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   168051篇
  免费   6940篇
  国内免费   376篇
耳鼻咽喉   2228篇
儿科学   4864篇
妇产科学   4030篇
基础医学   24189篇
口腔科学   5486篇
临床医学   9680篇
内科学   37187篇
皮肤病学   4658篇
神经病学   13551篇
特种医学   4123篇
外国民族医学   1篇
外科学   19354篇
综合类   841篇
一般理论   26篇
预防医学   20087篇
眼科学   4378篇
药学   13161篇
中国医学   690篇
肿瘤学   6833篇
  2023年   819篇
  2022年   649篇
  2021年   2757篇
  2020年   1558篇
  2019年   3129篇
  2018年   5015篇
  2017年   3129篇
  2016年   3125篇
  2015年   3468篇
  2014年   4023篇
  2013年   6056篇
  2012年   10224篇
  2011年   10856篇
  2010年   5470篇
  2009年   4105篇
  2008年   8870篇
  2007年   9498篇
  2006年   9085篇
  2005年   8705篇
  2004年   8053篇
  2003年   7555篇
  2002年   7186篇
  2001年   5006篇
  2000年   5548篇
  1999年   4258篇
  1998年   845篇
  1992年   2280篇
  1991年   2041篇
  1990年   2015篇
  1989年   1728篇
  1988年   1626篇
  1987年   1531篇
  1986年   1578篇
  1985年   1471篇
  1984年   1050篇
  1983年   912篇
  1979年   1217篇
  1978年   808篇
  1977年   785篇
  1976年   749篇
  1975年   883篇
  1974年   1130篇
  1973年   1177篇
  1972年   1125篇
  1971年   1087篇
  1970年   1012篇
  1969年   1087篇
  1968年   1112篇
  1967年   983篇
  1966年   884篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Synthetic amorphous silica (SAS) in its nanosized form is now used in food applications although the potential risks for human health have not been evaluated. In this study, genotoxicity and oxidative DNA damage of two pyrogenic (NM‐202 and 203) and two precipitated (NM‐200 and ‐201) nanosized SAS were investigated in vivo in rats following oral exposure. Male Sprague Dawley rats were exposed to 5, 10, or 20 mg/kg b.w./day for three days by gavage. DNA strand breaks and oxidative DNA damage were investigated in seven tissues (blood, bone marrow from femur, liver, spleen, kidney, duodenum, and colon) with the alkaline and the (Fpg)‐modified comet assays, respectively. Concomitantly, chromosomal damage was investigated in bone marrow and in colon with the micronucleus assay. Additionally, malondialdehyde (MDA), a lipid peroxidation marker, was measured in plasma. When required, a histopathological examination was also conducted. The results showed neither obvious DNA strand breaks nor oxidative damage with the comet assay, irrespective of the dose and the organ investigated. Similarly, no increases in chromosome damage in bone marrow or lipid peroxidation in plasma were detected. However, although the response was not dose‐dependent, a weak increase in the percentage of micronucleated cells was observed in the colon of rats treated with the two pyrogenic SAS at the lowest dose (5 mg/kg b.w./day). Additional data are required to confirm this result, considering in particular, the role of agglomeration/aggregation of SAS NMs in their uptake by intestinal cells. Environ. Mol. Mutagen. 56:218–227, 2015. © 2014 Wiley Periodicals, Inc.  相似文献   
52.

Objective

To discover the experiences of end-of-life patients attended by the emergency services, through the discourse of the family caregivers who accompanied the family member in this care transit.

Method

A qualitative approach study, based on the paradigm of hermeneutical phenomenology. In total, 81 family caregivers participated. The techniques used were the in-depth interview and the discussion group, with a total of 5 discussion groups and 41 interviews. The period of data collection was carried out between January 2013 and June 2014.

Results

In the network of discourses obtained with respect to “Urgent Care”, all the codes were grouped in relation to a single argumentative line: deficiencies in urgent care. Among them, we found different dimensions that are established depending on the different times of care, or the different determinant aspects of these deficiencies: disorganization of the care received, lack of experience of the professionals in emergencies, application of general protocols in the emergency services, inadequate care in the treatment received, delays in emergency care.

Conclusions

In general, we highlight the dissatisfaction of the family members with respect to the care received from the emergency services. The needs of these types of situation are not covered from these services and are of low quality. Therefore, it is necessary to reorient the care protocols for these patients.  相似文献   
53.
54.
Most of the patients who overcome the SARS-CoV-2 infection do not present complications and do not require a specific follow-up, but a significant proportion (especially those with moderate / severe clinical forms of the disease) require clinicalradiological follow-up. Although there are hardly any references or clinical guidelines regarding the long-term follow-up of post-COVID-19 patients, radiological exams are being performed and monographic surveillance consultations are being set up in most of the hospitals to meet their needs. The purpose of this work is to share our experience in the management of the post-COVID-19 patient in two institutions thathave had a high incidence of COVID-19 and to propose general follow-uprecommendations from a clinical and radiological perspective.  相似文献   
55.
IntroductionScales for predicting venous thromboembolism (VTE) recurrence are useful for deciding the duration of the anticoagulant treatment. Although there are several scales, the most appropriate for our setting has not been identified. For this reason, we aimed to validate the DASH prediction score and the Vienna nomogram at 12 months.MethodsThis was a retrospective study of unselected consecutive VTE patients seen between 2006 and 2014. We compared the ability of the DASH score and the Vienna nomogram to predict recurrences of VTE. The validation was performed by stratifying patients as low-risk or high-risk, according to each scale (discrimination) and comparing the observed recurrence with the expected rate (calibration).ResultsOf 353 patients evaluated, 195 were analyzed, with an average age of 53.5 ± 19 years. There were 21 recurrences in 1 year (10.8%, 95% CI: 6.8%-16%). According to the DASH score, 42% were classified as low risk, and the rate of VTE recurrence in this group was 4.9% (95% CI: 1.3%-12%) vs. the high-risk group that was 15% (95% CI: 9%-23%) (p <.05). According to the Vienna nomogram, 30% were classified as low risk, and the rate of VTE recurrence in the low risk group vs. the high risk group was 4.2% (95% CI:0.5%-14%) vs. 16.2% (95% CI: 9.9%-24.4%) (p <.05).ConclusionsOur study validates the DASH score and the Vienna nomogram in our population. The DASH prediction score may be the most advisable, both because of its simplicity and its ability to identify more low-risk patients than the Vienna nomogram (42% vs. 30%).  相似文献   
56.
57.
58.
Development of the Practical Solutions for Pesticide Safety guide used participatory research strategies to identify and evaluate solutions that reduce pesticide exposures for workers and their families and to disseminate these solutions. Project principles were (1) workplace chemicals belong in the workplace, and (2) pesticide handlers and farm managers are experts, with direct knowledge of production practices. The project’s participatory methods were grounded in self-determination theory. Practical solutions were identified and evaluated based on five criteria: practicality, adaptability, health and safety, novelty, and regulatory compliance. Research activities that had more personal contact provided better outcomes. The Expert Working Group, composed of farm managers and pesticide handlers, was key to the identification of solutions, as were farm site visits. Audience participation, hands-on testing, and orchard field trials were particularly effective in the evaluation of potential solutions. Small work groups in a Regional Advisory Committee provided the best direction and guidance for a “user-friendly” translational document that provided evidence-based practical solutions. The “farmer to farmer” format of the guide was endorsed by both the Expert Working Group and the Regional Advisory Committee. Managers and pesticide handlers wanted to share their solutions in order to “help others stay safe,” and they appreciated attribution in the guide. The guide is now being used in educational programs across the region. The fundamental concept that farmers and farmworkers are innovators and experts in agricultural production was affirmed by this study. The success of this process demonstrates the value of participatory industrial hygiene in agriculture.  相似文献   
59.
60.

Introduction

The fast track / ultra-fast-track protocols are techniques used to optimise the patient care process and a quick recovery after cardiac surgery. They are one of the mainstays of efficient practice. With their use, the length of hospital and intensive care unit (ICU) stays are reduced, with a direct impact on costs and the quality of the health service.

Objective

To compare the length of stay in the ICU, length of hospital stay, and post-operative mortality in ultra-fast-track extubated (uFTE) patients and those with conventional extubation (CE) after cardiac surgery.

Methods

Longitudinal, analytical, retrospective study was conducted, with the period between the time of surgery and discharge being included as the study period.

Results

A total of 396 patients older than 18 years who required cardiac surgery were included, of whom 207 patients had (uFTE) and 189 had CE. Although the groups were not comparable due to the statistical differences found, when performing the multivariate adjustment, uFTE maintained its statistical independence and was associated with lower cardiovascular morbidity, such as myocardial ischaemia (95% CI: 0.37-0.86; P = .01) and lower post-surgical vasopressor requirement (95% CI: 0.18-0.49; P < .01). No significant differences were found in the length of hospital stay, ICU stay, or post-operative mortality in the ICU.

Conclusion

Implementing the uFTE strategy, decreases cardiovascular morbidity and vasopressor requirement. The change to uFTE should be accompanied by changes in models and practices in patient recovery to standardised protocols. This study shows that uFTE did not reduce the length of ICU stay, hospital stay, or mortality.  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