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   696篇
  免费   57篇
  国内免费   14篇
耳鼻咽喉   4篇
儿科学   42篇
妇产科学   23篇
基础医学   39篇
口腔科学   8篇
临床医学   100篇
内科学   157篇
皮肤病学   8篇
神经病学   32篇
特种医学   56篇
外科学   78篇
综合类   38篇
预防医学   50篇
眼科学   15篇
药学   67篇
中国医学   12篇
肿瘤学   38篇
  2024年   5篇
  2023年   19篇
  2022年   29篇
  2021年   35篇
  2020年   34篇
  2019年   16篇
  2018年   20篇
  2017年   13篇
  2016年   11篇
  2015年   13篇
  2014年   13篇
  2013年   23篇
  2012年   27篇
  2011年   36篇
  2010年   16篇
  2009年   28篇
  2008年   22篇
  2007年   22篇
  2006年   22篇
  2005年   18篇
  2004年   24篇
  2003年   13篇
  2002年   18篇
  2001年   19篇
  2000年   13篇
  1999年   13篇
  1998年   17篇
  1997年   8篇
  1996年   9篇
  1995年   12篇
  1994年   11篇
  1993年   10篇
  1992年   9篇
  1991年   10篇
  1990年   7篇
  1989年   12篇
  1988年   13篇
  1987年   9篇
  1986年   11篇
  1985年   8篇
  1983年   12篇
  1982年   5篇
  1980年   6篇
  1979年   6篇
  1977年   7篇
  1976年   6篇
  1973年   5篇
  1968年   5篇
  1967年   5篇
  1966年   5篇
排序方式: 共有767条查询结果,搜索用时 15 毫秒
1.
2.
Forty-two patients (57 eyes) with diabetic retinopathy at various stages have been examined by nyctometry before and over the course of the follow-up period after argon laser coagulation of the retina. The findings evidence a marked reduction of the adaptation ability of the central retinal area even in high vision acuity in the patients with diabetic retinopathy vs. normal subjects. A stable rise of the nyctometric parameters has been observed after argon laser coagulation; these parameters characterize the function of the pigmented epithelium and of the retinal cone, and these data may be considered as an evidence of the improved trophics of these tissues, resultant from such therapy.  相似文献   
3.
Controlled studies of treatments effective with victims of natural disasters are almost nonexistent. This is a small study conducted under difficult conditions to test the effectiveness of Eye Movement Desensitization and Reprocessing (EMDR) in treating trauma related reactions following Hurricane Andrew. The results were positive in that EMDR produced significant improvement over wail list controls in perceived posttraumatic avoidance behaviors and thoughts as measured by changes in the Impact of Event Scale and significant improvement in subjective aversive reactions to representative experiences of the hurricane. These results suggest and support other studies that EMDR can be an effective therapeutic intervention for trauma reactions.  相似文献   
4.
Benign breast tumours with a mixed cartilaginous and epithelial component are distinctly rare as evident from the literature. A case of Mixed Tumour of the breast presenting pre-operatively as a hard mass in a 65 year old male is reported. Histologically, it was composed of a mixture of benign cartilage, myoepithelial cells, tubules and a myxoid stroma in fat. A brief review of cartilage bearing lesions and mixed tumour in the mammary region is discussed.  相似文献   
5.
Studies were conducted on the effect of heparin or 6-aminohexanoic acid (6-AH) on the activation of glutamic plasminogen (Glu-Plg) by streptokinase in the presence of different concentrations of buffer, NaCl and divalent cations. Heparin and 6-AH inhibited streptokinase-mediated activation of Glu-Plg using 10 mM Tris-HCl buffer pH 7.4. This inhibition was partially reversed by the addition of 0.2-1.0 mM of Mg ions. Increasing the ionic strength of Tris-HCl buffer from 10 to 50 mM or addition of 50-150 mM of NaCl to 50 mM Tris-HCl pH 7.4 inhibited the activation of Glu-Plg by streptokinase while decreasing the % inhibition by heparin over the control samples. Double reciprocal plot of the activation of Glu-Plg by streptokinase using 50 mM Tris-HCl pH 7.4 containing 100 mM NaCl showed that the addition of heparin lowered Vmax by 50% without affecting Km. To determine whether the inhibitory effect of heparin was specifically directed towards Glu-Plg or streptokinase, the ratios of the initial rate of plasmin generation in the presence of heparin over the controls were plotted against the inverse of the volume fraction of Glu-Plg or streptokinase after serial dilutions. The results indicated that the dilutions of streptokinase but not of Glu-Plg influenced the ratios, suggesting an interaction of heparin with streptokinase. Addition of 6-AH reversed the inhibitory effect of NaCl on the activation of Glu-Plg by streptokinase and the results of the near UV CD spectra of Glu-Plg showed that addition of 6-AH enhanced the spectra in this region with an increase in the ellipticity which was not affected by addition of NaCl.  相似文献   
6.
7.
Oscillatory motion of the normal cervical spinal cord   总被引:2,自引:0,他引:2  
  相似文献   
8.
The purpose is to incorporate clinically relevant factors such as patient-specific and dosimetric information as well as data from clinical trials in the decision-making process for the selection of prostate intensity-modulated radiation therapy (IMRT) plans. The approach is to incorporate the decision theoretic concept of an influence diagram into the solution of the multiobjective optimization inverse planning problem. A set of candidate IMRT plans was obtained by varying the importance factors for the planning target volume (PTV) and the organ-at-risk (OAR) in combination with simulated annealing to explore a large part of the solution space. The Pareto set for the PTV and OAR was analysed to demonstrate how the selection of the weighting factors influenced which part of the solution space was explored. An influence diagram based on a Bayesian network with 18 nodes was designed to model the decision process for plan selection. The model possessed nodes for clinical laboratory results, tumour grading, staging information, patient-specific information, dosimetric information, complications and survival statistics from clinical studies. A utility node was utilized for the decision-making process. The influence diagram successfully ranked the plans based on the available information. Sensitivity analyses were used to judge the reasonableness of the diagram and the results. In conclusion, influence diagrams lend themselves well to modelling the decision processes for IMRT plan selection. They provide an excellent means to incorporate the probabilistic nature of data and beliefs into one model. They also provide a means for introducing evidence-based medicine, in the form of results of clinical trials, into the decision-making process.  相似文献   
9.
Apoptosis (programmed cell death) plays important roles in many facets of normal mammalian physiology. Host-pathogen interactions have provided evolutionary pressure for apoptosis as a defense mechanism against viruses and microbes, sometimes linking apoptosis mechanisms with inflammatory responses through NFκB induction. Proteins involved in apoptosis and NFκB induction commonly contain evolutionarily conserved domains that can serve as signatures for identification by bioinformatics methods. Using a combination of public (NCBI) and private (RIKEN) databases, we compared the repertoire of apoptosis and NFκB-inducing genes in humans and mice from cDNA/EST/genomic data, focusing on the following domain families: (1) Caspase proteases; (2) Caspase recruitment domains (CARD); (3) Death Domains (DD); (4) Death Effector Domains (DED); (5) BIR domains of Inhibitor of Apoptosis Proteins (IAPs); (6) Bcl-2 homology (BH) domains of Bcl-2 family proteins; (7) Tumor Necrosis Factor (TNF)-family ligands; (8) TNF receptors (TNFR); (9) TIR domains; (10) PAAD (PYRIN; PYD, DAPIN); (11) nucleotide-binding NACHT domains; (12) TRAFs; (13) Hsp70-binding BAG domains; (14) endonuclease-associated CIDE domains; and (15) miscellaneous additional proteins. After excluding redundancy due to alternative splice forms, sequencing errors, and other considerations, we identified cDNAs derived from a total of 227 human genes among these domain families. Orthologous murine genes were found for 219 (96%); in addition, several unique murine genes were found, which appear not to have human orthologs. This mismatch may be due to the still fragmentary information about the mouse genome or genuine differences between mouse and human repertoires of apoptotic genes. With this caveat, we discuss similarities and differences in human and murine genes from these domain families.  相似文献   
10.
Hormones are believed to play a dominant role as promoters in the growth and development of hormone-dependent cancers. Much less is known about the circulating hormones in male patients with oesophageal cancer. This lack of attention led us to evaluate the role of peptide and steroid hormones (by RIA) in male patients with oesophageal cancer (n=49). Blood samples of patients were collected pretherapeutically and data was compared with age matched controls (n=25). In this retrospective study, significantly high levels of FSH (P<0.02), LH (P<0.001) and prolactin (P<0.001) were observed with concomitant low levels of estradiol (P<0.001), DHEA-S (P<0.02) and testosterone (P<0.001) in patients when compared with respective controls. The patients when grouped according to anatomical site and histological type of the tumor, intergroup variation was not observed in these hormones. From our, study, it seems that hormonal imbalance or altered ratio of peptide and steroid hormones might be playing a significant role in the development and/or progression of oesophageal carcinoma in men.  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