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   5657篇
  免费   439篇
  国内免费   5篇
耳鼻咽喉   30篇
儿科学   205篇
妇产科学   234篇
基础医学   716篇
口腔科学   52篇
临床医学   940篇
内科学   990篇
皮肤病学   333篇
神经病学   511篇
特种医学   141篇
外科学   335篇
综合类   46篇
一般理论   4篇
预防医学   862篇
眼科学   25篇
药学   363篇
中国医学   6篇
肿瘤学   308篇
  2023年   41篇
  2022年   33篇
  2021年   113篇
  2020年   70篇
  2019年   112篇
  2018年   135篇
  2017年   112篇
  2016年   128篇
  2015年   141篇
  2014年   188篇
  2013年   288篇
  2012年   389篇
  2011年   411篇
  2010年   193篇
  2009年   171篇
  2008年   384篇
  2007年   373篇
  2006年   410篇
  2005年   422篇
  2004年   407篇
  2003年   364篇
  2002年   335篇
  2001年   58篇
  2000年   37篇
  1999年   58篇
  1998年   71篇
  1997年   61篇
  1996年   53篇
  1995年   52篇
  1994年   33篇
  1993年   35篇
  1992年   31篇
  1991年   25篇
  1990年   30篇
  1989年   26篇
  1988年   18篇
  1987年   21篇
  1986年   19篇
  1985年   22篇
  1984年   27篇
  1983年   11篇
  1982年   22篇
  1981年   30篇
  1980年   28篇
  1979年   17篇
  1978年   17篇
  1976年   10篇
  1975年   11篇
  1974年   13篇
  1973年   9篇
排序方式: 共有6101条查询结果,搜索用时 31 毫秒
991.
Objective: To describe the initial benefits of a structured group exercise program on exercise frequency and intensity, perceived health, pain, mood, and television watching habits.

Design: Pre-test/post-test.

Participants/methods: Eighty-nine persons with SCI participated voluntarily in a no-cost, twice weekly physical therapy group exercise class over 3 months. Forty-five persons completed pre- and post-participation interviews on exercise frequency and intensity, perceived health, pain, mood, sleep, and television watching habits.

Results: Mean participant age of the respondents was 43.82 years. 49% had AIS C or D injuries, 24% had AIS A,B paraplegia, 9% had AIS A,B C1-C4 and 18% had AIS A,B C5–C8. 75.6% of participants were male and 84.4% had a traumatic etiology as the cause of their SCI. There was a significant improvement in days of strenuous and moderate exercise as well as health state. There was an average decrease in pain scores, depression scores, number of hours spent watching television, and days/week of mild exercise.

Conclusion: Participation in structured, small group exercise as a component of a wellness program after SCI shows promise for improving regular exercise participation and health state, but benefits may also occur across other areas of health and function including mood, pain, and hours spent watching television. Further follow-up is needed to determine whether improvements can be maintained after program completion and across all neurological levels.  相似文献   

992.
993.
Fibroblast growth factor 23 (FGF23) is the causative factor of X‐linked hypophosphatemia (XLH), a genetic disorder effecting 1:20,000 that is characterized by excessive phosphate excretion, elevated FGF23 levels and a rickets/osteomalacia phenotype. FGF23 inhibits phosphate reabsorption and suppresses 1α,25‐dihydroxyvitamin D (1,25D) biosynthesis, analytes that differentially contribute to bone integrity and deleterious soft‐tissue mineralization. As inhibition of ligand broadly modulates downstream targets, balancing efficacy and unwanted toxicity is difficult when targeting the FGF23 pathway. We demonstrate that a FGF23 c‐tail‐Fc fusion molecule selectively modulates the phosphate pathway in vivo by competitive antagonism of FGF23 binding to the FGFR/α klotho receptor complex. Repeated injection of FGF23 c‐tail Fc in Hyp mice, a preclinical model of XLH, increases cell surface abundance of kidney NaPi transporters, normalizes phosphate excretion, and significantly improves bone architecture in the absence of soft‐tissue mineralization. Repeated injection does not modulate either 1,25D or calcium in a physiologically relevant manner in either a wild‐type or disease setting. These data suggest that bone integrity can be improved in models of XLH via the exclusive modulation of phosphate. We posit that the selective modulation of the phosphate pathway will increase the window between efficacy and safety risks, allowing increased efficacy to be achieved in the treatment of this chronic disease. © 2017 American Society for Bone and Mineral Research.  相似文献   
994.

Purpose

The aim of the study is to investigate risk factors for sensitization to preservatives and to examine to which extent different preservatives are registered in chemical products for occupational use in Denmark.

Methods

A retrospective epidemiological observational analysis of data from a university hospital was conducted. All patients had occupational contact dermatitis and were consecutively patch tested with 11 preservatives from the European baseline series and extended patch test series during a 5-year period: 2009–2013. Information regarding the same preservatives in chemical products for occupational use (‘substances and materials’) registered in the Danish Product Register Database (PROBAS) was obtained.

Results

The frequency of preservative contact allergy was 14.2% (n?=?141) in 995 patients with occupational contact dermatitis. Patients with preservative contact allergy had significantly more frequently facial dermatitis (19.9 versus 13.1%) and age?>?40 years (71.6 versus 45.8%) than patients without preservative contact allergy, whereas atopic dermatitis was less frequently observed (12.1 versus 19.8%). Preservative contact allergy was more frequent in painters with occupational contact dermatitis as compared to non-painters with occupational contact dermatitis (p?<?0.001). This was mainly caused by contact allergy to methylisothiazolinone and contact allergy to formaldehyde. Analysis of the registered substances and materials in PROBAS revealed that preservatives occurred in several product categories, e.g., ‘paints and varnishes’, ‘cleaning agents’, ‘cooling agents’, and ‘polishing agents’. Formaldehyde and isothiazolinones were extensively registered in PROBAS.

Conclusions

The extensive use of formaldehyde and isothiazolinones in chemical products for occupational use may be problematic for the worker. Appropriate legislation, substitution, and employee education should be prioritized.
  相似文献   
995.

Objectives

What patients intend when they make health care choices and whether they understand the meaning of orders for life-sustaining treatment forms is not well understood. The purpose of this study was to analyze the directives from a sample of emergency department (ED) patients' MOLST forms.

Procedures

MOLST forms that accompanied 100 patients who were transported to an ED were collected and their contents analyzed. Data categories included age, gender, if the patient completed the form for themselves, medical orders for life-sustaining treatment including intubation, ventilation, artificial nutrition, artificial fluids or other treatment, and wishes for future hospitalization or transfer. Frequencies of variables were calculated and the associations between them were determined using chi-square. An a priori list of combinations of medical orders that were contradictory was developed. Contradictions with Orders for CPR (cardiopulmonary resuscitation) included the choice of one or more of the following: Comfort care; Limited intervention; Do Not Intubate; No rehospitalization; No IV (intravenous) fluids; and No antibiotics. Contradictions with DNR orders included the choice of one or more of the following: Intubation; No limitation on interventions. Contradictions with orders for Comfort Care were as follows: Send to the hospital; Trial period of IV fluids; Antibiotics. The frequencies of coexisting but contradictory medical orders were calculated using crosstabs. Free text responses to the “other instructions” section were submitted to content analysis.

Results

Sixty-nine percent of forms reviewed had at least one section left blank. Inconsistencies were found in patient wishes among a subset (14%) of patients, wherein their desire for “comfort measures only” seemed contradicted by a desire to be sent to the hospital, receive IV fluids, and/or receive antibiotics.

Conclusions

Patients and proxies may believe that making choices and documenting some, but not all, of their wishes on the MOLST form is sufficient for directing their end-of-life care. The result of making some, but not all, choices may result in patients receiving undesired, extraordinary, or invasive care.  相似文献   
996.

Background

Although practice patterns vary, scout radiographs are often routinely performed with pediatric fluoroscopic studies. However few studies have evaluated their utility in routine pediatric fluoroscopy.

Objective

To evaluate the value of scout abdomen radiographs in routine barium or water-soluble enema, upper gastrointestinal (GI) series, and voiding cystourethrogram pediatric fluoroscopic procedures.

Materials and methods

We retrospectively evaluated 723 barium or water-soluble enema, upper GI series, and voiding cystourethrogram fluoroscopic procedures performed at our institution. We assessed patient history and demographics, clinical indication for the examination, prior imaging findings and impressions, scout radiograph findings, additional findings provided by the scout radiograph that were previously unknown, and whether the scout radiograph contributed any findings that significantly changed management.

Results

We retrospectively evaluated 723 fluoroscopic studies (368 males and 355 females) in pediatric patients. Of these, 700 (96.8%) had a preliminary scout radiograph. Twenty-three (3.2%) had a same-day radiograph substituted as a scout radiograph. Preliminary scout abdomen radiographs/same-day radiographs showed no new significant findings in 719 (99.4%) studies. New but clinically insignificant findings were seen in 4 (0.6%) studies and included umbilical hernia, inguinal hernia and hip dysplasia. No findings were found on the scout radiographs that would either alter the examination performed or change management with regard to the exam.

Conclusion

Pre-procedural scout abdomen radiographs are unnecessary in routine barium and water-soluble enema, upper GI series, and voiding cystourethrogram pediatric fluoroscopic procedures and can be substituted with a spot fluoroscopic last-image hold.
  相似文献   
997.
The multidisciplinary consensus on the classification of prenatal and postnatal urinary tract dilation (UTD classification system) was created to unify the language used to describe urinary tract dilation on antenatal and postnatal ultrasound examinations and thereby facilitate communication among providers and improve outcomes research. The background and new classification system are described in this review, with imaging examples.  相似文献   
998.
999.
1000.
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