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   2255篇
  免费   155篇
  国内免费   6篇
耳鼻咽喉   31篇
儿科学   34篇
妇产科学   64篇
基础医学   243篇
口腔科学   27篇
临床医学   227篇
内科学   417篇
皮肤病学   34篇
神经病学   161篇
特种医学   138篇
外科学   321篇
综合类   78篇
一般理论   2篇
预防医学   274篇
眼科学   21篇
药学   196篇
中国医学   9篇
肿瘤学   139篇
  2023年   12篇
  2022年   47篇
  2021年   71篇
  2020年   43篇
  2019年   72篇
  2018年   102篇
  2017年   62篇
  2016年   50篇
  2015年   58篇
  2014年   67篇
  2013年   97篇
  2012年   147篇
  2011年   161篇
  2010年   77篇
  2009年   68篇
  2008年   112篇
  2007年   103篇
  2006年   112篇
  2005年   127篇
  2004年   110篇
  2003年   102篇
  2002年   93篇
  2001年   40篇
  2000年   39篇
  1999年   35篇
  1998年   15篇
  1997年   12篇
  1996年   8篇
  1995年   15篇
  1994年   15篇
  1993年   16篇
  1992年   26篇
  1991年   23篇
  1990年   38篇
  1989年   22篇
  1988年   18篇
  1987年   16篇
  1986年   18篇
  1985年   7篇
  1984年   7篇
  1979年   12篇
  1978年   10篇
  1975年   9篇
  1974年   10篇
  1973年   11篇
  1972年   9篇
  1969年   13篇
  1968年   11篇
  1966年   14篇
  1965年   6篇
排序方式: 共有2416条查询结果,搜索用时 0 毫秒
21.
SCL gene rearrangement is the most common molecular lesion (25%) identified so far in T-cell acute lymphoblastic leukemia (T-ALL). Since the frequency of T-ALL appears to be relatively higher in developing countries, we wished to determine as to what fraction of T-ALL from this population harbor SCL rearrangements. We show in this study that although the overall frequency of SCL/SIL rearrangements in T-ALL is similar to the Western countries this is at the expense of increased type A rearrangements. Whether the paucity of type B rearrangements reflects a difference in disease etiology in this part of the world is to be determined.  相似文献   
22.
Capsular metaplastic changes described as "synovial metaplasia" have been reported in association with silicone gel breast prostheses. Initially this finding was thought to be more common with textured implants. Recent studies have shown no relation between implant shell type (textured vs. smooth). The incidence of this metaplasia has been shown to decrease with the age of the implant, suggesting that it is a transitional finding in capsular maturation. The metaplastic cells in the synovial metaplasia may have secretory characteristics, but the exact etiology and function of the metaplasia are not yet fully understood. Experimentally, a similar connective tissue reaction has been induced by repeated injections of air to produce the so-called "air pouch." The current study describes cartilaginous metaplasia in the capsule surrounding a silicone-filled, Cronin-type, Dacron-backed breast prosthesis. At 26 years after bilateral breast augmentation, this patient presented with breast pain and firmness. During surgical removal the implants were intact but the capsules were densely hyalinized, irregularly calcified, and on one side there was cartilaginous metaplasia within the connective tissue of the capsule. This had occurred independently of calcification. This was believed to be an unusual tissue response. Review of the English literature failed to identify a comparable case.  相似文献   
23.
This report describes the balloon-gas procedure, a technique for obtaining large volumes of intraocular gas. With the balloon-gas procedure a kind of "external fluid-gas exchange" allows for the safe injection of up to 1.0 ml of gas without previous pars plana vitrectomy or surgical drainage of subretinal fluid. From April 1985 to October 1988, in Tübingen, this procedure was utilized in 36 retinal detachments with breaks not suited for scleral buckling: giant tears (nine eyes), large dialyses (seven eyes), posterior breaks (16 eyes), and multiple breaks at different latitudes (four eyes). Follow-up ranged from six to 28 months (average 16 months). Initial retinal reattachment was achieved in 28 eyes (77.8%). Reasons for initial failure were proliferative vitreoretinopathy in six eyes, and a missed break in two. Redetachment occurred in three eyes. All 11 failures were reoperated using segmental sponges (eight eyes) and gas injection (three eyes). Final reattachment was achieved in 29 of the 36 eyes (80.6%), and final failure was due to proliferative vitreoretinopathy in all seven detachments.  相似文献   
24.
Balloon occlusion is the accepted treatment for direct post-traumatic caroticocavernous fistula. We present a case of bilateral traumatic fistulae associated with a pseudoaneurysm. Resolution of both fistulae occurred following treatment of one of them by balloon occlusion of the internal carotid artery. This case highlights the importance of considering a more conservative approach to bilateral fistulae or those associated with a pseudoaneurysm. We review other treatment options. Received: 1 October 1999/Accepted: 20 October 1999  相似文献   
25.
In a group of 35 patients with relapsed and/or chemo-resistant non-Hodgkin's lymphoma (NHL), low-dose total body irradiation (LTBI) (+involved-field radiotherapy to bulky sites) achieved a complete remission rate of 29%, 2-years progression-free survival of 32% and a median progression-free survival of 12 months. The 2-year survival was 42% and the median survival was 17 months. Immuno-staining and flow cytometry of peripheral blood in 14 patients showed that LTBI leads to a significant increase in the percentage of CD4+ cells with a consequent significant increase in the CD4+/CD8+ ratio. High lymphocytic percent and a high percentage of CD4+ cells before LTBI were significantly correlated with longer response duration and overall survival. These data may suggest that the palliative potential of LTBI should be investigated as an alternative to chemotherapy in NHL patients. The pre-treatment percentage of lymphocytes and CD4+ cells may be used as predictors for response to LTBI.  相似文献   
26.
27.
Vascular calcification contributes to cardiovascular morbidity and mortality. A recently developed serum calcification propensity assay is based on the half-transformation time (T50) from primary calciprotein particles (CPPs) to secondary CPPs, reflecting the serum’s endogenous capacity to prevent calcium phosphate precipitation. We sought to identify and review the results of all published studies since the development of the T50-test by Pasch et al. in 2012 (whether performed in vitro, in animals or in the clinic) of serum calcification propensity. To this end, we searched PubMed, Elsevier EMBASE, the Cochrane Library and Google Scholar databases from 2012 onwards. At the end of the selection process, 57 studies were analyzed with regard to the study design, sample size, characteristics of the study population, the intervention and the main results concerning T50. In patients with primary aldosteronism, T50 is associated with the extent of vascular calcification in the abdominal aorta. In chronic kidney disease (CKD), T50 is associated with the severity and progression of coronary artery calcification. T50 is also associated with cardiovascular events and all-cause mortality in CKD patients, patients on dialysis and kidney transplant recipients and with cardiovascular mortality in patients on dialysis, kidney transplant recipients, patients with ischemic heart failure and reduced ejection fraction, and in the general population. Switching from acetate-acidified dialysate to citrate-acidified dialysate led to a longer T50, as did a higher dialysate magnesium concentration. Oral administration of magnesium (in CKD patients), phosphate binders, etelcalcetide and spironolactone (in hemodialysis patients) was associated with a lower serum calcification propensity. Serum calcification propensity is an overall marker of calcification associated with hard outcomes but is currently used in research projects only. This assay might be a valuable tool for screening serum calcification propensity in at-risk populations (such as CKD patients and hemodialyzed patients) and, in particular, for monitoring changes over time in T50.  相似文献   
28.
From 2010 to 2013, genotype I avian influenza A(H9N2) viruses of the G1-lineage were isolated from several poultry species in Egypt. In 2014, novel reassortant H9N2 viruses were detected in pigeons designated as genotype II. To monitor the subsequent genetic evolution of Egyptian A(H9N2) viruses, we characterized the full genomes of 173 viruses isolated through active surveillance from 2017 to 2022. In addition, we compared the virological characteristics and pathogenicity of representative viruses. Phylogenetic analysis of the HA indicated that all studied sequences from 2017–2021 were grouped into G1-like H9N2 viruses previously detected in Egypt. Phylogenetic analysis indicated that the Egyptian A(H9N2) viruses had undergone further reassortment, inheriting four genes (PB2, PB1, PA, NS) from genotype II, with their remaining segments deriving from genotype I viruses (these viruses designated as genotype III). Studying the virological features of the two most dominant genotypes (I and III) of Egyptian H9N2 viruses in vitro and in vivo indicated that both replicated well in mammalian cells, but did not show any clinical signs in chickens, ducks, and mice. Monitoring avian influenza viruses through surveillance programs and understanding the genetic and antigenic characteristics of circulating H9N2 viruses are essential for risk assessment and influenza pandemic preparedness.  相似文献   
29.
The case of a female with disseminated pelvic cystic hydatidosis presenting as ovarian carcinomatosis 2.5 years after repeated abdominal paracentesis is reported. The diagnosis was made during surgery and confirmed by serology and histological examination. Over 100 cysts were removed from the abdominal cavity and wall. Innumerable small cysts studded the viscera; these and larger inaccessible ones were untouched. Medical cure in this patient was achieved with a combination of partial resection and special irrigation, broad spectrum antibiotic for coverage of infectious episodes and high dose long term mebendazole therapy for 25 months. The danger of blind aspiration in patients coming from endemic areas is emphasized.  相似文献   
30.
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