全文获取类型
收费全文 | 837篇 |
免费 | 42篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 31篇 |
妇产科学 | 18篇 |
基础医学 | 131篇 |
口腔科学 | 18篇 |
临床医学 | 89篇 |
内科学 | 105篇 |
皮肤病学 | 9篇 |
神经病学 | 64篇 |
特种医学 | 96篇 |
外科学 | 95篇 |
综合类 | 49篇 |
预防医学 | 86篇 |
眼科学 | 9篇 |
药学 | 38篇 |
肿瘤学 | 43篇 |
出版年
2022年 | 4篇 |
2021年 | 10篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 13篇 |
2017年 | 10篇 |
2016年 | 8篇 |
2015年 | 13篇 |
2014年 | 18篇 |
2013年 | 35篇 |
2012年 | 27篇 |
2011年 | 47篇 |
2010年 | 38篇 |
2009年 | 36篇 |
2008年 | 28篇 |
2007年 | 38篇 |
2006年 | 50篇 |
2005年 | 39篇 |
2004年 | 53篇 |
2003年 | 29篇 |
2002年 | 28篇 |
2001年 | 20篇 |
2000年 | 15篇 |
1999年 | 10篇 |
1998年 | 33篇 |
1997年 | 23篇 |
1996年 | 25篇 |
1995年 | 31篇 |
1994年 | 17篇 |
1993年 | 8篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 8篇 |
1989年 | 19篇 |
1988年 | 13篇 |
1987年 | 8篇 |
1986年 | 13篇 |
1985年 | 6篇 |
1984年 | 11篇 |
1983年 | 13篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1978年 | 9篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1972年 | 2篇 |
1966年 | 2篇 |
1914年 | 1篇 |
排序方式: 共有884条查询结果,搜索用时 15 毫秒
1.
2.
3.
The first 150 words of the full text of this article appear below. Key points Coronary artery disease accounts for >30% ofdeaths in Western society. The diagnosis of myocardial infarctionshould be qualified by size, causation and time from occurrence. Mortalityis reduced by immediate or primary percutaneouscoronary intervention or thrombolysis within the first 24 hof onset of ST-segment elevation myocardial infarction. Strategiesto reduce platelet activation (glycoprotein IIb/IIIa receptorantagonists, or clopidogrel) are now recommended in the treatmentof high-risk non-ST-segment myocardial infarction/unstable angina. Elevatedserum troponins may be the result of non-ischaemic myocardialdamage, especially in critical illness.
Pathophysiology
Changes in the definition of terms relating to the diagnosisof myocardial infarction (MI) have evolved by better understandingof the pathophysiology culminating in the new term of acutecoronary syndrome (ACS). Figure 1 illustrates the processesthat occur in the development of an acute coronary event. 相似文献
4.
5.
6.
Berbaum KS; el-Khoury GY; Franken EA Jr; Kathol M; Montgomery WJ; Hesson W 《Radiology》1988,168(2):507-511
The effect of knowledge of localizing symptoms and signs in the detection of fractures was studied. Forty radiographs of the extremities were examined twice by seven radiologists; the sessions were separated by 4 months. In 26 cases, a subtle fracture was present; 14 cases were normal. In half of the cases at each session, the precise location of pain, tenderness, or swelling was provided. The observer was asked to determine if the case was normal or abnormal (provide the exact location of the fracture) and to indicate the degree of confidence in the diagnosis. Responses were converted to a numeric scale for analysis. Analysis of receiver operator characteristic parameters indicates that clues regarding location of trauma facilitate detection of fractures. The improvement is based largely on an increased true-positive rate without an increased false-positive rate, regardless of the decision criteria of the radiologist (overall willingness to "overread" or "underread"). This has direct clinical applicability and reinforces the plea of radiologists for precise clinical information. 相似文献
7.
I?Satish?RaoEmail author Anand?C?Loya KS?Ratnakar VR?Srinivasan 《BMC clinical pathology》2005,5(1):11
Background
Lymph node infarction is known to occur in association with many non-neoplastic and neoplastic conditions however its occurrence in association with DIC is not reported hitherto in the literature. 相似文献8.
David W. Ingersoll George Bobotas Ching-Tse Lee Aaron Lukton 《Physiology & behavior》1982,29(5):789-793
The present study was designed to investigate the chemical properties of the aggression-promoting cues present in bladder urine of male mice. The results of the first experiment confirmed earlier work by demonstrating the presence of an aggression-promoting chemosignal in bladder urine. In Experiment 2, behavioral assays were separately performed on the organic and aqueous layers of bladder urine obtained by repeated dichloromethane extractions. Only the combined organic layers of the initial three extractions demonstrated behavioral activity. A fourth extraction showed no behavioral activity for both organic and aqueous layers. However, the findings of Experiment 3 showed that incubation of the aqueous layer from the third CH2Cl2 extraction in β-glucuronidase can free additional aggression-promoting cues into a subsequent CH2Cl2 extraction. It is concluded that two forms of the aggression-promoting chemosignal are present in bladder urine. One is lipophilic and behaviorally active, whereas the other is conjugated, possessing latent chemosignal properties. 相似文献
9.
Detection of reactive oxygen species (ROS) and apoptosis in human fragmented embryos 总被引:8,自引:2,他引:8
Yang HW; Hwang KJ; Kwon HC; Kim HS; Choi KW; Oh KS 《Human reproduction (Oxford, England)》1998,13(4):998-1002
In human in-vitro fertilization (IVF)-embryo transfer, the in-vitro culture
environment differs from in-vivo conditions in that the oxygen
concentration is higher, and in such conditions the mouse embryos show a
higher concentration of reactive oxygen species (ROS) in simple culture
media. ROS are believed to cause damage to cell membranes and DNA
fragmentation in somatic cells. This study was conducted to ascertain the
level of H2O2 concentration within embryos and the morphological features
of cell damage induced by H2O2. A total of 62 human oocytes and embryos (31
fragmented, 15 non-fragmented embryos, 16 unfertilized oocytes) was
obtained from the IVF-embryo transfer programme. The relative intensity of
H2O2 concentrations within embryos was measured using
2',7'-dichlorodihydrofluorescein diacetate by Quanti cell 500 fluorescence
imaging and DNA fragmentation was observed with transmission electron
microscopy and an in-situ apoptosis detection kit. The H2O2 concentrations
were significantly higher in fragmented embryos (72.21 +/- 9.62, mean +/-
SEM) compared to non-fragmented embryos (31.30 +/- 3.50, P < 0.05) and
unfertilized oocytes (30.75 +/- 2.67, P < 0.05). Apoptosis was observed
only in fragmented embryos, and was absent in non-fragmented embryos.
Electron microscopic findings confirmed apoptotic bodies and cytoplasmic
condensation in the fragmented blastomeres. We conclude that there is a
direct relationship between increased H2O2 concentration and apoptosis, and
that further studies should be undertaken to confirm these findings.
相似文献
10.
Ellen R Julian Deborah J Ingersoll Patricia M Etienne Anthony E Hilger 《Academic medicine》2004,79(4):360-364
PURPOSE: Medical College Admission Test (MCAT) examinees with disabilities who receive accommodations receive flagged scores indicating nonstandard administration. This report compares MCAT examinees who received accommodations and their performances with standard examinees. METHOD: Aggregate history records of all 1994-2000 MCAT examinees were identified as flagged (2,401) or standard (297,880), then further sorted by race/ethnicity (broadly identified as underrepresented minority and non-URM, at the time of testing) and gender. Those with flagged scores were also classified by disability (LD = learning disability, ADHD = attention deficit hyperactivity disorder, LD/ADHD = learning disability and attention deficit hyperactivity disorder, and Other = other disability) and type of accommodation. Mean MCAT scores were calculated for all groups. A group of 866 examinees took the MCAT first as a standard administration and subsequently with accommodations. In a separate analysis, their two sets of scores were compared. RESULTS: Less than 1% of examinees (2,401) had accommodations; of these, 55% were LD, 17% ADHD, 5% LD/ADHD, and 23% Other. Extended time was the most frequently provided accommodation. Mean flagged scores slightly exceeded mean standard scores on all MCAT sections. Examinees who retook the MCAT with accommodations after a standard administration increased their scores by six points, quadrupling the average gain Standard-Standard retest cohort from another study. CONCLUSION: The small but statistically significant different higher flagged scores may reflect either appropriate compensation or overly generous accommodations. Extended time had a positive impact on the scores of those who retested with this accommodation. The validity the flagged MCAT in predicting success in medical school is not known, and further investigation is underway. 相似文献