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   106800篇
  免费   6011篇
  国内免费   648篇
耳鼻咽喉   1041篇
儿科学   3472篇
妇产科学   2449篇
基础医学   15356篇
口腔科学   3923篇
临床医学   9693篇
内科学   24042篇
皮肤病学   2708篇
神经病学   10428篇
特种医学   2484篇
外国民族医学   1篇
外科学   9492篇
综合类   395篇
一般理论   48篇
预防医学   10694篇
眼科学   1716篇
药学   7466篇
中国医学   417篇
肿瘤学   7634篇
  2024年   120篇
  2023年   1027篇
  2022年   2208篇
  2021年   3649篇
  2020年   2287篇
  2019年   3072篇
  2018年   3486篇
  2017年   2660篇
  2016年   3096篇
  2015年   3421篇
  2014年   4494篇
  2013年   5869篇
  2012年   8922篇
  2011年   9282篇
  2010年   5062篇
  2009年   4257篇
  2008年   7373篇
  2007年   7367篇
  2006年   6779篇
  2005年   6316篇
  2004年   5676篇
  2003年   5047篇
  2002年   4540篇
  2001年   533篇
  2000年   368篇
  1999年   581篇
  1998年   787篇
  1997年   642篇
  1996年   544篇
  1995年   448篇
  1994年   427篇
  1993年   349篇
  1992年   283篇
  1991年   188篇
  1990年   191篇
  1989年   176篇
  1988年   170篇
  1987年   141篇
  1986年   156篇
  1985年   109篇
  1984年   132篇
  1983年   128篇
  1982年   155篇
  1981年   115篇
  1980年   124篇
  1979年   71篇
  1978年   77篇
  1977年   70篇
  1976年   58篇
  1974年   52篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
991.
Objectives. We investigated whether eventual causes of death among a cohort of inmates imprisoned in the southeastern United States differed from those in previous prisoner studies.Methods. We matched 23 510 prisoners in Georgia, a state with historically low levels of heroin consumption but moderate amounts of injection drug use, who were incarcerated on June 30, 1991, to death registries through 2010. Main exposure was 4-year time intervals over 2 decades of observation; main outcome was mortality from liver disease, HIV, and overdose.Results. Although the HIV-related mortality rate exceeded that from liver-related conditions before 2003, liver disease subsequently surpassed HIV as a cause of death. Among 3863 deaths, 22 (0.6%) occurred within 2 weeks after release from prison. Of these, only 2 were caused by accidental poisoning (likely drug overdose). Cardiovascular disease and cancer were the most frequent causes of death in this aging cohort.Conclusions. Our study design deemphasized immediate deaths but highlighted long-term sequelae of exposure to viral hepatitis and alcohol. Treating hepatitis C and implementing interventions to manage alcohol use disorders may improve survival among prisoners in the Southeast.Drug use, incarceration, and mortality are intertwined: the use of illicit drugs can result in both incarceration and premature death. A 2010 international meta-analysis of prisoners'' survival after their release into the community emphasized mortality from overdose in the 2 weeks following discharge, possibly attributable to loss of opiate tolerance after forced sobriety in prison,1 but a more recent publication illustrates how this pattern may vary among subpopulations.2Long-term consequences of injection drug use include hepatitis C and HIV infection. In the United States, sexual exposure is the most common mode of HIV transmission, but the hepatitis C epidemic is mainly driven by the injection of drugs, even if the drug use is not sustained.3 HIV prevalence is 3 times as common among prisoners as among the general population,4 but hepatitis C prevalence is 13 times as high.5,6 Sequelae that could lead to death from hepatitis C typically occur 2 to 4 decades after injection drug use was initiated. Little is known about the long-term survival of inmates, particularly in the southeastern United States, where historical and recent patterns of drug use may differ from those in other regions.In contrast with other studies that have examined cohorts of released inmates, we sought to assess long-term prisoner survival by retrospectively following a cohort composed of a cross section of all imprisoned persons in the state of Georgia on a single day in 1991. In a previous study, we did not observe significantly higher mortality among members of this cohort immediately after release from prison than in the subsequent postrelease period.7 Multiple sources suggest that heroin use is less common in Georgia than in other states. Between 2002 and 2012, consistently fewer than 6.5% of men jailed in Atlanta, the capital of and largest city in Georgia, had evidence of heroin in their urine samples.8,9 The prevalence of opiate use in Atlanta was among the lowest for any city studied in the past decade by the Office of the National Drug Control Policy.8–10 In particular, heroin use was lower than in Washington State, site of a previous study of former inmate mortality.11 According to the Treatment Episode Data Set–Admissions for 1992 to 2010 from the Substance Abuse and Mental Health Services Administration, heroin addiction accounted for only 1.6% of admissions for drug rehabilitation in Georgia, but 9.7% in Washington State and 14.2% nationally.12In assessment of risk for hepatitis C, needle use—whether for heroin, cocaine, or another drug—is more important than what is injected. Needle use in Georgia is not uncommon. According to population-wide National Survey on Drug Use and Health data for 2002 to 2009, 1.1% of Georgians have ever used a needle to inject drugs, including cocaine—a moderate rate compared with the frequency in Washington State, where lifetime prevalence is 2.7%, and nationally, where prevalence is 1.6%.13 State-level data on needle use prior to 2002 are not publically available from the Substance Abuse and Mental Health Services Administration.The prevalence of hepatitis C in the Georgia general population is moderately high, especially in Atlanta. At Grady Memorial Hospital, the safety net charity hospital for Atlanta, the prevalence of hepatitis C among ambulatory primary care patients is 7%. A liver clinic established at this hospital saw 807 unique patients in its first 5 years of existence and was still receiving 60 new patient referrals each month through 2010.14 Three quarters of the patients were African American, and most patients were born between 1945 and 1965; 64% were former drug users, and only 4% were currently using.14 High prevalence of hepatitis C in this baby boomer birth cohort probably reflects time-limited parenteral drug use decades ago, perhaps as early as the Vietnam war era.15 Despite relatively low levels of heroin use in the state, we hypothesized that the prevalence of hepatitis C would be high among inmates in the Georgia prison system who were born between 1945 and 1965.We sought to describe the leading causes of death over 2 decades in a large cohort of all Georgians who were in state prisons on June 30, 1991, and to evaluate whether the immediate mortality following prison discharge was low, because Georgia is a state with low heroin use. In light of the moderate background rates of injection drug use in Georgia, we hypothesized that mortality from liver-related causes would rise over time as the cohort aged. Our first aim was to rank the causes of death and categorize which deaths occurred in prison, immediately after release, and subsequently. Second, we compared deaths from liver disease to those from HIV in 4-year intervals between 1991 and 2010.  相似文献   
992.
993.
994.
995.

Objective

To examine associations between antidepressant use and health care utilization in young adults beginning maintenance hemodialysis (HD) therapy.

Patients and Methods

Antidepressant use, hospitalizations, and emergency department (ED) visits were examined in young adults (N=130; age, 18-44 years) initiating HD (from January 1, 2001, through December 31, 2013) at a midwestern US institution. Primary outcomes included hospitalizations and ED visits during the first year.

Results

Depression diagnosis was common (47; 36.2%) at HD initiation, yet only 28 patients (21.5%) in the cohort were receiving antidepressant therapy. The antidepressant use group was more likely to have diabetes mellitus (18 [64.3%] vs 33 [32.4%]), coronary artery disease (8 [28.6%] vs 12 [11.8%]), and heart failure (9 [32.1%] vs 15 [14.7%]) (P<.05 for all) than the untreated group. Overall, 68 (52.3%) had 1 or more hospitalizations and 33 (25.4%) had 1 or more ED visits in the first year. The risk of hospitalization during the first year was higher in the antidepressant use group (hazard ratio, 2.35; 95% CI, 1.39-3.96; P=.001), which persisted after adjustment for diabetes, coronary artery disease, and heart failure (hazard ratio, 1.94; 95% CI, 1.22-3.10; P=.006). Emergency department visit rates were similar between the groups.

Conclusion

Depression and antidepressant use for mood indication are common in young adult incident patients initiating HD and and are associated with higher hospitalization rates during the first year. Further research should determine whether antidepressants are a marker for other comorbidities or whether treated depression affects the increased health care use in these individuals.  相似文献   
996.
Objectives: There is evidence that increasing severity of hypertriglyceridemia increases the risk of acute pancreatitis. There is a debate about superiority of treatment methods and previous works have specifically called for direct comparison between IV insulin and apheresis techniques. Identify patient characteristics predictive of lipid-lowering therapy selection in a large community hospital for treatment of hypertriglyceridemia; evaluate for a concentration-dependent relationship between hypertriglyceridemia severity and risk of acute pancreatitis; assess for differences in clinical outcomes between patients treated with IV insulin versus apheresis.

Methods: Single center, retrospective cohort study including patients with hypertriglyceridemia between January 2007 and December 2016. Main measures included frequency of pancreatitis, choice of lipid-lowering therapy, and clinical comparisons of diet, oral lipid-lowering agents, IV insulin, and apheresis.

Results: Initial serum triglyceride level and disease acuity was higher among patients in insulin and apheresis groups. Neither triglyceride level, Charlson comorbidity index, age, BISAP score, nor initial CRP predicted use of IV insulin versus apheresis. Prevalence of pancreatitis increased with higher triglyceride level, reaching 48% with triglycerides >2000 md/dL (p < 0.001). There was a significant decrease in serum triglycerides at each time interval (p < 0.05) in patients treated with IV insulin and apheresis, but no difference in clearance rate between the two. Length of stay did not differ between IV insulin and apheresis.

Conclusion: The presence of pancreatitis, hyperglycemia, and hypertriglyceridemia severity influenced selection of therapies like IV insulin and apheresis. We found no superiority of either IV insulin or apheresis in the treatment of severe hypertriglyceridemia among patients hospitalized for pancreatitis.  相似文献   

997.
998.
Dialectical behavior therapy (DBT) has been shown to be successful in the treatment of borderline personality disorder and eating disorders separately. The present study compares Standard Dialectical Behavior Therapy with a Treatment as Usual Cognitive Behavior Therapy (TAU CBT) for the treatment of borderline personality disorder and eating disorders comorbid features. A total of 118 women diagnosed with borderline personality disorders and eating disorders were assigned to one of two treatment groups in a naturalistic setting (DBT?=?71; TAU CBT?=?47). DBT showed a greater decrease in dysfunctional behaviors used to regulate emotions and related to borderline personality disorder (i.e. substance abuse, impulsive money spending, unprotected sex, etc.), non-suicidal self-injuries, and depressive symptoms, as well as an increase in cognitive reappraisal and global functioning. DBT and TAU CBT showed similar improvements in suicide attempts, dysfunctional eating behaviors (i.e. binge eating, purgative behaviors, and restriction), hospitalizations, negative and positive affect, and expressive suppression. Results of this study support the utility and effectiveness of standard DBT for comorbid borderline personality disorder and eating disorders in naturalistic settings. Replications of this study and randomized controlled trials are needed.  相似文献   
999.
Previous studies indicate that emotion-relevant impulsivity is related to depression and relatedly, suicidal ideation and behavior. Little is known, however, about underlying mechanisms driving this impulsivity. We hypothesized that participants diagnosed with depression would show difficulties with emotion-related impulsivity and inhibition compared to controls, and that there would be a link between inhibition deficits and emotion-relevant impulsivity. To test these hypotheses, 60 participants diagnosed with lifetime major depressive disorder (MDD; 47 full-remission, 8 current MDD, 5 partial remission) and 100 nondepressed controls completed measures of impulsivity and current depressive symptoms, underwent a negative mood induction, and completed tasks that assessed components of inhibition: the ability to suppress pre-potent responses (antisaccade task) and the ability to resist interference (word-naming task). Although people with a history of MDD did not show cognitive inhibition deficits, they did endorse more emotion-related impulsivity, which in turn related to difficulty suppressing pre-potent responses. Limitations, as well as implications for future research and treatment are discussed.  相似文献   
1000.

Background

As the number of obese patients in the United States continues to grow, there is a parallel increase in the number of bariatric surgery patients. A quarter of these patients will return to the Emergency Department (ED) within the first two years of the index procedure.

Objective

An understanding of the most common bariatric procedures and their related complications will greatly aide the Emergency Medicine physician in the care of these patients.

Discussion

Abdominal pain is the most common reason for bariatric patients to present to the ED and can represent a diagnostic challenge to EM physicians. It is important that EM physicians have a good understanding of bariatric procedures. We describe the three most common bariatric procedures: 1) the Laparoscopic Adjustable Gastric Banding (LAGB); 2) the Laparoscopic Sleeve Gastrectomy (LSG); 3) and the Roux-en-Y Gastric Bypass (RYGB). Due to the unique altered anatomy following the procedures there are specific complications related to each individual procedure. We will describe the most common presentations of abdominal pain in the post bariatric surgery patient. Finally, we will review new endoscopic procedures and the associated complications that may cause patients to present to the ED.

Conclusion

Certain complications in bariatric surgery patients can have a high rate of morbidity and mortality. An improved understanding of bariatric procedures and their complications will allow for improved vigilance and management.  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