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   1398718篇
  免费   104805篇
  国内免费   7281篇
耳鼻咽喉   17211篇
儿科学   44995篇
妇产科学   37831篇
基础医学   202508篇
口腔科学   38039篇
临床医学   135752篇
内科学   267020篇
皮肤病学   26849篇
神经病学   113258篇
特种医学   51631篇
外国民族医学   366篇
外科学   188702篇
综合类   43430篇
现状与发展   2篇
一般理论   467篇
预防医学   121534篇
眼科学   30201篇
药学   103752篇
  11篇
中国医学   8390篇
肿瘤学   78855篇
  2021年   11269篇
  2019年   11869篇
  2018年   16658篇
  2017年   12603篇
  2016年   13625篇
  2015年   15651篇
  2014年   21482篇
  2013年   33053篇
  2012年   45783篇
  2011年   51466篇
  2010年   29744篇
  2009年   26743篇
  2008年   44931篇
  2007年   47100篇
  2006年   47328篇
  2005年   46791篇
  2004年   49144篇
  2003年   46407篇
  2002年   43774篇
  2001年   65118篇
  2000年   65202篇
  1999年   55492篇
  1998年   16826篇
  1997年   15199篇
  1996年   14370篇
  1995年   13554篇
  1994年   12774篇
  1993年   12708篇
  1992年   43078篇
  1991年   42054篇
  1990年   40438篇
  1989年   38156篇
  1988年   35200篇
  1987年   34203篇
  1986年   32649篇
  1985年   30879篇
  1984年   23158篇
  1983年   19660篇
  1982年   11810篇
  1979年   20861篇
  1978年   14847篇
  1977年   12112篇
  1976年   11910篇
  1975年   12162篇
  1974年   14840篇
  1973年   14512篇
  1972年   13379篇
  1971年   12445篇
  1970年   11508篇
  1969年   10425篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Thirty-one full-term newborn babies were investigated in order to establish reference values for ionized calcium. Only children fulfilling certain optimality criteria (with best possible maternal and infant conditions and uncomplicated pregnancy and delivery) were included. All infants were breast fed. Capillary blood for analysis of ionized calcium was collected by heel puncture on day 1 (6-36 h post partum, p.p.), day 3 (60-84 h p.p.) and day 5 (108-132 h p.p.). Ionized calcium was measured with a semi-automatic electrode system ICA 1 (Radiometer A/S, Copenhagen, Denmark). The reference ranges (mean +/- 2 SD) for days 1, 3 and 5 were 1.05-1.37, 1.10-1.42 and 1.20-1.48 mmol/l, respectively. The mean ionized calcium concentration on day 1 was significantly lower than on days 3 and 5. Reference values are also given for total calcium, magnesium and phosphate. We emphasize that it is impossible to calculate ionized calcium from total calcium or vice versa.  相似文献   
992.
Fifty-five patients with vascular insufficiency resulting in above-knee (AK) and through-knee (TK) amputations were studied to determine factors related to prosthetic candidacy and functional outcome. Chart review showed that the only difference between patients who were fitted with prostheses and those who were not fitted with prostheses was their respective number of medical complications. Twenty-three of 31 patients with prostheses were evaluated 7 to 35 months after receiving the prostheses. Ten (44%) of these patients wore their prostheses all day every day and used wheelchairs minimally or not at all. Over half of the patients evaluated used their wheelchairs most of the time. Two (9%) of the 23 patients had stopped wearing their prostheses. Patients who demonstrated increased walking distances and velocities at follow-up used their prostheses more and their wheelchairs less than did the other patients. Neither gait factors nor hip range of motion at discharge was predictive of continued prosthetic use. Functional outcome and prosthetic use were limited in this group of elderly patients with dysvascular AK and TK amputations. The results of this study may serve as a basis for clinical determination of prosthetic candidacy and functional goals.  相似文献   
993.
Peripheral arterial thromboembolism and thrombosis of arterial grafts continue to threaten viability of extremities. Percutaneous intra-arterial thrombolysis (IAT) and angiodilatation have afforded limb salvage in some of these patients. Proper patient selection appears to be the hallmark of success with IAT. During a recent three-year period, we used IAT in 32 extremities in 28 patients who had acute arterial insufficiency. Before IAT, 16 extremities were painful at rest, and 16 had incapacitating claudication. The overall success rate was 38%, but some degree of thrombolysis occurred in 88%. Limb salvage was achieved in 27 of 32 extremities (84%). Only five of 17 limbs (29%) with arterial graft thrombosis required no operation or an operation of lesser magnitude than predicted before IAT. Of six extremities with native arterial embolism, four (67%) were completely cleared with IAT. Major complications occurred in eight cases (25%), with two IAT-related deaths (6%). This study suggests that IAT is best reserved for individuals with acute limb ischemia caused by arterial embolus, those whose degree of ischemia would tolerate a 24-hour trial of IAT, and those whose femoral or tibial runoff is not likely to require remedial operation.  相似文献   
994.
Trichinosis is a rare cause of a neck mass, but should be considered by the physician when contemplating a differential diagnosis. This disease is still endemic in parts of the world and is directly related to the ingestion of incompletely cooked pork. A case is presented in which a 68-year-old man was diagnosed as having a squamous cell carcinoma of the mandible only to have trichinosis diagnosed on the final pathologic report. The case presentation is followed by a historical review and discussion.  相似文献   
995.
A goal for the obstetrician and neonatologist is to screen for risk factors associated with intraventricular hemorrhage (IVH) in the low-birthweight infant. Perinatal events that lead to neonatal metabolic and cardiovascular derangements seem to provoke IVH, and conflicting reports have implicated labor as being contributory. A fetal heart rate (FHR) abnormality during premature labor may be a predictor of subsequent neonatal IVH. For this reason, 5 years of FHR tracings at two university medical centers were reviewed for inborn infants who were delivered after premature labor and weighed less than or equal to 2000 gm. Sixty-four infants developed IVH, but pre-existing labor with a discernible FHR pattern was recorded in only 38 (59%) cases. Interpretations were reassuring in 17 (45%) cases, suspicious in 7 (18%) cases, and ominous in 14 (37%) cases. This proportion of FHR patterns was not significantly different from a matched group of premature infants without IVH during the same period. Interpretations of intrapartum FHR patterns of low-birthweight infants are limited, especially before 30 weeks gestation, and not useful in predicting neonatal IVH.  相似文献   
996.
Several types of neurons were differentiated on the basis of a study of neuronal activity in various parts of the cortex near the sulcus principalis during the execution of spatial delayed reactions by monkeys. It was established that the different types of neurons are represented in different numbers in. different parts of the cortex near the sulcus principalis. The determination of several factors influencing the activity of these neurons and the comparison of data on their quantitative representation in the anterior, middle, and posterior parts of the cortex near the sulcus principalis with the existing behavioral data obtained after local ablations of identical regions of the brain made it possible to postulate that neurons belonging to the different types are involved in the analysis of different processes and represent different functional units.Translated from Fiziologicheskii. Zhurnal SSSR imeni I. M. Sechenova, Vol. 71, No. 12, pp. 1488–1494, December, 1985.  相似文献   
997.
高血压的社区管理与医院内科门诊管理效果比较   总被引:6,自引:1,他引:5  
目的 评价健康教育在社区高血压患者管理中的效果。方法 随机抽取北京复兴医院月坛社区卫生服务中心管理的高血压患者603例作为研究对象,以同期该院三里河内科门诊就诊的高血压患者617例作为对照,进行血压测量和问卷调查。结果 社区高血压患者高血压知识知晓率明显好于内科门诊高血压患者(P<0.01);其生活方式(遵医行为、体育锻炼、食盐量等)较好;血压控制情况也好于门诊患者(P<0.01)。结论 规范、定期的健康教育可以提高高血压患者对高血压知识的知晓情况,改善高血压患者的不良行为习惯;利用社区卫生服务站固定的合作关系及新型医患模式有利于健康教育、健康知识普及和取得治疗成效。  相似文献   
998.
Delayed graft function (DGF) in cadaver kidney transplants is a common problem and is often due to acute tubular necrosis (ATN). DGF in transplants may have a deleterious effect on long-term graft survival. Since thyroid hormone has been shown to hasten recovery from ATN in experimental models, we designed a trial to determine if a defined course of triiodothyronine (T3) would improve the short- or long-term outcome of patients with DGF in cadaveric transplants. A prospective, randomized, placebo controlled, double blind trial of T3 was carried out in patients with DGF in cadaveric renal transplants. End-points were percentage requiring dialysis, percentage recovering function, time to recovery and length of hospital stay. Long-term outcomes were percentage grafts functioning at 1 year and mean serum creatinine at 1 year. Forty-four patients were randomized to receive either T3 or placebo. Three patients were dropped from each group when early biopsies disclosed that DGF was due to rejection. The groups were well matched by age, cold ischemia time of the graft, and percentage reactivity to a random panel of antigens. Baseline thyroid function studies, including T3, reverse T3 (rT3), and thyroid stimulating hormone (TSH) levels, were similar between the two groups and typical of 'euthyroid-sick syndrome'. T3 had no effect on percentage requiring dialysis, time to recovery, percentage recovering function, or length of stay. At 1 year follow-up, graft function was similar in both groups and significantly lower than that seen in patients with good initial function. Thyroid hormone, given early in the course of DGF in cadaver kidney recipients, had no effect on the course of DGF. Long-term graft function is impaired in patients who experience post-transplant DGF compared to those who have good initial function.  相似文献   
999.
目的 建立小鼠溃疡性结肠炎模型。方法 给小鼠自由饮用5%葡聚糖硫酸钠(DSS)溶液7d后,改为蒸馏水自由饮用10d,如此进行4个循环,每天观察症状。在第1个循环和第4个循环后剖杀小鼠,取出整段结肠行实体显微镜观察及切片组织学研究。结果 所观察的症状、实体显微镜像、组织学病理改变均与人类溃疡性结肠炎类似。结论 此模型制作方法简便,重复性良好,可应用于多种实验研究。  相似文献   
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