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   3370篇
  免费   247篇
  国内免费   13篇
耳鼻咽喉   41篇
儿科学   106篇
妇产科学   90篇
基础医学   444篇
口腔科学   64篇
临床医学   287篇
内科学   794篇
皮肤病学   49篇
神经病学   221篇
特种医学   112篇
外科学   577篇
综合类   53篇
预防医学   261篇
眼科学   64篇
药学   229篇
中国医学   20篇
肿瘤学   218篇
  2023年   27篇
  2022年   71篇
  2021年   107篇
  2020年   74篇
  2019年   114篇
  2018年   124篇
  2017年   67篇
  2016年   74篇
  2015年   98篇
  2014年   132篇
  2013年   165篇
  2012年   235篇
  2011年   237篇
  2010年   149篇
  2009年   119篇
  2008年   182篇
  2007年   171篇
  2006年   156篇
  2005年   155篇
  2004年   154篇
  2003年   123篇
  2002年   111篇
  2001年   41篇
  2000年   52篇
  1999年   54篇
  1998年   25篇
  1997年   20篇
  1996年   29篇
  1995年   23篇
  1994年   20篇
  1993年   23篇
  1992年   40篇
  1991年   36篇
  1990年   33篇
  1989年   48篇
  1988年   44篇
  1987年   34篇
  1986年   32篇
  1985年   29篇
  1984年   23篇
  1983年   20篇
  1982年   8篇
  1981年   7篇
  1980年   15篇
  1979年   25篇
  1978年   22篇
  1977年   12篇
  1976年   7篇
  1974年   11篇
  1973年   11篇
排序方式: 共有3630条查询结果,搜索用时 203 毫秒
41.
The pathogenesis of primary vasculitides, which are assumed to have an autoimmune pathogenesis, is not well understood. The endothelial cell adhesion molecules seem to play an active role, which varies according to the histopathologic stage of vascular lesions. The role of genetic factors also seems quite important, at least in an experimental model. The reliability of antineutrophil cytoplasmic antibodies testing in diagnosis and follow-up of patients with vasculitis is reviewed. The conclusion is that antineutrophil cytoplasmic antibodies status can be a very useful diagnostic adjunct to the evaluation of patients with suspected Wegener's granulomatosis, but is not a substitute for clinical expertise and histopathologic data during the course of providing patient care. The neurological manifestations of Churg-Strauss syndrome (a variant of polyarteritis nodosa) are very similar to those that occur in polyarteritis nodosa. A role for vasculitis has been confirmed in proximal diabetic neuropathy, which may pave the way for new therapeutic developments.  相似文献   
42.
43.
44.
Patient-based questionnaires were designed with the aim to identify and rank long-term somatic and psychosocial morbidity in patients with low-stage testicular cancer. A further intention was to compare patients' assessments with experienced doctors' general opinion on quality of life items in cured testicular cancer patients. In pilot study I, 103 tumour-free patients ranked items of physical and psychosocial morbidity after having had various kinds of treatment. Though the ranking procedure appeared to cause some difficulties amongst the patients and subsequently was abandoned, the results indicated considerable differences between the patients' and doctors' evaluations. In pilot study II patients were asked to score the different items. The questionnaire of pilot study II was completed by 107 patients from the Norwegian Radium Hospital (NRH) and 99 relapse-free patients from the Royal Marsden Hospital (RMH) with testicular cancer stage I at least 1 year after infradiaphragmatic radiotherapy (n = 94) or adjuvant chemotherapy (2 cycles,n=26), or patients who had been followed on the surveillance program (n = 86). A total of 93 doctors completed a similar questionnaire, thereby expressing their general opinion on long-term morbidity in comparable testicular cancer patients as seen during routine clinical follow-up. Both the irradiated patients and those on the surveillance program reported slight degrees of Raynaud-like phenomena, neurotoxicity and ototoxicity, most probably representing background morbidity in an age-matched general male population. Doctors tended to underestimate their patients' somatic morbidity, but often overestimated the degree of psychological distress, in particular in patients on the surveillance program. Significant differences between RMH and NRH patients with regard to sexual problems and to leisure time activity may be explained by cultural differences in the two countries. The items presented in the questionnaire used identify important issues for patients cured of testicular cancer which may be used in future multicentre trans-cultural studies assessing these patients' quality of life. This will provide sufficient data for psychometric testing and, together with the findings from patients' free comments, support the final design of a testicular cancer quality of life module.  相似文献   
45.
46.
Amyotrophic lateral sclerosis (ALS) is a paralytic disorder characterized by degeneration of large motor neurons of the brain and spinal cord. A subset of ALS is inherited (familial ALS, FALS) and is associated with more than 70 different mutations in the SOD1 gene. Here we report that lymphoblast cell lines derived from FALS patients with 16 different mutations in SOD1 gene exhibit significant increase of intracellular reactive oxygen species (ROS) compared with sporadic ALS (SALS) and normal controls (spouses of ALS patients). The ROS generation did not correlate with SOD1 activity. Further, cells incubated with vitamin C, catalase or the flavinoid quercetin significantly reduced ROS in all groups. The catalase inhibitor 3-amino-1,2,4-triazole resulted in a ten-fold increase of ROS in all groups. Neither L-nitroarginine, a nitric oxide synthase inhibitor or vitamin E altered the ROS levels. Thus, these studies suggest that hydrogen peroxide (H(2)O(2)) is a major ROS elevated in FALS lymphoblasts and it may contribute to the degeneration of susceptible cells. Further, we postulate a mechanism by which increased H(2)O(2) could be generated by mutant SOD1.  相似文献   
47.
Loss of RhoB expression in human lung cancer progression.   总被引:6,自引:0,他引:6  
PURPOSE: RhoB is a low molecular weight GTPase belonging to the Ras protein superfamily. Whereas most Rho proteins have been shown to have a positive role in proliferation and malignant transformation, the specific role of RhoB appears more divergent. We reported previously that RhoB inhibits cell proliferation in various human cancer cells. Here, we studied the specific role played by RhoB in human lung cancer. EXPERIMENTAL DESIGN: We analyzed the expression of RhoB protein by immunostaining in human lung tissues ranging from normal to invasive carcinoma from different histological types in two large independent studies of, respectively, 94 and 45 samples. We then studied the cellular effect of RhoB overexpression in a model of lung cancer (A549, adenocarcinoma) and tumorigenicity in nude mice. RESULTS: We showed in both studies that RhoB protein was expressed in normal lung and decreased dramatically through lung cancer progression (P < 0.01). Interestingly, RhoB expression was lost in 96% of invasive tumors and reduced by 86% in poorly differentiated tumors compared with the nonneoplastic epithelium. Moreover, the loss of expression of RhoB correlated significantly with tumor stage and proliferative index, whereas no correlation was found between RhoB and p53 or Bcl-2 expression. We then showed that ectopic expression of RhoB in lung cancer cell line A549 suppressed cell proliferation, anchorage-independent growth, and xenograft tumor growth in nude mice. CONCLUSIONS: RhoB loss of expression occurs very frequently in lung carcinogenesis, reinforcing its putative tumor suppressive activity, and raising the value of its potential use in cancer therapy.  相似文献   
48.
PURPOSE: As kinase inhibitors transition from the laboratory to patients, it is imperative to develop biomarkers that can be used in the clinic. The primary objectives are to identify patients most likely to benefit from molecularly targeted therapies and to document modulation of the drug target. Constitutive activation of the phosphoinositide 3-kinase (PI3K) pathway and its downstream effectors, as a result of PTEN loss or by other mechanisms, occurs in a high proportion of prostate cancers, making it an ideal template for the design of clinical trials involving PI3K pathway inhibitors. Prostate cancers also present unique organ-specific challenges, in that tumors are heterogeneous and diagnostic tissue is extremely limited. EXPERIMENTAL DESIGN: Working within these limitations, we have developed a set of immunohistochemical assays that define activation of the PI3K pathway in clinical samples. Results and CONCLUSIONS: Using both univariate and multivariate analyses, we show that loss of PTEN is highly correlated with the activation of AKT, and this, in turn, is associated with the phosphorylation of S6, one of its main effectors. These three antibodies are potentially able to define a molecular signature of PTEN loss and/or AKT pathway activation in prostate cancer.  相似文献   
49.
50.
Langerhans cell histiocytose is a rare condition in childhood. It presents in different ways ranging from a single bony disease to a multisystemic disease involving vital organs. CASE REPORT: We report a case of single bone involvement revealed by torticollis in an eight-year-old boy. The diagnosis was evocated on radiological findings and confirmed by histologic aspects. After a period of 2,5 years, this child is in total spontaneous remission. CONCLUSION: Torticollis must be explored and watched. Eosinophilic granuloma can be a rare aetiology in children. The outcome is often favorable.  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