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   9052篇
  免费   567篇
  国内免费   44篇
耳鼻咽喉   55篇
儿科学   210篇
妇产科学   111篇
基础医学   1285篇
口腔科学   30篇
临床医学   858篇
内科学   2323篇
皮肤病学   118篇
神经病学   754篇
特种医学   351篇
外科学   1649篇
综合类   23篇
一般理论   2篇
预防医学   370篇
眼科学   75篇
药学   585篇
中国医学   22篇
肿瘤学   842篇
  2023年   45篇
  2022年   75篇
  2021年   230篇
  2020年   122篇
  2019年   242篇
  2018年   244篇
  2017年   194篇
  2016年   199篇
  2015年   266篇
  2014年   328篇
  2013年   421篇
  2012年   704篇
  2011年   726篇
  2010年   412篇
  2009年   388篇
  2008年   590篇
  2007年   623篇
  2006年   589篇
  2005年   661篇
  2004年   563篇
  2003年   539篇
  2002年   557篇
  2001年   73篇
  2000年   55篇
  1999年   90篇
  1998年   119篇
  1997年   73篇
  1996年   69篇
  1995年   46篇
  1994年   60篇
  1993年   52篇
  1992年   21篇
  1991年   25篇
  1990年   31篇
  1989年   17篇
  1988年   20篇
  1987年   20篇
  1986年   13篇
  1985年   13篇
  1984年   14篇
  1983年   13篇
  1982年   12篇
  1981年   16篇
  1980年   11篇
  1979年   12篇
  1976年   9篇
  1973年   7篇
  1972年   10篇
  1971年   6篇
  1969年   6篇
排序方式: 共有9663条查询结果,搜索用时 15 毫秒
81.
82.
ObjectiveUveitis is a frequent extra rheumatological manifestation in axial Spondyloarthritis (SpA). The aim of study was to evaluate the prevalence and incidence of uveitis over the first five years of a prospective nationwide cohort of patients with high suspicion of early axial SpA, and to evaluate its associated factors.MethodsDESIR is a prospective observational cohort of patients with recent onset inflammatory back pain (more than 3 months, less than 3 years), suggestive of axial SpA, All available factors in the database were compared between patients with and without uveitis at 5 years, by uni and then multivariate analysis. Baseline factors associated with new cases of uveitis occurrence over the 5 years were also analyzed. Significance: P less than 0.05.ResultsAfter 5 years, 91 patients (out of 480 with complete follow-up) had at least one uveitis episode, giving an estimated prevalence of 18.9% [95% CI: 15.4–22.4]. In multivariate analysis, uveitis was significantly associated with dactylitis, and elevated ESR. New incident uveitis occurred in 31 cases over 5 years, giving an estimated incidence rate of 1.29 [0.84–1.74]/100 patient-years. Incidence of new uveitis was associated in multivariate analysis with baseline factors: diagnosis of SpA, sacro iliac MRI inflammatory SPARCC score, dactylitis, syndesmophyte score. No significant association was found with HLA-B27, DMARDs, BASDAI, ASDAS, BASFI.ConclusionFive-years data of the DESIR cohort allowed an estimation of incidence rate of uveitis of 1.3/100p-y; over five years, uveitis was associated with dactylitis, biologic and sacro iliac MRI inflammation.  相似文献   
83.
BackgroundEndoscopy plays a pivotal role in the management of adverse events (AE) following bariatric surgery. Leaks, fistulae, and post-operative collection after sleeve gastrectomy (SG) may occur in up to 10% of cases.ObjectivesTo evaluate the efficacy and safety of endoscopic internal drainage (EID) for the management of leak, fistula, and collection following SG.SettingRetrospective, observational, single center study on patients referred from several bariatric surgery departments to an endoscopic referral center.MethodsEID was used as first-line treatment for the management of leaks, fistulae, and collections. Leaks and fistulae were treated with double pigtail stent (DPS) deployment in order to guarantee internal drainage and second intention cavity obliteration. Collections were treated with endoscropic ultrasound (EUS)–guided deployment of DPS or lumen apposing metal stents.ResultsA total of 617 patients (83.3% female; mean age, 43.1 yr) were enrolled in the study for leak (n = 300, 48.6%), fistula (n = 285, 46.2%), and collection (n = 32, 5.2%). Median follow-up was 19.5 months. Overall clinical success was 84.7% whereas 15.3% of cases required revisional surgery after EID failure. Clinical success according to type of AE was 89.5%, 78.5%, and 90% for leak, fistula, and collection, respectively. A total of 10 of 547 (1.8%) presented a recurrence during follow-up. A total of 28 (4.5%) AE related to the endoscopic treatment occurred. At univariate logistic regression predictors of failure were: fistula (OR 2.012), combined endoscopic approach (OR 2.319), need for emergency surgery (OR 1.755), and previous endoscopic treatment (OR 4.818).ConclusionEarly EID for the management of leak, fistula, and post-operative collection after SG seems a safe and effective first-line approach with good long-term results.  相似文献   
84.
85.
Despite national guidelines, medical practices and kidney transplant waiting list registration policies may differ from one dialysis/transplant unit to another. Benefit risk assessment variations, especially for elderly patients, have also been described. The aim of this study was to identify sources of variation in early kidney transplant waiting list registration in France. Among 16 842 incident patients during the period 2016–2017, 4386 were registered on the kidney transplant waiting list at the start of, or during the first year after starting, dialysis (26%). We developed various log-linear mixed effect regression models on three levels: patients, dialysis networks, and transplant centers. Variability was expressed as variance from the random intercepts (± standard error). Although patient characteristics have an important impact on the likelihood of registration, the overall magnitude of variability in registration was low and shared by dialysis networks and transplant centers. Between-transplant center variability (0.23 ± 0.08) was 1.8 higher than between-dialysis network variability (0.13 ± 0.004). Older age was associated with a lower probability of registration and greater variability between networks (0.04, 0.20, & 0.93 in the 18–64, 65–74, and 75–84 age groups). Targeted interventions should focus on elderly patients and/or certain regions with greater variability in waiting list access.  相似文献   
86.
IntroductionSex differences have already been reported in sub‐Saharan Africa for attrition and immunological response after antiretroviral therapy (ART) initiation, but follow‐up was usually limited to the first two to three years after ART initiation. We evaluated sex differences on the same outcomes in the 10 years following ART initiation in West African adults.MethodsWe used cohort data of patients included in the IeDEA West Africa collaboration, who initiated ART between 2002 and 2014. We modelled no‐follow‐up and 10‐year attrition risks, and immunological response by sex using logistic regression analysis, survival analysis with random effect and linear mixed models respectively.ResultsA total of 71,283 patients (65.8% women) contributed to 310,007 person‐years of follow‐up in 16 clinics in eight West African countries. The cumulative attrition incidence at 10‐year after ART initiation reached 75% and 68% for men and women respectively. Being male was associated with an increased risk of no follow‐up after starting ART (5.1% vs. 4.0%, adjusted Odds Ratio: 1.25 [95% CI: 1.15 to 1.35]) and of 10‐year attrition throughout the 10‐year period following ART initiation: adjusted Hazard Ratios were 1.22 [95% CI: 1.17 to 1.27], 1.08 [95% CI: 1.04 to 1.12] and 1.04 [95% CI: 1.01 to 1.08] during year 1, years 2 to 4 and 5 to 10 respectively. A better immunological response was achieved by women than men: monthly CD4 gain was 30.2 and 28.3 cells/mL in the first four months and 2.6 and 1.9 cells/μL thereafter. Ultimately, women reached the average threshold of 500 CD4 cells/μL in their sixth year of follow‐up, whereas men failed to reach it even at the end of the 10‐year follow‐up period. The proportion of patients reaching the threshold was much higher in women than in men after 10 years since ART initiation (65% vs. 44%).ConclusionsIn West Africa, attrition is unacceptably high in both sexes. Men are more vulnerable than women on both attrition and immunological response to ART in the 10 years following ART initiation. Innovative tracing strategies that are sex‐adapted are needed for patients in care to monitor attrition, detect early high‐risk groups so that they can stay in care with a durably controlled infection.  相似文献   
87.
88.
Purpose. The concept of Hydrophilic Sphere Stabilization, or Hydrophobic Shielding, has been postulated in the synthesis of biocompatible contrast agents in vascular imaging. To improve the safety of these polyiodinated agents, interactions with protein hydrophobic sites in biomacromolecules should be kept as low as possible. In order to evaluate the level of interactions with proteins, we have selected the serine proteinase Elastase, in presence of Iobitridol (Xenetix®), as a model. Methods. The complex between Iobitridol and Pancreatic Porcine Elastase was investigated by X-ray diffraction techniques, on saturated monocrystals, using the synchrotron radiation at 0.98. Results. In contrast to Iohexol, which displays several interactions including one in the active site, Iobitridol is unable to interact directly with elastase. Only one partially occupied site is found in between two molecules of the crystal packing. Conclusions. The validation of the 'hydrophobic shielding' concept, which was at the origin of the design of the Iobitridol molecule, has been proven to be an essential feature in minimizing in vivo protein interactions.  相似文献   
89.
PURPOSE: This paper intends to stress the importance of early diagnosis and discuss surgical treatment of Type IV Ehlers-Danlos syndrome (EDS-4), an autosomal dominant connective tissue disease characterized by typical features of the face and extremities, inappropriate and easy bruising, and extreme tissue fragility, which may lead to dramatic and often fatal complications, mostly spontaneous arterial or intestinal rupture. METHODS: We report the case of a 41-year-old female who presented with spontaneous perforation of the sigmoid colon. RESULTS: The patient was seen over a nine-year period, during which time she required six operations and presented with a great number of surgical complications including stenosis of an end-colostomy, repeated subocclusive episodes caused by intraperitoneal adhesions, and enterocutaneous fistulas, finally ending with an ileostomy and short bowel syndrome. It is only after a difficult laparotomy for ovarian cyst excision, marked by numerous adhesions and friable bowel, that the diagnosis of EDS-4 was considered and established. CONCLUSIONS: In case of “idiopathic” spontaneous perforation of the colon in a young adult, features of EDS-4 should be thoroughly looked into and, if found, skin fibroblast culture with collagen Type III analysis performed. The surgical treatment of choice consists of subtotal colectomy and permanent endileostomy. In case of patient refusal, a second-stage ileorectal anastomosis can be performed but carries the high risk of anastomotic leakage.  相似文献   
90.
In a rat model, the left kidney was subjected to 60 min of normothermic ischemia followed by 15 min of reperfusion, whereas the right kidney, serving as a paired control, was not rendered ischemic. Both kidneys were then perfused in situ with either Euro-Collins (EC) solution (n=12) or University of Wisconsin (UW) solution (n=6) for 10 min. Each kidney was then harvested and stored at 4°C in its respective solution. After 24 and 48 h of cold storage, the following vasoactive substances were measured in the preservation media: endothelin (ET), angiotensin II (A-II), thromboxane (B2) (TxB2), and prostaglandin I2 (PGI2). After 24 h in EC solution, left kidneys uniformly produced significantly higher concentrations of each vasoactive substance than right kidneys: ET 1.64±0.3 pg/ml vs 0.82±0.1 pg/ml (P0.009); A-II 20.8±6.2 pg/ml vs 7.75+2.3 pg/ml (P0.007); TxB2 100.8±17.7 pg/ml vs 40.1±11.7 pg/ml (P0.04); PGI2 638.3±41.1 pg/ml vs 318.3±36.4 pg/ml (P0.001), respectively. At 48 h, a similar pattern of results was obtained as the kidney continued to produce TxB2 and prostacyclins during the 24–48 h period. In the UW solution, basal levels of ET and A-II were lower than those in EC solution, but similarly increased after initial ischemia. At 24 h, the concentrations produced by the left and right kidneys were as follows: ET 0.66±0.1 pg/ml vs 0.48±0.1 pg/ml (P0.14); A-II 10.36±3.7 pg/ml vs 2.14±0.7 pg/ml (P0.006); TxB2 178±53 pg/ml vs 52±23.1 pg/ml (P0.001); and PGI2 448.3±49 pg/ml vs 323±44.3 pg/ml (P0.01), respectively. After 48 h, the range of concentrations of each substance was similar to that obtained after 24 h. In further studies, the concentrations of ET and A-II were measured in solution previously used to preserve human kidneys (n=7). The mean concentration of ET and A-II in these samples was 3.82±1.14 pg/ml and 21.3±9.2 pg/ml, respectively, whereas in control media both substances were below the limits of detection. These results demonstrate that vasoconstrictive substances can be measured in the preservation media after a kidney has been stored cold and that higher concentrations are found when the organ has been subjected to prior normothermic ischemia. The measurement of these vasoactive substances before transplantation may reveal that the kidney has been subjected to previous ischemic events. Moreover, these vasoactive substances could be involved in the early recovery of renal function after kidney transplantation.  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