全文获取类型
收费全文 | 1195篇 |
免费 | 74篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 37篇 |
妇产科学 | 21篇 |
基础医学 | 141篇 |
口腔科学 | 31篇 |
临床医学 | 144篇 |
内科学 | 173篇 |
皮肤病学 | 71篇 |
神经病学 | 111篇 |
特种医学 | 57篇 |
外科学 | 126篇 |
综合类 | 35篇 |
预防医学 | 125篇 |
眼科学 | 80篇 |
药学 | 84篇 |
中国医学 | 2篇 |
肿瘤学 | 28篇 |
出版年
2022年 | 16篇 |
2021年 | 18篇 |
2020年 | 15篇 |
2018年 | 21篇 |
2017年 | 13篇 |
2016年 | 20篇 |
2015年 | 10篇 |
2014年 | 19篇 |
2013年 | 25篇 |
2012年 | 42篇 |
2011年 | 50篇 |
2010年 | 22篇 |
2009年 | 39篇 |
2008年 | 42篇 |
2007年 | 62篇 |
2006年 | 41篇 |
2005年 | 41篇 |
2004年 | 44篇 |
2003年 | 54篇 |
2002年 | 54篇 |
2001年 | 37篇 |
2000年 | 26篇 |
1999年 | 32篇 |
1998年 | 14篇 |
1997年 | 13篇 |
1995年 | 12篇 |
1992年 | 16篇 |
1991年 | 21篇 |
1990年 | 23篇 |
1989年 | 17篇 |
1988年 | 19篇 |
1987年 | 38篇 |
1986年 | 32篇 |
1985年 | 33篇 |
1984年 | 36篇 |
1983年 | 20篇 |
1982年 | 22篇 |
1981年 | 17篇 |
1980年 | 10篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1976年 | 9篇 |
1975年 | 9篇 |
1974年 | 10篇 |
1973年 | 9篇 |
1972年 | 9篇 |
1971年 | 9篇 |
1968年 | 12篇 |
1967年 | 17篇 |
1966年 | 11篇 |
排序方式: 共有1274条查询结果,搜索用时 15 毫秒
1.
2.
A method for evaluating systems of epidemiological surveillance 总被引:3,自引:0,他引:3
S B Thacker R G Parrish F L Trowbridge 《Rapport trimestriel de statistiques sanitaires mondiales》1988,41(1):11-18
Epidemiological surveillance is the systematic collection, analysis and dissemination of health data for the planning, implementation and evaluation of public health programmes. Established surveillance systems should be regularly reviewed on the basis of explicit criteria of usefulness, cost and quality; systems should be modified as a result of such review. Attributes of quality include: (i) sensitivity, (ii) specificity, (iii) representativeness, (iv) timeliness, (v) simplicity, (vi) flexibility and (vii) acceptability. To date, evaluation of surveillance systems has been limited in scope and content. The evaluation method proposed in this article offers an organized approach to the evaluation of epidemiological surveillance systems. The usefulness of a surveillance system is measured by whether it leads to prevention or control or a better understanding of adverse health events. The measure can be qualitative, in terms of the subjective views of those using the system, or quantitative in terms of the impact of surveillance data on policies, interventions or the occurrence of a health event. The cost of a system includes indirect as well as direct costs, and should be measured in relation to the benefits obtained, such as reduction of medical-care expenses and of time lost from work. All elements of the system should be included in the cost: data collection, analysis and dissemination. The sensitivity of a surveillance system is its ability to detect health events (completeness of reporting). Its specificity is inversely proportional to the number of false positives it reports. Reports of a disease that do not meet the case definition are false positives, and may result in resources being wasted in investigating them.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
3.
Dara L. Kraitchman Norbert Wilke Erik Hexeberg Michael Jerosch-Herold Ying Wang Todd B. Parrish Cheng-Ning Chang Yi Zhang Robert J. Bache Leon Axel 《Magnetic resonance in medicine》1996,35(5):771-780
MRI studies of first-pass contrast enhancement with polylysine-Gd-DTPA and myocardial tagging using spatial modulation of magnetization (SPAMM) were performed to assess the feasibility of a combined regional myocardial blood flow and 2D deformation exam. Instrumented closed-chest dogs were imaged at a baseline control state (Cntl) followed by two interventions: moderate coronary stenosis (St) achieved by partial occlusion of the left anterior descending (LAD) and moderate coronary stenosis with dobutamine loading (StD). Hypoperfusion of the anterior region (ANT) of the myocardium (LAD distribution) relative to the posterior wall (POS) based on the upslope of the signal intensity time curve from the contrast-enhanced MR images was demonstrated only with dobutamine loading (ANT:POS Cntl=1.077 ± 0.15 versus ANT:POS StD=0.477 ± 0.11, P<0.03) and was confirmed with radio-labeled microspheres measurements (ANT:POS Cntl=1.18 ± 0.2 ml/min/g versus ANT:POS StD=0.44 ± 0.1 ml/min/g; P<0.002). Significant changes in regional myocardial shortening were only seen in the StD state (P<0.02); the anterior region showed impaired myocardial shortening with dobutamine loading (P=NS), whereas the nonaffected POS region showed a marked increase in shortening when compared with Cntl (Cntl=0.964 ± 0.02 versus StD=0.884 ± 0.03; P<0.001). These results demonstrate that an integrated quantitative assessment of regional myocardial function and semiquantitative assessment of myocardial blood flow can be performed noninvasively with ultrafast MRI. 相似文献
4.
Monoclonal antibody to desmosomal glycoprotein 1--a new epithelial marker for diagnostic pathology 总被引:1,自引:0,他引:1
Desmosomes are intercellular adhesive junctions that occur in almost all epithelia and should therefore be useful as epithelial markers in tumour diagnosis. Here, we describe a monoclonal antibody, 32-2B, to a major desmosomal glycoprotein (dgl) which reacts with human tissues in paraffin sections. This antibody was tested for its ability to stain epithelia and tumours. It reacted with all epithelia tested and with every specimen of a wide range of carcinomas. It also stained meningiomas, another desmosome-containing tumour. It did not stain other types of tumours including lymphomas, melanomas, and various sarcomas, or normal tissues which lack desmosomes. These characteristics demonstrate that 32-2B is a reliable epithelial marker that may have a useful role in diagnostic histopathology. 相似文献
5.
We cloned the heavy- and light-chain variable domains of two monoclonal antibodies that recognize each of the two major neutralizing antigenic sites of the canine parvovirus (CPV) capsid. After expression in Escherichia coli as single-chain variable domains (scFv) with glycine-serine linker sequences, both scFv bound CPV capsids with the same specificity as the intact IgG, but with 10- to 20-fold lower avidity. Both scFvs neutralized CPV infectivity with efficiency similar to that of the IgG. Although both IgGs inhibited hemagglutination by CPV, only one scFv was inhibiting. The binding of one of the antibodies has previously been analyzed by cryoelectron microscopic reconstruction and the epitope-binding residues predicted. Mutagenesis of predicted contact residues in three heavy-chain complementarity-determining regions (CDR) showed that mutants of CDR1 or CDR3 reduced the binding of the scFv by about 10-fold compared with the wild-type scFv, while no effect was seen for one mutant of CDR2. The levels of neutralization of CPV and of hemagglutination inhibition by the scFv mutants were proportional to their reduction in binding affinity compared with the wild type. Neither scFv blocked virus binding to host cells, but they both caused aggregation of the capsids and appeared to affect the process of infection after virus uptake into the cells. 相似文献
6.
Huisman JA; Paulussen RJ; Geurts TB; Odink J; Rekers H 《Human reproduction (Oxford, England)》1997,12(1):34-38
The objective was to demonstrate bioequivalence between s.c. and i.m.
administration of Humegon (FSH/LH ratio 1:1) and Normegon (FSH/LH ratio
3:1). In two randomized, single-centre, cross-over studies, 18 healthy
volunteers on each formulation were assigned to one of the two
administration sequences. Subjects were given single doses of one of the
above gonadotrophins after endogenous gonadotrophin production had first
been suppressed using high-dose oral contraceptive. Subsequently, rate
(Cmax, tmax) and extent (AUC) of absorption of follicle stimulating hormone
(FSH) and luteinizing hormone (LH) were determined for 14 days. For Cmax
and AUC, analysis of variance (ANOVA) was performed on log-transformed data
and for tmax ANOVA was performed on ranks. Intramuscular and s.c.
injections of Humegon were bioequivalent with respect to the main
pharmacokinetic parameters, being AUC and Cmax of FSH absorption.
Intramuscular and s.c. injections of Normegon were bioequivalent with
respect to the AUC of FSH and not bioequivalent with respect to the Cmax of
FSH. For tmax of FSH as well as for most LH variables of both preparations,
bioequivalence could not be proven due to the high intra- and
interindividual variability and/or concentrations being close to the
detection limit. Thus, the main pharmacokinetic FSH variables after i.m.
and s.c. administration of Humegon and Normegon were bioequivalent.
相似文献
7.
Howard Mary Beth Jarvis Lenore R. Badolato Gia M. Parrish Benjamin T. Donnelly Katie A. 《Maternal and child health journal》2022,26(5):1059-1066
Maternal and Child Health Journal - Sleep-related infant deaths in the District of Columbia (DC) varies, with rates in certain geographical areas three times higher than DC and seven times higher... 相似文献
8.
9.
Michael H Parrish Janine M Dutcher Keely A Muscatell Tristen K Inagaki Mona Moieni Michael R Irwin Naomi I Eisenberger 《Social cognitive and affective neuroscience》2022,17(8):723
Self-enhancement, the tendency to view oneself positively, is a pervasive social motive widely investigated in the psychological sciences. Relatively little is known about the neurocognitive mechanisms underlying this motive, specifically in social-evaluative situations. To investigate whether positive emotion regulation circuitry, circuitry involved in modulating positive affect, relates to the self-enhancement motive in social contexts, we conducted an functional magnetic resonance imaging (fMRI) study in a healthy young adult sample. We hypothesized that self-enhancement indices (state and trait self-esteem) would relate to greater functional connectivity between right ventrolateral prefrontal cortex (RVLPFC), a region implicated in emotion regulation, and the ventral striatum (VS), a region associated with reward-related affect, during a social feedback task. Following social evaluation, participants experienced stable or decreased state self-esteem. Results showed that stable state self-esteem from pre- to post-scan and higher trait self-esteem related to greater RVLPFC–VS connectivity during positive evaluation. Stable-state self-esteem also related to greater RVLPFC–VS connectivity during negative evaluation. Moreover, RVLPFC activation during all types of feedback processing and left VS activation during negative feedback processing was greater for participants with stable-state self-esteem. These findings implicate neurocognitive mechanisms underlying emotion regulation in the self-enhancement motive and highlight a pathway through which self-enhancement may restore feelings of self-worth during threatening situations. 相似文献
10.
Acute traumatic spinal cord injury, 1993-2000A population-based assessment of methylprednisolone administration and hospitalization 总被引:3,自引:0,他引:3
BACKGROUND: Administration of methylprednisolone sodium succinate (MPSS) after acute traumatic spinal cord injury (TSCI) is controversial. This study compared differences in acute care charge, hospital stay, and related variables as a function of MPSS receipt. METHODS: Determinants of MPSS administration were examined after acute TSCI for South Carolina patients during the period 1993 to 2000 in a multivariate logistic regression model. RESULTS: Administration of MPSS was documented for 48.7% of 1,227 randomly selected patients with TSCI. Patients admitted via trauma centers and emergency departments were more likely to receive MPSS (trama center level 1 odds ratio [OR], 4.06; 95% CI confidence interval [CI], 2.11-7.83; emergency department OR, 1.64; 95% CI, 1.20-2.23). Hospital charge and length of stay were significantly higher for MPSS recipients. CONCLUSIONS: The study findings indicate MPSS use is associated with higher acute care charges and longer hospital stays. These findings suggest the need for outcome studies to assess the long-term benefits of MPSS administration. 相似文献