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   54682篇
  免费   4509篇
  国内免费   110篇
耳鼻咽喉   573篇
儿科学   2025篇
妇产科学   1431篇
基础医学   6992篇
口腔科学   658篇
临床医学   6805篇
内科学   9774篇
皮肤病学   1082篇
神经病学   5443篇
特种医学   1144篇
外科学   6041篇
综合类   560篇
现状与发展   1篇
一般理论   88篇
预防医学   7464篇
眼科学   1019篇
药学   3861篇
中国医学   66篇
肿瘤学   4274篇
  2023年   490篇
  2022年   380篇
  2021年   1733篇
  2020年   1165篇
  2019年   1883篇
  2018年   2030篇
  2017年   1570篇
  2016年   1662篇
  2015年   1726篇
  2014年   2439篇
  2013年   3202篇
  2012年   4761篇
  2011年   4722篇
  2010年   2586篇
  2009年   2154篇
  2008年   3742篇
  2007年   3730篇
  2006年   3469篇
  2005年   3248篇
  2004年   2850篇
  2003年   2376篇
  2002年   2098篇
  2001年   480篇
  2000年   398篇
  1999年   405篇
  1998年   361篇
  1997年   238篇
  1996年   201篇
  1995年   189篇
  1994年   166篇
  1993年   137篇
  1992年   250篇
  1991年   202篇
  1990年   173篇
  1989年   204篇
  1988年   177篇
  1987年   155篇
  1986年   152篇
  1985年   140篇
  1984年   107篇
  1983年   112篇
  1981年   65篇
  1980年   64篇
  1979年   76篇
  1978年   93篇
  1977年   76篇
  1976年   57篇
  1975年   57篇
  1973年   63篇
  1972年   58篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
ABSTRACT

The lack of stable housing can impair access and continuity of care for patients living with human immunodeficiency virus (HIV). This study investigated the relationship between housing status assessed at multiple time points and several core HIV-related outcomes within the same group of HIV patients experiencing homelessness. Patients with consistently stable housing (CSH) during the year were compared to patients who lacked CSH (non-CSH group). The study outcomes included HIV viral load (VL), CD4 counts, and health care utilization. Multivariable and propensity weighted analyses were used to assess outcomes adjusting for potential group differences. Of 208 patients, 88 (42%) had CSH and 120 (58%) were non-CSH. Patients with CSH had significantly higher proportion of VL suppression and higher mean CD4 counts. The frequency of nurse visits in the CSH group was less than a half of that in the non-CSH group. Patients with CSH were less likely to be admitted to the medical respite facility, and if admitted, their length of stay was about a half of that for the non-CSH group. Our study findings show that patients with CSH had significantly better HIV virologic control and immune status as well as improved health care utilization.  相似文献   
72.
73.
74.
PurposeTwitter is an increasingly popular social media platform within the health care community. The objective of this analysis is to characterize the profile of radiation oncology–related tweets and Twitter users over the past 6 years.Methods and MaterialsUsing the web-based social media analytics platform Symplur Signals, we filtered tweets containing at least 1 of the following hashtags or key words: #radonc, #radiationoncology, "rad onc," or "radiation oncology." We evaluated radiation oncology–related Twitter activity between October 2014 and March 2020 for tweet frequency, tweet content, and individuals or groups posting tweets. We identified the most influential Twitter users contributing to radiation oncology–related tweets.ResultsFrom 2014 to 2020, the quarterly volume of radiation oncology–related tweets increased from 5027 to 29,763. Physicians contributed the largest growth in tweet volume. Academic radiation oncologists comprise 60% of the most influential Twitter accounts responsible for radiation oncology–related content. The number of radiation-oncology resident physicians on Twitter increased from 25 to 328 over the past 6 years, and 20% of radiation-oncology residency programs have a Twitter account. Seventy-one percent of radiation oncology–related tweets generated direct communication via mentions, and 59% of tweets contain links to external sources, including scientific articles.ConclusionsThe number of physicians contributing radiation oncology–related Twitter content has increased significantly in recent years. Academic radiation oncologists are the primary influencers of radiation oncology–related Twitter activity. Twitter is used by radiation oncologists to both professionally network and discuss findings related to the field. There remains the opportunity for radiation oncologists to broaden their audience on Twitter to encompass a more diverse community, including patients.  相似文献   
75.
Lessons Learned
  • Oral selective HDAC6 inhibitors could allow for decreased toxicity compared to pan‐class inhibitors, and increased ease of use.
  • ACY‐1215 is well tolerated and led to disease stabilization in 50% of patients treated on a twice‐daily dosing schedule.
  • Rational drug combinations with ACY‐1215 improve efficacy in patients with lymphoma.
  • Biomarkers such as XBP‐1 level or HDAC6‐score may improve patient selection.
BackgroundACY‐1215, ricolinostat, is an oral, first‐in‐class isoform‐selective HDAC6 inhibitor. HDAC6 is a class IIb deacetylase and plays a critical role in protein homeostasis via the unfolded protein response (UPR). Lymphocytes generate a large repertoire of antibodies and depend on an activated UPR to maintain proteostasis. Lymphomas utilize this biology to evade programmed cell death. In preclinical models of lymphoma, ACY‐1215 disrupted proteostasis, triggering apoptosis.MethodsWe translated these findings into a multi‐institution, open‐label, dose‐escalation phase Ib/II study aimed to determine the safety and efficacy in patients with relapsed and refractory lymphoma.ResultsTwenty‐one patients with heavily pretreated lymphoma were accrued. Patients in the phase Ib portion were enrolled on one of two dose cohorts [Arm A: 160 mg daily (n = 3) or Arm B: 160 mg twice daily (n = 10)]. ACY‐1215 was well tolerated. There were no dose limiting toxicities. Most adverse events were grade 1–2, including diarrhea (57%), nausea (57%), and fatigue (43%). Grade 3–4 toxicities were rare and included anemia (9.5%) and hypercalcemia (9.5%). An additional 8 patients were enrolled on the phase II portion, at 160 mg twice daily. Sixteen patients were evaluable for response. ACY‐1215 did not result in any complete or partial responses in patients treated. Eight patients had stable disease (50%) lasting a median duration of 4.5 months, all of whom were treated twice daily. Disease progressed in eight patients (50%) at cycle 2. Five patients were not evaluable due to disease progression prior to cycle 2. The median PFS was 56 days.ConclusionACY‐1215 is an oral selective HDAC6 inhibitor that was safe in patients with relapsed and refractory lymphoid malignancies and led to disease stabilization in half of the evaluable patients.  相似文献   
76.
77.
ABSTRACT

Adolescents and young adults smoke waterpipe tobacco (WT) and cigarillos, at least in part, based on erroneous beliefs that these products are safer than cigarettes. To address this challenge, we used a systematic, three-phase process to develop a health communication campaign to discourage WT and cigarillo smoking among at-risk (tobacco users and susceptible non-users) 16- to 25-year-olds. In Phase 1, we used a national phone survey (N = 896) to determine salient message beliefs. Participants reported constituents (i.e., harmful chemicals) emitted by the products were worrisome. In Phase 2, we developed and evaluated four message executions, with varying imagery, tone, and unappealing products with the same constituents, using focus groups (N = 38). Participants rated one execution highly, resulting in our development of a campaign where each message: (1) identified a tobacco product and constituent in the smoke; (2) included an image of an unappealing product containing the constituent (e.g., pesticides, gasoline) to grab attention; and (3) used a humorous sarcastic tone. In Phase 3, we tested the campaign messages (17 intervention and six control) with a nationally representative online survey (N = 1,636). Participants rated intervention and control messages highly with few differences between them. Exposure to messages resulted in significant increases in all risk beliefs from pre to post (< 0.05). For WT, intervention messages increased beliefs about addiction more than control messages (p < 0.05). This systematic, iterative approach resulted in messages that show promise for discouraging WT and cigarillo use.  相似文献   
78.
79.
Inflammatory bowel disease (IBD) is an established risk factor for colorectal cancer. Recent reports suggesting IBD is also a risk factor for prostate cancer (PC) require further investigation. We studied 218 084 men in the population-based UK Biobank cohort, aged 40 to 69 at study entry between 2006 and 2010, with follow-up through mid-2015. We assessed the association between IBD and subsequent PC using multivariable Cox regression analyses, adjusting for age at assessment, ethnic group, UK region, smoking status, alcohol drinking frequency, body mass index, Townsend Deprivation Index, family history of PC and previous prostate-specific antigen testing. Mean age at study entry was 56 years, 94% of the men were white, and 1.1% (n = 2311) had a diagnosis of IBD. After a median follow-up of 78 months, men with IBD had an increased risk of PC (adjusted hazard ratio [aHR] = 1.31, 95% confidence interval [CI] = 1.03-1.67, P = .029). The association with PC was only among men with the ulcerative colitis (UC; aHR = 1.47, 95% CI = 1.11-1.95, P = .0070), and not Crohn's disease (aHR 1.06, 95% CI = 0.63-1.80, P = .82). Results are limited by lack of data on frequency of health care interactions. In a large-scale, prospective cohort study, we detected an association between IBD, and UC specifically, with incident PC diagnosis.  相似文献   
80.
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