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   1790篇
  免费   121篇
  国内免费   6篇
耳鼻咽喉   3篇
儿科学   31篇
妇产科学   22篇
基础医学   217篇
口腔科学   133篇
临床医学   100篇
内科学   338篇
皮肤病学   7篇
神经病学   316篇
特种医学   48篇
外科学   412篇
综合类   2篇
一般理论   1篇
预防医学   79篇
眼科学   13篇
药学   58篇
肿瘤学   137篇
  2023年   8篇
  2022年   24篇
  2021年   39篇
  2020年   21篇
  2019年   42篇
  2018年   57篇
  2017年   35篇
  2016年   37篇
  2015年   48篇
  2014年   37篇
  2013年   60篇
  2012年   106篇
  2011年   97篇
  2010年   64篇
  2009年   67篇
  2008年   95篇
  2007年   74篇
  2006年   79篇
  2005年   77篇
  2004年   87篇
  2003年   51篇
  2002年   63篇
  2001年   51篇
  2000年   48篇
  1999年   42篇
  1998年   23篇
  1997年   8篇
  1996年   17篇
  1995年   20篇
  1994年   17篇
  1993年   12篇
  1992年   58篇
  1991年   40篇
  1990年   31篇
  1989年   23篇
  1988年   23篇
  1987年   23篇
  1986年   23篇
  1985年   21篇
  1984年   15篇
  1983年   15篇
  1982年   13篇
  1981年   8篇
  1979年   14篇
  1978年   11篇
  1975年   10篇
  1974年   12篇
  1973年   12篇
  1972年   9篇
  1971年   8篇
排序方式: 共有1917条查询结果,搜索用时 15 毫秒
101.
PURPOSE: The aim of the present paper is to describe the normal radiological findings and the fragmentation time of the VALTRAC BAR (V-BAR). MATERIALS AND METHODS: Ten cases of Roux-en-Y jejuno-jejunostomy with anastomosis with a n.25 Valtrac ring for gastric cancer were followed up during the postoperative period by plain abdominal X-ray examination. RESULTS: Abdominal X-ray examination showed V-BAR fragmentation between day 14 and 21 after surgery. In one case only did fragmentation fail and the V-BAR migrated resulting in mechanical ileus. CONCLUSIONS: The possible non-fragmentation and migration of the V-BAR confirms the need to follow up patients with plain abdominal radiography performed at short intervals during the postoperative period.  相似文献   
102.
BACKGROUND: The authors conducted a study to evaluate the predictive value of five radiographic markers on the panoramic radiograph, or PR, to point out the relationship between the mandibular canal and the impacted third molar. METHODS: The authors evaluated the accuracy of the radiographic markers by comparing the PR with an axial computed tomographic, or CT, scan. They identified a sample of 73 third molars that showed a close relationship between the tooth roots and the mandibular canal on the PR, and then classified them on the basis of five radiographic markers. They also detected contact between the third molar and the mandibular canal on the CT scan. RESULTS: The distribution of the five radiographic markers was as follows: 37 teeth exhibited increased radiolucency, 13 exhibited superimposition, 14 exhibited interruption of the radiopaque border, 14 exhibited narrowing of the canal and seven exhibited diversion of the canal. In 11 cases, two or more markers were recognizable. The predictive values of a positive test result were as follows: increased radiolucency, 73 percent; superimposition, 38.5 percent; interruption of the radiopaque border, 71.4 percent; narrowing, 78.6 percent; and diversion, 100 percent. The authors detected contact in all of the cases that exhibited two or more markers. CONCLUSION: Increased radiolucency, narrowing and interruption of the radiopaque border, as well as the concomitant presence of two or more radiographic markers, on the PR were highly predictive of contact between the third molar and the mandibular canal. An axial CT scan probably is indicated in such cases. CLINICAL IMPLICATIONS: The results of this study may lead to some guidelines for oral surgeons evaluating whether to obtain an axial CT scan for further investigation after examining an impacted mandibular third molar via PR.  相似文献   
103.
In the analysis of the characteristics of a pleasant smile, a gummy smile has negative components, which most affect the esthetics of non-verbal communication. For this purpose a proposed classification based upon etiopathogenetic criteria as useful indications for a therapeutical approach is given. The nature of a high smile line can be: dento-gingival, connected to an abnormal dental eruption, which is revealed by a short clinic crown; muscular, caused by an hyperactivity of the elevator muscle of the upper lip; dento-alveolar (skeletal), due to an excessive protuberance or vertical growth of the jawbone (maxillary); lastly, a mixed nature, in the presence of more than one of the above described factors The diagnosis of gummy smile must be precocious and based, with reference to specific parameters, upon a careful analysis of the etiopathogenetic factors and the degree of seriousness of the alteration. A correct treatment plan must contemplate the possibility of an orthognatodontic, orthopedic and/or surgical therapeutic resolution considering the seriousness and complexity of the gums exposures (high smile line) in connection with the age of the subject.  相似文献   
104.
105.
Increased interest in aneurysms involving therenal artery and its branches has occurredduring the past 3 decades. The prevalence ofrenal artery aneurysms is approximately 0.01%–1% in the general population as well as2.5% in hypertensive patients undergoingangiography. Intraparenchymal renal arteryaneurysms (IPRAAs) are rare since beingdetected in less than 10% of patients withrenal artery aneurysms. The Authorsreport an unusual case of multiple smallintrarenal artery aneurysms associatedwith a large IPRAA located in the mid portionof the right kidney. Usually, IPRAAs aresecondary to diseases or injuries of the kidneyvascular network. They are classified as true,false, saccular, fusiform, dissecting, andmicroaneurysms. Potential complications ofIPRAAs include peripheral dissection,thrombosis, hypertension, renal infarction andrupture. IRAAs may be detected incidentally aswell as present with urologic symptoms andsigns related to complications. Actually, IRAAsare investigated by non invasive modalitiesincluding duplex ultrasound, magnetic resonanceangiography, spiral three-dimensional computedtomography angiography, and three-dimensionalreconstructed rotational digital substractionangiography of the segmental and distantbranches of the renal artery. Angiography withintrarterial injection of contrast material isthe gold standard in diagnosing IPRAAs.Treatment options for IPRAAs includeobservation, aneurysmectomy with surgicalrepair, endovascular procedures, nephrectomy orpartial nephrectomy. Observation is indicatedfor asymptomatic intraparenchymal renal arteryaneurysms measuring less than 2 cm in diameter.Surgical repair of IPRAAs includesaneurysmectomy and reconstruction of the renalartery by in vivo or ex vivo technique. Theprocedure is indicated for IPRAAs causingrenovascular hypertension, dissection, urologicsymptoms, embolization, local expansion andwomen of childbearing age with a potential forpregnancy. In recent years, transcatheterarterial embolization has emerged as a simple,useful and effective technique in managingIRAAs. The procedure is performed bytransfemoral catheterization as well as bysuperselective catheterization and embolizationof interlobar arteries with 3F microcatheters.Endovascular occlusion is obtained by usinggelatin sponge, steel coils, detachablebaloons, and conventional non-detachablemicrocoils delivered through a microcatheter.Nephrectomy or partial nephrectomy are reservedfor conditions precluding renalrevascularization which include overt RAArupture, covert RAA rupture, artery-to-veinfistula, renal cell carcinoma, end stagenephropaty, renal infarction, severe ischemicrenal atrophy or complex intrarenal aneurysms.Recently, partial nephrectomy by thelaparoscopic approach has been proposed formanaging IPRAAs and the procedure is consideredfeasible and safe.  相似文献   
106.
The aim of this study was to investigate factors influencing the engraftment potential of acute myeloid leukemia (AML) CD34+ cells in nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice. We examined the relationship between engraftment, CXCR4 expression on CD34+ and CD34+CD38- cells, and patient (Pt) clinical/laboratory characteristics in 44 samples from 11 Pts. Engraftment, evaluated by Southern blot and CD45 flow cytometric analyses, was observed in murine bone marrow of 6 of 11 Pt samples, ranging from 0.1% to 73.9% by Southern blot and from 0.1%-36.8% by flow cytometry. Poor Pt prognosis was inversely correlated with engraftment; the median overall survival was 95.9 weeks for Pts whose cells did not engraft and 26.1 weeks for those whose cells did engraft (p = 0.012, log-rank test). No other clinical/laboratory variable predicted engraftment. No correlation between the level of CXCR4 expression on AML cells and engraftment was observed. Cells with virtually absent CXCR4 expression were able to engraft, and cells from two Pts with high expression levels of CXCR4 did not engraft. Furthermore, anti-CXCR4 antibody failed to block the engraftment of AML cells into NOD/SCID mice. In conclusion, we demonstrated that CXCR4 is not critical for the engraftment of AML CD34+ cells in NOD/SCID mice. The model may, however, reflect the clinical course of the disease.  相似文献   
107.
We investigated the pro-apoptotic potential of pericardial fluids from patients with different clinical conditions on cultured neonatal rat cardiomyocytes. Pericardial fluids were obtained during open heart surgery from 88 patients with ischemic heart disease (n=44), valvular heart disease (n=32), or aortic disease (n=12). The terminal deoxynucleotidyl transfer-mediated end labeling fragmented nuclei assay was performed on primary cardiac myocytes from neonatal rats in the presence of 1% pericardial fluid from each patient. We evaluated relations between these patients' clinical characteristics and the extent of myocardial cell apoptosis. Induction of myocardial cell apoptosis by pericardial fluids was observed in 29 of the 88 patients (33.0%). The prevalence of myocardial cell apoptosis was significantly influenced by diabetes mellitus (DM) (53.6% with vs. 23.3% without, P<0.005), acute coronary syndrome (ACS) (64.7% with vs. 25.4% without, P<0.005), and poor left ventricular systolic function (60.0% with vs. 25.0% without, P<0.005). Multivariate stepwise logistic regression analysis revealed that the presence of DM, ACS, and poor left systolic function were significant predictors of myocardial cell apoptosis. DM, ACS and left ventricular dysfunction may play important roles in the pathogenesis of myocardial cell apoptosis in the clinical setting.  相似文献   
108.
Abstract Few papers report the results of revision ACL reconstruction with hamstrings tendons. We report our results with revision anterior cruciate ligament (ACL) surgery using a doubled gracilis and semitendinosus tendons (DGST) graft, in association with an exta-articular procedure. Twelve patients underwent ACL revision surgery using autogenous homolateral DGST graft in association with an extra-articular procedure and were evaluated at a mean follow-up of 35 months. At follow-up evaluation, all patients scored negatively on the Lachman test and normally or near normally on the jerk test. The KT 1000 evaluation showed a average side-to-side difference at 30 lb and MM of 1.4±1.7 mm and 1.6±1.6 mm, respectively. The Lysholm score was 98±2 (range, 94–100); excellent results (score 95–100) were obtained in 83% of cases, good results (score 84–94) in 17%, and no fair or poor results. At the IKDC evaluation, the result was excellent (normal) in one-thirds of cases and good (nearly normal) in twothirds. Therefore, the use of hamstring tendons in association with lateral tenodesis seems to be a good alternative to the use of allografts or contralateral bone-patellar tendon-bone graft in revision ACL reconstructions.  相似文献   
109.
Familiari D  Pavia R  Monaco F  Mondello B  Monaco M 《Rays》2004,29(4):419-421
Chest wall reconstruction after resection, for locally advanced lung cancer but also for some selected secondary tumors, is a demanding challenge to surgeons, anesthetists and experts in respiratory function rehabilitation who must guarantee a regular natural ventilation, adequate protection of intrathoracic organs and acceptable cosmetic outcome. To this aim, many procedures using autologous, heterologous, or prosthetic materials, are available. A study conducted on 13 lung cancer patients who after resection underwent reconstruction with heterologous prosthetic material is presented. No intraoperative mortality or septic complications were observed. There was prompt wall stabilization in 10 patients; it occurred 3 weeks later in another patient (polytetrafluoridethylene patch). Only in one patient (prolene mesh) a seroma developed, treated with US-guided drainage. In the authors' experience, even for fairly small defects reconstruction with prosthetic material is suitable, to prevent, in case of the presence of risk factors, pulmonary hernia-induced major respiratory symptoms. Prosthetic materials are also preferred for benign lesions characterized by a long-term survival.  相似文献   
110.
Currently, definite peripheral markers for the in vivo diagnosis of sporadic Creutzfeldt-Jakob disease (CJD) are not available. Here, we report the presence of pathological prion protein in the olfactory mucosa of a case with sporadic Creutzfeldt-Jakob disease. Prion protein immunoreactivity was detected in an olfactory biopsy performed 45 days after the disease onset, suggesting that the involvement of olfactory epithelium is an early event in sporadic Creutzfeldt-Jakob disease.  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