全文获取类型
收费全文 | 2012篇 |
免费 | 174篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 76篇 |
妇产科学 | 20篇 |
基础医学 | 305篇 |
口腔科学 | 29篇 |
临床医学 | 233篇 |
内科学 | 473篇 |
皮肤病学 | 13篇 |
神经病学 | 178篇 |
特种医学 | 188篇 |
外国民族医学 | 1篇 |
外科学 | 196篇 |
综合类 | 56篇 |
一般理论 | 2篇 |
预防医学 | 193篇 |
眼科学 | 42篇 |
药学 | 124篇 |
中国医学 | 3篇 |
肿瘤学 | 62篇 |
出版年
2020年 | 18篇 |
2019年 | 27篇 |
2018年 | 22篇 |
2017年 | 16篇 |
2016年 | 27篇 |
2015年 | 25篇 |
2014年 | 47篇 |
2013年 | 56篇 |
2012年 | 79篇 |
2011年 | 66篇 |
2010年 | 42篇 |
2009年 | 53篇 |
2008年 | 72篇 |
2007年 | 96篇 |
2006年 | 71篇 |
2005年 | 83篇 |
2004年 | 90篇 |
2003年 | 77篇 |
2002年 | 75篇 |
2001年 | 59篇 |
2000年 | 57篇 |
1999年 | 53篇 |
1998年 | 52篇 |
1997年 | 39篇 |
1996年 | 31篇 |
1995年 | 23篇 |
1994年 | 19篇 |
1993年 | 24篇 |
1992年 | 53篇 |
1991年 | 46篇 |
1990年 | 54篇 |
1989年 | 43篇 |
1988年 | 53篇 |
1987年 | 48篇 |
1986年 | 55篇 |
1985年 | 34篇 |
1984年 | 19篇 |
1983年 | 27篇 |
1982年 | 23篇 |
1981年 | 18篇 |
1980年 | 20篇 |
1979年 | 21篇 |
1978年 | 21篇 |
1977年 | 24篇 |
1976年 | 21篇 |
1975年 | 20篇 |
1974年 | 21篇 |
1972年 | 21篇 |
1971年 | 23篇 |
1970年 | 16篇 |
排序方式: 共有2197条查询结果,搜索用时 18 毫秒
1.
Victoria M. Williams Adhil Bhagwandin Jordan Swiegers Mads F. Bertelsen Therese Hård Thomas C. Thannickal Jerome M. Siegel Chet C. Sherwood Paul R. Manger 《Anatomical record (Hoboken, N.J. : 2007)》2022,305(6):1459-1475
Employing orexin-A immunohistochemical staining we describe the nuclear parcellation of orexinergic neurons in the hypothalami of a lar gibbon and a chimpanzee. The clustering of orexinergic neurons within the hypothalamus and the terminal networks follow the patterns generally observed in other mammals, including laboratory rodents, strepsirrhine primates and humans. The orexinergic neurons were found within three distinct clusters in the ape hypothalamus, which include the main cluster, zona incerta cluster and optic tract cluster. In addition, the orexinergic neurons of the optic tract cluster appear to extend to a more rostral and medial location than observed in other species, being observed in the tuberal region in the anterior ventromedial aspect of the hypothalamus. While orexinergic terminal networks were observed throughout the brain, high density terminal networks were observed within the hypothalamus, medial and intralaminar nuclei of the dorsal thalamus, and within the serotonergic and noradrenergic regions of the midbrain and pons, which is typical for mammals. The expanded distribution of orexinergic neurons into the tuberal region of the ape hypothalamus, is a feature that needs to be investigated in other primate species, but appears to correlate with orexin gene expression in the same region of the human hypothalamus, but these neurons are not revealed with immunohistochemical staining in humans. Thus, it appears that apes have a broader distribution of orexinergic neurons compared to other primate species, but that the neurons within this extension of the optic tract cluster in humans, while expressing the orexin gene, do not produce the neuropeptide. 相似文献
2.
Victoria M. Williams Adhil Bhagwandin Jordan Swiegers Mads F. Bertelsen Therese Hård Chet C. Sherwood Paul R. Manger 《Anatomical record (Hoboken, N.J. : 2007)》2022,305(6):1476-1499
Using tyrosine hydroxylase immunohistochemistry, we describe the nuclear parcellation of the catecholaminergic system in the brains of a lar gibbon (Hylobates lar) and a chimpanzee (Pan troglodytes). The parcellation of catecholaminergic nuclei in the brains of both apes is virtually identical to that observed in humans and shows very strong similarities to that observed in mammals more generally, particularly other primates. Specific variations of this system in the apes studied include an unusual high-density cluster of A10dc neurons, an enlarged retrorubral nucleus (A8), and an expanded distribution of the neurons forming the dorsolateral division of the locus coeruleus (A4). The additional A10dc neurons may improve dopaminergic modulation of the extended amygdala, the enlarged A8 nucleus may be related to the increased use of communicative facial expressions in the hominoids compared to other primates, while the expansion of the A4 nucleus appears to be related to accelerated evolution of the cerebellum in the hominoids compared to other primates. In addition, we report the presence of a compact division of the locus coeruleus proper (A6c), as seen in other primates, that is not present in other mammals apart from megachiropteran bats. The presence of this nucleus in primates and megachiropteran bats may reflect homology or homoplasy, depending on the evolutionary scenario adopted. The fact that the complement of homologous catecholaminergic nuclei is mostly consistent across mammals, including primates, is advantageous for the selection of model animals for the study of specific dysfunctions of the catecholaminergic system in humans. 相似文献
3.
Lavanya Bamini I Anand Sherwood Paul V. Abbott Ramesh Uthandakalaipandian Vijay Velu 《Australian endodontic journal : the journal of the Australian Society of Endodontology Inc》2020,46(1):73-81
One of the main objectives of root canal treatment is to alleviate the pain associated with irreversibly inflamed pulps. However, some patients may have moderate to severe pain following treatment. The aim of this study was to compare and assess the effect of ketorolac tromethamine on substance P expression in the pulp and periapical tissues when used as a root canal irrigant for single‐visit root canal treatment in teeth with irreversible pulpitis. Thirty‐six patients were randomly allotted to three irrigant groups – saline (n = 14), 3% sodium hypochlorite (n = 11) and ketorolac tromethamine (n = 11). Pulp blood samples (S1) were collected on gaining access to the pulp, and periapical blood samples (S2) were collected after root canal preparation. Quantification of substance P was done by ELISA test. The ketorolac tromethamine group had greater reduction in substance P expression (S2). Post‐operative pain levels were not significantly influenced by the different root canal irrigants. 相似文献
4.
Mark K Donnelly Elizabeth A Crago Yvette P Conley Jeffery R Balzer Dianxu Ren Andrew F Ducruet Patrick M Kochanek Paula R Sherwood Samuel M Poloyac 《Journal of cerebral blood flow and metabolism》2015,35(9):1515-1522
Emerging evidence has suggested that patients experiencing aneurysmal subarachnoid hemorrhage (aSAH) develop vascular dysregulation as a potential contributor to poor outcomes. Preclinical studies have implicated the novel microvascular constrictor, 20-hydroxyeicosatetraenoic acid (20-HETE) in aSAH pathogenesis, yet the translational relevance of 20-HETE in patients with aSAH is largely unknown. The goal of this research was to determine the relationship between 20-HETE cerebrospinal fluid (CSF) levels, gene variants in 20-HETE synthesis, and acute/long-term aSAH outcomes. In all, 363 adult patients (age 18 to 75) with aSAH were prospectively recruited from the University of Pittsburgh Medical Center neurovascular Intensive Care Unit. Patients were genotyped for polymorphic variants and cytochrome P450 (CYP)-eicosanoid CSF levels were measured over 14 days. Outcomes included delayed cerebral ischemia (DCI), clinical neurologic deterioration (CND), and modified Rankin Scores (MRS) at 3 and 12 months. Patients with CND and unfavorable 3-month MRS had 2.2- and 2.7-fold higher mean 20-HETE CSF levels, respectively. Patients in high/moderate 20-HETE trajectory groups (35.7%) were 2.5-, 2.1-, 3.1-, 3.3-, and 2.1-fold more likely to have unfavorable MRS at 3 months, unfavorable MRS at 12 months, mortality at 3 months, mortality at 12 months, and CND, respectively. These results showed that 20-HETE is associated with acute and long-term outcomes and suggest that 20-HETE may be a novel target in aSAH. 相似文献
5.
6.
Maja Šešelj Richard J. Sherwood Lyle W. Konigsberg 《Anatomical record (Hoboken, N.J. : 2007)》2019,302(10):1733-1753
Estimating chronological age or assessing the rate of maturation in immature individuals is an important task in biological anthropology and clinical practice. One of the most reliable ways of doing this is by evaluating one's dental development, specifically tooth mineralization. However, few chronologies include reference values for very young children, and few provide an extensive documentation of the range of variation surrounding the reported reference values. We present a new chronology of development of permanent mandibular canine and postcanine teeth from birth through age 28 years, based on over 6,000 radiographs of 590 participants of the Fels Longitudinal Study, recorded between 1940 and 1982. Tooth mineralization was scored following the 14-stage system of Moorrees, Fanning, and Hunt (Moorrees et al., 1963a) with an additional crypt stage. We calculated ages of attainment, as well as average age in stage, using transition analysis. We find that variation increases throughout ontogeny for all teeth, though it is generally comparable between girls and boys. The tempo of dental development tends to be faster in girls. Compared to the classic chronology of Moorrees et al. (1963a), partly based on Fels radiographs, in our sample the development of crowns tends to occur at earlier, and development of roots at increasingly later ages. Our results are more similar to chronologies based on more recent, clinical samples (Liversidge, 2009), though the development of tooth roots in our sample occurs at older ages. Anat Rec, 302:1733–1753, 2019. © 2019 American Association for Anatomy 相似文献
7.
8.
9.
Adeladza Kofi Amegah Jouni JK Jaakkola 《Bulletin of the World Health Organization》2016,94(3):215-221
Globally, 41% of households, over 2.8 billion people, rely on solid fuels (coal and biomass) for cooking and heating. In developing countries in Asia and sub-Saharan Africa where these fuels are predominantly used, women who are customarily responsible for cooking, and their young children, are most exposed to the resulting air pollution. Solid fuels are still in widespread use and it appears that intervention efforts are not keeping pace with population growth in developing countries. Here we pinpoint the challenges and identify opportunities for addressing household air pollution while mitigating global climate change and promoting the sustainable development goals. We recommend the following actions: implementation of the WHO indoor air quality guidelines
on household fuel combustion; effective promotion and dissemination of improved cookstoves through formation of country alliances for clean cookstoves; expansion of liquefied petroleum gas production facilities and distribution networks; harnessing renewable energy potential; promotion of biogas production at both household and community level; ensuring improved ventilation of homes through education and enforcement of building standards; and exploiting opportunities in the health and other sectors for changing health-damaging cooking behaviour. 相似文献
10.
JK Dickson A Davies S Rahman C Sethu JRO Smith A Orlando D Ayers 《Annals of the Royal College of Surgeons of England》2015,97(1):52-55
IntroductionDissection of regional lymph nodes (RLNs) can lead to significant morbidity and a high prevalence of complications. Published guidance states that these procedures should be carried out by surgeons who are members of a specialist skin multidisciplinary team who carry out a combined minimum of 15 axillary/groin dissections per year. However, there is little evidence to guide this minimum figure of procedures. We report on the burden of service provision and prevalence of complications across the South West of England and Wales.MethodsA 12-month review of dissections of RLNs for skin cancer was undertaken covering five Plastic Surgery Units with a collective catchment of 8.4 million people. Detailed data were collected on patient demographics, pathology, timing of surgery, and prevalence of complications.ResultsA total of 163 dissections were carried out. Forty-three per cent of patients experienced one or more complication. In that 12-month period, an average of 8 axillary/groin dissections was carried out per surgeon. A funnel plot demonstrated that the prevalence of complications for individual surgeons was within the limit of the plot but, in many cases, this was based only on a relatively small number of procedures per consultant. If surgeons carried out 10 procedures per year, the upper and lower limits on the plot were 73% and 11%, respectively.ConclusionsFunnel plots can provide a useful guide as to whether the prevalence of complications for procedures for individual surgeons lies within acceptable limits. Based on these results, 10 procedures per consultant per year should be sufficient to enable meaningful assessment of the prevalence of complications. 相似文献