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   25618篇
  免费   2094篇
  国内免费   35篇
耳鼻咽喉   304篇
儿科学   862篇
妇产科学   749篇
基础医学   3548篇
口腔科学   362篇
临床医学   3219篇
内科学   4617篇
皮肤病学   406篇
神经病学   2753篇
特种医学   566篇
外科学   2686篇
综合类   362篇
现状与发展   1篇
一般理论   20篇
预防医学   3460篇
眼科学   363篇
药学   1560篇
  1篇
中国医学   19篇
肿瘤学   1889篇
  2023年   252篇
  2022年   398篇
  2021年   885篇
  2020年   540篇
  2019年   767篇
  2018年   859篇
  2017年   662篇
  2016年   743篇
  2015年   764篇
  2014年   933篇
  2013年   1407篇
  2012年   2069篇
  2011年   2028篇
  2010年   1028篇
  2009年   901篇
  2008年   1428篇
  2007年   1555篇
  2006年   1361篇
  2005年   1248篇
  2004年   1186篇
  2003年   1019篇
  2002年   961篇
  2001年   321篇
  2000年   290篇
  1999年   299篇
  1998年   201篇
  1997年   176篇
  1996年   127篇
  1995年   117篇
  1994年   103篇
  1993年   102篇
  1992年   196篇
  1991年   188篇
  1990年   179篇
  1989年   186篇
  1988年   179篇
  1987年   154篇
  1986年   175篇
  1985年   151篇
  1984年   157篇
  1983年   142篇
  1982年   95篇
  1981年   80篇
  1980年   77篇
  1979年   97篇
  1978年   80篇
  1976年   66篇
  1975年   68篇
  1974年   72篇
  1971年   59篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Characteristics of 1096 recidivistic mentally ill criminal offenders admitted to a specialized hospital in France are described. All subjects were mentally ill and had been judged nonresponsible for an act of crime. Crimes against persons (murder or assault) accounted for 42% of the crimes for which these patients were admitted. The remaining causes of admission were crimes against property (theft) and "victimless" crimes. Subject files indicated a wide difference in cause of admission for violent acts among the different diagnostic categories. Although the frequency of readmission and violent acts at readmission did not change for the group as a whole, they did change between admissions for the different diagnostic groups. Results indicate that differences exist between diagnostic categories of mentally ill offenders in terms of not only the type of crime committed but also the likelihood of recidivism.  相似文献   
102.
A Pavlovian conditioning model of tolerance emphasizes that an association between predrug cues and the systemic effects of the drug contributes to tolerance. On the basis of this model, established tolerance should be attenuated by external inhibition, i.e., by presentation of a novel, extraneous stimulus. This prediction was evaluated in the present experiment. Rats that were so tolerant to the hypothermic effect of ethanol that they evidenced no drug-induced decrease in temperature were presented with a bright strobe light following ethanol administration. The light precipitated a large decrease in temperature in these rats. These results provide further evidence that tolerance to the hypothermic effect of ethanol is, in part, mediated by learning.  相似文献   
103.
Maternal and Child Health Journal - This study assessed whether the use of a peer-to-peer educational book, written and illustrated by women who experienced common mental disorders (CMDs) in the...  相似文献   
104.
Context  Herpes simplex virus type 2 (HSV-2) is one of the most common sexually transmitted infections in the United States. No prospective study has shown the ability of condoms to reduce transmission of HSV-2. Objective  To evaluate risk factors for HSV-2 acquisition and efficacy of condoms in prevention of HSV-2 transmission. Design  Analysis of data from a randomized, double-blind, placebo-controlled trial conducted December 13, 1993, to June 28, 1996, of an ineffective candidate HSV-2 vaccine with 18 months of follow-up. Setting  Eighteen clinical trial centers in the United States. Participants  A total of 528 monogamous couples discordant for HSV-2 infection, including an HSV-2–susceptible population of 261 men and 267 women. Main Outcome Measure  Acquisition of HSV-2 infection by susceptible partners, compared with those remaining free of HSV-2 with regard to demographic characteristics, sexual activity, and condom use. Results  Twenty-six women (9.7%) vs 5 men (1.9%) acquired HSV-2, for a rate per 10 000 sex acts (episodes of sexual intercourse) of 8.9 vs 1.5, respectively (P<.001). In multivariable analysis, younger age (adjusted hazard ratio [HR] per 5 years, 1.57; 95% confidence interval [CI], 1.22-2.04), seropositivity for HSV-1 and HSV-2 vs HSV-2 alone in the source partner (adjusted HR, 2.34; 95% CI, 1.14-4.82), and more frequent sexual activity (adjusted HR per additional sex act per week, 1.10; 95% CI, 1.01-1.19) were associated with higher risk of HSV-2 acquisition. Condom use during more than 25% of sex acts was associated with protection against HSV-2 acquisition for women (adjusted HR, 0.085; 95% CI, 0.01-0.67) but not for men (adjusted HR, 2.02; 95% CI, 0.32-12.50). Risk of HSV-2 transmission declined from 8.5 per 100 person-years in the initial 150-day interval to 0.9 per 100 person-years in the final 150-day interval (P = .002 for trend), concurrent with a decrease in sexual activity and proportion of sex acts occurring when the source partner had genital lesions. Conclusions  Condom use offers significant protection against HSV-2 infection in susceptible women. Changes in sexual behavior, correlated with counseling about avoiding sex when a partner has lesions, were associated with reduction in HSV-2 acquisition over time. These data suggest that identification of discordant couples can reduce transmission of HSV-2, especially for heterosexual couples in which the male partner has HSV-2 infection.   相似文献   
105.
BackgroundMost pediatric cholecystectomies are performed by adult general surgeons, but it is unclear whether outcomes differ by surgeon pediatric subspecialization, hospital procedure volume, or surgeon procedure volume. We aimed to determine whether higher hospital or surgeon laparoscopic cholecystectomy (LC) volume or surgeon pediatric subspecialization is associated with better outcomes after LC in children.MethodsWe performed a retrospective cohort study using statewide hospital discharge databases from the states of Florida, Georgia, and Iowa. We included children aged 4–18 years who underwent inpatient or outpatient LC for acute or chronic gallbladder disease in January 2010–August 2015.Propensity score weighting was used to estimate relationships between operative volumes or surgeon pediatric subspecialization and rates of readmission or emergency department (ED) visit within 30 days.ResultsA total of 5391 children were included (mean age 15.9 years, 81.6% female). Children operated on by surgeons with high LC volumes in hospitals with high LC volumes were less likely to experience a readmission or ED visit within 30 days (10.8% vs. 13.7%, p = 0.04). Additionally, children operated on by adult general surgeons in hospitals with high LC volumes were less likely to experience a readmission or ED visit within 30 days (10.9% vs. 13.8%, p = 0.03).ConclusionsChildren are less likely to be readmitted to the hospital or present to the ED after laparoscopic cholecystectomy if they receive their care from adult general surgeons at hospitals that frequently perform this procedure in both adults and children.Level of evidenceIII  相似文献   
106.
107.
BackgroundPrior studies have demonstrated declines in androgen levels in men with cancer and patients undergoing anesthesia and surgery. In this study, we hypothesized that decreased serum androgen levels are prevalent in male patients undergoing radical cystectomy (RC) for bladder cancer and that it persists in the postoperative period. We characterized perioperative androgen hormonal profiles and examined for associated changes indicative of sarcopenia on computed tomography scans in men undergoing RC.MethodsWe implemented a prospective observational trial in men with newly diagnosed non-metastatic bladder cancer undergoing RC. Baseline pre-operative total testosterone (TT), free testosterone (FT), and luteinizing hormone (LH) were obtained on morning lab draws with 30 days of surgery. TT and FT were then repeated on postoperative days (POD) 2, 3, 30, and 90. The threshold for normal TT was defined as >300 ng/dl, consistent with the AUA Guidelines for Evaluation and Management of Testosterone Deficiency. We evaluated postoperative changes in weight and psoas muscle cross-sectional area using computed tomography scans to assess for sarcopenic changes.ResultsUnivariable statistical analysis was performed. 25 patients were enrolled. The mean patient age was 68.9 years. The mean pre-operative TT was 308 ng/dl, and 12/23 (52.5%) patients had low testosterone. Mean TT onPOD 2 and 3 were 166 ng/dl and 161 ng/dl, respectively (range 24–345). 19/20 (95%) of men who had morning lab draws had decreased TT. The mean TT at 30 days was 253 ng/dl with 37.5% of men having low TT. Mean TT at 90 days was 306 ng/dl. The mean FT levels were 43 ng/dl, 29.25 ng/dl, 28.2 ng/dl, 40.89 ng/dl, and 42.62 ng/dl at baseline, POD 2, POD 3, POD 30, and POD 90, respectively. Mean LH at baseline was 9.9 IU/L. Average weight loss at 30- and 90- days postop was -4.29 and -4.38 kilograms, respectively. Weight loss was persistent with only 3/23 (13%) returning to their presurgery weight by 90 days. Despite significant declines in weight and perioperative TT, no significant differences in psoas muscle cross-sectional area were observed (net change -92 mm2, P= 0.13)ConclusionsPerioperative disruption of androgen levels is prevalent in men undergoing RC. Our trial demonstrates a pre-op, immediate postop, 30- and 90-day postoperative prevalence of low TT of 52%, 95%, 63%, and 37.5%, respectively. Significant changes in baseline weight were noted, although no significant changes in psoas muscle cross-sectional area were observed, limiting conclusions regarding a link between changes in androgens and sarcopenia in this setting.  相似文献   
108.
Primary hyperoxaluria type 1 is a rare inherited disorder caused by abnormal liver glyoxalate metabolism leading to overproduction of oxalate, progressive kidney disease, and systemic oxalosis. While the disorder typically presents with nephrocalcinosis, recurrent nephrolithiasis, and/or early chronic kidney disease, the diagnosis is occasionally missed until it recurs after kidney transplant. Allograft outcomes in these cases are typically very poor, often with early graft loss. Here we present the case of a child diagnosed with primary hyperoxaluria type 1 after kidney transplant who was able to maintain kidney function, thanks to aggressive renal replacement therapy as well as initiation of a new targeted therapy for this disease. This case highlights the importance of having a high index of suspicion for primary hyperoxaluria in patients with chronic kidney disease and nephrocalcinosis/nephrolithiasis or with end stage kidney disease of uncertain etiology, as initiating therapies early on may prevent poor outcomes.  相似文献   
109.
110.
Journal of Community Health - While human papilloma virus (HPV) vaccinations and Pap smear screenings are known to improve the survival rates and incidence of cervical cancer, refugee populations...  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