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   6643篇
  免费   274篇
  国内免费   37篇
耳鼻咽喉   93篇
儿科学   163篇
妇产科学   288篇
基础医学   626篇
口腔科学   75篇
临床医学   471篇
内科学   1613篇
皮肤病学   143篇
神经病学   949篇
特种医学   192篇
外科学   1125篇
综合类   14篇
一般理论   2篇
预防医学   247篇
眼科学   217篇
药学   288篇
中国医学   22篇
肿瘤学   426篇
  2023年   56篇
  2022年   112篇
  2021年   184篇
  2020年   122篇
  2019年   136篇
  2018年   181篇
  2017年   133篇
  2016年   174篇
  2015年   164篇
  2014年   248篇
  2013年   314篇
  2012年   463篇
  2011年   459篇
  2010年   286篇
  2009年   276篇
  2008年   424篇
  2007年   425篇
  2006年   385篇
  2005年   378篇
  2004年   324篇
  2003年   287篇
  2002年   264篇
  2001年   101篇
  2000年   92篇
  1999年   82篇
  1998年   57篇
  1997年   46篇
  1996年   48篇
  1995年   47篇
  1994年   39篇
  1993年   34篇
  1992年   65篇
  1991年   56篇
  1990年   51篇
  1989年   54篇
  1988年   46篇
  1987年   32篇
  1986年   36篇
  1985年   35篇
  1984年   49篇
  1983年   20篇
  1982年   13篇
  1981年   15篇
  1980年   18篇
  1979年   23篇
  1978年   11篇
  1977年   9篇
  1975年   7篇
  1974年   10篇
  1972年   6篇
排序方式: 共有6954条查询结果,搜索用时 15 毫秒
1.
2.
ObjectiveWe examine remission rate probabilities, recovery rates, and residual symptoms across 36 weeks in the Treatment for Adolescents with Depression Study (TADS).MethodThe TADS, a multisite clinical trial, randomized 439 adolescents with major depressive disorder to 12 weeks of treatment with fluoxetine, cognitive–behavioral therapy, their combination, or pill placebo. The pill placebo group, treated openly after week 12, was not included in the subsequent analyses. Treatment differences in remission rates and probabilities of remission over time are compared. Recovery rates in remitters at weeks 12 (acute phase remitters) and 18 (continuation phase remitters) are summarized. We also examined whether residual symptoms at the end of 12 weeks of acute treatment predicted later remission.ResultsAt week 36, the estimated remission rates for intention-to-treat cases were as follows: combination, 60%; fluoxetine, 55%; cognitive–behavioral therapy, 64%; and overall, 60%. Paired comparisons reveal that, at week 24, all active treatments converge on remission outcomes. The recovery rate at week 36 was 65% for acute phase remitters and 71% for continuation phase remitters, with no significant between-treatment differences in recovery rates. Residual symptoms at the end of acute treatment predicted failure to achieve remission at weeks 18 and 36.ConclusionsMost depressed adolescents in all three treatment modalities achieved remission at the end of 9 months of treatment.  相似文献   
3.
4.
Targeted imaging requires site-specific accumulation of a contrast agent (CA), and the properties of that agent must be selected according to the abundance of the target to obtain a signal above the detection limit of the instrument. However, numerical estimates of receptors per cell are rarely found in the literature. Integrin receptors would be particularly promising targets because of their accessibility from the blood stream and expression on activated neovascular endothelial cells. We systematically estimated the number of integrin receptors of cell lines and primary cells by flow cytometry analysis. Since integrin receptors are heterodimeric molecules, and alpha(v) forms complexes with various beta subunits, the numbers of alpha(v) and beta(3) subunits are therefore dissimilar. The observed values are 3 . 10(3)-1.4 . 10(4)/cell for alpha(v), and 5.3 . 10(2)-1.1 . 10(4)/cell for beta(3). Despite the low number of exposed receptors, we show that up to single-cell MR visualization can be achieved with the use of iron oxide beads complexed with antibodies as CAs.  相似文献   
5.
Several attempts have been made to enhance doxorubicin (DOXO) concentrations in tumour cells by drug conjugation with human albumin (HSA). HSA-DOXO has the drawback of causing DOXO accumulation in spleen and bone marrow, with a consequent leucopoenia not produced when lactose molecules are coupled to the carrier protein. In the present experiments we demonstrated that the effect of HSA lactosamination is not a consequence of a more rapid disappearance from the bloodstream of the lactosaminated conjugate (L-HSA-DOXO), which is rapidly internalized by the liver through the asialoglycoprotein receptor, but is due to a hindered uptake by spleen and bone marrow cells caused by the coupled lactose molecules. Experiments in vitro showed that HSA-DOXO produced an inhibition of murine macrophage proliferation not caused by L-HSA-DOXO. This result can be explained by higher amounts of the former conjugate entering in these cells and suggests macrophages as the cell type responsible for the spleen and bone marrow internalization of HSA-DOXO hindered by lactose coupling. Importantly, lactosamination of HSA did not reduce the marked uptake of HSA-DOXO by chemically induced rat hepatocellular carcinoma. L-HSA-DOXO, by avoiding DOXO accumulation in bone marrow is an attractive candidate for clinical trials against tumors which were found to actively internalize this conjugate in laboratory animals, such as hepatocellular carcinoma.  相似文献   
6.
This retrospective study was made to evaluate the significance of different sports activities that cause variable haemarthrosis with intraarticular lesions of the knee joint. Throughout 1984 to 1988 arthroscopy was performed in 337 patients with acute haemarthrosis. The average time between trauma and arthroscopy was 8 days. ACL rupture was diagnosed in most of these cases. Regarding the different types of sport activities ACL lesions were found in skiers (74%), other winter sports (47%), soccer (53%), tennis and squash (58%), athletics (41%) and indoor (61%). Peripheral meniscus tears associated with haemarthrosis were found in 36% and patellar dislocations in 8%. Isolated MCL ruptures were diagnosed clinically and arthroscopy was not performed in these cases. Throughout 1987 isolated ACL ruptures were fixed by reattachment. This technique was not continued any longer and ACL replacement by patellar tendon as bone-ligament-bone was performed routinely since 1988 in those patients, who required surgery. 56 patients required ACL reconstruction following conservative treatment because of ACL deficiency, when they went back to sports activities. Longitudinal peripheral meniscus tears were fixed by the scape in inside-out technique.  相似文献   
7.
From 1980 to the end of 1988, arthroscopy has been performed on 620 patients with acute hemarthrosis of the knee joint. Of all the intraarticular lesions, 89.4% required surgery. Arthroscopy has changed in the last decade from diagnostic screening to invasive instrumentation for exact operative planing and alternative operative techniques. Hemarthrosis in stable knee joints was caused by minor lesions (7.84%) that did not require surgical procedures. Seventy-three patients had traumatic patellar dislocations--in 33 cases associated with chondral or osteochondral fractures. In 54.8% of the isolated medial retinacular ruptures, simple suture was performed in 14 cases--3 times arthroscopically and 11 times open, combined with lateral retinacular release without redislocation following. Associated chondral fracture indicated surgery in all cases. Isolated meniscus pathology (12.48%) was treated by arthroscopy alone, and refixation of the medial meniscus was carried out using the inside-out technique in 27 cases. Arthroscopic elevation of lateral tibia plateau fracture--indicated by type II fracture according to the AO classification--was performed in 3 cases with excellent results, and was associated with screw fixation and image intensification in 2 patients. Intercondylar eminence fracture is an excellent indication for arthroscopic refixation in the presence of the mono- or two-fragment type of fracture. ACL rupture is the main intra-articular pathology (64.8%) for hemarthrosis of the knee joint, which was diagnosed as an acute injury within the 1st week following trauma (51.04%). Anterior instability can be detected clinically if a careful examination with the Lachman test, combined with the missing end-point and pivot-shift test, is performed.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
8.
Syndesmosis transfixation screw   总被引:1,自引:0,他引:1  
Instability of the distal tibia-fibular joint necessitates the implant of a fibular tibial transfixation screw. The screw should be placed 2 cm above the anterior syndesmosis. The angle of insertion is 30 degrees upwards from dorsal in relation to the frontal plane. If tibiofibular stability cannot be maintained following anatomical reconstruction of the fibula the transfixation screw must engage the medial tibial cortex. This is imperative, since the transfixation screw cannot withstand the biomechanical forces during motion and bearing of load if the screw penetrates only three corticals.  相似文献   
9.
Summary The endoscopic insertion of self-expanding mesh stents in four patients affected by obstructing rectal malignant tumors is reported. The preliminary experience shows that, in the short term, normal defecation was achieved, with no complications. Longer follow-up is necessary to evaluate the duration and the quality of the palliative effect.  相似文献   
10.
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