全文获取类型
收费全文 | 14850篇 |
免费 | 1116篇 |
国内免费 | 43篇 |
专业分类
耳鼻咽喉 | 93篇 |
儿科学 | 523篇 |
妇产科学 | 417篇 |
基础医学 | 2092篇 |
口腔科学 | 220篇 |
临床医学 | 1858篇 |
内科学 | 2673篇 |
皮肤病学 | 273篇 |
神经病学 | 1388篇 |
特种医学 | 312篇 |
外科学 | 1822篇 |
综合类 | 251篇 |
一般理论 | 26篇 |
预防医学 | 1676篇 |
眼科学 | 169篇 |
药学 | 1044篇 |
中国医学 | 32篇 |
肿瘤学 | 1140篇 |
出版年
2023年 | 60篇 |
2022年 | 104篇 |
2021年 | 254篇 |
2020年 | 203篇 |
2019年 | 296篇 |
2018年 | 363篇 |
2017年 | 217篇 |
2016年 | 276篇 |
2015年 | 285篇 |
2014年 | 439篇 |
2013年 | 671篇 |
2012年 | 1011篇 |
2011年 | 930篇 |
2010年 | 561篇 |
2009年 | 551篇 |
2008年 | 904篇 |
2007年 | 1002篇 |
2006年 | 872篇 |
2005年 | 970篇 |
2004年 | 860篇 |
2003年 | 839篇 |
2002年 | 774篇 |
2001年 | 184篇 |
2000年 | 166篇 |
1999年 | 186篇 |
1998年 | 156篇 |
1997年 | 158篇 |
1996年 | 141篇 |
1995年 | 137篇 |
1994年 | 97篇 |
1993年 | 106篇 |
1992年 | 135篇 |
1991年 | 117篇 |
1990年 | 98篇 |
1989年 | 108篇 |
1988年 | 92篇 |
1987年 | 105篇 |
1986年 | 90篇 |
1985年 | 124篇 |
1984年 | 84篇 |
1983年 | 83篇 |
1982年 | 90篇 |
1981年 | 87篇 |
1980年 | 70篇 |
1979年 | 66篇 |
1978年 | 85篇 |
1977年 | 74篇 |
1975年 | 48篇 |
1973年 | 47篇 |
1972年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Lesley Barclay RN CM BA MEd Louise Everitt RN CM Post Grad Dip-Comm Health Frances Rogan RN CM B App S M Com Nurs Virginia Schmied RN CM BA MA Hons Aileen Wyllie RN CM BA MHPEd 《Journal of advanced nursing》1997,25(4):719-728
This paper presents the results of a qualitative study conducted by midwife researchers into women's experience of new motherhood. Data were collected using focus groups involving 55 first-time mothers and analysed using grounded theory method. The analysis produced six categories: 'realizing', 'unready', 'drained', 'aloneness', 'loss' and 'working it out'. The core category, 'becoming a mother', integrates all other categories and encapsulates the process of change experienced by women. Also explained are factors mediating the often distressing experience of becoming a mother. The analysis provides a conceptualization of early motherhood enabling the development of strategies for midwives, nurses and others helping women negotiate this challenge. 相似文献
62.
63.
Lorenzo Melani Richard Mills David Hassman Robert Lipetz Leslie Lipka Alexandre LeBeaut Ramachandran Suresh Pabak Mukhopadhyay Enrico Veltri 《European heart journal》2003,24(8):717-728
AIMS: To evaluate the efficacy and safety of ezetimibe 10 mg administered with pravastatin in patients with primary hypercholesterolemia. METHODS AND RESULTS: After dietary stabilization, 2-12 week screening/washout period, and 4-week, single-blind, placebo lead-in period, 538 patients with baseline LDL-C > or =3.8 to < or =6.5 mmol/l and TG < or =4.0 mmol/l were randomized to one of eight possible treatments administered daily for 12 weeks: ezetimibe 10mg; pravastatin 10, 20, or 40 mg; ezetimibe 10 mg plus pravastatin 10, 20, or 40 mg; or placebo. The primary efficacy endpoint was percent reduction in LDL-C from baseline to study endpoint for ezetimibe 10 mg plus pravastatin (pooled doses) compared to pravastatin alone (pooled doses) and ezetimibe alone. The combined use of ezetimibe and pravastatin resulted in significant incremental reductions in LDL-C and TG compared to pooled pravastatin alone (p<0.01). Coadministration therapy reduced LDL-C by 34-41%, TG by 21-23%, and increased HDL-C by 7.8-8.4%, depending on the dose of pravastatin. The combined regimen was well tolerated, with a safety profile similar to pravastatin alone and placebo. CONCLUSIONS: When coadministered with pravastatin, ezetimibe provided significant incremental reductions in LDL-C and TG and was well tolerated with a safety profile similar to pravastatin alone. 相似文献
64.
Allan L. Reiss Lisa Freund Leslie Plotnick Thomas Baumgardner Kathleen Green Amanda C. Sozer Mark Reader Corinne Boehm Martha B. Denckla 《Annals of neurology》1993,34(1):95-107
Monosomy for the X chromosome is the most frequent cause of Turner's syndrome, a common clinical syndrome associated with particular physical and neurobehavioral features. The results from comprehensive assessment of prepubertal monozygotic female twins discordant for X monosomy are presented. Zygosity was established with DNA Fingerprinting and no evidence of chromosomal mosaicism was seen in either child. Physical features in the affected twin were relatively mild with respect to the full spectrum of physical malformations and disabilities associated with Turner's syndrome. The neurobehavioral phenotypes of the twins were compared. Although both sisters scored in the superior range of intelligence, the affected twin's Performance IQ was 18 points less than her sister, whereas Verbal IQ showed only a 3-point difference between the sisters. Other relative differences were noted within the executive, visuospatial, and visuomotor domains of function. Behavioral evaluation indicated greater problems with attention, hyperactivity, and anxiety in the affected twin. Quantitative analysis of brain anatomy revealed evidence of both general and regional effects of X monosomy on neurodevelopment. Cerebrospinal fluid volume was increased by 25% in the affected twin compared with her sister with a corresponding decrease in gray matter volume. The right frontal, right parietal–occipital, and left parietal-perisylvian regions showed the greatest discrepancy between the sisters with respect to increased cerebrospinal fluid and decreased gray matter volumes in the twin with X monosomy. Differences in the posterior fossa were also noted with a 50% relative increase in the volumes of the fourth ventricle and cisterna magna and a 10 to 15% relative reduction in size of the cerebellar vermis, pons, and medulla in the affected twin. The association between the neurobehavioral and neuroanatomical findings in the affected twin is discussed. The unique nature of the naturally occurring genetic phenomenon seen in this twin pair provides an opportunity to more fully elucidate the neurobehavioral phenotype associated with X monosomy and Turner's syndrome. 相似文献
65.
Alison Bushell Leslie Klenerman Helen Davies Ian Grierson Malcolm J. Jackson 《Acta orthopaedica》1996,67(4):393-398
We examined the potential protective effect of pretreatment with corticosteroids or antioxidants (ascorbic acid or allopurinol) in rabbits with reper-fusion-induced damage to skeletal muscle after ischemia.
4 hours of limb ischemia induced by a pneumatic tourniquet, followed by reperfusion for 1 hour, caused a considerable amount of ultrastructural damage to the anterior tibialis muscles accompanied by a rise in circulating creatine kinase activity. Pretreatment of animals with depomedrone by a single 8 mg bolus injection led to a preservation of the anterior tibialis structure on both light and electron microscopy. High-dose continuous intravenous infusion with ascorbic acid (80 mg/hr) throughout the period of ischemia and reperfusion also preserved skeletal muscle structure, although allopurinol in various doses had no protective effect.
These data are fully compatible with a mechanism of ischemia/reperfusion-induced injury to skeletal muscle, involving generation of oxygen radicals and neutrophil sequestration and activation. They also indicate that damage to human skeletal muscle caused by prolonged use of a tourniquet is likely to be reduced by simple pharmacological interventions. 相似文献
4 hours of limb ischemia induced by a pneumatic tourniquet, followed by reperfusion for 1 hour, caused a considerable amount of ultrastructural damage to the anterior tibialis muscles accompanied by a rise in circulating creatine kinase activity. Pretreatment of animals with depomedrone by a single 8 mg bolus injection led to a preservation of the anterior tibialis structure on both light and electron microscopy. High-dose continuous intravenous infusion with ascorbic acid (80 mg/hr) throughout the period of ischemia and reperfusion also preserved skeletal muscle structure, although allopurinol in various doses had no protective effect.
These data are fully compatible with a mechanism of ischemia/reperfusion-induced injury to skeletal muscle, involving generation of oxygen radicals and neutrophil sequestration and activation. They also indicate that damage to human skeletal muscle caused by prolonged use of a tourniquet is likely to be reduced by simple pharmacological interventions. 相似文献
66.
Objective. Bone infarction (BI) of the calcaneus is an uncommon entity which has received little mention in the recent literature. In
this paper, we review the MR images of six calcanei with BI, which demonstrate a pattern of presentation that may explain
the etiology of BI at this unusual location. Design. A retrospective review was performed of the transcribed reports of the foot or ankle MR examinations at our institution.
MR images of examinations with any marrow signal abnormality were reviewed for presence of BI and its distribution. Patients. Based on MRI criteria, four patients had calcaneal BI (none biopsy proven); they ranged in age from 37 to 51 years old. Two
patients were diagnosed with systemic lupus erythematosus, one with fibrositis, and another with polymyositis. All were treated
with corticosteroids. Results. Six calcanei (in four patients) contained a region of calcaneal BI. In five of the six, the lesions were entirely or predominantly
located in the posterior half of the calcaneus. Conclusion. Two theories are proposed which may explain why BI predominantly occurs in the posterior half of the calcaneus. First, the
convergence of the recurrent intraosseous calcaneal vessels may occasionally produce the equivalent of a single dominant vessel
that is more prone to vascular accidents. Secondly, the region between the recurrent and the epiphyseal vessels may act as
a watershed zone, increasing its susceptibility to ischemia. 相似文献
67.
Studies of clinical teaching roles have not appeared in the athletic training literature. The purposes of this study were to: 1) describe clinical teaching roles of Midwest ATCs, and 2) determine the effect of educational preparation on teaching activities and opinions of ATCs. A three-part questionnaire was returned by 154 ATCs (78%) in NATA District 5. The questionnaire included demographic, teaching, and opinion items. More than 50% of the ATCs were teacher-certified and the majority had a master's or higher degree. Most ATCs clinically supervised between one to eight students who received clinical instruction about 20 hours weekly. The ATCs who taught clinically either presented information or directed tasks from five to six Role Delineation Domains. They used three or more teaching methods and six or more audiovisual aids with their presentations. The ATCs saw the importance of clinical education and the responsibility to present clinical information, and expressed positive opinions about academic preparation for clinical teaching. Those with teaching degrees felt more prepared to teach (p<.05) than did nonteachers. Teachers conducted clinical teaching activities similar to nonteachers. We concluded that less experienced athletic trainers feel educationally prepared and enjoy clinical teaching as much as their more experienced peers. The ATCs with a teaching background presented a broader content through more mature teaching methods than did nonteachers. It appeared that adequate preparation for teaching and the attainment of an advanced degree may inspire confidence in clinical teaching. These attributes may become important characteristics to look for when recruiting clinical instructors. 相似文献
68.
Spahn Hildegard Iwakawa Seigo Lin Emil T. Benet Leslie Z. 《Pharmaceutical research》1989,6(2):125-132
The diastereoisomeric glucuronic acid conjugates of R/S-benoxaprofen are the major benoxaprofen metabolites and are found in urine at high concentrations. The conjugates of R- and S-benoxaprofen can be separated directly on a C18 reversed-phase column using a mixture of acetonitrile and tetrabutylammonium hydroxide buffer, pH 2.5 (28:72, v/v), as the mobile phase. The k values of S- and R-benoxaprofen glucuronides are 57.5 and 63.0, respectively. Diluted urine or deproteinized plasma samples were injected without further treatment. With fluorescence detection at 313/365 nm, quantifiable limits of 50 ng equiv./ml were found for the conjugates. The intra- and interday variability was below 12%. Utilizing this analytical procedure it is possible to characterize enantioselective glucuronidation both in vivo and in vitro. For in vitro procedures, apparent rates of formation and the R/S ratio may be substrate (benoxaprofen) and cosubstrate (UDPGA) dependent. Moreover, enantioselective cleavage of the formed benoxaprofen glucuronides by alkaline hydrolysis, hydrolytic enzymes, and acyl migration must be controlled for both in vitro and in vivo studies since R-benoxaprofen glucuronide is degraded faster than the S-diastereomer under certain conditions. 相似文献
69.
With the rise in chronic, behavior-related disease, computerized behavioral protocols (CBPs) that help individuals improve behaviors have the potential to play an increasing role in the future health of society. To be effective and widely used CBPs should be based on accepted behavioral theory. However, designing CBPs while at the same time specifying their linkages to behavioral theory and developing reusable CBP components (interventions) are challenges to developers of CBPs. Having an ontology with which to describe CBPs could help with these issues. As a first step towards creating such an ontology, we modeled PACE-Adolescent, a theory-based behavioral protocol that uses the Stages of Change Model and Social Cognitive Theory, using PROTEGE-2000, an ontology editor and knowledge acquisition system. We created a three-part knowledge model. Two sub-ontologies described behavioral interventions and psychological theories. The third component, implemented using Guideline Interchange Format (GLIF3), provided a way to describe the structure of a protocol and to link intervention resources and groups of actions to elements of psychological theory. Using this framework, we formally described the PACE-Adolescent protocol. Creating knowledge models such as this may lead to improvements in the design and evaluation of computerized health behavior protocols. 相似文献
70.