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   386篇
  免费   18篇
  国内免费   14篇
耳鼻咽喉   2篇
儿科学   10篇
妇产科学   4篇
基础医学   53篇
口腔科学   12篇
临床医学   21篇
内科学   86篇
皮肤病学   21篇
神经病学   11篇
特种医学   68篇
外科学   36篇
综合类   10篇
预防医学   5篇
眼科学   9篇
药学   45篇
中国医学   3篇
肿瘤学   22篇
  2021年   3篇
  2020年   7篇
  2019年   3篇
  2018年   4篇
  2017年   6篇
  2016年   5篇
  2015年   5篇
  2014年   8篇
  2013年   11篇
  2012年   11篇
  2011年   9篇
  2010年   19篇
  2009年   21篇
  2008年   6篇
  2007年   11篇
  2006年   17篇
  2005年   11篇
  2004年   13篇
  2003年   11篇
  2002年   8篇
  2001年   12篇
  2000年   4篇
  1999年   7篇
  1998年   22篇
  1997年   16篇
  1996年   20篇
  1995年   16篇
  1994年   12篇
  1993年   10篇
  1992年   5篇
  1991年   6篇
  1990年   7篇
  1989年   15篇
  1988年   9篇
  1987年   7篇
  1986年   8篇
  1985年   12篇
  1984年   2篇
  1983年   5篇
  1982年   8篇
  1981年   3篇
  1980年   3篇
  1978年   3篇
  1977年   3篇
  1976年   4篇
  1975年   3篇
  1973年   1篇
  1972年   1篇
  1971年   1篇
  1969年   1篇
排序方式: 共有418条查询结果,搜索用时 15 毫秒
101.
Interleukin (IL)-12 is thought to be a key factor for the induction of interferon gamma (IFN-gamma), a cytokine essential for the lethal effects of endotoxin. We report here on the release of the nonfunctional subunit of IL-12, p40, as well as biologically active heterodimeric IL-12, p70, after administration of a lethal (n = 5) or sublethal (n = 8) dose of live Escherichia coli to baboons. Remarkably, on lethal challenge, peak levels of p40 were observed at 3 hours that were about twofold lower than those elicited after sublethal challenge (2,813 +/- 515 pg/mL v 4,972 +/- 732 pg/mL, P < .05). This disparity was also observed, although to a lesser extent, for IL-12 p70 antigen, of which maximum levels of 91 +/- 47 pg/mL and 151 +/- 41 pg/mL were measured 6 hours after a lethal or sublethal dose of E coli, respectively. Circulating p70 antigen correlated with IL-12 biologic activity (r = 0.869; P < .001). When comparing lethal to sublethal conditions, lower peak levels of IL-12 on lethal E coli sharply contrasted with higher levels of other proinflammatory cytokines, such as tumor necrosis factor (TNF)-alpha, IL-1beta, IL-6, and IL-8 observed in these animals. Lower IL-12 concentrations in the lethal group may have resulted in part from the enhanced production of IL-10, a known inhibitor of IL-12 synthesis in vitro, as peak levels of this cytokine 3 hours postchallenge inversely correlated with peak levels of IL-12, in particular p40 (r = -0.802; P < .01). Contrary to what might be expected if IFN-gamma were solely induced by IL-12, lethally challenged baboons generated threefold more IFN-gamma at 6 hours than those receiving a sublethal dose (P < .05). Moreover, higher levels of IFN- gamma were associated with lower p40/p70 ratios, suggesting that, in agreement with observations in vitro, IFN-gamma may have preferentially upregulated the release of p70 over p40. These data show that IL-12 is released in experimental septic shock in nonhuman primates and suggest that IL-10 and IFN-gamma are involved in the regulation of this release. Furthermore, this study indicates that the systemic release of IL-12 might be essential, but is not likely sufficient, to promote lethal production of IFN-gamma in sepsis.  相似文献   
102.
背景和目的:乳酸水平增高与患者的致病率和病死率显著相关.该研究探讨了在危重患者的早期治疗中,监测乳酸水平是否可以改善患者的预后及其效果.方法:将入住ICU时血乳酸水平≥3.0 mmol/L(3.0 mEq/L)的患者随机分为2组,乳酸组以乳酸水平指导治疗,使患者在最初8h内乳酸水平每2h 下降20%以上;对照组仅有基线乳酸水平,不进行乳酸水平监测.  相似文献   
103.
104.
Background: Glycaemic control is a key issue in the care of people with diabetes mellitus (DM). Some studies have suggested a bidirectional relationship between glycaemic control and periodontal disease. Objectives: To investigate the relationship between periodontal therapy and glycaemic control in people with diabetes and to identify the appropriate future strategy for this question. Search strategy: A comprehensive approach was adopted employing handsearching; searching of electronic databases including the Cochrane Oral Health Group’s Trials Register, CENTRAL, MEDLINE, EMBASE, CINAHL, ZETOC, ISI Web of Knowledge and LILACS; contact with appropriate non‐English language healthcare professionals; authors and organizations. The final date for searching for studies was 24 March 2010. Selection criteria: This review studied randomized controlled trials of people with Type 1 or 2 diabetes mellitus (DM) with a diagnosis of periodontitis. Suitable interventions included mechanical periodontal therapy with or without adjunctives and oral hygiene education. Data collection and analysis: The titles and abstracts of 690 papers were examined by two review authors independently. Ultimately, seven studies were included and 19 excluded after full text scrutiny. All trials were assessed for risk of bias. Main results: Three studies had results pooled into a meta‐analysis. The effect for the mean percentage difference in HbA1c for scaling/root planing and oral hygiene (+/? antibiotic therapy) versus no treatment/usual treatment after 3–4 months was ?0.40% (95% confidence interval (CI) fixed effect ?0.78% to ?0.01%), representing a statistically significant reduction in HbA1c (P = 0.04) for scaling/root planing. One study was assessed as being at low risk of bias with the other two at moderate to high risk of bias. A subgroup analysis examined studies without adjunctive antibiotics ?0.80% (one study: 95% CI ?1.73% to 0.13%; P = 0.09), with adjunctive antibiotics in the test group ?0.36% (one study: 95% CI ?0.83% to 0.11%; P = 0.14), and with antibiotics in both test and control groups after 3/4 months ?0.15% (one study: 95% CI ?1.04% to 0.74%; P = 0.74). Authors’ conclusions: There is some evidence of improvement in metabolic control in people with diabetes, after treating periodontal disease. There are few studies available and individually these lacked the power to detect a significant effect. Most of the participants in the study had poorly controlled Type 2 DM with little data from randomized trials on the effects on people with Type 1 DM.  相似文献   
105.
106.
Swift PGF, Skinner TC, de Beaufort CE, Cameron FJ, Åman J, Aanstoot H‐J, Castaño L, Chiarelli F, Daneman D, Danne T, Dorchy H, Hoey H, Kaprio EA, Kaufman F, Kocova M, Mortensen HB, Njølstad PR, Phillip M, Robertson KJ, Schoenle EJ, Urakami T, Vanelli M, Ackermann RW, Skovlund SE for the Hvidoere Study Group on Childhood Diabetes. Target setting in intensive insulin management is associated with metabolic control: the Hvidoere Childhood Diabetes Study Group Centre Differences Study 2005. Objective: To evaluate glycaemic targets set by diabetes teams, their perception by adolescents and parents, and their influence on metabolic control. Methods: Clinical data and questionnaires were completed by adolescents, parents/carers and diabetes teams in 21 international centres. HbA1c was measured centrally. Results: A total of 2062 adolescents completed questionnaires (age 14.4 ± 2.3 yr; diabetes duration 6.1 ± 3.5 yr). Mean HbA 1c = 8.2 ± 1.4% with significant differences between centres (F = 12.3; p < 0.001) range from 7.4 to 9.1%. There was a significant correlation between parent (r = 0.20) and adolescent (r = 0.21) reports of their perceived ideal HbA1c and their actual HbA1c result (p < 0.001), and a stronger association between parents' (r = 0.39) and adolescents' (r = 0.4) reports of the HbA1c they would be happy with and their actual HbA1c result. There were significant differences between centres on parent and adolescent reports of ideal and happy with HbA1c (8.1 < F > 17.4;p < 0.001). A lower target HbA1c and greater consistency between members of teams within centres were associated with lower centre HbA1c (F = 16.0; df = 15; p < 0.001). Conclusions: Clear and consistent setting of glycaemic targets by diabetes teams is strongly associated with HbA1c outcome in adolescents. Target setting appears to play a significant role in explaining the differences in metabolic outcomes between centres.  相似文献   
107.
108.
It is not always possible to prevent the growth of microorganisms in organ culture for cornea preservation, despite many prophylactic measures. It is especially difficult to prove the presence of fungi in the cultural medium. MATERIALS AND METHODS: A culture medium was examined for sterility after 8 days' storage of cornea in organ culture. To prove the presence of fungi a culture of Sabouraud 2% glucose-agar was prepared and its growth examined by light microscopy. RESULTS: After 8 days of preservation we noticed a color change in the cultural medium and suspected contamination with fungi. Coagulase-negative Staphylococci could be cultivated from the conjunctival smear obtained before preparation of the cornea only. Routine screening of microbiological contamination did not show any results. We were able to identify an Aspergillus species only after preparing a special culture. The conjunctival smear as well as the cultural medium of the other eye of the same donor showed no contamination. CONCLUSIONS: In spite of the fact that microbiological contamination can be seen macroscopically, it is difficult to prove the presence of a specific microorganism and even more so when dealing with fungus. Especially in these cases the incubation of the cornea in media might have an advantage because contamination can be suspected by just looking at the medium. By excluding these preparations from transplantation we can possibly prevent infections, even when routine examinations show negative results.  相似文献   
109.
110.
BACKGROUND AND OBJECTIVE: The purpose of the present study was to determine the pharmacokinetics of the micro-agonist opioid pirinitramide (piritramide) after prolonged administration. METHODS: Nine patients requiring intensive care therapy and artificial ventilation for several days received piritramide with a median infusion rate of 5 mg h(-1) (range 4.8-10 mg h(-1)) for a median period of 69.9 h (range 49-89 h) for analgesia and sedation. After the end of the infusion, frequent arterial blood samples were withdrawn for 96 h and assayed for piritramide using a gas chromatographic method. Standard compartmental models were fitted to the individual concentration-time courses to characterize the elimination of piritramide after prolonged administration. RESULTS: The concentration-time course after the end of the infusion was adequately described with a three-compartment model in eight patients and a two-compartment model in one patient (standard two-stage geometric mean and 16-84% quantile: volumes of distribution V1 = 47.9 (26.8-85.8)L, V2 = 402 (241-672)L, V3 = 332 (124-885)L; clearances Cl1 = 66.5 (53.2-83.0)Lh(-1), Cl2 = 215 (125-369)Lh(-1), Cl3 = 18.4 (9.2-36.8) Lh(-1)). Both the steady-state volume of distribution (782 L) and the terminal elimination half-life (17.4 h) were larger than predicted from single bolus pharmacokinetic studies (412.5 L and 10.4 h, respectively), the context-sensitive half-time after more than 72 h of administration was 32% shorter than predicted (285 vs. 420 min). CONCLUSIONS: Despite increasing terminal elimination half-life and volume of distribution at steady state (increasing drug load for a given plasma concentration), the context-sensitive half-time of piritramide after 3 days of administration is lower than predicted from bolus kinetics, making the drug a suitable candidate for intensive care unit analgesia.  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