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   109243篇
  免费   9244篇
  国内免费   314篇
耳鼻咽喉   1221篇
儿科学   2597篇
妇产科学   1929篇
基础医学   14923篇
口腔科学   2005篇
临床医学   12377篇
内科学   22145篇
皮肤病学   1330篇
神经病学   10767篇
特种医学   3929篇
外国民族医学   62篇
外科学   17228篇
综合类   1604篇
一般理论   90篇
预防医学   9468篇
眼科学   2356篇
药学   7789篇
中国医学   95篇
肿瘤学   6886篇
  2023年   688篇
  2022年   1121篇
  2021年   2624篇
  2020年   1605篇
  2019年   2415篇
  2018年   2871篇
  2017年   2062篇
  2016年   2215篇
  2015年   2490篇
  2014年   3634篇
  2013年   4832篇
  2012年   7211篇
  2011年   7444篇
  2010年   4128篇
  2009年   3721篇
  2008年   6300篇
  2007年   6378篇
  2006年   6202篇
  2005年   5925篇
  2004年   5526篇
  2003年   5135篇
  2002年   4741篇
  2001年   1895篇
  2000年   1921篇
  1999年   1739篇
  1998年   1193篇
  1997年   984篇
  1996年   840篇
  1995年   793篇
  1994年   716篇
  1993年   663篇
  1992年   1269篇
  1991年   1269篇
  1990年   1147篇
  1989年   1112篇
  1988年   1119篇
  1987年   971篇
  1986年   954篇
  1985年   919篇
  1984年   817篇
  1983年   676篇
  1982年   486篇
  1981年   453篇
  1980年   456篇
  1979年   707篇
  1978年   561篇
  1977年   482篇
  1976年   446篇
  1974年   469篇
  1973年   456篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
To measure intestinal absorption by using a single, random stool sample, polyethylene glycol (PEG), 1 g/d, and a constant diet were given to healthy infants, with a constant PEG-to-macronutrient ratio. After 10 d equilibration, apparent intestinal absorption of macronutrients was estimated from a standard 3-d metabolic balance and compared with that estimated by using the ratio of PEG to macronutrients in a single random sample of feces. Correlation coefficients for this comparison were 0.649, 0.715, and 0.924 for nitrogen, carbohydrate, and fat, respectively. Additionally, apparent intestinal absorptions estimated from two separate consecutive 3-d metabolic-balance studies were compared, showing correlation coefficients of 0.106, 0.653, and 0.463 for nitrogen, carbohydrate, and fat, respectively. The random sample-marker technique appears to be acceptable for measuring apparent absorption of macronutrients and is at least as accurate as a standard 3-d metabolic-balance study.  相似文献   
72.
Quantitative studies of morbidity, food intake, and somatic growth were done prospectively during 14 mo for 70 children aged 5-18 mo in two Bangladeshi villages. When random-effect regression models were used, monthly changes in weight were inversely related to proportions of days in the month with fever and diarrhea and positively related to energy intake per kilogram body weight. Interestingly, weight changes did not vary with age in this interval. Estimates indicate that increasing energy intakes to the recommended World Health Organization level would have a significantly greater effect on weight gain than would the elimination of diarrhea and fever. With energy at recommended intake and diarrhea and fever prevalence as found in US children, weight gain is predicted to be near that of the international reference population. Therefore, interventions aimed at improving dietary intake may be as important as infection-control programs for improving growth of children in poor developing nations.  相似文献   
73.
Breast pumps are medical devices used to express milk and maintain the milk supply. The purpose of this study was to characterize adverse events reported to the United States Food and Drug Administration (FDA) on breast pumps. Thirty-seven adverse event reports on breast pumps were identified from the Manufacturer and User Facility Device Experience database between 1992 and 2003. Four additional reports were found in the Device Experience Network database from 1992 to 1996. The most commonly reported adverse events for electric breast pumps were pain, soreness, or discomfort; the need for medical intervention; and breast tissue damage. Most frequently reported problems for manual breast pumps were breast tissue damage and infection. Contamination of breast milk during pumping was also reported. Breast pump adverse events are likely underreported to the FDA. Reporting adverse events is important for improving the design and manufacture of breast pumps and subsequently decreasing adverse events.  相似文献   
74.
OBJECTIVE: To assess the impact and cost-effectiveness of two information-based provider reminder interventions designed to improve self-care management and outcomes of heart failure (HF) patients. DATA SOURCES/STUDY SETTING: Interview and agency administrative data on 628 home care patients with a primary diagnosis of HF. STUDY DESIGN: Patients were treated by nurses randomly assigned to usual care or one of two intervention groups. The basic intervention was an e-mail to the patient's nurse highlighting six HF-specific clinical recommendations. The augmented intervention supplemented the initial nurse reminder with additional clinician and patient resources. DATA COLLECTION: Patient interviews were conducted 45 days post admission to measure self-management behaviors, HF-specific outcomes (Kansas City Cardiomyopathy Questionnaire-KCCQ), health-related quality of life (EuroQoL), and service use. PRINCIPAL FINDINGS: Both interventions improved the mean KCCQ summary score (15.3 and 12.9 percent, respectively) relative to usual care (p< or =.05). The basic intervention also yielded a higher EuroQoL score relative to usual care (p< or =.05). In addition, the interventions had a positive impact on medication knowledge, diet, and weight monitoring. The basic intervention was more cost-effective than the augmented intervention in improving clinical outcomes. CONCLUSIONS: This study demonstrates the positive impact of targeting evidence-based computer reminders to home health nurses to improve patient self-care behaviors, knowledge, and clinical outcomes. It also advances the field's limited understanding of the cost-effectiveness of selected strategies for translating research into practice.  相似文献   
75.
ABSTRACT Freud's paper on the Schreber Case is considered from a contemporary perspective drawing on the object relations theorists. Some of Winnicott's ideas are used to illustrate how one might understand Schreber's predicament today. Although Freud's views on the role of repressed homosexual longings in the aetiology of Schreber's illness are not endorsed his prescience in the search for meaning in the patient's discourse is applauded.  相似文献   
76.
77.
Many older treatments should not be discarded because of newer modalities. Various dermatologic disorders may be controlled effectively by prescribing these older topical agents.  相似文献   
78.
A variety of nutritional factors influence the bioavailability of calcium and increase a woman's risk of osteoporosis. Eight healthy women completed an 8-week metabolic study designed to investigate the effect of nonalcoholic carbonated beverage consumption on calcium metabolism. Compared with women receiving a control diet, women consuming a diet high in nonalcoholic carbonated beverages demonstrated similar mean serum levels of calcium, ionized calcium, phosphorus, alkaline phosphatase, parathyroid hormone, 1,25-dihydroxyvitamin D3, and osteocalcin. Twenty-four-hour urine volume, creatinine clearance, calcium-creatinine ratio, and phosphorus-creatinine ratio were similar during consumption of the diet high in nonalcoholic carbonated beverages and the control diet. Twenty-four-hour cyclic adenosine monophosphate-creatinine ratio was significantly lower in women consuming the diet high in nonalcoholic carbonated beverage compared with women receiving the control diet (342 +/- 27.4 nmol/mmol vs 409 +/- 22.1 nmol/mmol). Consumption of a diet high in nonalcoholic carbonated beverages on a short-term basis does not appear to affect adversely the serum or urinary markers of calcium metabolism.  相似文献   
79.
Alemtuzumab is a powerful lymphocyte depleting antibody currently being evaluated in solid organ transplantation. This paper describes 5-year results of a single center study of alemtuzumab as induction in renal transplantation. Thirty-three renal transplant recipients received 20 mg alemtuzumab on day 0 and 1, followed by half-dose cyclosporin monotherapy (trough concentration 75-125 ng/mL) from day 3. They were compared in a retrospective contemporaneous-controlled manner with 66 kidney transplant recipients transplanted in the same period and center who received conventional immunosuppression with cyclosporin, azathioprine and prednisolone. In the alemtuzumab group 12% of recipients died compared to 17% in the control group (p = 0.48); likewise graft loss was similar in both groups (21% vs. 26%, respectively, p = 0.58). Incidence of acute rejection was also comparable at 5 years (31.5% vs. 33.6%), although the pattern of rejection was different with 14% patients in the alemtuzumab group experiencing rejection over 1 year post-transplant compared to none in the control group. There was no significant difference between groups in terms of infection or serious adverse events. While acknowledging the limitations of a relatively small single-center study, results suggest that alemtuzumab induction allowed satisfactory long-term patient and graft survival equivalent to that seen with standard triple immunosuppression, while avoiding steroid therapy.  相似文献   
80.
The assessment of the medical lethality and intent of suicide attempts has been considered an important area of research for those interested in suicide. The current study examined the usefulness of the Risk-Rescue Rating Scale with 109 adolescent suicide attempters and found a restricted range of variability, which, in turn, resulted in poor interrater reliability on a number of items. Results suggest that the Risk-Rescue Rating Scale is of limited usefulness with adolescents, and alternative approaches to assessing lethality and suicidal intent with this age group are discussed.  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