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   1649319篇
  免费   117655篇
  国内免费   3699篇
耳鼻咽喉   22859篇
儿科学   47395篇
妇产科学   41399篇
基础医学   244909篇
口腔科学   47860篇
临床医学   147278篇
内科学   316776篇
皮肤病学   36687篇
神经病学   123516篇
特种医学   64571篇
外国民族医学   151篇
外科学   255009篇
综合类   32805篇
现状与发展   7篇
一般理论   456篇
预防医学   114465篇
眼科学   39068篇
药学   128915篇
  4篇
中国医学   5669篇
肿瘤学   100874篇
  2021年   14782篇
  2019年   13784篇
  2018年   19447篇
  2017年   14972篇
  2016年   17275篇
  2015年   20320篇
  2014年   26916篇
  2013年   38326篇
  2012年   52812篇
  2011年   54538篇
  2010年   32304篇
  2009年   29927篇
  2008年   49767篇
  2007年   52072篇
  2006年   52450篇
  2005年   49771篇
  2004年   47732篇
  2003年   44991篇
  2002年   43426篇
  2001年   84756篇
  2000年   86697篇
  1999年   71998篇
  1998年   18281篇
  1997年   15784篇
  1996年   16013篇
  1995年   15099篇
  1994年   13913篇
  1993年   12733篇
  1992年   54339篇
  1991年   53021篇
  1990年   51125篇
  1989年   50112篇
  1988年   45565篇
  1987年   44337篇
  1986年   41740篇
  1985年   39642篇
  1984年   28650篇
  1983年   24369篇
  1982年   13070篇
  1979年   25777篇
  1978年   17753篇
  1977年   15190篇
  1976年   13851篇
  1975年   15152篇
  1974年   18141篇
  1973年   17275篇
  1972年   16334篇
  1971年   15297篇
  1970年   14648篇
  1969年   13637篇
排序方式: 共有10000条查询结果,搜索用时 145 毫秒
991.
An expert system for evaluation of X-ray diffraction patterns of urinary calculi is described and evaluated. The software was developed using the PERSONAL CONSULTANT expert system shell from Texas Instruments.  相似文献   
992.
993.
Existing methods for estimating additional days of hospital stay due to nosocomial infections (NI) have a number of documented limitations. An alternative method described in this paper uses the Appropriateness Evaluation Protocol (AEP) to determine whether each day of acute inpatient care is appropriate based on the need for care of the NI, original cause of hospitalization (OC), or combined NI-OC requirements. Using this method to identify specific days of hospitalization due to Staphylococcus aureus nosocomial infection, we find: 1) length of stay is increased for only a minority of patients (38%); 2) an average of 20 additional days of stay occurred for patients with 1 or more days attributed to NI; and 3) an average of 52% of length of stay of patients with 1 or more days attributed to NI can be attributed to the NI. Application of the AEP-based method is a useful alternative for identifying additional days of stay due to NI.  相似文献   
994.
The authors have presented the results of a 14-day open randomized trial of the efficacy of 3 calcium inlet blocking agents: nifedipine, verapamil and phendilin in 61 patients with Raynaud's syndrome. In the group of patients receiving 30-80 mg of nifedipine (20) there was a significant decrease in the frequency and expression of Raynaud's syndrome attacks, a positive effect of varying degree was noted in 19 patients. The drug raised slightly the skin and muscular blood flow and skin temperature. The use of 120-360 mg of verapamil in 21 patients caused no significant inhibition of Raynaud's syndrome and rise of hemocirculation. Phendilin (150-300 mg) though being comparable with nifedipine in efficacy, often produced side-effects resulting in the drug cancellation (8 out of 20). The efficacy of the calcium inlet blocking agents, especially nifedipine, for therapy of Raynaud's syndrome was emphasized.  相似文献   
995.
T Lohner 《Primary care》1987,14(1):13-23
This discussion has dealt with the nature of adolescence in the context of our culture. The stages of early adolescence (10 to 13 years), middle adolescence (14 to 17 years), and late adolescence (over 17 years) were examined separately and in some detail. Other characteristics of adolescence in general were examined, as were some of the factors influencing adult-adolescent interactions as well as the relationship between the adolescent and the society. Lastly, some of the ways in which this knowledge can be useful clinically were discussed, along with approaches to working successfully with teenagers and making their care a most enjoyable and rewarding part of clinical practice.  相似文献   
996.
997.
Patients with Fabry disease on dialysis in the United States.   总被引:9,自引:0,他引:9  
BACKGROUND.: Fabry disease results from an X-linked deficiency of lysosomal alpha-galactosidase A and is a rare cause of end-stage renal disease. Little is known about the characteristics of patients with Fabry disease that initiate dialysis in the United States, although data from Europe suggests these individuals have a poor survival. METHODS.: Using the United States Renal Disease System database, we first studied in detail 42 Fabry patients who initiated dialysis between April 1995 (following the introduction of the new detailed HCFA 2728 form) and July 1998. To examine crude survival in a larger cohort, 95 Fabry patients were studied who initiated dialysis between 1985 and 1993, similar to the European Registry. Diabetic and non-diabetic controls matched by age, gender, race, year of dialysis initiation, and initial dialysis modality were examined for comparison. RESULTS.: During the years 1995 to 1998, the mean age of Fabry patients that initiated dialysis was 42 years, 83% were Caucasian, and 10% were African American. Despite the X-linked inheritance of Fabry disease, 12% of Fabry patients on dialysis were female. At initiation of dialysis mean serum albumin and creatinine were significantly higher and mean body mass index was significantly lower among Fabry patients, but mean glomerular filtration rate was similar to controls. Fabry patients tended to have a lower three-year survival compared to non-diabetic controls, but the results were not significantly different. In a larger cohort of Fabry patients who initiated dialysis between 1985 and 1993, the three-year survival of Fabry patients was significantly lower than non-diabetic controls: 63% (95% CI, 50 to 75%) versus 74% (95% CI, 67 to 80%; P=0.03). CONCLUSION.: End-stage renal disease is associated with significant morbidity and mortality among patients with Fabry disease. Recent evidence that progression of Fabry disease may be attenuated by enzyme replacement therapy necessitates increased awareness of Fabry disease and its comorbidities.  相似文献   
998.
Nail plate and nail unit abnormalities may be helpful as diagnostic tools or as a part of the puzzle for confirmation of systemic disease. There are specific and nonspecific nail signs, which can be seen involving one or more nails, that occur simultaneously or secondary to systemic disease. Occasionally these clues can be diagnostic, while most are nonspecific reaction patterns. Nail changes occur in the nail plate as a result of nail matrix abnormalities caused by systemic disease and other systemic insults such as reactions to medications. In this article we review some of the more common nail signs that can be used to help diagnose systemic disease.  相似文献   
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