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   1177篇
  免费   103篇
  国内免费   42篇
耳鼻咽喉   4篇
儿科学   78篇
妇产科学   14篇
基础医学   125篇
口腔科学   16篇
临床医学   194篇
内科学   261篇
皮肤病学   22篇
神经病学   43篇
特种医学   89篇
外科学   130篇
综合类   22篇
一般理论   3篇
预防医学   149篇
眼科学   43篇
药学   87篇
肿瘤学   42篇
  2023年   14篇
  2022年   9篇
  2021年   18篇
  2020年   26篇
  2019年   21篇
  2018年   15篇
  2017年   23篇
  2016年   10篇
  2015年   31篇
  2014年   33篇
  2013年   43篇
  2012年   48篇
  2011年   57篇
  2010年   41篇
  2009年   31篇
  2008年   39篇
  2007年   79篇
  2006年   58篇
  2005年   40篇
  2004年   50篇
  2003年   40篇
  2002年   31篇
  2001年   35篇
  2000年   33篇
  1999年   23篇
  1998年   26篇
  1997年   23篇
  1996年   28篇
  1995年   15篇
  1994年   29篇
  1993年   15篇
  1992年   30篇
  1991年   24篇
  1990年   27篇
  1989年   24篇
  1988年   20篇
  1987年   21篇
  1986年   20篇
  1985年   22篇
  1984年   15篇
  1983年   12篇
  1982年   13篇
  1981年   11篇
  1979年   7篇
  1978年   7篇
  1977年   9篇
  1976年   6篇
  1974年   8篇
  1973年   12篇
  1970年   7篇
排序方式: 共有1322条查询结果,搜索用时 15 毫秒
1.
2.
3.
Beckmann  CF; Roth  RA; Luedke  MD 《Radiology》1986,159(3):643-645
In 44 patients with one or more calculi in the upper two-thirds of the ureter, single-stage percutaneous nephrolithotomy was performed through a middle or upper calyceal nephrostomy after cystoscopic placement of an occlusion balloon catheter distal to the calculus; in 42, the procedure was successful. The occlusion balloon catheter permitted retrograde opacification of all systems for enhanced renal puncture. In the last 30 patients an attempt was made either to push the calculus upward mechanically or to flush it upward into the renal pelvis with carbon dioxide or dilute contrast material. This was successful in 24 of these patients. Prior overnight occlusion of the ureter by means of ureteral dilatation further facilitates dislodgment of the calculus, which was successful in 12 of 13 patients.  相似文献   
4.
5.
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   
6.
The influence of the thermal environment on evaporation and heat loss from patients with severe burns treated by exposure has been studied. Simple heat transfer equations can be used to predict changes resulting from alterations in environmental conditions and these have been tested using phantoms. The method relies upon the derivation of surface diffusion resistances to describe the moisture properties of burn wounds. Clinical measurements revealed wide variations in evaporation rates and diffusion resistances for different wounds. Evaporation rates changed by less than 30 per cent during the first 5-6 days following injury, after which evaporation from partial skin thickness wounds gradually fell whereas that from full skin thickness wounds tended to remain higher. Raising ambient temperature can compensate for increased evaporation heat losses. Patients can be treated at ambient temperatures of 32-35 degrees C in the intensive care room with a specially designed airflow system. However, raising the temperatures of standard wards with no special airflow or temperature control facilities often caused patients to sweat, further increasing heat loss.  相似文献   
7.
8.
Elevated blood pressure is an important risk factor for renal-, cerebro- and cardiovascular diseases. We used an efficient discordant sib-pair ascertainment scheme to investigate the impact of the distal end of the long arm of human chromosome 5 (chromosomal region 5q31.1-qter) containing genes for the alpha1B and beta2 adrenergic receptors and the dopamine receptor type 1A on variation of systolic blood pressure in young Caucasians. We measured eight highly polymorphic markers spanning this positional candidate gene-rich region in 427 individuals from 55 three-generation pedigrees containing 69 discordant sibling pairs, and calculated multipoint identity by descent (MIBD) probabilities. The results of genetic linkage and association tests indicate that the region between markers D5S2093 and D5S462 is significantly linked to one or more polymorphic genes influencing interindividual variation in systolic blood pressure levels. Since the alpha1B adrenergic receptor and dopamine receptor type 1A genes are located close to these markers, these data suggest that genetic variation in one or both of these G protein-coupled receptors, which participate in the control of vascular tone, plays an important role in influencing interindividual variation in systolic blood pressure levels.   相似文献   
9.
The presence of endotoxin (detected by the Limulus amebocyte lysate assay) was compared to the presence of viable Haemophilus influenzae and Moraxella catarrhalis (detected by PCR) in 106 middle-ear effusions from pediatric patients with chronic otitis media. Endotoxin was found in 81 of the 106 specimens. Of these 81 specimens, 66 (81.5%) also tested positive for one or both of the gram-negative bacteria H. influenzae and M. catarrhalis. The data suggest that viable gram-negative bacteria, detectable by PCR but often undetectable by culture, may be the source of endotoxin in middle-ear effusions.  相似文献   
10.
A gene fragment encoding for the amino acids (aa) 286-426 from the dengue Envelope (E) protein was expressed in Escherichia coli as two forms of fusion proteins. In one case, the E fragment was fused to the first 45 aa of the P64k protein from Neisseria meningitidis (PD2) while, in the other, it was inserted within the lipoil-binding domain of the aforementioned bacterial protein (PD3). PD2 was obtained as insoluble form within the cytoplasm of the bacteria while PD3 was distributed equally as soluble and insoluble forms. The insoluble forms of each protein as well as the soluble fraction of PD3 were semipurified to test the antigenicity and the immunogenicity in mice. The forms containing the entire P64k protein exhibited the highest recognition with different polyclonal and monoclonal antibodies. Consequently, the neutralizing antibodies elicited by the recombinant proteins were higher in the case of PD3 forms than with PD2, independently of the solubility status. In addition, mice inoculated with the semipurified insoluble form of PD3 were partially protected against lethal challenge with dengue-2 virus, administered by intracerebral inoculation. The results suggested the folding and carrier capacity of the P64k protein over the E fragment, converting PD3 as an attractive vaccine candidate against dengue-2 virus.  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