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   10609篇
  免费   820篇
  国内免费   497篇
耳鼻咽喉   57篇
儿科学   144篇
妇产科学   31篇
基础医学   652篇
口腔科学   75篇
临床医学   892篇
内科学   1839篇
皮肤病学   49篇
神经病学   329篇
特种医学   142篇
外科学   1275篇
综合类   1576篇
预防医学   481篇
眼科学   87篇
药学   3223篇
  5篇
中国医学   938篇
肿瘤学   131篇
  2024年   16篇
  2023年   131篇
  2022年   197篇
  2021年   358篇
  2020年   334篇
  2019年   315篇
  2018年   355篇
  2017年   308篇
  2016年   269篇
  2015年   356篇
  2014年   667篇
  2013年   821篇
  2012年   774篇
  2011年   783篇
  2010年   593篇
  2009年   561篇
  2008年   507篇
  2007年   597篇
  2006年   480篇
  2005年   421篇
  2004年   329篇
  2003年   363篇
  2002年   326篇
  2001年   283篇
  2000年   247篇
  1999年   190篇
  1998年   150篇
  1997年   178篇
  1996年   120篇
  1995年   109篇
  1994年   84篇
  1993年   97篇
  1992年   68篇
  1991年   50篇
  1990年   45篇
  1989年   36篇
  1988年   46篇
  1987年   44篇
  1986年   29篇
  1985年   35篇
  1984年   42篇
  1983年   24篇
  1982年   41篇
  1981年   31篇
  1980年   31篇
  1979年   15篇
  1978年   19篇
  1977年   12篇
  1976年   15篇
  1973年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Recent epidemiological studies suggested that proton pump inhibitor (PPI) use was associated with an increased risk of biliary tract cancer (BTC), however, confounders were not adequately controlled. Our study aimed to evaluate PPI use and subsequent risk of BTC and its subtypes in three well-established cohorts. We conducted a pooled analysis of the subjects free of cancers in UK Biobank (n = 463 643), Nurses' Health Study (NHS, n = 80 235) and NHS II (n = 95 869). Propensity score weighted Cox models were used to estimate marginal HRs of PPIs use on BTC risk, accounting for potential confounders. We documented 284 BTC cases in UK Biobank (median follow-up: 7.6 years), and 91 cases in NHS and NHS II cohorts (median follow-up: 15.8 years). In UK biobank, PPI users had a 96% higher risk of BTC compared to nonusers in crude model (HR 1.96, 95% CI 1.44-2.66), but the effect was attenuated to null after adjusting for potential confounders (HR 0.95, 95% CI 0.60-1.49). PPI use was not associated with risk of BTC in the pooled analysis of three cohorts (HR 0.93, 95% CI 0.60-1.43). We also observed no associations between PPI use with risk of intrahepatic (HR 1.00, 95% CI 0.49-2.04), extrahepatic bile duct (HR 1.09, 95% CI 0.52-2.27) and gallbladder cancers (HR 0.66, 95% CI 0.26-1.66) in UK Biobank. In summary, regular use of PPIs was not associated with the risk of BTC and its subtypes.  相似文献   
3.
Iron deficiency anemia is often listed among potential adverse effects of gastric acid-suppressive medications, given that gastric acidity promotes intestinal absorption of nonheme iron. Additionally, the antacid calcium carbonate can inhibit iron absorption. However, there is little direct clinical evidence that proton-pump inhibitors, histamine-2 receptor antagonists, or calcium carbonate cause iron deficiency anemia. Most case reports have had substantial limitations (e.g., minimal follow-up and presence of other causes of iron deficiency), and retrospective cohort studies have lacked sufficient patient-specific detail to make strong causal inferences. We present 2 cases—both with detailed, prospective 10-year follow-up—in which combinations of proton-pump inhibitors, histamine-2 receptor antagonists and calcium carbonate were clearly associated with development of iron deficiency anemia. Overt iron-deficiency anemia is probably uncommon in patients who use acid-modifying medications and who have no other conditions that predispose to iron deficiency. Nevertheless, clinicians should be aware of this potential complication, given widespread use of these agents.  相似文献   
4.
5.
Rotary ventricular assist devices (VADs) are less sensitive to preload than the healthy heart, resulting in inadequate flow regulation in response to changes in patient cardiac demand. Starling‐like physiological controllers (SLCs) have been developed to automatically regulate VAD flow based on ventricular preload. An SLC consists of a cardiac response curve (CRC) which imposes a nonlinear relationship between VAD flow and ventricular preload, and a venous return line (VRL) which determines the return path of the controller. This study investigates the importance of a physiological VRL in SLC of dual rotary blood pumps for biventricular support. Two experiments were conducted on a physical mock circulation loop (MCL); the first compared an SLC with an angled physiological VRL (SLC‐P) against an SLC with a vertical VRL (SLC‐V). The second experiment quantified the benefit of a dynamic VRL, represented by a series of specific VRLs, which could adapt to different circulatory states including changes in pulmonary (PVR) and systemic (SVR) vascular resistance versus a fixed physiological VRL which was calculated at rest. In both sets of experiments, the transient controller responses were evaluated through reductions in preload caused by the removal of fluid from the MCL. The SLC‐P produced no overshoot or oscillations following step changes in preload, whereas SLC‐V produced 0.4 L/min (12.5%) overshoot for both left and right VADs. Additionally, the SLC‐V had increased settling time and reduced controller stability as evidenced by transient controller oscillations. The transient results comparing the specific and standard VRLs demonstrated that specific VRL rise times were improved by between 1.2 and 4.7 s ( = 3.05 s), while specific VRL settling times were improved by between 2.8 and 16.1 seconds ( = 8.38 s) over the standard VRL. This suggests only a minor improvement in controller response time from a dynamic VRL compared to the fixed VRL. These results indicate that the use of a fixed physiologically representative VRL is adequate over a wide variety of physiological conditions.  相似文献   
6.
Diabetes is a complex, chronic metabolic disorder affecting approximately 9.3% of the adult population with the estimated number of adults with diabetes worldwide having more than tripled since 2000. This increase has largely been attributed to global urbanization and lifestyle changes. Diabetes affects 10–15% of the surgical population. These patients are frequently elderly, have complex medical co-morbidities and present for both high-risk elective and emergency surgery. This multisystem disease poses a significant challenge to both anaesthesia and surgery with patients with diabetes demonstrating higher morbidity and mortality rates compared to their non-diabetic counterparts. It is crucial that good glycaemic control is maintained throughout the perioperative period as this has been shown to correlate with positive patient outcomes. It is well-recognized that a co-ordinated, multidisciplinary approach aimed at optimizing every point in the patient pathway from GP referral to post-discharge care is required to obtain the best outcomes for the surgical patient with diabetes. The anaesthetist has a key role in the perioperative diabetes multidisciplinary team. Patients themselves are well experienced in manging their own diabetes and should be involved in doing so whenever possible.  相似文献   
7.
Central illustration: geographic distribution of the 49 centres participating in the FRENSHOCK registry (35 academic hospitals, 10 general hospitals and four private clinics). Inclusion per centre varied from 1 to 72 patients.
  相似文献   
8.
Prescribing of proton pump inhibitors (PPIs) has markedly increased since their inception more than 30 years ago. The increase is related to inappropriate and long-term prescribing of PPIs, associated with a lack of education and unclear prescribing and deprescribing guidelines. The implementation of prescribing stewardship programs influences the reduction and inappropriate use of this medication. The purpose of this review is to address the gaps that exist regarding the use of PPIs along with determining methods for deprescribing. Guidelines and stewardship programs, along with education, are needed to reduce the adverse health effects of long-term PPI therapy.  相似文献   
9.
扶正固本法对青少年哮喘患者基因表达的影响   总被引:1,自引:0,他引:1  
目的 研究复方中药敏康片治疗青少年哮喘的疗效和作用机理。方法 选择20例青少年哮喘患者进行治疗,另设青少年特应性皮炎患者组(20例)和青少年正常组(19例)为对照。哮喘组和皮炎组口服敏康片,疗程为6个月,观察疗效、血清总IgE及FcεRIβ、IL-4Rα基因表达改变情况。结果 哮喘组显效6例,有效12例,无效2例,总有效率90%;皮炎组显效4例,有效13例,无效3例,总有效率85%;哮喘组IgE治疗前后有显著差异(P〈0.01)。皮炎组IgE治疗前后有差异(P〈0.05);用Northern blot法检测FctRlt3、IL-4Rα基因,IL-4Rα吸光度值两组治疗前均较正常组高,哮喘组治疗后降低。FcεRIβ吸光度值两组治疗前均较正常组高,治疗后均降低。结论 复方中药可以调整青少年哮喘患者相关基因表达,改善患者过敏状态,缓解临床症状。  相似文献   
10.
目的:探讨生化修饰疗法对晚期恶性肿瘤病人的治疗效果。方法:对57例晚期恶性肿瘤病人采用置管经输注泵输注化疗药物治疗与护理。结果:此法较全身化疗疗效高,毒副作用小。尤其适用于一般状况差又难于耐受全身化疗的晚期消化系统恶性肿瘤病人。结论:生化修饰疗法安全、有效、方便、费用低,值得推广。  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