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   12997篇
  免费   1197篇
  国内免费   92篇
耳鼻咽喉   99篇
儿科学   556篇
妇产科学   337篇
基础医学   1821篇
口腔科学   401篇
临床医学   1495篇
内科学   2663篇
皮肤病学   210篇
神经病学   1011篇
特种医学   719篇
外科学   1560篇
综合类   329篇
一般理论   19篇
预防医学   1341篇
眼科学   106篇
药学   963篇
中国医学   25篇
肿瘤学   631篇
  2021年   204篇
  2020年   85篇
  2019年   179篇
  2018年   250篇
  2017年   153篇
  2016年   200篇
  2015年   225篇
  2014年   272篇
  2013年   406篇
  2012年   630篇
  2011年   588篇
  2010年   377篇
  2009年   378篇
  2008年   564篇
  2007年   612篇
  2006年   533篇
  2005年   516篇
  2004年   469篇
  2003年   433篇
  2002年   431篇
  2001年   412篇
  2000年   419篇
  1999年   373篇
  1998年   226篇
  1997年   218篇
  1996年   203篇
  1995年   174篇
  1994年   194篇
  1993年   170篇
  1992年   308篇
  1991年   302篇
  1990年   284篇
  1989年   281篇
  1988年   271篇
  1987年   262篇
  1986年   266篇
  1985年   224篇
  1984年   163篇
  1983年   177篇
  1982年   108篇
  1981年   98篇
  1980年   98篇
  1979年   170篇
  1978年   132篇
  1977年   118篇
  1976年   93篇
  1975年   97篇
  1974年   104篇
  1973年   89篇
  1972年   77篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
We report the results and one-year follow-up of 20 elderly patients (age range 70-82 years) with severe rheumatic mitral stenosis treated by mitral balloon valvuloplasty (MBV). All 20 were breathless at rest despite treatment with diuretics and digoxin. At cardiac catheterization, successful dilatation was achieved in 17 patients: mean transvalvular mitral gradient fell by 45%, mean cardiac output rose by 24% and mean valve area increased by 76%. There was no procedure-related mortality. At one month, 15 patients had experienced an improvement in symptoms of at least one New York Heart Association class and, at one year, ten had maintained this improvement. Three patients proceeded to mitral valve replacement because of a suboptimal symptomatic result. Mitral balloon valvuloplasty can be successfully performed with significant symptomatic benefit in frail elderly patients unfit for surgery and may also be offered to other selected elderly patients as an alternative to surgical treatment.  相似文献   
32.
33.
The normal thymus in children is highly variable in size and shape. In some cases this has led to the misdiagnosis of mediastinal pathology and an unnecessary thoracotomy. Twenty-five children without suspicion of mediastinal pathology and five children with suspected mediastinal pathology were imaged using magnetic resonance imaging (MRI). MRI is recommended to distinguish between the normal and abnormal thymus in difficult cases where other imaging techniques are inconclusive.  相似文献   
34.
A 13 year old Asian girl presenting with apparent hysterical paralysis and subsequent rapid cycling bipolar mood disorder was found to have biochemical evidence of pseudohypoparathyroidism type II. The mood disorder responded to treatment of the pseudohypoparathyroidism with a vitamin D analogue. Investigation of her parents and siblings showed phenotypes consistent with two distinct types of pseudohypoparathyroidism (type I and type II) in different family members.  相似文献   
35.
36.
Pulmonary Function in Survivors of Wilms' Tumor   总被引:1,自引:0,他引:1  
The respiratory status of 47 patients surviving childhood Wilms' tumor was studied. The group that had receivedflnnk irradiation (which impinges on the lower lung) (n - 17) had a sisnijGantly lower mean percent predicted for forced expiratory volume in one second, residual volume, and total lung capaci(v when compared to those who had received no irradiation (n - 23). Those patients who had received whole-lung irradiation (n - 3) had sisnijicantly lower transfn. foctor for carbon monoxide and gas transfer per unit lung volume whm compared to the nonirradiated group (n - 23). There was no sipiftiant dimue in the prevalence of respiratory symptoms between the three groups. Patients receiving any form of radiotherapy for Wilms' tumor may have abnormulities o f pulmonary function and should have pulmonary function tests performed as part o f their long-tmn follow-up.  相似文献   
37.
Two human parathyroid hormone-related protein (hPTHrP) fragments were tested for effects on maternofetal transfer of 45Ca and Mg across the in-situ perfused rat placenta at 21 days of gestation (term = 23 days). The fetal placental circulation was perfused with a Mg-free Krebs-Ringer solution and the unidirectional maternofetal clearance (Kmf) of 45Ca and Mg compared with that of 51Cr-EDTA, the latter being employed as a paracellular diffusional marker. Placental perfusion with hPTHrP(1-34) (100 ng/ml) or hPTHrP(75-86)amide (50 ng/ml) did not significantly alter the Kmf of 45Ca or that of Mg. In separate rats, however, hPTHrP(1-34) but not hPTHrP(75-86)amide stimulated marked placental cyclic AMP (cAMP) release, the peak response of 63 +/- 7 pmol/min occurring 10 min after the beginning of the peptide perfusion. A lower dose of hPTHrP(1-34) (4 ng/ml) produced a similar peak release of cAMP, as did [Nle8,21, Tyr34]-rPTH(1-34)amide (4 ng/ml) and the adenylate cyclase agonist forskolin (17 mumol/l). Forskolin also rapidly increased the Kmf of 45Ca but not that of Mg or 51Cr-EDTA. The present study indicates that hPTHrP does not acutely affect maternofetal transfer of Ca or Mg across the perfused rat placenta. The data also question the role played by cAMP in the stimulatory actions of forskolin on placental Ca transport.  相似文献   
38.
A toxicologic-pathologic study of isobutyl-2-cyanoacrylate (Bucrylate) was carried out first in dogs and then in humans whose arteriovenous malformations were infused with this embolic agent. The canine specimens obtained at 7, 18, 28, and 147 days after embolization showed the development of a mild histiocytic giant cell reaction, which evolved to end-state sclerotic arteritis. The response was confined to the vessels and did not involve contiguous parenchymal tissues. Ten human specimens, obtained from 1 hr to 7 years after treatment, showed a similar bland reaction with no evidence of suppuration or premalignant changes.  相似文献   
39.
A study was made of the pattern of distribution of mercury in the tissues of some plant species collected around a chlor-alkali factory in India. Different plants accumulated different levels of mercury in their tissues. Accumulation in leaves was the highest, followed by the stem and the root and, in some cases, the root and the stem. A significant correlation was noted between the mercury concentration of the soil and the plant tissues and between different tissues. Grazers (goats, sheep) also accumulated significant levels of mercury in their tissues.  相似文献   
40.
Reproductive and social histories of the first 100 patients attending the in vitro fertilisation (IVF) programme at National Women's Hospital, Auckland, have been studied. The average age at first treatment was 31.6 (SD 3.9) for women, and 34.2 (4.6) for men. The couples had been married 7.6 (3.3) years and had experienced 6.7 (3.2) years infertility. It was a second marriage for 16. The husbands had on average a higher social classing than the population (class: number [population]--1:16 (7%), 2:18 (14%), 3:42 (28%), 4:19 (29%), 5:4 (14%), 6:1 (8%); but this bias diminished in the next 159 couples. Nine couples withdrew before their quota of cycles, 7 from stress. Tubal disease was the cause of infertility in 93, but in 69 its origin was untraceable. In 22 it could be attributed to pelvic inflammatory disease (eight associated with IUCDs and 2 with sexually transmitted disease) and in two to sterilisation. Although 59 women had a history of having conceived, only 34 were parous, and only 11 had a child of the current union.  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