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   3120篇
  免费   201篇
  国内免费   19篇
耳鼻咽喉   20篇
儿科学   114篇
妇产科学   48篇
基础医学   334篇
口腔科学   9篇
临床医学   430篇
内科学   525篇
皮肤病学   14篇
神经病学   306篇
特种医学   27篇
外科学   324篇
综合类   330篇
一般理论   4篇
预防医学   430篇
眼科学   52篇
药学   165篇
中国医学   1篇
肿瘤学   207篇
  2024年   4篇
  2023年   25篇
  2022年   30篇
  2021年   86篇
  2020年   58篇
  2019年   99篇
  2018年   110篇
  2017年   69篇
  2016年   99篇
  2015年   75篇
  2014年   96篇
  2013年   142篇
  2012年   283篇
  2011年   313篇
  2010年   142篇
  2009年   113篇
  2008年   217篇
  2007年   247篇
  2006年   242篇
  2005年   224篇
  2004年   129篇
  2003年   127篇
  2002年   132篇
  2001年   15篇
  2000年   16篇
  1999年   14篇
  1998年   26篇
  1997年   7篇
  1996年   14篇
  1995年   14篇
  1994年   12篇
  1993年   14篇
  1992年   11篇
  1991年   7篇
  1990年   6篇
  1988年   4篇
  1987年   10篇
  1986年   5篇
  1984年   11篇
  1983年   8篇
  1982年   9篇
  1981年   10篇
  1980年   9篇
  1978年   6篇
  1975年   4篇
  1974年   8篇
  1973年   4篇
  1971年   3篇
  1970年   5篇
  1968年   6篇
排序方式: 共有3340条查询结果,搜索用时 31 毫秒
21.
BackgroundDespite policies and programmes aimed at housing people who are homeless, there are still people who live and sleep rough. This project used the skills and knowledge of people in this situation to identify a strategy to mitigate some of the risks.ObjectiveTo describe the development and conduct of a co‐design project involving people who are homeless.Setting/Group MembersA Working Group of 11 was formed following a careful recruitment process from people who had volunteered after consultation by the project team. The co‐design approach was guided by a set of principles.MethodsEight members of the Working Group were interviewed by an external researcher (RM). The approach was primarily deductive, with the principles adopted by the project team used as a framework for data collection and analysis. The co‐design process was captured by the project leaders (BK, PC) supplemented with documentation review and team discussions.ResultsThe group met weekly for 12 weeks, with 8‐10 members present on average. They reviewed information from the survey, contributed ideas for solutions and ultimately decided to provide information via print, a website and an event. Important factors in on‐going involvement were carefully selecting group members and making participation rewarding for them.Discussion/ConclusionsVulnerable people such as those experiencing homelessness can be excluded from decision‐making processes affecting them, as they can be perceived as hard to reach and unable to make a meaningful contribution. This project demonstrated that a carefully managed project, with sufficient resources and commitment, it was possible to involve people who are homeless and maintain involvement over an extended time period.Public ContributionThe Working Group reviewed survey findings and developed an intervention to minimize the health, social and legal harms of sleeping rough. Several members reviewe this paper.  相似文献   
22.
23.
Case reports are presented on three patients treated for morbid obesity by vertical gastroplasty. Prior to surgery the patients had diabetes which required insulin, up to 200 units per day, or oral hypoglycaemics for its control. Six months after surgery the diabetes had been resolved in all three patients, and they were no longer dependent on medication. Subjective reports from the patients suggests that their quality of life improved significantly.  相似文献   
24.
A prospective study of biochemical changes after vertical banded gastroplasty for morbid obesity, in 94 patients (10 males and 84 females, ages ranging from 18 to 59 years) has been carried out. Liver function tests and electrolyte estimations were performed preoperatively, during hospitalisation for surgery, at 6 weeks and at 6 months postoperatively, and demonstrated no significant changes in liver function in these patients 6 months after surgery. The study concludes that there is no increase in the risk of liver damage or electrolyte disturbance after vertical gastroplasty, but that there may be subtle hepatic changes present as gall bladder disease developed in 18 patients postoperation (19%).  相似文献   
25.
Vinflunine (VFL) is a novel derivative of vinorelbine (NVB, Navelbine®), which has shown markedly superior antitumor activity to NVB, in various experimental animal models. To establish whether this new Vinca alkaloid participates in P-glycoprotein (Pgp)-mediated multidrug resistance (MDR), VFL-resistant murine P388 cells (P388/VFL) were established in vivo and used in conjunction with the well established MDR P388/ADR subline, to define the in vivo resistance profile for VFL. P388/VFL cells proved cross-resistant to drugs implicated in MDR (other Vinca alkaloids, doxorubicin, etoposide), but not to campothecin or cisplatin and showed an increased expression of Pgp, without any detectable alterations in topoisomerase II or in glutathione metabolism. The P388/ADR cells proved cross-resistant to VFL both in vivo and in vitro, and this VFL resistance was efficiently modulated by verapamil in vitro. Cellular transport experiments with tritiated-VFL revealed differential uptake by P388 sensitive and P388/ADR resistant cells, comparable with data obtained using tritiated-NVB. In various in vitro models of human MDR tumor cells, whilst full sensitivity was retained in cells expressing alternative non-Pgp-mediated MDR mechanisms, cross resistance was identified in Pgp-overexpressing cells. Differences were, however, noted in terms of the drug resistance profiles relative to the other Vincas, with tumor cell lines proving generally least cross-resistant to VFL. Overall, these results suggest that VFL, like other Vinca alkaloids, participates in Pgp-mediated MDR, with tumor cells selected for resistance to VFL overexpressing Pgp, yet MDR tumor cell lines proved generally less cross resistant to VFL relative to the other Vinca alkaloids.  相似文献   
26.
Vinflunine, or 20′,20′-difluoro-3′,4′-dihydrovino‐relbine, is a novel Vinca alkaloid obtained by hemisynthesis using superacidic chemistry. The most impressive structural modification of this vinorelbine derivative was the selective introduction of two fluorine atoms at the 20′ position, a part of the molecule previously inaccessible by classic chemistry. The antitumor activity of vinflunine was evaluated against a range of transplantable murine and human tumors. Vinflunine exhibited marked activity against murine P388 leukemia grafted i.v. when given i.p. in single or multiple doses according to various schedules or in single i.v. or p.o. doses. Increases in life span achieved with vinflunine, as assessed by T/C ratios, ranged from 200% to 457% and proved markedly superior to those of 129–186% obtained with the other Vinca alkaloids tested. Against s.c.-implanted B16 melanoma, multiple i.p. administration of vinflunine proved active in terms of both survival prolongation and tumor growth inhibition, with optimal T/C values and relative areas under the tumor growth curves (rAUC) being 24% and 36%, respectively. The extent of this activity was superior to that noted for vinorelbine under the same experimental conditions. Growth inhibition of human tumor xenografts LX-1 (lung) and MX-1 (breast) was also observed following four weekly i.p. injections of vinflunine as reflected by optimal T/C values of 23% and 26%, respectively, and significant differences in the rAUCs noted for treated versus control animals. It was also noticeable that vinflunine induced considerably more prolonged inhibitory effects on tumor growth than did vinorelbine. These results demonstrate that vinflunine is well tolerated and is definitively active against a range of experimental animal tumor models. Vinflunine activity has been documented in terms of both survival prolongation and tumor growth inhibition, with definite superiority over vinorelbine being shown in each tumor model evaluated. Received: 13 July 1997 / Accepted: 21 October 1997  相似文献   
27.
OBJECTIVE: To determine the effect of the type of information sources used on health services use. METHODS: Population-based random-digit dialing survey of 498 women, between December 1999 and January 2000, on use of health information sources and health visits. RESULTS: After adjustment for sociodemographic and medical factors, use of print health media and computer-based resources was associated with 1.9 and 1.6 more visits, respectively compared to non-use (Regression coefficients 1.9; [95% confidence interval {CI} 0.1, 3.7] and 1.6; [95% CI 0.3, 3.0]). CONCLUSIONS: Print health media and computer-based sources are associated with a higher number of health care visits.  相似文献   
28.
Improving the quality of care for patients with chronic illness has become a high priority. Implementing training programs in disease management (DM) so the next generation of physicians can manage chronic illness more effectively is challenging. Residency training programs have no specific mandate to implement DM training. Additional barriers at the training facility include: 1) lack of a population-based perspective for service delivery; 2) weak support for self-management of illness; 3) incomplete implementation due to physician resistance or inertia; and 4) few incentives to change practices and behaviors. In order to overcome these barriers, training programs must take the initiative to implement DM training that addresses each of these issues. We report the implementation of a chronic illness management curriculum based on the Improving Chronic Illness Care (ICIC) Model. Features of this process included both patient care and learner objectives. These were: development of a multidisciplinary diabetes DM team; development of a patient registry; development of diabetes teaching clinics in the family practice center (nutrition, general management classes, and one-on-one teaching); development of a group visit model; and training the residents in the elements of the ICIC Model, ie, the community, the health system, self-management support, delivery system design, decision support, and clinical information systems. Barriers to implementing these curricular changes were: the development of a patient registry; buy-in from faculty, residents, clinic leadership, staff, and patients for the chronic care model; the ability to bill for services and maintain clinical productivity; and support from the health system key stakeholders for sustainability. Unique features of each training site will dictate differences in emphasis and structure; however, the core principles of the ICIC Model in enhancing self-management may be generalized to all sites.  相似文献   
29.
PURPOSE: We determined the maximum-tolerated dose (MTD) and the dose-limiting toxicities (DLT) of 17-allylamino-17-demethoxygeldanamycin (17-AAG) when infused on days 1, 8, and 15 of a 28-day cycle in advanced solid tumor patients. We also characterized the pharmacokinetics of 17-AAG, its effect on chaperone and client proteins, and whether cytochrome P450 (CYP) 3A5 and NAD(P)H:quinone oxidoreductase 1 (NQO1) polymorphisms affected 17-AAG disposition or toxicity. PATIENTS AND METHODS: An accelerated titration design was used. Biomarkers were measured in peripheral-blood mononuclear cells (PBMCs) at baseline and on days 1 and 15, and pharmacokinetic analysis was performed on day 1 of cycle 1. CYP3A5*3 and NQO1*2 genotypes were determined and correlated with pharmacokinetics and toxicity. RESULTS: Twenty-one patients received 52 courses at 11 dose levels. DLTs at 431 mg/m(2) were grade 3 bilirubin (n = 1), AST (n = 1), anemia (n = 1), nausea (n = 1), vomiting (n = 1), and myalgias (n = 1). No tumor responses were seen. 17-AAG consistently increased heat shock protein (Hsp) 70 levels in PBMCs. At the MTD, the clearance and half-life (t(1/2)) of 17-AAG were 11.6 L/h/m(2) and 4.15 hours, respectively; whereas the active metabolite 17-aminogeldanamycin had a t(1/2) of 7.63 hours. The CYP3A5*3 and NQO1*2 polymorphisms were not associated with 17-AAG toxicity. The CYP3A5*3 polymorphism was associated with higher 17-AAG clearance. CONCLUSION: The MTD of weekly 17-AAG is 308 mg/m(2). 17-AAG induced Hsp70 in PBMCs, indicating that Hsp90 has been affected. Further evaluation of 17-AAG is ongoing using a twice-weekly regimen, and this schedule of 17-AAG is being tested in combination with chemotherapy.  相似文献   
30.
PURPOSE: To compare the preclinical and clinical pharmacokinetic properties of paclitaxel formulated as a Cremophor-free, albumin-bound nanoparticle (ABI-007) and formulated in Cremophor-ethanol (Taxol). EXPERIMENTAL DESIGN: ABI-007 and Taxol were given i.v. to Harlan Sprague-Dawley male rats to determine pharmacokinetic and drug disposition. Paclitaxel pharmacokinetic properties also were assessed in 27 patients with advanced solid tumors who were randomly assigned to treatment with ABI-007 (260 mg/m(2), 30 minutes; n = 14) or Taxol (175 mg/m(2), 3 hours; n = 13), with cycles repeated every 3 weeks. RESULTS: The volume of distribution at steady state and clearance for paclitaxel formulated as Cremophor-free nanoparticle ABI-007 were significantly greater than those for paclitaxel formulated with Cremophor (Taxol) in rats. Fecal excretion was the main elimination pathway with both formulations. Consistent with the preclinical data, paclitaxel clearance and volume of distribution were significantly higher for ABI-007 than for Taxol in humans [21.13 versus 14.76 L/h/m(2) (P = 0.048) and 663.8 versus 433.4 L/m(2) (P = 0.040), respectively]. CONCLUSIONS: Paclitaxel formulated as ABI-007 differs from paclitaxel formulated as Taxol, with a higher plasma clearance and a larger volume of distribution. This finding is consistent with the absence of paclitaxel-sequestering Cremophor micelles after administration of ABI-007. This unique property of ABI-007 could be important for its therapeutic effectiveness.  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