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   29390篇
  免费   2449篇
  国内免费   504篇
耳鼻咽喉   489篇
儿科学   1169篇
妇产科学   487篇
基础医学   2419篇
口腔科学   1219篇
临床医学   3200篇
内科学   4713篇
皮肤病学   453篇
神经病学   7894篇
特种医学   633篇
外科学   1551篇
综合类   1998篇
现状与发展   3篇
一般理论   1篇
预防医学   3208篇
眼科学   205篇
药学   1931篇
  7篇
中国医学   440篇
肿瘤学   323篇
  2024年   96篇
  2023年   721篇
  2022年   936篇
  2021年   1578篇
  2020年   1486篇
  2019年   1441篇
  2018年   1394篇
  2017年   1319篇
  2016年   1242篇
  2015年   1105篇
  2014年   1849篇
  2013年   2741篇
  2012年   1415篇
  2011年   1700篇
  2010年   1279篇
  2009年   1364篇
  2008年   1399篇
  2007年   1263篇
  2006年   1096篇
  2005年   871篇
  2004年   777篇
  2003年   776篇
  2002年   611篇
  2001年   447篇
  2000年   399篇
  1999年   349篇
  1998年   340篇
  1997年   299篇
  1996年   224篇
  1995年   216篇
  1994年   186篇
  1993年   166篇
  1992年   180篇
  1991年   124篇
  1990年   132篇
  1989年   76篇
  1988年   95篇
  1987年   86篇
  1986年   74篇
  1985年   101篇
  1984年   72篇
  1983年   55篇
  1982年   47篇
  1981年   44篇
  1980年   32篇
  1979年   35篇
  1978年   32篇
  1977年   26篇
  1976年   15篇
  1975年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
ObjectivesCocaine is the second most frequently used illicit drug worldwide (after cannabis), and cocaine use disorder (CUD)-related deaths increased globally by 80% from 1990 to 2013. There is yet to be a regulatory-approved treatment. Emerging preclinical evidence indicates that deep brain stimulation (DBS) of the nucleus accumbens may be a therapeutic option. Prior to expanding the costly investigation of DBS for treatment of CUD, it is important to ensure societal cost-effectiveness.AimsWe conducted a threshold and cost-effectiveness analysis to determine the success rate at which DBS would be equivalent to contingency management (CM), recently identified as the most efficacious therapy for treatments of CUDs.Materials and MethodsQuality of life, efficacy, and safety parameters for CM were obtained from previous literature. Costs were calculated from a societal perspective. Our model predicted the utility benefit based on quality-adjusted life-years (QALYs) and incremental-cost-effectiveness ratio resulting from two treatments on a one-, two-, and five-year timeline.ResultsOn a one-year timeline, DBS would need to impart a success rate (ie, cocaine free) of 70% for it to yield the same utility benefit (0.492 QALYs per year) as CM. At no success rate would DBS be more cost-effective (incremental-cost-effectiveness ratio <$50,000) than CM during the first year. Nevertheless, as DBS costs are front loaded, DBS would need to achieve success rates of 74% and 51% for its cost-effectiveness to exceed that of CM over a two- and five-year period, respectively.ConclusionsWe find DBS would not be cost-effective in the short term (one year) but may be cost-effective in longer timelines. Since DBS holds promise to potentially be a cost-effective treatment for CUDs, future randomized controlled trials should be performed to assess its efficacy.  相似文献   
55.
56.
Basic biochemical tests are frequently obtained in acutely unwell neonates and children, as well as in some elective situations. Correct interpretation can be invaluable in identifying rare inherited primary metabolic disorders, but secondary causes of hyperammonaemia, elevated blood lactate or blood gas derangement are more common and require appropriate treatment of the underlying cause. This Personal Practice guide provides an overview of these tests and their interpretation.  相似文献   
57.
ABSTRACT

Objectives: Limited evidence has suggested that cefoperazone-sulbactam causes coagulation disorders and bleeding.

Methods: The authors conducted a retrospective study to compare patients receiving cefoperazone-sulbactam versus those treated with cefoperazone-tazobactam or ceftazidime. Propensity-score matching was used to explore whether treatment with cefoperazone-sulbactam increased the risk of prothrombin time (PT) prolongation, coagulation disorders, and bleeding, or decreased platelets (PLT).

Results: The cohort included 23,242 patients. Among patients receiving cefoperazone-sulbactam, the risk of PT prolongation, coagulation disorders, decreased PLT, and bleeding was 5.3%, 9.2%, 15.7%, and 4.2%, respectively. Propensity-score matching analyses suggested that cefoperazone-sulbactam increased the risk of PT prolongation (aOR 2.26, 95% CI 1.61–3.18), coagulation disorders (aOR 1.81, 95% CI 1.43–2.30), and decreased PLT (aOR 1.46, 95% CI 1.25–1.72), but not increase bleeding (aOR 1.05, 95% CI 0.79–1.40) compared with ceftazidime. Patients receiving cefoperazone-sulbactam had higher risk of PT prolongation (aOR 1.53, 95% CI 1.11–2.10), coagulation disorders (aOR 1.53, 95% CI 1.21–1.95), but not decreased PLT (aOR 0.93, 95% CI 0.81–1.07) or bleeding (aOR 1.11, 95% CI 0.87–1.42), compared with those receiving cefoperazone-tazobactam.

Conclusion: Cefoperazone-sulbactam may be associated with a higher risk of PT prolongation and coagulation disorders compared with cefoperazone-tazobactam and ceftazidime.  相似文献   
58.
IntroductionGrowing geriatric mental health needs of urban population in India pose several programmatic challenges. This study aimed to assess anxiety, depression and cognitive disorders among urban elderly, and explore availability of social support mechanisms and of a responsive health system to implement the national mental health programme.Methods244 respondents were randomly selected from Berhampur city. We administered a semi-structured interview schedule to assess substance abuse, chronic morbidity, anxiety, depression and cognitive abilities. Further, in-depth interviews were conducted with 25 key informants including district officials, psychiatrists, and programme managers. We used R software and ‘thematic framework’ approach, respectively, for quantitative and qualitative data analysis. Ethical standards were complied with.ResultsAbout half of the respondents were economically dependent; 57.3% had moderate to severe anxiety; 46.7% had moderate to severe depression; while about 25% had severe cognitive impairments. We found association of chewing tobacco (1.34(0.28–2.40)) and depression (0.52(0.37–0.68)) with anxiety; negative perception about elderly-friendly society (1.64(0.75–2.53)) and physical inactivity (2.88(1.60–4.16)) with depression; and age (-0.11(-0.20 – -0.02)) and physical inactivity (-3.44(-5.13 – -1.74)) with cognitive disorders. Qualitative analysis revealed lack of awareness, social stigma, poor availability of trained human resources, and poor political commitment as important systemic barriers to early detection and treatment of mental ailments among the elderly.ConclusionEstablishing tobacco cessation centres, sensitizing community about mental health needs of elderly, incentivizing physical activity of elderly, integrating mental health with primary care, multi-skilling providers and developing a cadre of community counsellors need urgent attention of policy makers and programme implementers.  相似文献   
59.
60.

Purpose

To quantify eating disorder (ED) stability and diagnostic transition among a community-based sample of adolescents and young adult females in the United States.

Methods

Using 11 prospective assessments from 9,031 U.S. females ages 9–15 years at baseline of the Growing Up Today Study, we classified cases of the following EDs involving bingeing and purging: bulimia nervosa (BN), binge ED, purging disorder (PD), and subthreshold variants defined by less frequent (monthly vs. weekly) bingeing and purging behaviors. We measured number of years symptomatic and probability of maintaining symptoms, crossing to another diagnosis, or resolving symptoms across consecutive surveys.

Results

Study lifetime disorder prevalence was 2.1% for BN and roughly 6% each for binge ED and PD. Most cases reported symptoms during only one survey year. Twenty-six percent of cases crossed between diagnoses during follow-up. Among participants meeting full threshold diagnostic criteria, transition from BN was most prevalent, crossing most frequently from BN to PD (12.9% of BN cases). Within each disorder phenotype, 20%–40% of cases moved between subthreshold and full threshold criteria across consecutive surveys.

Conclusions

Diagnostic crossover is not rare among adolescent and young adult females with an ED. Transition patterns from BN to PD add support for considering these classifications in the same diagnostic category of disorders that involve purging. The prevalence of crossover between monthly and weekly symptom frequency suggests that a continuum or staging approach may increase utility of ED classification for prognostic and therapeutic intervention.  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