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   5142篇
  免费   292篇
  国内免费   82篇
耳鼻咽喉   87篇
儿科学   150篇
妇产科学   116篇
基础医学   548篇
口腔科学   619篇
临床医学   361篇
内科学   1111篇
皮肤病学   133篇
神经病学   286篇
特种医学   356篇
外科学   664篇
综合类   31篇
一般理论   2篇
预防医学   459篇
眼科学   132篇
药学   279篇
中国医学   64篇
肿瘤学   118篇
  2022年   67篇
  2021年   105篇
  2020年   69篇
  2019年   106篇
  2018年   156篇
  2017年   123篇
  2016年   121篇
  2015年   146篇
  2014年   200篇
  2013年   243篇
  2012年   271篇
  2011年   309篇
  2010年   189篇
  2009年   187篇
  2008年   255篇
  2007年   354篇
  2006年   266篇
  2005年   265篇
  2004年   201篇
  2003年   156篇
  2002年   152篇
  2001年   131篇
  2000年   117篇
  1999年   86篇
  1998年   101篇
  1997年   97篇
  1996年   70篇
  1995年   75篇
  1994年   48篇
  1993年   48篇
  1992年   45篇
  1991年   63篇
  1990年   36篇
  1989年   50篇
  1988年   52篇
  1987年   42篇
  1986年   49篇
  1985年   65篇
  1984年   34篇
  1983年   25篇
  1982年   27篇
  1981年   22篇
  1980年   34篇
  1979年   18篇
  1977年   24篇
  1976年   22篇
  1975年   18篇
  1970年   22篇
  1969年   27篇
  1967年   20篇
排序方式: 共有5516条查询结果,搜索用时 0 毫秒
111.
This case report demonstrates the possibility of functional and aesthetic rehabilitation using an interdisciplinary approach in a child following avulsion of a tooth. Autotransplantation after the development of calcific metamorphosis of the pulp and acute apical periodontitis provided satisfactory repair after root canal treatment. A 7-year-old white boy avulsed the right maxillary central incisor (tooth 11). The extra-alveolar time exceeded 60 minutes, and this triggered external replacement resorption of the avulsed tooth. At 11 years of age, the child underwent tooth autotransplantation. After 4 years of follow-up, intraoral clinical and radiographic examination led to the diagnosis of calcific metamorphosis of the pulp and acute apical periodontitis. The patient had minimally invasive root canal treatment, orthodontic treatment and esthetic rehabilitation with a porcelain crown. Control periapical radiography and tomography of the autotransplanted tooth after 7 years revealed bone repair in the periapical region. This case report indicates that tooth autotransplantation can be used to replace anterior teeth after avulsion followed by replacement resorption. Interdisciplinary management helped to maintain the esthetics and function of the rehabilitated area.  相似文献   
112.
113.

Objective

To evaluate the influence of pulmonary hypertension in the ultra-fast-track anesthesia technique in adult cardiac surgery.

Methods

A retrospective study. They were included 40 patients divided into two groups: GI (without pulmonary hypertension) and GII (with pulmonary hypertension). Based on data obtained by transthoracic echocardiography. We considered as the absence of pulmonary hypertension: a pulmonary artery systolic pressure (sPAP) <36 mmHg, with tricuspid regurgitation velocity <2.8 m/s and no additional echocardiographic signs of PH, and PH as presence: a sPAP >40 mmHg associated with additional echocardiographic signs of PH. It was established as influence of pulmonary hypertension: the impossibility of extubation in the operating room, the increase in the time interval for extubation and reintubation the first 24 hours postoperatively. Univariate and multivariate analyzes were performed when necessary. Considered significant a P value <0.05.

Results

The GI was composed of 21 patients and GII for 19. All patients (100%) were extubated in the operating room in a medium time interval of 17.58±8.06 min with a median of 18 min in GII and 17 min in GI. PH did not increase the time interval for extubation (P=0.397). It required reintubation of 2 patients in GII (5% of the total), without statistically significant as compared to GI (P=0.488).

Conclusion

In this study, pulmonary hypertension did not influence on ultra-fast-track anesthesia in adult cardiac surgery.  相似文献   
114.
115.
116.
117.
Rabbit platelets were aggregated by adenosine diphosphate (ADP), allowed to deaggregate and then separated into density subpopulations by centrifugation through discontinuous Stractan density gradients. Although ADP causes little or no release of the contents of the amine storage granules of rabbit platelets, ADP caused a decrease in platelet density as compared with control platelets subjected to the same procedures except for exposure to ADP. The density change persisted for at least four hours. The apparent size of platelets stimulated with ADP increased initially, but returned to control values during a one-hour period. A similar decrease in platelet density was observed with an albumin density gradient. Under conditions in which aggregation did not occur in response to ADP with ethylenediaminetetraacetic acid (EDTA) in the medium, little or no decrease in platelet density was observed. Agglutination with polylysine did not change platelet density. Thus, not only agents such as thrombin and plasmin that cause the release of the contents of the platelet granules decrease platelet density, but ADP also has this effect. Platelets would be exposed to all of these stimuli during thromboembolic processes, and their effect on platelets may account for the decrease in platelet density observed previously in experiments with rabbits with indwelling aortic catheters. Agents that increase the concentration of cyclic AMP (cAMP) in platelets (PGE1, adenosine, dibutyryl cAMP, forskolin, and papaverine) also decreased platelet density. This effect persisted when the platelets were washed and resuspended in fresh medium and was also demonstrable in plasma. Platelet size was gradually increased by prostaglandin E1 (PGE1) which maintains platelets in a disc shape and does not cause the release of granule contents, indicating that the decrease in platelet density caused by PGE1 may be attributable to platelet swelling.  相似文献   
118.
McColl  SR; Kreis  C; DiPersio  JF; Borgeat  P; Naccache  PH 《Blood》1989,73(2):588-591
Pre-incubation of human neutrophils with pertussis toxin significantly inhibited the neutrophil-directed biologic actions of granulocyte- macrophage colony-stimulating factor (GM-CSF) in three separate assays: the induction of c-fos mRNA, the enhancement of both platelet- activating factor-induced mobilization of intracellular calcium, and stimulation of leukotriene synthesis by the calcium ionophore A23187. Cholera toxin did not have an effect on the latter two assays. Pre- treatment of human neutrophils with pertussis toxin did not affect the binding of GM-CSF to its surface receptor. These results provide the first evidence that a pertussis toxin substrate plays an important mediatory role in the mechanism of action of GM-CSF.  相似文献   
119.
Thirty-nine patients with acute cervical spine fractures and/or dislocations between C3 and C7 were submitted to an anterior approach using bone graft fixation without screw and plate systems and three required a preliminary posterior approach to reduce a dislocation. Graft dislodgement due to technical problems occurred at a rate of 7.7% postoperatively and 2.8% 1 month later. No redislodgement occurred. All fusions became solid after 3 months. Their progress was based on the Frankel scale, before surgery, at the moment of the discharge, and at 6 months follow-up. This experience shows how patients with an acute cervical injury can improve even when admitted late after trauma.  相似文献   
120.
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