected at the end of the 10th day were evaluated under a JEM 100 B electron microscope. Platelet degranulation and agglutination was observed in the control group. Fibrin materials were detected in the cytoplasms and surroundings of degranulated platelets. Erythrocyte accumulation was remarkable on the vascular endothelium with intact coagulation periods. In the test group, outer membranes of platelets, hyalomere, and granular structures in the granulomeres were detected to be nearly intact. There were rare erythrocytes in the large vascular lumens. The aggregation phase had occurred but no agglutination was detected. Nadroparine seems to preserve consistency of lipoprotein membranes of platelets and granular structures containing enzymes, which contribute to the coagulation mechanisms.  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