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   500篇
  免费   45篇
  国内免费   7篇
儿科学   40篇
妇产科学   7篇
基础医学   70篇
口腔科学   6篇
临床医学   42篇
内科学   45篇
皮肤病学   4篇
神经病学   120篇
特种医学   48篇
外科学   13篇
综合类   15篇
一般理论   1篇
预防医学   36篇
眼科学   77篇
药学   20篇
肿瘤学   8篇
  2021年   6篇
  2019年   7篇
  2018年   6篇
  2017年   3篇
  2016年   5篇
  2015年   8篇
  2014年   10篇
  2013年   11篇
  2012年   14篇
  2011年   15篇
  2010年   9篇
  2009年   14篇
  2008年   21篇
  2007年   24篇
  2006年   18篇
  2005年   10篇
  2004年   18篇
  2003年   11篇
  2002年   16篇
  2001年   19篇
  2000年   19篇
  1999年   18篇
  1998年   19篇
  1997年   18篇
  1996年   17篇
  1995年   11篇
  1994年   6篇
  1993年   10篇
  1992年   16篇
  1991年   10篇
  1990年   7篇
  1989年   9篇
  1988年   10篇
  1987年   10篇
  1986年   11篇
  1985年   16篇
  1984年   12篇
  1983年   4篇
  1981年   8篇
  1980年   6篇
  1979年   5篇
  1978年   9篇
  1977年   14篇
  1976年   9篇
  1975年   6篇
  1974年   3篇
  1971年   4篇
  1961年   2篇
  1947年   2篇
  1941年   2篇
排序方式: 共有552条查询结果,搜索用时 27 毫秒
1.
We describe a 15-y-old girl with Fechtner-like syndrome, who is the first Chinese reported to have this rare syndrome. She presented with left homonymous hemianopia and neuroimaging revealed haemorrhage in both parietal and occipital lobes. Peripheral blood smear showed macrothrombocytopenia and intracytoplasmic inclusion bodies inside leucocytes. Thrombocytopenia and proteinuria responded to intravenous immunoglobulin and pulsed methylprednisolone. This case illustrates that life-threatening haemorrhage can occur in patients with Fechtner syndrome. Although there was no effective treatment reported in the literature, high dose steroid and immunoglobulin seemed to be useful in our patient. Our patient also had nephritic-nephrotic syndrome with renal insufficiency, which is unusual in adolescent female patients.  相似文献   
2.
Akathisia as a side-effect of metoclopramide has received increasing attention in consultation-liaison psychiatry in recent years. A case of metoclopramide-induced akathisia resulting in a suicide attempt is reported in order to highlight the suffering of such patients and the factors that lead to misdiagnosis.  相似文献   
3.
Freshly isolated rabbit lenses were cultured in isosmolar TC-199 medium or hyperosmolar medium containing 180 mM sorbitol or mannitol. These experiments were performed to investigate the probable effects of hyperosmolar media on lens clarity and the ability of lens fiber cells to synthesize membrane intrinsic protein, MP-26. The data from these experiments show that incubation in hyperosmolar medium causes depressed MP-26 synthesis, whereas the presence of sugar alcohols in the culture medium induced anterior and posterior subcapsular opacities. The cation levels of lenses incubated in iso- and hyperosmolar medium were also measured. Data from these experiments revealed that although the experimental lenses display prominent opacities, their cation levels are generally similar to those of control lenses. It is proposed that the observed lens opacities are due to the presence of sugar alcohols in the culture medium and not to hyperosmolar shock.  相似文献   
4.
PURPOSETo develop an objective method for measuring the optic chiasm and to document its normal range in size.METHODSMeasurements of the height and area of the optic chiasm, made on coronal T1-weighted MR images with the use of commercially available region-of-interest software, were obtained in 114 healthy subjects who had a total of 123 MR studies. A normal range and standard deviation were calculated, and the information was broken down by age and sex.RESULTSThe mean area of the optic chiasm was 43.7 mm2, with a standard deviation of 5.21. The mean width was 14.0 mm, with a standard deviation of 1.68.CONCLUSIONThe area and width of the optic chiasm can be measured with the use of commercially available software, which allows an objective estimate of the chiasm''s size. Knowledge of the normal size range of the optic chiasm can be helpful in the early detection of some disorders.  相似文献   
5.
6.
7.
The present study was designed to obtain further information on the nature of the corneal macromolecule(s) to which Pseudomonas aeruginosa adheres and how adherence might be prevented. Scarified adult mouse corneas in organ culture were treated with trypsin or lipase to determine whether the receptor molecule(s) was protein or lipid in nature. Trypsin (20 micrograms/ml) treatment of the cornea for 5 min had no significant effect on bacterial adherence, and longer periods of enzyme exposure resulted in extensive surface cell lysis. In contrast, lipase treatment (50,000 U/ml) for 1 h caused little visible cell lysis and significantly reduced bacterial adherence. To test further the lipid nature of the receptor, a highly purified monosialoganglioside (GM1) preparation (500 micrograms/ml) was used to preincubate (1 h) the cornea prior to bacterial application, and this also inhibited bacterial adherence. Similar corneal treatment with gangliotetraosylceramide (asialo GM1) (500 micrograms/ml) had little effect on ocular bacterial binding. Premixing of the bacterial inoculum with GM1 prior to corneal application had no significant effect on inhibiting bacterial binding, but similarly premixing the bacterial inoculum with asialo GM1 transiently decreased adherence. Lastly, premixing of the bacterial inoculum or preincubation of corneas with fibronectin (500 micrograms/ml for 1 h) both decreased bacterial adherence. These findings provide evidence that the receptor-adhesin interactions of P. aeruginosa at the ocular surface in organ culture are complex, involve a glycolipid moiety, and may be blocked by a ganglioside containing at least one sialosyl residue or by fibronectin, which may bind to membrane-associated gangliosides.  相似文献   
8.
The ocular damage in young adult mice produced by purified Pseudomonas aeruginosa exotoxin A was microscopically characterized at 1 and 5 h and at 1, 3, 5, 7, 10, 14, and 21 days after toxin A challenge, using light, transmission, and scanning electron microscopic techniques. Similarly to previously described infection with viable organisms, toxin A killed both epithelial and endothelial cells and induced stromal cell swelling within 5 to 24 h after application onto the nonpenetrating wounded corneal surface. Other toxin-induced damage similar to the damage produced by infection with the viable bacteria was production of electron-dense particles within the corneal stroma, dispersal of undamaged collagen fibrils, and apparent loss of stromal proteoglycan ground substance. Toxin A damage differed from infection with the viable bacteria in essentially two ways. First, more purulent exudate and more polymorphonuclear neutrophilic leukocyte (PMN) infiltration of the corneal stroma were produced by infection with the viable organisms than by the toxin. Additionally, PMN did not appear within the toxin-treated corneas until 3 days after treatment, whereas in corneas infected with the viable organisms, PMN were numerous by 18 h. Secondly, toxin A produced cataract of the ocular lens, whereas infection with the viable organisms did not.  相似文献   
9.
Predictive value of normal sperm morphology: a structured literature review   总被引:12,自引:0,他引:12  
The aim of the study was to conduct a structured review of theliterature published on the use of normal sperm morphology,as an indicator of male fertility potential in the in-vitrofertilization (IVF) situation, and to establish the universalpredictive value of this semen parameter. Published literaturein which normal sperm morphology was used to predict fertilizationand pregnancy, during the period 1978-1996, was reviewed. Atotal of 216 articles were identified by the sourcing methodology,but only 49 provided data that could be tabulated and analysed.Of these, only 18 provided sufficient data for statistical analysis.Fifteen studies used the strict criteria to evaluate sperm morphology,two used World Health Organization (WHO) guidelines and oneused both the strict criteria and the WHO guidelines. All thestudies (n=10) using the 5 and 14% normal sperm morphology thresholds(strict criteria) produced positive predictive values for IVFsuccess. In the prediction of pregnancy, 82% (9/11) and 75%(6/8) of the studies produced positive predictive values whenusing the 5% and 14% thresholds respectively. Aggregating thedata produced around the 5% normal sperm morphology threshold(strict criteria), the overall fertilization rates were 59.3%(1979/3337; per oocyte) for the 4% group and 77.6% (10345/13327;per oocyte) for the >4% group, and the overall pregnancyrates were 15.2% (60/395; per cycle) and 26.0% (355/1368; percycle) respectively. The no-transfer rates across the 5% thresholdwere 24.0% (86/359; per cycle) in the 4% group compared to 7.4%(80/1088; per cycle) in the >4% group. The inclusion of anaccurately evaluated normal sperm morphology count as an integralpart of the standard semen analysis makes this analysis stillthe most cost-effective means of evaluating the male factor.  相似文献   
10.
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