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   24829篇
  免费   1580篇
  国内免费   477篇
耳鼻咽喉   131篇
儿科学   509篇
妇产科学   748篇
基础医学   1588篇
口腔科学   503篇
临床医学   2625篇
内科学   3446篇
皮肤病学   235篇
神经病学   845篇
特种医学   735篇
外科学   2327篇
综合类   3586篇
一般理论   10篇
预防医学   4044篇
眼科学   335篇
药学   2717篇
  61篇
中国医学   1971篇
肿瘤学   470篇
  2024年   91篇
  2023年   437篇
  2022年   786篇
  2021年   1102篇
  2020年   1048篇
  2019年   1284篇
  2018年   1200篇
  2017年   998篇
  2016年   845篇
  2015年   807篇
  2014年   1592篇
  2013年   1899篇
  2012年   1470篇
  2011年   1480篇
  2010年   1093篇
  2009年   965篇
  2008年   982篇
  2007年   861篇
  2006年   749篇
  2005年   555篇
  2004年   417篇
  2003年   376篇
  2002年   266篇
  2001年   245篇
  2000年   213篇
  1999年   147篇
  1998年   111篇
  1997年   107篇
  1996年   105篇
  1995年   90篇
  1994年   77篇
  1993年   62篇
  1992年   58篇
  1991年   44篇
  1990年   33篇
  1988年   35篇
  1987年   32篇
  1985年   291篇
  1984年   488篇
  1983年   406篇
  1982年   406篇
  1981年   342篇
  1980年   319篇
  1979年   391篇
  1978年   284篇
  1977年   195篇
  1976年   284篇
  1975年   249篇
  1974年   256篇
  1973年   245篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
BackgroundNew antidiabetic agents (sodium-glucose cotransporter-2 inhibitor [SGLT2i] and glucagon-like peptide-1 receptor agonist [GLP-1RA]) and metabolic surgery have protective effects on metabolic syndromes.ObjectivesTo compare the changes of metabolic parameters and costs among patients with obesity and type 2 diabetes undergoing metabolic surgery and initiating new antidiabetic agents over 12 months.SettingHong Kong Hospital Authority database from 2006–2017.MethodsThis is a population-wide retrospective cohort study consisting of 2616 patients (1810 SGLT2i, 528 GLP-1RA, 278 metabolic surgery). Inverse probability treatment weighting of propensity score was applied to balance baseline covariates of patients with obesity and type 2 diabetes who underwent metabolic surgery, or initiated SGLT2i or GLP-1RA. Metabolic parameters and direct medical costs were measured and compared from baseline to 12 months in metabolic surgery, SGLT2i, and GLP-1RA groups.ResultsPatients in all 3 groups had improved metabolic parameters over a 12-month period. Patients with metabolic surgery achieved significantly better outcomes in BMI (?5.39, ?.56, ?.40 kg/m2, P < .001), % total weight loss (15.16%, 1.34%, 1.63%, P < .001), systolic (?2.21, ?.59, 1.28 mm Hg, P < .001) and diastolic (?1.16, .50, ?.13 mm Hg, P < .001) blood pressure, HbA1c (?1.80%, ?.77%, ?.80%, P < .001), triglycerides (?.64, ?.11, ?.09 mmol/L, P < .001), and estimated glomerular filtration rate (3.08, ?1.37, ?.41 mL/min/1.73m2, P < .001) after 12 months compared with patients with SGLT2i and GLP1-RA. Although the metabolic surgery group incurred the greatest direct medical costs (US$33,551, US$10,945, US$10,627, P < .001), largely due to the surgery itself and related hospitalization, the total monthly direct medical expenditure of metabolic surgery group became lower than that of SGLT2i and GLP-1RA groups at 7 months.ConclusionBeneficial weight loss and metabolic outcomes at 12 months were observed in all 3 groups, among which the metabolic surgery group showed the most remarkable effects but incurred the greatest medical costs. However, studies with a longer follow-up period are warranted to show long-term outcomes.  相似文献   
32.
Standard cost-effectiveness models compare incremental cost increases to incremental average gains in health, commonly expressed in Quality-Adjusted Life Years (QALYs). Our research generalizes earlier models in several ways. We introduce risk aversion in Quality of Life (QoL), which leads to “willingness-to-pay” thresholds that rise with illness severity, potentially by an order of magnitude. Unlike traditional CEA analyses, which discriminate against persons with disabilities, our analysis implies that the marginal value of improving QoL rises for disabled individuals. Our model can also value the uncertain benefits of medical interventions by employing well-established analytic methods from finance. Finally, we show that traditional QALYs no longer serve as a single index of health, when consumers are risk-averse. To address this problem, we derive a generalized single-index of health outcomes—the Generalized Risk-Adjusted QALY (GRA-QALY). Earlier models of CEA that abstract from risk-aversion nest as special cases of our more general model.  相似文献   
33.
利用计算机技术,搭建执业药师网上远程继续教育的平台,将主管部门审核的有关执业药师继续教育的教学内容放到网上,供参加执业药师继续教育的人员浏览学习。通过加强管理,严格考核,变传统教学模式为现代教育方式,实现教育的个性化,有效提高执业药师的继续教育质量。  相似文献   
34.
中国新疆与哈萨克斯坦共和国生态环境特点极为相似,荒漠、半荒漠草地类型占草原面积的首位。由草原研究所派出的科技交流团,先后考察了哈国荒漠草地现状与改良利用情况,就优良旱生牧草新品种选育和荒漠、半荒漠区无灌溉条件下人工草地建植与管理技术模式达成技术合作事宜。  相似文献   
35.
对鲜山药中水溶性粗多糖的提取工艺进行了研究,通过单因素试验和L9(34)正交试验,研究了料液比、提取温度、时间和乙醇体积分数对粗多糖得率的影响,极差分析及方差分析结果表明提取温度和料液比是影响山药粗多糖提取的主要因素,较优的工艺为料液比1 g:9 mL,温度50 ℃,时间2.5 h,乙醇体积分数75%,在此工艺条件下,鲜山药粗多糖得率为0.2449%(以鲜山药质量计).  相似文献   
36.
原北京医科大学(现为北京大学医学部)从20世纪90年代初开始,积极寻求与美国中华医学基金会的合作以促进医学伦理学的学科发展和国际化水平的提高。十几年来,北京大学医学部作为基地和依托极大地支持和引领了我国医学伦理学的教学改革与发展,增强了相关人员的医学伦理意识以及医学伦理学理论对实践的指导作用,促进了伦理学知识和能力的培训,提升了我国生物医学科研伦理的实力,奠定了医学伦理学继续教育的基础,使医学伦理学实现了系统性和跨越式的发展。  相似文献   
37.
BACKGROUND/AIMS: The purpose of this work was to develop a new sensor for objective in vivo measurement of the cutaneous temperature based on micro-electro-mechanical systems (MEMS), and to compare these performances with those of a classical thermocouple. Research on this new sensor was carried out to allow the quantification of the thermal properties of the made-up skin. METHODS: Sixteen female subjects divided into two different age groups (18-35 and >50 years old) were recruited for this study. Several zones of the face and forearms were made up at random with foundations containing or not a thermoregulator raw material. The quantity of foundation applied on the skin was standardized and measurements were carried out first before make-up, and then 10 s and 5 min after make-up. The new sensor and the thermocouple were used successively on each zone. The cutaneous temperature was expressed in degrees celsius. RESULTS/CONCLUSION: The two systems are similar in terms of repeatability and reproducibility, with some differences in sensibility. The data measured by the MEMS sensor appear lower than those measured by the thermocouple. After make-up, the MEMS sensor detects a progressive increase of the temperature in time whereas the thermocouple detects a decrease. We found the same evolution on the face but in a more attenuated way. These results tend to show that the devices do not measure the same phenomenon. The thermocouple appears more sensitive to the thermal response of the made-up surface whereas the MEMS sensor appears more sensitive to the heat transfers in the interface between the skin and make-up.  相似文献   
38.
Objective: To investigate on the feasibility, safety, and effectiveness of a new bioabsorbable material for lung staple-line reinforcement. Methods: This prospective open trial included 66 patients (mean age of 56 ± 17 years) who underwent various types of lung resection using staplers with knitted calcium alginate sleeves for buttressing (FOREseal™, Laboratoires Brothier, Nanterre, France) at three academic centers: 29 lobectomies, 22 emphysema surgeries, 15 wedge resections or lung biopsies. Intraoperative air leakage was assessed at a mean respiratory peak pressure of 30 cmH2O, and rated as grade 1, 2, or 3. Persistent air leakage in the postoperative course, as well as any relevant event, was assessed daily. The follow-up period was of 6 months. Results: No technical problem linked to the device occurred. Hemostasis of the cutting edges was completed in all patients. Fifty-six percent of the patients had no intraoperative air leak and 27.3% had grade 1 leaks. Mean postoperative air leaks and thoracic drainage times were 1.9 ± 2.3 days and 6 ± 5.3 days, respectively. In-hospital mortality was nil. There was no empyema. Mean hospital stay was 9.1 ± 6.6 days. At follow-up, one patient underwent lung transplantation, and pathology of the explanted specimen showed the absence of device-related foreign-body inflammation. One patient complained from metalloptysis, and another one, with a metastatic invasive aspergillosis, developed an infectious recurrence that required reoperation. Conclusions: FOREseal is an ergonomic, safe, and promising new material instead of nonabsorbable materials and xenomaterials for staple-line reinforcement. A randomized comparative study is now in progress.  相似文献   
39.
40.
Introduction Vitamin D plays an important role in bone health. Our purpose was to measure serum 25-hydroxyvitamin D concentrations and their determinants in a national sample (n=2,946) of New Zealanders aged 15 years and over.Findings Mean (99% CI) serum 25-hydroxyvitamin D concentrations were 47 (45–50) nmol/l in women and 52 (49–55) nmol/l in men. Mean concentrations in New Zealand European and Others (NZEO, n=2,440), Mori (n=370), and Pacific (n=136) were 51 (49–53), 42 (38–46) and 37 (33–42) nmol/l, respectively. Three percent of New Zealanders had serum 25-hydroxyvitamin D concentrations indicative of deficiency (≤17.5 nmol/l); 48% and 84% were insufficient based on cutoffs of ≤50 and ≤80 nmol/l. Determinants of serum 25-hydroxyvitamin D concentrations in women were age, ethnicity, obesity, latitude and season; determinants in men were ethnicity and season. Serum 25-hydroxyvitamin D in women declined with age; mean concentration was 13 (8–18) nmol/l lower in women 65 years or older and 9 (5–13) nmol/l lower in women 45–64 years compared with women 15–18 years. Spring to summer differences in serum 25-hydroxyvitamin D were 31 (28–34) and 28 (25–31) nmol/l in women and men, respectively. Obese women had lower vitamin status than normal-weight women by 6 (3–10). Women living in the South Island had a mean serum 25-hydroxyvitamin D that was 6 (3–9) nmol/l lower than women living in the North Island. Ethnicity and season are the major determinants of serum 25-hydroxyvitamin D in New Zealanders.Conclusion The high prevalence of vitamin D insufficiency in New Zealanders, particularly in older women, may warrant strategies to improve vitamin D status.  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