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   1845篇
  免费   118篇
  国内免费   22篇
耳鼻咽喉   6篇
儿科学   23篇
妇产科学   123篇
基础医学   235篇
口腔科学   3篇
临床医学   121篇
内科学   311篇
皮肤病学   151篇
神经病学   126篇
特种医学   19篇
外科学   233篇
综合类   9篇
一般理论   3篇
预防医学   307篇
眼科学   22篇
药学   241篇
中国医学   1篇
肿瘤学   51篇
  2021年   20篇
  2020年   22篇
  2019年   32篇
  2018年   33篇
  2017年   30篇
  2016年   33篇
  2015年   34篇
  2014年   32篇
  2013年   41篇
  2012年   76篇
  2011年   68篇
  2010年   50篇
  2009年   45篇
  2008年   96篇
  2007年   101篇
  2006年   105篇
  2005年   105篇
  2004年   76篇
  2003年   71篇
  2002年   63篇
  2001年   60篇
  2000年   45篇
  1999年   50篇
  1998年   25篇
  1997年   10篇
  1996年   17篇
  1995年   13篇
  1994年   12篇
  1993年   14篇
  1992年   40篇
  1991年   32篇
  1990年   37篇
  1989年   44篇
  1988年   32篇
  1987年   35篇
  1986年   40篇
  1985年   39篇
  1984年   21篇
  1983年   14篇
  1980年   16篇
  1979年   22篇
  1978年   13篇
  1976年   15篇
  1974年   25篇
  1973年   22篇
  1971年   11篇
  1970年   18篇
  1969年   15篇
  1968年   16篇
  1966年   9篇
排序方式: 共有1985条查询结果,搜索用时 15 毫秒
1.
High tibial osteotomy changes the patella and tibial condyle position, which makes the subsequent total knee replacement technically demanding. From 1 January 1993 to 31 December 2000, combined osteotomy [After the first osteotomy made 2 cm distally to the joint line, a bone wedge is removed based laterally. Its tip ends at the center of the tibial condyle (half bone wedge). The distal part of the tibia is placed into the valgus position and the half bone wedge is placed into the gap opened medially.] was performed on 103 knees and closing wedge osteotomy was performed on 47 consecutive knees. Eighty combined (group A) and 41 closing wedge (group B) osteotomy were studied. All knees were assessed radiologically before surgery, in the 10th postoperative week, in the 12th postoperative month and at the time of the final follow-up (in group A—66.15 months, in group B—66.61 months). We examined the change of the femorotibial angle, of the patellar height according to the method of Insall and Salvati, of the tibial slope angle according to the method of Bonnin, of the tibial condylar offset according to the method of Yoshida and of the distance between the lateral tibial plateau and the top of the fibular head. In group A and B, the recurrence of the varus deformity was not noted and valgus alignment did not increase in any case. In group-A, the Insall–Salvati ratio remained unchanged in 65% of knees. The tibial slope angle decreased in both groups. There was correlation between the change of the tibial condylar offset and the angle of the correction in both groups. There was correlation between the change of the distance between the lateral tibial plateau and the top of the fibular head. After combined osteotomy, the transposition of the tibial condyle and the decrease of the distance between the lateral tibial plateau and the top of the fibular head was less than after closing wedge osteotomy, although the average angle of correction was more after combined osteotomy (11.835°), than after closing wedge osteotomy (9.465°). Theoretically, the recurrence of the varus deformity, the increase of the valgus alignment and (in majority of cases) the shortening of the patellar tendon do not compromise the likelihood of successful conversion to the subsequent total knee replacement, either after combined or after closing wedge osteotomy. The combined osteotomy does not lead to considerable transposition of the tibial condyle and to considerable lateral tibial bone loss; therefore, theoretically, the combined osteotomy does not impair the subsequent total knee replacement.  相似文献   
2.
1. The haemodynamic effects of a novel cardiotonic drug, levosimendan, which has both calcium-sensitizing and phosphodiesterase III (PDE III) inhibitory properties, were studied in conscious dogs in which heart failure had been induced by prolonged cardiac pacing in the presence of aortic constriction. These effects were compared with those in sham-operated dogs with essentially normal cardiac function. 2. Eighteen mongrel dogs were instrumented for the measurement of left ventricular pressure (LVSP, LVEDP) and contractile function (dP/dt; dP/dt/P). In twelve dogs a balloon catheter, positioned in the thoracic aorta, was inflated producing an approximate 60% reduction in effective aortic diameter. Twenty min later rapid ventricular pacing (240 beats mean-1) was commenced and maintained for 48 h by means of a bipolar pacing electrode introduced into the right ventricle. This electrode served also for recording changes in the endocardial electrogram in the absence of pacing. Six of these dogs were used to evaluate the haemodynamic changes of pacing-induced heart failure; a further six of these dogs the haemodynamic changes elicited by levosimendan under these conditions. Six sham-operated dogs (group 2) served as controls. 3. In six dogs (group 1) the haemodynamic alterations were assessed after the development of heart failure. In the presence of aortic constriction, 48 h continuous rapid cardiac pacing resulted in a marked deterioration in left ventricular function which remained stable for at least 48 h after cessation of pacing. Thus, there was a marked reduction in LVSP (15%), +dP/dtmax (35%), -dP/dtmax (36%) and also in dP/dt/P (29%), whereas LVEDP was increased considerably (from 6.4 +/- 1.4 to 20.0 +/- 2.2 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
3.
J Gaál  Z Sziray  G Papp  M Gávai 《Orvosi hetilap》1989,130(9):447-452
The incidence over 10% of premature delivery in Hungary was studied. The cause which motivated this work was the fact that despite of several preventive and therapeutic measures the incidence e.g. in BAZ county surpassed even the average of the country. Professors of clinics in different countries of Europe as well as medical societies dealing with this question have been consulted about the matter of whether it was sufficient to consider a neonate a premature infant and the delivery a premature one solely on the basis of birth weight (under 2.500 g). Data of BAZ county proved that this determination was misleading and proposals are made concerning the modification on the basis of the examinations of the authors.  相似文献   
4.
5.
In Hungary valve replacement is still a major indication for heart surgery in adults. In the Cardiovascular Surgical Clinic of Semmelweis Medical University of Budapest from 1976 to 1990 2435 patients were operated for valve disease. Majority of the cases had single (aortic n = 856, mitral n = 912) or double (aortic + mitral n = 513) valve replacement. Over this 15 years period there have been many alterations in patients characteristics and surgical technique as well. In spite of the increasing mean age of patients the operative mortality has decreased (in the last 5 years period it was 2.7%, 5.5% and 7.9% in the three groups respectively). At the same time the number of patients requiring valve re-replacement or combined valve + coronary procedure has increased. The use of bioprosthetic valves has fallen below 10 percent from the 60--80 percent observed between 1976--1980. The analysis showes excellent surgical results in the field of valve replacement in Hungary.  相似文献   
6.
Conflicting results are to be found in the literature on the relationship between the M235T polymorphism of the angiotensinogen (AGT) gene and hypertension. The controversy may be due to insufficient numbers of subjects, the variability of the inclusion criteria and the different genotype analysis methods used. We have experienced that the most frequently used, original polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method involves significant uncertainties when the TT genotype is determined, independently of the restriction digestion. To make the determination more accurate, we improved the PCR by designing a new antisense primer containing only one mismatch instead of the two in the original protocol and also by adding DMSO to the PCR reaction mixture. The original and our improved methods were compared by using DNA from 123 patients: parallel determinations resulted in values of 33 MM, 90 MT and 0 TT with the original method and of 33 MM, 56 MT and 34 TT with the improved RFLP protocol. In summary, a plausible explanation for some of the conflicting data published on AGT M235T polymorphism may be that inaccuracies arose during the determination of the genotype.  相似文献   
7.
8.
After giving a short account on the possible ways of male contraception, the authors outline the administration of surgical sterilization and its professional follow-up based on their own experience. Their suggestions concerning legal regulations aim, on the one hand, at the extension of the topic, on the other hand at supporting the specialists interested in surgical contraception.  相似文献   
9.
10.
Trisomy 18 is the second most common genetic defect after trisomy 21, almost 90% of which are due to additional chromosome from the mother. The parental origin of the additional chromosome can, if required, be determined by two methods: karyotyping, which takes several weeks; or, more recently, by polymerase chain reaction (PCR) which is often problematic. Fluorescent PCR of small tandem repeats (STRs) can determine the parental origin in the majority of cases within 5 h. Although the incidence of paternal origin is known for both trisomy 21 and trisomy 18, this technique can rapidly determine the parental origin in cases where there is insufficient samples to perform conventional tests. Determining parental origin by these methods may also have clinical significance in the diagnosis of chromosomal translocations or in the diagnosis of genetic disease using linkage analysis.  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