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   11481篇
  免费   872篇
  国内免费   27篇
耳鼻咽喉   124篇
儿科学   317篇
妇产科学   217篇
基础医学   1315篇
口腔科学   296篇
临床医学   1243篇
内科学   1976篇
皮肤病学   107篇
神经病学   964篇
特种医学   446篇
外科学   2106篇
综合类   155篇
一般理论   9篇
预防医学   1162篇
眼科学   186篇
药学   954篇
中国医学   6篇
肿瘤学   797篇
  2023年   56篇
  2022年   141篇
  2021年   290篇
  2020年   166篇
  2019年   261篇
  2018年   321篇
  2017年   250篇
  2016年   250篇
  2015年   303篇
  2014年   432篇
  2013年   548篇
  2012年   876篇
  2011年   799篇
  2010年   437篇
  2009年   364篇
  2008年   615篇
  2007年   661篇
  2006年   585篇
  2005年   613篇
  2004年   560篇
  2003年   542篇
  2002年   453篇
  2001年   150篇
  2000年   143篇
  1999年   169篇
  1998年   93篇
  1997年   74篇
  1996年   73篇
  1995年   63篇
  1994年   60篇
  1993年   62篇
  1992年   106篇
  1991年   116篇
  1990年   107篇
  1989年   97篇
  1988年   98篇
  1987年   85篇
  1986年   94篇
  1985年   76篇
  1984年   108篇
  1983年   89篇
  1982年   54篇
  1981年   70篇
  1980年   52篇
  1979年   75篇
  1978年   78篇
  1977年   64篇
  1976年   67篇
  1974年   66篇
  1973年   68篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Nutritional status was evaluated on 210 occasions in 90 pediatric oncology inpatients during a 7-month period; 39 had solid tumors and 51 leukemia. Ages ranged from 3 months to 20 yr. Nutritional parameters were defined as normal, "at risk," or "probably malnourished." Fifty-seven and 29% of assessments revealed at least one parameter "at risk" or "probably malnourished," respectively. Prognosis was negatively related to the number of abnormal nutritional parameters. Serum albumin was most frequently abnormal. However, on most occasions, hypoalbuminemia was associated with weight/height, arm muscle area, and triceps skinfold measurements in the normal range. In order to further identify determinants of serum albumin, we analyzed dietary, chemotherapy, and temperature data in 10 prospectively studied leukemia patients, half of whom received parenteral nutrition. In these patients there was little relationship of serum albumin to chemotherapy or dietary intake. In all of these patients, especially those receiving total parenteral nutrition, low serum albumin was highly associated with fever (p less than 0.0005). We concluded that febrile illness is an important determinant of abnormal serum albumin concentrations. In pediatric cancer patients, abnormal serum albumin may more often reflect the acute metabolic response to fever and infection than depletion of body mass.  相似文献   
102.
Interferon-, interferon-, and interferon- differ in their antiproliferative effects for several cell lines. Interferons were thus assessed for their activity in inhibiting proliferation of three renal cell carcinoma cell lines. The malignant epithelial phenotype of each of these cell lines was confirmed by electron microscopy, histology, karyotype and tumorigenicity. When compared on an anti-viral unit basis, naturally produced interferon- was more effective than natural interferon- for all cell lines and clones. Proliferation of each of the cell lines was inhibited by interferon-. In all cases, removal of interferons from culture media resulted in resumption of the rate of cell growth after a variable delay of 6–10 days. If the antiproliferative effects of interferons predominate in mediating tumor regression, clinical response may depend upon the type of interferon to which the tumor is exposed.  相似文献   
103.
The use of radioactive materials in medicine is one of the most highly regulated areas the physician has to deal with. There are three basic types of licenses for use of radioactive material defined in the Code of Federal Regulations (CFR), chapter 10, part 35. These are the general license, which is mainly applicable to small volume in vitro work; the specific license, which is used in most medical facilities; and the broad license, which is suited for larger research-oriented practices. Licensing requires proof of competence of the user and of adequate provision for protection of public health. Materials used in medicine are grouped for convenience into three diagnostic categories and two therapeutic categories. A sixth group, for sealed implants, is not generally applicable in nuclear medicine. Training and experience of users may be documented in a number of ways, including board certification in nuclear medicine. Therapeutic applications require additional proof of direct personal experience. The radiation safety officer is a pivotal individual in the licensing procedure, being directly responsible for carrying out the highly detailed requirements for protection of personnel and patients. A radiation safety program based on the "as low as reasonably achievable" (ALARA) concept requires personal monitoring, inventory control, detection and control of contamination, and strict adherence to licensing rules. Training of personnel and proper maintenance of equipment and facilities are also vital parts of the licensing process. The requirements of licensing and for renewal are clearly spelled out by the various regulatory agencies and require meticulous record keeping with documentation that all prescribed procedures have been followed and duly recorded.  相似文献   
104.
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   
105.
Maternal and infant nutrition are problematic in areas of Ethiopia. Health extension workers (HEWs) work in Ethiopia’s primary health care system, increasing potential health service coverage, particularly for women and children, providing an opportunity for health improvement. Their roles include improving maternal and infant nutrition, disease prevention, and health education. Supporting HEWs’ practice with ‘non-clinical’ skills in behavior change and health communication can improve effectiveness. This intervention study adapted and delivered a UK-developed training intervention for Health Extension Workers (HEWs) working with the United Nations World Food Programme in Ethiopia. The intervention included communication and behavioral training adapted with local contextual information. Mixed methods evaluation focused on participants’ reaction to training, knowledge, behavior change, and skills use. Overall, 98 HEWs were trained. The intervention was positively received by HEWs. Pre-post evaluations of communication and behavior change skills found a positive impact on HEW skills, knowledge, and motivation to use skills (all p < 0.001) to change women’s nutritional behavior, also demonstrated in role-play scenarios. The study offered substantial learning about intervention delivery. Appropriate cultural adaptation and careful consideration of assessment of psychological constructs are crucial for future delivery.  相似文献   
106.
ObjectivesUnderstanding the level of investment needed for the 2021-2030 decade is important as the global community faces the next strategic period for vaccines and immunization programs. To assist with this goal, we estimated the aggregate costs of immunization programs for ten vaccines in 94 low- and middle-income countries from 2011 to 2030.MethodWe calculated vaccine, immunization delivery and stockpile costs for 94 low- and middle-income countries leveraging the latest available data sources. We conducted scenario analyses to vary assumptions about the relationship between delivery cost and coverage as well as vaccine prices for fully self-financing countries.ResultsThe total aggregate cost of immunization programs in 94 countries for 10 vaccines from 2011 to 2030 is $70.8 billion (confidence interval: $56.6-$93.3) under the base case scenario and $84.1 billion ($72.8-$102.7) under an incremental delivery cost scenario, with an increasing trend over two decades. The relative proportion of vaccine and delivery costs for pneumococcal conjugate, human papillomavirus, and rotavirus vaccines increase as more countries introduce these vaccines. Nine countries in accelerated transition phase bear the highest burden of the costs in the next decade, and uncertainty with vaccine prices for the 17 fully self-financing countries could lead to total costs that are 1.3-13.1 times higher than the base case scenario.ConclusionResource mobilization efforts at the global and country levels will be needed to reach the level of investment needed for the coming decade. Global-level initiatives and targeted strategies for transitioning countries will help ensure the sustainability of immunization programs.  相似文献   
107.
108.
109.
Annals of Surgical Oncology - Telemedicine was adopted to minimize exposure risks for patients and staff during the coronavirus disease 2019 pandemic. This study measured patient satisfaction and...  相似文献   
110.
BackgroundSelection of the optimal treatment modality for primary liver cancers remains complex, balancing patient condition, liver function, and extent of disease. In individuals with preserved liver function, liver resection remains the primary approach for treatment with curative intent but may be associated with significant mortality. The purpose of this study was to establish a simple scoring system based on Model for End-stage Liver Disease (MELD) and extent of resection to guide risk assessment for liver resections.MethodsThe 2005–2015 NSQIP database was queried for patients undergoing liver resection for primary liver malignancy. We first developed a model that incorporated the extent of resection (1 point for major hepatectomy) and a MELD-Na score category of low (MELD-Na =6, 1 point), medium (MELD-Na =7–10, 2 points) or high (MELD-Na >10, 3 points) with a score range of 1–4, called the Hepatic Resection Risk Score (HeRS). We tested the predictive value of this model on the dataset using logistic regression. We next developed an optimal multivariable model using backwards sequential selection of variables under logistic regression. We performed K-fold cross validation on both models. Receiver operating characteristics were plotted and the optimal sensitivity and specificity for each model were calculated to obtain positive and negative predictive values.ResultsA total of 4,510 patients were included. HeRS was associated with increased odds of 30-day mortality [HeRS =2: OR =3.23 (1.16–8.99), P=0.025; HeRS =3: OR =6.54 (2.39–17.90), P<0.001; HeRS =4: OR =13.69 (4.90–38.22), P<0.001]. The AUC for this model was 0.66. The AUC for the optimal multivariable model was higher at 0.76. Under K-fold cross validation, the positive predictive value (PPV) and negative predictive value (NPV) of these two models were similar at PPV =6.4% and NPV =97.7% for the HeRS only model and PPV =8.4% and NPV =98.1% for the optimal multivariable model.ConclusionsThe HeRS offers a simple heuristic for estimating 30-day mortality after resection of primary liver malignancy. More complicated models offer better performance but at the expense of being more difficult to integrate into clinical practice.  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