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   2660452篇
  免费   191223篇
  国内免费   5172篇
耳鼻咽喉   36603篇
儿科学   88328篇
妇产科学   74723篇
基础医学   380388篇
口腔科学   76915篇
临床医学   234473篇
内科学   517132篇
皮肤病学   58948篇
神经病学   206833篇
特种医学   101746篇
外国民族医学   597篇
外科学   406636篇
综合类   59830篇
现状与发展   5篇
一般理论   775篇
预防医学   197639篇
眼科学   63066篇
药学   197735篇
  8篇
中国医学   6126篇
肿瘤学   148341篇
  2018年   28264篇
  2017年   21390篇
  2016年   23778篇
  2015年   27145篇
  2014年   37708篇
  2013年   55919篇
  2012年   77206篇
  2011年   81992篇
  2010年   48512篇
  2009年   45525篇
  2008年   77223篇
  2007年   82773篇
  2006年   83655篇
  2005年   80834篇
  2004年   78046篇
  2003年   74752篇
  2002年   72673篇
  2001年   129793篇
  2000年   133165篇
  1999年   111286篇
  1998年   30411篇
  1997年   26806篇
  1996年   26968篇
  1995年   25705篇
  1994年   23990篇
  1993年   22074篇
  1992年   86823篇
  1991年   84422篇
  1990年   81965篇
  1989年   79277篇
  1988年   72951篇
  1987年   71429篇
  1986年   67737篇
  1985年   64513篇
  1984年   47650篇
  1983年   40986篇
  1982年   23661篇
  1981年   21116篇
  1979年   43666篇
  1978年   30309篇
  1977年   26046篇
  1976年   24332篇
  1975年   26250篇
  1974年   31529篇
  1973年   30312篇
  1972年   28541篇
  1971年   26403篇
  1970年   24637篇
  1969年   23419篇
  1968年   21977篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.

Aims

To examine the influence of pre-existing psychiatric disorder on the choice of treatment in patients with gynaecological cancer.

Materials and methods

The analyses were based on all patients who underwent surgical treatment for endometrial, ovarian or cervical cancer who were registered in the Danish Gynecological Cancer Database in the years 2007–2014 (3059 patients with ovarian cancer, 5100 patients with endometrial cancer and 1150 with cervical cancer). Logistic regression model and Cox regression model, adjusted for relevant confounders, were used to estimate the effect of pre-existing psychiatric disorder on the course of cancer treatment. Our outcomes were (i) presurgical oncological treatment, (ii) macroradical surgery for patients with ovarian cancer, (iii) radiation/chemotherapy within 30 days and 100 days after surgery and (iv) time from surgery to first oncological treatment.

Results

In the group of patients with ovarian cancer, more patients with a psychiatric disorder received macroradical surgery versus patients without a psychiatric disorder, corresponding to an adjusted odds ratio of 1.24 (95% confidence interval 0.62–2.41) and the chance for having oncological treatment within 100 days was odds ratio = 1.26 (95% confidence interval 0.77–2.10). As for patients with endometrial cancer, all outcome estimates were close to unity. The adjusted odds ratio for oncological treatment within 30 days after surgery in patients with cervical cancer with a history of psychiatric disorder was 0.20 (95% confidence interval 0.03–1.54).

Conclusions

We did not find any significant differences in the treatment of ovarian and endometrial cancer in patients with pre-existing psychiatric diagnoses. When it comes to oncological treatment, we suggest that increased attention should be paid to patients with cervical cancer having a pre-existing psychiatric diagnosis.  相似文献   
12.

Objective

To determine whether differences in combination DTaP vaccine types at 2, 4 and 6?months of age were associated with mortality (all-cause or non-specific), within 30?days of vaccination.

Design

Observational nationwide cohort study.

Setting

Linked population data from the Australian Childhood Immunisation Register and National Death Index.

Participants

Australian infants administered a combination trivalent, quadrivalent or hexavalent DTaP vaccine (DTaP types) between January 1999 and December 2010 at 2, 4 and 6?months as part of the primary vaccination series. The study population included 2.9, 2.6, & 2.3?million children in the 2, 4 and 6?month vaccine cohorts, respectively.

Main outcome measures

Infants were evaluated for the primary outcome of all-cause mortality within 30?days. A secondary outcome was non-specific mortality (unknown cause of death) within 30?days of vaccination. Non-specific mortality was defined as underlying or other cause of death codes, R95 ‘Sudden infant death syndrome’, R96 ‘Other sudden death, cause unknown’, R98 ‘Unattended death’, R99 ‘Other ill-defined and unspecified cause of mortality’ or where no cause of death was recorded.

Results

The rate of 30?day all-cause mortality was low and declined from 127.4 to 59.3 deaths per 100,000 person-years between 2 and 6?month cohorts. When compared with trivalent DTaP vaccines, no elevated risk in all-cause or non-specific mortality was seen with any quadrivalent or hexavalent DTaP vaccines, for any cohort.

Conclusion

Use of routine DTaP combination vaccines with differing disease antigens administered during the first six months of life is not associated with infant mortality.  相似文献   
13.

Background

The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.

Objectives

The purpose of this study was to assess whether a diagnostic strategy based on coronary computed tomographic angiography (CTA) is superior to functional stress testing in reducing adverse cardiovascular (CV) outcomes (CV death or myocardial infarction [MI]) among symptomatic patients with diabetes.

Methods

PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) was a randomized trial evaluating an initial strategy of CTA versus functional testing in stable outpatients with symptoms suggestive of CAD. The study compared CV outcomes in patients with diabetes (n = 1,908 [21%]) and without diabetes (n = 7,058 [79%]) based on their randomization to CTA or functional testing.

Results

Patients with diabetes (vs. without) were similar in age (median 61 years vs. 60 years) and sex (female 54% vs. 52%) but had a greater burden of CV comorbidities. Patients with diabetes who underwent CTA had a lower risk of CV death/MI compared with functional stress testing (CTA: 1.1% [10 of 936] vs. stress testing: 2.6% [25 of 972]; adjusted hazard ratio: 0.38; 95% confidence interval: 0.18 to 0.79; p = 0.01). There was no significant difference in nondiabetic patients (CTA: 1.4% [50 of 3,564] vs. stress testing: 1.3% [45 of 3,494]; adjusted hazard ratio: 1.03; 95% confidence interval: 0.69 to 1.54; p = 0.887; interaction term for diabetes p value = 0.02).

Conclusions

In diabetic patients presenting with stable chest pain, a CTA strategy resulted in fewer adverse CV outcomes than a functional testing strategy. CTA may be considered as the initial diagnostic strategy in this subgroup. (PROspective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550)  相似文献   
14.
In this review we summarize the impact of the various modalities of breast cancer therapy coupled with intrinsic patient factors on incidence of subsequent treatment-induced myelodysplasia and acute myelogenous leukemia (t-MDS/AML). It is clear that risk is increased for patients treated with radiation and chemotherapy at younger ages. Radiation is associated with modest risk, whereas chemotherapy, particularly the combination of an alkylating agent and an anthracycline, carries higher risk and radiation and chemotherapy combined increase the risk markedly. Recently, treatment with granulocyte colony-stimulating factor (G-CSF), but not pegylated G-CSF, has been identified as a factor associated with increased t-MDS/AML risk. Two newly identified associations may link homologous DNA repair gene deficiency and poly (ADP-ribose) polymerase inhibitor treatment to increased t-MDS/AML risk. When predisposing factors, such as young age, are combined with an increasing number of potentially leukemogenic treatments that may not confer large risk singly, the risk of t-MDS/AML appears to increase. Patient and treatment factors combine to form a biological cascade that can trigger a myelodysplastic event. Patients with breast cancer are often exposed to many of these risk factors in the course of their treatment, and triple-negative patients, who are often younger and/or BRCA positive, are often exposed to all of them. It is important going forward to identify effective therapies without these adverse associated effects and choose existing therapies that minimize the risk of t-MDS/AML without sacrificing therapeutic gain.

Implications for Practice

Breast cancer is far more curable than in the past but requires multimodality treatment. Great care must be taken to use the least leukemogenic treatment programs that do not sacrifice efficacy. Elimination of radiation and anthracycline/alkylating agent regimens will be helpful where possible, particularly in younger patients and possibly those with homologous repair deficiency (HRD). Use of colony-stimulating factors should be limited to those who truly require them for safe chemotherapy administration. Further study of a possible leukemogenic association with HRD and the various forms of colony-stimulating factors is badly needed.
  相似文献   
15.
Abstract

This study is a single-center, retrospective analysis of postmenopausal women presenting with dyspareunia and vulvar pain, aiming to evaluate relative effectiveness of vestibular CO2 laser therapy as a treatment. Three monthly sessions of laser were performed to each patient and thereafter a three-months follow-up was stablished. A total number of 72 patients undergoing vestibular laser treatment were recruited from patient files in the period between 2016 and 2018. Among these, 39 women also received a concomitant treatment with ospemifene (60?mg/day) during the study period. There was a statistically significant reduction of all the symptoms in both groups up to the three month follow-up. Regarding dryness and dyspareunia, the relief tent to be more prominent in the ospemifene?+?laser group at all follow-ups and remained statistically significant at three-month follow-up. Specifically, vestibular dryness was significantly lower in the ospemifene?+?laser group compared with the laser treatment group (?87% vs???34%, respectively), and the vestibular health score started declining faster in the ospemifene?+?laser group. Although, additional research is needed to understand the mechanism of action, our data shows that a combination regimen of laser and ospemifene may improve clinical effectiveness for long-term treatment of symptoms associated with the under-recognized genitourinary syndrome of menopause.  相似文献   
16.
17.
18.

Background

Nursing Home Compare (NHC) ratings, created and maintained by Medicare, are used by both hospitals and consumers to aid in the skilled nursing facility (SNF) selection process. To date, no studies have linked NHC ratings to actual episode-based outcomes. The purpose of this study was to evaluate whether NHC ratings are valid predictors of 90-day complications, readmission, and bundle costs for patients discharged to an SNF after primary total joint arthroplasty (TJA).

Methods

All SNF-discharged primary TJA cases in 2017 at a multihospital academic health system were queried. Demographic, psychosocial, and clinical variables were manually extracted from the health record. Medicare NHC ratings were then collected for each SNF. For patients in the Medicare bundle, postacute and total bundle cost was extracted from claims.

Results

Four hundred eighty-eight patients were discharged to a total of 105 unique SNFs. In multivariate analysis, overall NHC rating was not predictive of 90-day readmission/major complications, >75th percentile postacute cost, or 90-day bundle cost exceeding the target price. SNF health inspection and quality measure ratings were also not predictive of 90-day readmission/major complications or bundle performance. A higher SNF staffing rating was independently associated with a decreased odds for >75th percentile 90-day postacute spend (odds ratio, 0.58; P = .01) and a 90-day bundle cost exceeding the target price (odds ratio = 0.69; P = .02) but was similarly not predictive of 90-day readmission/complications.

Conclusion

Results of our study suggest that Medicare's NHC tool is not a useful predictor of 90-day costs, complications, or readmissions for SNFs within our health system.  相似文献   
19.

Aims

Variations of the anatomy of donor hepatic arteries increase the number of arterial anastomoses during liver transplantation and, possibly, the incidence of hepatic artery thrombosis (HAT). In this study, we describe the arterial anatomic variations in liver grafts procured and transplanted by a single center in Greece, the techniques of arterial anastomosis, and their effect on the incidence of early HAT.

Materials and Methods

From January 2013 to December 2017, the arterial anatomy of 116 grafts procured for liver transplantation were recorded, as well as the technique of arterial anastomosis and the incidence of early hepatic artery thrombosis (HAT <30 days).

Results

A single hepatic artery was recorded in 72.41% of the procured grafts, an aberrant left hepatic artery (accessory or replaced) in 18 grafts (15.52%), and an aberrant right hepatic artery (accessory or replaced) in 17 grafts (14.66%), while other variations were observed in less than 1% of the procured livers. Of the 116 primary liver transplantations, 6 patients (5.17%) developed early HAT <30 days. Two of these patients (1.72%) had 1 anastomosis of the hepatic artery and 4 (3.45%) had 2 anastomoses due to anatomic variations.

Conclusions

Anatomic variations of the hepatic artery in liver grafts is a common finding and increase the incidence of early HAT but not to a degree to make these grafts unusable.  相似文献   
20.
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