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   1273091篇
  免费   87793篇
  国内免费   1548篇
耳鼻咽喉   16392篇
儿科学   41029篇
妇产科学   34947篇
基础医学   189577篇
口腔科学   34754篇
临床医学   117962篇
内科学   248355篇
皮肤病学   27301篇
神经病学   102166篇
特种医学   46804篇
外国民族医学   265篇
外科学   178707篇
综合类   25768篇
现状与发展   3篇
一般理论   568篇
预防医学   104776篇
眼科学   28097篇
药学   92698篇
  39篇
中国医学   2027篇
肿瘤学   70197篇
  2019年   10391篇
  2018年   13573篇
  2017年   10440篇
  2016年   11368篇
  2015年   13079篇
  2014年   18004篇
  2013年   27477篇
  2012年   37572篇
  2011年   39966篇
  2010年   23053篇
  2009年   22250篇
  2008年   37752篇
  2007年   40382篇
  2006年   39962篇
  2005年   39095篇
  2004年   37543篇
  2003年   35954篇
  2002年   34865篇
  2001年   56029篇
  2000年   57042篇
  1999年   48095篇
  1998年   13396篇
  1997年   12222篇
  1996年   12643篇
  1995年   11914篇
  1994年   11107篇
  1993年   10399篇
  1992年   38198篇
  1991年   37672篇
  1990年   36445篇
  1989年   35258篇
  1988年   32690篇
  1987年   32027篇
  1986年   30525篇
  1985年   28787篇
  1984年   21941篇
  1983年   19192篇
  1982年   11364篇
  1979年   20944篇
  1978年   15393篇
  1977年   12790篇
  1976年   11845篇
  1975年   12810篇
  1974年   15588篇
  1973年   15362篇
  1972年   14512篇
  1971年   13552篇
  1970年   12786篇
  1969年   12065篇
  1968年   11229篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.
Sleep is an essential biologic function vital for physiologic rest, healing, and emotional well-being. Sleep disruption is commonly seen in patients and caregivers with lengthy hospital stays such as patients undergoing hematopoietic stem cell transplantation and cellular therapy (TCT). Sleep disruption can lead to increased stress and fatigue, affecting caregivers’ ability to support their loved one. The global aim of our quality improvement initiative was to improve sleep quality in TCT patients and caregivers. The smart aim of our project was to decrease nighttime hallway noise from 47 dB to 43 dB and decrease the number of overnight noise peaks greater than 60 dB from 865 to 432 in 6 months. Through a cross-sectional quantitative and qualitative evaluation of sleep we had previously identified poor sleep quality, and with a cross-sectional focus group analysis of patients, caregivers, and medical staff we identified the factors associated with poor sleep. Hallway noise was a major factor. A simplified failure mode analysis identified 4 main key drivers; unobtrusive nighttime cleaning process, nighttime awareness maintenance system, quiet nighttime nursing system, and reliable nighttime awareness system. Several plan-do-study-act interventions took place and were adopted. From January to June 2018 the overnight mean decibel level decreased from 47 dB to 44 dB (6% reduction). Overnight noise spikes above 60 dB decreased from a mean of 865 spikes to a mean of 463 spikes (46% reduction). With a quality improvement initiative, we identified the causes of hallway nighttime hospital unit noise that negatively impact sleep and through a team-based approach performed interventions that successfully mitigated these factors.  相似文献   
92.
93.
94.
The Hematopoietic Cell Transplantation-Specific Comorbidity Index (HCT-CI) was developed and validated to weigh the burden of pretransplantation comorbidities and estimate their impact on post-transplantation risks of nonrelapse mortality (NRM). Recently, the HCT-CI was augmented by the addition of both age and the values of 3 markers: ferritin, albumin, and platelet count. So far, research involving The HCT-CI has been limited almost exclusively to recipients of allogeneic hematopoietic cell transplantation (HCT) from HLA-matched grafts. To this end, we sought to investigate the discriminative capacity of an augmented comorbidity/age index among 724 recipients of allogeneic HCT from HLA-mismatched (n = 345), haploidentical (n = 117), and umbilical cord blood (UCB; n = 262) grafts between 2000 and 2013. In the overall cohort, the augmented comorbidity/age index had a higher c-statistic estimate for prediction of NRM compared with the original HCT-CI (.63 versus .59). Findings were similar for recipients of HLA-mismatched (.62 versus .59), haploidentical (.60 versus .54), or UCB grafts (.65 versus .61). Compared with patients with an HCT-CI score ≥4, those with a score <4 had a higher survival rate among recipients of HLA-mismatched (55% versus 39%; P < .0008), HLA-haploidentical (58% versus 38%; P = .01), or UCB (67% versus 48%; P = .004) grafts. Our results demonstrate the utility of the augmented comorbidity/age index as a valid prognostic tool among recipients of allogeneic HCT from alternative graft sources.  相似文献   
95.
Although myeloablative conditioning (MAC) before haploidentical donor transplant (HIDT) with post-transplant cyclophosphamide is being increasingly used, the optimal preparative regimen remains unclear. In our initial trial, the feasibility of HIDT following a MAC preparative regimen using fludarabine and 12 Gy of total-body irradiation was demonstrated in 30 patients. We now present long-term outcome results, including an additional 52 patients, now with 47 months (16 to 96) median follow-up. Median patient age was 42 (19 to 61) years. The most common diagnoses were acute myelogenous leukemia (51%) and acute lymphoblastic leukemia (33%), and 39% had a high/very high disease risk index (DRI). Engraftment was universal with no cases of primary or secondary graft failure. Grade 3 to 4 acute graft-versus-host disease (GVHD) and moderate to severe chronic GVHD occurred in 17% and 23%, respectively. Nonrelapse mortality (NRM) was 7% at 1 year and 13% at 4 years. Estimated 4-year overall survival (OS), disease-free survival, and cumulative incidence of relapse (CIR) were 67%, 60%, and 27%, respectively. CIR was significantly higher in patients with high/very high- versus low/intermediate-risk DRI (38% versus 20%, P= .032), which led to inferior 4-year OS (50% versus 77%, P = .001). Median time to systemic immunosuppressive therapy (IST) discontinuation was 7.8 months, with 84% of patients off IST at 2 years post-transplant. Current GHVD-free, relapse-free survival (CGRFS) at 2, 3, and 4 years was 60%, 57%, and 60%, respectively. This approach to MAC HIDT results in universal engraftment; low rates of NRM, infection, and clinically significant GVHD; and relatively rapid IST discontinuation, resulting in high rates of CGRFS and survival.  相似文献   
96.
97.
98.
ObjectiveThe study objective was to identify biobehavioral variables associated with greater intake of nicotine and a tobacco carcinogen among Black light smokers who smoke 1 to 10 cigarettes per day (CPD).MethodsWe analyzed baseline data collected from 426 Black light smokers enrolled in Kick It at Swope III (KIS III), a smoking cessation trial for Black smokers. We examined differences in concentrations of tobacco biomarkers, including urinary total nicotine equivalents (TNE) and total 4-(methylnitrosamino)-1-(3)pyridyl-1-butanonol (NNAL; a human carcinogen), across gender, age, plasma nicotine metabolite ratio (NMR), CPD, and measures of tobacco dependence, including time to first cigarette (TFC), using ANOVA.ResultsTobacco biomarker levels were significantly higher among those who smoked more CPD (6–10 vs 1–5 CPD) and those with greater reported physical dependence on tobacco. Concurrently, those who smoked 1–5 CPD smoked each cigarette more intensely than those who smoked 6–10 CPD. While we found no gender differences overall, among those who smoked 1–5 CPD, women had higher NNAL levels compared to men. The rate of nicotine metabolism, measured by the nicotine metabolite ratio, was not significantly related to TNE or NNAL levels.ConclusionAmong Black Light smokers, higher cigarette consumption and greater physical dependence—but not rate of nicotine metabolism, menthol use, or socioeconomic status—were associated with greater toxicant exposure and thus a likely increased risk of tobacco-related diseases. The lack of data on light smokers, and specifically on Blacks, make this observation important given the disproportionate burden of lung cancer in this population.  相似文献   
99.
100.
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