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   163827篇
  免费   6276篇
  国内免费   345篇
耳鼻咽喉   2218篇
儿科学   4731篇
妇产科学   3798篇
基础医学   23538篇
口腔科学   5393篇
临床医学   9301篇
内科学   36140篇
皮肤病学   4465篇
神经病学   13169篇
特种医学   3995篇
外国民族医学   1篇
外科学   18886篇
综合类   775篇
一般理论   25篇
预防医学   19651篇
眼科学   4330篇
药学   12792篇
中国医学   661篇
肿瘤学   6579篇
  2023年   816篇
  2021年   2431篇
  2020年   1369篇
  2019年   2808篇
  2018年   4946篇
  2017年   3077篇
  2016年   3071篇
  2015年   3408篇
  2014年   3726篇
  2013年   5740篇
  2012年   10044篇
  2011年   10625篇
  2010年   5225篇
  2009年   3780篇
  2008年   8696篇
  2007年   9345篇
  2006年   8972篇
  2005年   8587篇
  2004年   7944篇
  2003年   7472篇
  2002年   7101篇
  2001年   4874篇
  2000年   5460篇
  1999年   4153篇
  1998年   705篇
  1992年   2219篇
  1991年   1989篇
  1990年   1973篇
  1989年   1679篇
  1988年   1604篇
  1987年   1504篇
  1986年   1543篇
  1985年   1451篇
  1984年   1040篇
  1983年   893篇
  1979年   1206篇
  1978年   804篇
  1977年   780篇
  1976年   741篇
  1975年   877篇
  1974年   1120篇
  1973年   1168篇
  1972年   1110篇
  1971年   1079篇
  1970年   1008篇
  1969年   1085篇
  1968年   1105篇
  1967年   977篇
  1966年   878篇
  1965年   548篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
105.
A randomized, placebo-controlled clinical pilot study was performed in order to examine the effect of magnesium-orotate in male idiopathic infertility. Ten males were treated daily for 90 consecutive days with 3000 mg magnesium-orotate (Magnerot) tablets (Group M). As a control, ten other males were treated in the same way with placebo (Group P). Conventional microscopic sperm characteristics (sperm concentration, motility ratio, total number of motile sperm cells, normal morphology ratio), plus total and ionized magnesium levels in seminal plasma and blood serum were evaluated both prior to treatment and on day 90, at the conclusion of the study. No significant changes in sperm characteristics, blood ionized or total Mg, or ejaculate total Mg levels were detected. However, ejaculate ionized Mg levels increased in Group M from 0.18 +/- 0.05 to 0.30 +/- 0.05 (mmol/l; mean +/- SD, p < 0.05). Within the observation period of 3 months, one pregnancy occurred in the partner of a male from Group M. In conclusion, magnesium-orotate treatment at a dose of 3000 mg/day leads neither to a significant improvement of sperm variables nor does it increase the pregnancy rates of female partners of treated males as compared to those of controls. Thus, magnesium-orotate treatment was not shown to be effective therapy for idiopathic male infertility.  相似文献   
106.
A retrospective study was performed to describe the features of the pollinosis caused by Betula in the area of Ourense, Spain. The pollen count was carried out with a Lanzoni volumetric Hirts spore trap (1993-2000). The Betula pollen represented 5% over the annual total (annual mean quantity: 965 grains). It was present in the air from March to mid-May. The highest peaks took place in April (maximum values mean: 131 grains/m3). The medical records of 222 patients (mean age 25.66 years) diagnosed with pollinosis (1998-2000), who lived at less than 30 km. from the spore trap, were reviewed. In all of them, the skin-prick test (SPT) was carried out with pollen allergens. The percentages of positive SPT were: Lolium perenne, 91.89% (16.6% monosensitized); Plantago lanceolata, 71.17% (1.26% monosensitized); Betula alba, 41.89% (10.75% monosensitized); Platanus hybrida, 34.95%; Olea europea, 10.36%; and Parietaria judaica, 6.3%. The mean age of Betula monosensitized patients was 44.7 years. The majority of them had symptoms in March-April, 40% had asthma symptoms, 80% had lived in Central Europe, and 30% of them presented an oral allergy syndrome to fruits. There were 41.93% of the patients with positive SPT to Betula pollen who had asthma symptoms, in comparison with 23.25% of the patients with negative SPT to Betula (p = 0.0034). There were 20.28% of the patients with positive SPT to Betula pollen, who had lived in Central Europe, in comparison with 4.27% of the patients with negative SPT to Betula, p: 0.00049. The relative risk of sensitization was 2.05. CONCLUSIONS: Betula pollen was the second cause of clinical pollinosis in our patients, after grass, being responsible of the symptoms in the early spring, in a small number of the patients in their forties. The presence of asthma was higher in Betula sensitized patients, and the residence in Central Europe was a sensitization risk factor.  相似文献   
107.
6-keto-prostaglandin F1a and thromboxane B2 were determined in order to obtain more information about the prostacyclin synthesis and thromboxane A2 release in 3- to 18-year-old healthy children and in offspring of parents who have had an acute myocardial infarction before the age of 45. The authors demonstrated a reduction of plasma prostacyclin synthesis in children with a positive family history of premature coronary arterial disease. Thromboxane levels in the affected adolescent boys were significantly lower compared with the controls. The ratio of thromboxane:prostacyclin in endangered children did not show a significant difference from that of healthy controls. These data indicate that prostaglandins are a definitive marker for identifying cardiovascular risk children. It must be supposed that in adolescence, only in boys, with a positive family history of premature coronary arterial disease, a compensatory mechanism exists to protect them from developing an imbalance in the regulation of prostaglandins.  相似文献   
108.
Three cases with suspected pulmonary artery embolism are presented, in which transesophageal echocardiography showed a mass in the right pulmonary artery consistent with thrombus. The relevant diagnostic contributions of transesophageal echocardiography are discussed.  相似文献   
109.
110.
Cavernous haemangiomas of the liver were surgically treated in 36 women and 14 men over a 10-year period. The tumours were solitary in 42 cases and multiple in 8. Locations were the right lobe in 39 cases, the left one in 5 and both lobes in 6. The size of the tumours ranged from 0.4 to 14 cm in diameter. Enucleation of tumours was carried out in 29 cases, an atypical liver resection in 19 cases, anatomical lobectomy in 2 cases and a right trisegmentectomy in 1 case. There was no mortality. Morbidity rate seems to be lower in patients who underwent enucleation. The authors indicate the importance of enucleation for removal of liver haemangiomas of various sizes.
Chirurgische Behandlung kavernöser Hämangiome der Leber
Zusammenfassung Über einen Zeitraum von 10 Jahren wurden kavernöse Hämangiome der Leber bei 36 Frauen und 14 Männern chirurgisch behandelt. Bei 42 Patienten waren die Tumoren solitär, bei 8 multipel. Sie waren in 39 Fällen im rechten, bei 5 Patienten im linken und bei 6 in beiden Leberlappen lokalisiert, ihr Durchmesser betrug 0,4 bis 14 cm. In 29 Fällen wurde eine Enukleation, in 19 eine atypische Leberresektion, in 2 eine anatomische Lobektomie und in einem Falle eine rechtsseitige Trisegmentektomie durchgeführt. Die Mortalität war gleich Null; die Morbiditätsrate scheint bei den Patienten geringer, die mit Enukleation behandelt wurden. Der Beitrag hebt die Bedeutung der Enukleation zur Beseitigung von Leberhämangiomen unterschiedlicher Größe hervor.
  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