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   6446篇
  免费   719篇
  国内免费   32篇
耳鼻咽喉   32篇
儿科学   153篇
妇产科学   115篇
基础医学   893篇
口腔科学   103篇
临床医学   809篇
内科学   1599篇
皮肤病学   241篇
神经病学   554篇
特种医学   382篇
外科学   591篇
综合类   90篇
一般理论   2篇
预防医学   891篇
眼科学   55篇
药学   351篇
中国医学   3篇
肿瘤学   333篇
  2023年   75篇
  2022年   35篇
  2021年   73篇
  2020年   94篇
  2019年   81篇
  2018年   140篇
  2017年   103篇
  2016年   137篇
  2015年   149篇
  2014年   211篇
  2013年   289篇
  2012年   336篇
  2011年   371篇
  2010年   201篇
  2009年   203篇
  2008年   312篇
  2007年   312篇
  2006年   283篇
  2005年   260篇
  2004年   270篇
  2003年   215篇
  2002年   225篇
  2001年   215篇
  2000年   166篇
  1999年   184篇
  1998年   143篇
  1997年   125篇
  1996年   126篇
  1995年   108篇
  1994年   106篇
  1993年   85篇
  1992年   105篇
  1991年   86篇
  1990年   103篇
  1989年   133篇
  1988年   104篇
  1987年   104篇
  1986年   98篇
  1985年   88篇
  1984年   55篇
  1983年   53篇
  1982年   47篇
  1981年   49篇
  1979年   52篇
  1978年   32篇
  1977年   41篇
  1976年   41篇
  1975年   34篇
  1973年   34篇
  1971年   38篇
排序方式: 共有7197条查询结果,搜索用时 31 毫秒
81.
Ultrasound scans of 51 consecutive patients with gallbladder wall thickening were reviewed, and specific sonographic features were correlated with surgical and clinical follow-up. Two patterns of thickening were identified as specific indicators of the presence or absence of acute cholecystitis. "Striated" wall thickening, consisting of several alternating, irregular, discontinuous, lucent and echogenic bands, was seen in eight of 13 patients (62%) with acute cholecystitis. This pattern was not encountered in any of the patients who did not have acute cholecystitis. Conversely, "three-layer" thickening, consisting of a single circumferential lucent zone between two relatively uniform echogenic layers, was seen in only one of 13 patients (8%) with acute cholecystitis but in 11 of 38 patients (29%) with other diagnoses. Other abnormalities, including the presence of intramural echogenic foci and wall irregularities, were more frequently seen in patients with acute cholecystitis but were not as helpful. Use of these features may suggest or help exclude a diagnosis of acute cholecystitis in those patients in whom the cause of gallbladder wall thickening is otherwise not apparent.  相似文献   
82.
Quality of Life Research - This study examined the clinical utility of post-traumatic stress disorder (PTSD), low resilience, poor sleep, and lifetime blast exposure as risk factors for predicting...  相似文献   
83.
Anthropogenic environmental change will heavily impact cities, yet associated health risks will depend significantly on decisions made by urban leaders across a wide range of non-health sectors, including transport, energy, housing, basic urban services, and others. A subset of planetary health researchers focus on understanding the urban health impacts of global environmental change, and how these vary globally and within cities. Such researchers increasingly adopt collaborative transdisciplinary approaches to engage policy-makers, private citizens, and other actors in identifying and evaluating potential policy solutions that will reduce environmental impacts in ways that simultaneously promote health, equity, and/or local economies—in other words, maximising ‘co-benefits’. This report presents observations from a participatory workshop focused on challenges and opportunities for urban planetary health research. The workshop, held at the 16th International Conference on Urban Health (ICUH) in Xiamen, China, in November 2019, brought together 49 participants and covered topics related to collaboration, data, and research impact. It featured research projects funded by the Wellcome Trust’s Our Planet Our Health (OPOH) programme. This report aims to concisely summarise and disseminate participants’ collective contributions to current methodological practice in urban planetary health research.  相似文献   
84.
BackgroundAddition of vitamin E to polyethylene is theorized to reduce the potential for oxidative wear in acetabular components. This paper presents a multicenter prospective cohort study that reports on outcomes from use of a Vitamin E–infused highly cross-linked polyethylene acetabular cup.MethodsPatients were recruited across nine medical institutions. Clinical outcome measures recorded were the Harris Hip Score, visual analogue score for pain and satisfaction. Evidence of implant loosening or osteolysis was collected radiologically. Cup survival and reasons for revision in relevant cases were also recorded. Data collection was undertaken preoperatively, at 6-12 weeks, 6 months, 1 year, 2 years, and 5 years. A total of 675 patients were recruited, with 450 cases available at final review. Data regarding cup survival was available to 8 years and 9 months postoperatively.ResultsImprovements in both the Harris Hip Score and visual analogue score for pain and satisfaction were recorded at all time points, with these being maintained through the length of follow-up. In total, 89% of cups were implanted within the Lewinnek safe zone. A lucent line was identified in one case, with no evidence of acetabular osteolysis observed throughout the follow-up period. Cup survival was 98.9% at 8 years and 9 months. No revisions for aseptic loosening were observed.ConclusionsThe use of a vitamin E–infused polyethylene acetabular cup demonstrates reassuring patient-reported outcomes, radiological measures, and cup survival at medium to long-term follow-up.  相似文献   
85.
Recent studies showed that the COVID‐19 pandemic caused collateral damage in health care in terms of reduced hospital submissions or postponed treatment of other acute or chronic ill patients. An anonymous survey was sent out by mail to patients with chronic wounds in order to evaluate the impact of the pandemic on wound care. Sixty‐three patients returned the survey. In 14%, diagnostic workup or hospitalisation was cancelled or postponed. Thirty‐six percent could not seek consultation by their primary care physician as usual. The use of public transport or long travel time was not related to limited access to medical service (P = .583). In ambulatory care, there was neither a significant difference in the frequency of changing wound dressings (P = .67), nor in the person, who performed wound care (P = .39). There were no significant changes in wound‐specific quality of life (P = .505). No patient used telemedicine in order to avoid face‐to‐face contact or anticipate to pandemic‐related restrictions. The COVID‐19 pandemic impaired access to clinical management of chronic wounds in Germany. It had no significant impact on ambulatory care or wound‐related quality of life. Telemedicine still plays a negligible role in wound care.  相似文献   
86.
87.
Fertility awareness apps, which help to identify the ‘fertile window’ when conception is most likely, have been hailed as ‘revolutionising’ women’s reproductive health. Despite rapidly growing popularity, little research has explored how people use these apps when trying to conceive and what these apps mean to them. We draw on in‐depth, qualitative interviews, adopting a critical digital health studies lens (a sub‐field of science and technology studies), to explore the experiences of cisgender women and partners with one such app, Natural Cycles, in the context of their daily lives. We found that many women valued the technology as a ‘natural’, inobtrusive alternative to biomedical intervention, and a means of controlling and knowing their bodies, amid a dearth of fertility‐related education and care. Yet this technology also intervened materially and affectively into the spaces of their lives and relationships and privileged disembodied metrics (temperature) over embodied knowledge. Meanwhile, app language, advertising and cost have contributed to characterising ‘typical’ users as white, heterosexual, affluent, cisgender women without disabilities. In the context of neoliberal shifts towards bodily self‐tracking, technologies appealing as novel, liberating and ‘natural’ to individuals who can access them may nevertheless reproduce highly gendered reproductive responsibilities, anxieties and broader health and social inequalities.  相似文献   
88.
Advances in techniques of molecular biology have made possible the amplification of specific genes from single cells. This has a major clinical application in preimplantation diagnosis of monogenic disorders. However, the incidence of allele specific amplification failure (allele drop out) in heterozygous single cells can lead to misdiagnosis and the transfer of affected embryos. Few studies have been done to investigate the actual cause of allele drop out, although some investigators have succeeded in reducing but not eliminating it. Here we report the efficiency of amplifying both alleles in heterozygous cells lysed according to two different protocols. A total of 177 heterozygous cells from carriers of cystic fibrosis (CF) and haemoglobin C (HbC) were lysed using two different lysis buffers. Interestingly none of the cells that were lysed with sodium dodecyl sulphate/proteinase K showed any example of allele specific amplification failure whereas in those lysed by KOH/dithiothreitol it was present in 17.6 and 4.7% of the CF and HbC cells respectively. Our results suggest that the phenomenon of allele specific amplification failure is at least in part dependent on the lysis buffer used.   相似文献   
89.
90.
Dietary and physical activity correlates of long-term weight loss   总被引:5,自引:0,他引:5  
Covariations in body mass index (BMI), physical activity, macronutrient intake, and the frequency of consumption of specific foods were examined among 82 men and 75 women participating in a behavioral weight loss program over a period of 18 months. Results of repeated measures analyses of covariance showed that BMI change was inversely related to change in physical activity and change in frequency of vegetable consumption. BMI change was positively related to change in calorie intake from fat and change in frequency of consumption of beef, hot dogs, and sweets. Change in fat calories predicted BMI change better than change in total calories. In addition, change in the frequency of consumption of specific foods accounted for a larger percentage of the variance in BMI change than did change in macronutrients (10.4% vs. 5.2%). No differences were found between predictors of weight loss vs. weight maintenance.  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