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   55327篇
  免费   3753篇
  国内免费   187篇
耳鼻咽喉   552篇
儿科学   1801篇
妇产科学   1405篇
基础医学   7562篇
口腔科学   698篇
临床医学   7230篇
内科学   11333篇
皮肤病学   909篇
神经病学   5638篇
特种医学   1466篇
外国民族医学   1篇
外科学   5065篇
综合类   792篇
一般理论   43篇
预防医学   5535篇
眼科学   991篇
药学   3845篇
中国医学   95篇
肿瘤学   4306篇
  2023年   257篇
  2022年   465篇
  2021年   1103篇
  2020年   625篇
  2019年   1001篇
  2018年   1175篇
  2017年   912篇
  2016年   1027篇
  2015年   1203篇
  2014年   1664篇
  2013年   2456篇
  2012年   3678篇
  2011年   3924篇
  2010年   2015篇
  2009年   1931篇
  2008年   3465篇
  2007年   3726篇
  2006年   3727篇
  2005年   3649篇
  2004年   3521篇
  2003年   3314篇
  2002年   3091篇
  2001年   769篇
  2000年   680篇
  1999年   790篇
  1998年   624篇
  1997年   518篇
  1996年   484篇
  1995年   446篇
  1994年   352篇
  1993年   375篇
  1992年   478篇
  1991年   464篇
  1990年   450篇
  1989年   428篇
  1988年   379篇
  1987年   315篇
  1986年   314篇
  1985年   355篇
  1984年   309篇
  1983年   282篇
  1982年   304篇
  1981年   223篇
  1980年   227篇
  1979年   217篇
  1978年   145篇
  1977年   168篇
  1976年   139篇
  1975年   124篇
  1974年   125篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.

Background

Schizophrenia is a chronic mental illness that affects the client, family, and community. Nurses are educated to use the nurse-patient relationship to provide health education and collaborative health decision-making. However, challenges abound for nurses and clients with schizophrenia to effectively utilize the relationship to reach these goals.

Problem

There is a lack of evidence-based information to assist nurses to meet the challenges of building effective therapeutic relationships with clients for whom schizophrenia hinders health education and decision-making.

Purpose

To examine current research findings on factors that influence therapeutic relationships in psychiatric treatment settings as an initial effort to provide empirically based guidance for psychiatric nurses who seek to better use the relationship to work with the client toward health-related goals.

Method

This integrative review of the literature follows Whittemore and Knafl's (2015) method, analyzes 15 studies from multiple databases between the years 2006–2017, and assesses the rigor of each.

Findings

Numerous methods are used to assess therapeutic relationships. Few studies included nurses. Provider perception of client symptoms can negatively affect provider assessment of quality of relationship; no such association was found on the part of clients. Providers and clients prioritize client needs differently, with providers influenced by treatment setting demands, but provider-training programs can have a beneficial effect on their relationships.

Conclusion

Nurses and nurse educators can use the findings to guide assessment of how perceptions and priorities influence relationships. Findings also provide the foundation for further study of nurses' perceptions of therapeutic relationship, in progress, to yield more detailed information on what nurses and educators need to strengthen therapeutic relationships.  相似文献   
22.
23.
BACKGROUND AND PURPOSE: There is concern about the increase of radiation-induced malignancies with the application of modern radiation treatment techniques such as intensity-modulated radiotherapy (IMRT) and proton radiotherapy. Therefore, X-ray scatter and neutron radiation as well as the impact of the primary dose distribution on secondary cancer incidence are analyzed. MATERIAL AND METHODS: The organ equivalent dose (OED) concept with a linear-exponential and a plateau dose-response curve was applied to dose distributions of 30 patients who received radiation therapy of prostate cancer. Three-dimensional conformal radiotherapy was used in eleven patients, another eleven patients received IMRT with 6-MV photons, and eight patients were treated with spot-scanned protons. The treatment plans were recalculated with 15-MV and 18-MV photons. Secondary cancer risk was estimated based on the OED for the different treatment techniques. RESULTS: A modest increase of 15% radiation-induced cancer results from IMRT using low energies (6 MV), compared to conventional four-field planning with 15-MV photons (plateau dose-response: 1%). The probability to develop a secondary cancer increases with IMRT of higher energies by 20% and 60% for 15 MV and 18 MV, respectively (plateau dose-response: 2% and 30%). The use of spot-scanned protons can reduce secondary cancer incidence as much as 50% (independent of dose-response). CONCLUSION: By including the primary dose distribution into the analysis of radiation-induced cancer incidence, the resulting increase in risk for secondary cancer using modern treatment techniques such as IMRT is not as dramatic as expected from earlier studies. By using 6-MV photons, only a moderate risk increase is expected. Spot-scanned protons are the treatment of choice in regard to secondary cancer incidence.  相似文献   
24.
Chronic exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been shown to lead to the development of hepatotoxicity and carcinogenicity in the liver of female rats. In this study, we investigated hepatic gene downregulation in response to acute and subchronic TCDD exposure. We identified 61 probes which exhibited a downregulation of twofold or greater following subchronic (13 weeks) exposure to TCDD. Comparative analysis of the hepatic expression of these 61 probes was conducted with rats subchronically exposed to PeCDF, PCB126, PCB153, and a mixture of PCB126 and PCB153. PCB153 produced little or no alteration in these probes, while the binary mixture mimicked most closely the downregulation observed with TCDD. To discern if the repression of genes within this probe set occur as a primary response to TCDD exposure, we analyzed the early responsiveness of 11 genes at 6, 24, and 72 h following a single exposure to TCDD. We observed early repression of the 11 genes within this early time course, indicating that the repression of this subset of genes occurs as a primary response to TCDD exposure and not as a secondary response to 13 weeks of subchronic treatment. In addition, the gender, species, and AhR dependence of these responses were also investigated. Gender- and species-dependent repression was observed within this subset of genes. Furthermore, utilizing AhR knockout mice, we were able to determine the AhR-dependent downregulation of seven of 11 genes. Together these results assist efforts to understand the multitude of effects imposed by TCDD and AhR ligands on gene expression.  相似文献   
25.
26.

The increasing prevalence of overweight and obesity among women of childbearing age is a growing public health concern in the United States. The average body mass index (BMI) is increasing among all age categories and women enter pregnancy at higher weights. Women are also more likely to retain gestational weight with each pregnancy. Women who are overweight (BMI 25–30) and obese (BMI ≥30) are at greater risk of adverse reproductive health outcomes compared to women of normal weight status (BMI 19.8–25). This article provides an overview of the complications associated with maternal overweight and obesity including diabetes, pre-eclampsia, c-sections, and birth defects. We present updated information on the weight trends among women. Finally, we present an overview of the prevention studies aimed at adolescents and women prior to pregnancy.

  相似文献   
27.
28.
The purposes of this pilot study were to identify and adapt instruments for future use in assessing diabetes self-management in a sample of Cuban Americans with Type 2 diabetes. Eight instruments were selected from the literature, translated into Spanish, and administered to a sample of 20 Cuban Americans with Type 2 diabetes. Psychometric properties were examined along with clarity of wording, cultural appropriateness, and ease of use. Reliability data were compared, when possible, with original scores generated with non-Cuban populations. Results indicated that reliability scores among populations were similar. Support for using these instruments in clinical practice to assess initial knowledge and beliefs about aspects of diabetes management and to monitor changes is provided.  相似文献   
29.
Antioxidant preservatives prolong the quality of food and ensure the nutritional adequacy, palatability and safety of many processed foods and beverages. Effects of sodium sulfite (E221) and sorbic acid (E200) were investigated in human peripheral blood mononuclear cells (PBMC) which were purified from blood of healthy donors. Cells were stimulated with the mitogen phytohaemagglutinin in vitro, which induces proliferation of T-cells and the production of Th1-type cytokines like interferon-γ. The latter triggers enzyme indoleamine (2,3)-dioxygenase, which degrades tryptophan, and GTP cyclohydrolase I, which leads to increased neopterin production, in monocyte-derived macrophages. Sodium sulfite and sorbic acid suppressed both these biochemical changes in a dose-dependent way (P < 0.01 at 1 mM sodium sulfite and 50 mM sorbic acid). Data demonstrate a suppressive influence of sodium sulfite and sorbic acid on the activated Th1-type immune response.  相似文献   
30.
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