全文获取类型
收费全文 | 85572篇 |
免费 | 5904篇 |
国内免费 | 353篇 |
专业分类
耳鼻咽喉 | 848篇 |
儿科学 | 1946篇 |
妇产科学 | 1281篇 |
基础医学 | 11705篇 |
口腔科学 | 1722篇 |
临床医学 | 8990篇 |
内科学 | 18607篇 |
皮肤病学 | 1743篇 |
神经病学 | 9375篇 |
特种医学 | 3842篇 |
外国民族医学 | 11篇 |
外科学 | 13279篇 |
综合类 | 726篇 |
一般理论 | 42篇 |
预防医学 | 5242篇 |
眼科学 | 1365篇 |
药学 | 5537篇 |
中国医学 | 162篇 |
肿瘤学 | 5406篇 |
出版年
2023年 | 679篇 |
2022年 | 897篇 |
2021年 | 2335篇 |
2020年 | 1496篇 |
2019年 | 2120篇 |
2018年 | 2475篇 |
2017年 | 1945篇 |
2016年 | 2270篇 |
2015年 | 2525篇 |
2014年 | 3307篇 |
2013年 | 4084篇 |
2012年 | 6514篇 |
2011年 | 6661篇 |
2010年 | 3881篇 |
2009年 | 3385篇 |
2008年 | 5436篇 |
2007年 | 5682篇 |
2006年 | 5302篇 |
2005年 | 5045篇 |
2004年 | 4600篇 |
2003年 | 4191篇 |
2002年 | 3819篇 |
2001年 | 1040篇 |
2000年 | 939篇 |
1999年 | 944篇 |
1998年 | 811篇 |
1997年 | 614篇 |
1996年 | 534篇 |
1995年 | 445篇 |
1994年 | 408篇 |
1993年 | 309篇 |
1992年 | 458篇 |
1991年 | 424篇 |
1990年 | 401篇 |
1989年 | 330篇 |
1988年 | 337篇 |
1987年 | 333篇 |
1986年 | 354篇 |
1985年 | 337篇 |
1984年 | 323篇 |
1983年 | 255篇 |
1982年 | 199篇 |
1981年 | 176篇 |
1980年 | 172篇 |
1979年 | 284篇 |
1978年 | 207篇 |
1977年 | 188篇 |
1975年 | 166篇 |
1974年 | 175篇 |
1973年 | 176篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Nathan Scudder James Robertson Sally F. Kelty Simon J. Walsh Dennis McNevin 《The Australian journal of forensic sciences》2020,52(2):235-241
ABSTRACTForensic DNA analysis is dependent on comparing the known and the unknown. Expand the number of known profiles, and the likelihood of a successful match increases. Forensic use of DNA is moving towards comparing samples of unknown origin with publicly available genetic data, such as the records held by genetic genealogy providers. Use of forensic genetic genealogy has yielded a number of recent high-profile successes but has raised ethical and privacy concerns. Navigating family trees is complex, even more so when combined with a comparison of genetic relationships. This intelligence-gathering process has led to occasional false leads, and its use also risks a public backlash, similar to concerns over Cambridge Analytica. A cautious approach to use of this technique is therefore warranted. 相似文献
52.
Subdental synchondrosis and anatomy of the axis in aging: a histomorphometric study on 30 autopsy cases 总被引:4,自引:4,他引:0
Matthias Gebauer Christian Lohse Florian Barvencik Pia Pogoda Johannes M. Rueger Klaus Püschel Michael Amling 《European spine journal》2006,15(3):292-298
During skeletal development the two ossification centers of the odontoid process are separated from the corpus of the axis by a subdental synchondrosis. This synchondrosis is thought to close and disappear spontaneously in adolescence although this has never been studied in detail. The basis of the dens is of clinical relevance as type II dens fractures are located here. To characterize the morphological architecture of the axis with particular attention to the subdental synchondrosis, the complete axis was harvested from thirty age-matched and gender-matched patients of the three different age groups at autopsy. The subdental synchondrosis and the bone structure of the dens, the basis of the dens and the body of C2 were analyzed by radiography, histology and quantitative histomorphometry. At the macroscopic level the persistency of the subdental synchondrosis in the adult cervical spine was detected in 87% (26 of 30) of the specimens. Histomorphometry revealed a residual disc blastema with an average size of 25.8% of the sagittal depth of the basis of the dens at this level. Bony integration of the synchondrosis was poor throughout all ages. Histologically a cartilaginous matrix composition of the subdental synchondrosis persisted throughout all groups. The trabecular microarchitecture demonstrated a significant reduction of bone volume and trabecular number as well as an increased trabecular separation within the basis of the dens as compared to the corpus or the dens of C2. This histomorphometric data regarding a poor integration of the synchondrosis into the trabecular network and the reduced bone mass within the basis of the dens might offer a previously underestimated explanation for the occurrence of type II dens fractures and their association with pseudoarthrosis, respectively.Matthias Gebauer and Christian Lohse contributed equally to this study and therefore share first authorship. 相似文献
53.
TG Berger F Kiesewetter C Maczek N Bauer M Lueftl G Schuler M Simon Jr 《Journal of the European Academy of Dermatology and Venereology》2006,20(2):178-183
Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis. 相似文献
54.
Rodolphe Korichi Sophie Mac-Mary Ahmed Elkhyat Jean-Marie Sainthillier Pascal Ränsch Philippe Humbert Eric Viviant Germaine Gazano Christian Mahé 《Skin research and technology》2006,12(3):206-210
BACKGROUND/AIMS: The purpose of this work was to develop a new sensor for objective in vivo measurement of the cutaneous temperature based on micro-electro-mechanical systems (MEMS), and to compare these performances with those of a classical thermocouple. Research on this new sensor was carried out to allow the quantification of the thermal properties of the made-up skin. METHODS: Sixteen female subjects divided into two different age groups (18-35 and >50 years old) were recruited for this study. Several zones of the face and forearms were made up at random with foundations containing or not a thermoregulator raw material. The quantity of foundation applied on the skin was standardized and measurements were carried out first before make-up, and then 10 s and 5 min after make-up. The new sensor and the thermocouple were used successively on each zone. The cutaneous temperature was expressed in degrees celsius. RESULTS/CONCLUSION: The two systems are similar in terms of repeatability and reproducibility, with some differences in sensibility. The data measured by the MEMS sensor appear lower than those measured by the thermocouple. After make-up, the MEMS sensor detects a progressive increase of the temperature in time whereas the thermocouple detects a decrease. We found the same evolution on the face but in a more attenuated way. These results tend to show that the devices do not measure the same phenomenon. The thermocouple appears more sensitive to the thermal response of the made-up surface whereas the MEMS sensor appears more sensitive to the heat transfers in the interface between the skin and make-up. 相似文献
55.
Baher Husain Christian Kuehne Christian Waydhas Ulrike Lewan Claudia Ose Dieter Nast-Kolb Steffen Ruchholtz 《European Journal of Trauma》2006,32(6):548-554
Abstract
Background: Does there exist a difference in the outcome of severely injured children and severely injured healthy adults?
Methods: The data of 1,566 severely injured patients, treated between May 1998 and December 2002 in our emergency department of the
University Essen/Germany, were analyzed. Patients with an injury severity score (ISS) > 24 were included in the present study.
Patients younger as 18 (17) years were located to the children group c. Patients aged 18 and up to the age of 54 were included
in the adult group a.
Results: Fifty-four children and 252 adults met the selection criteria. ISS and the Glasgow coma scale (GCS) before intubation were
not statistically different in both groups. Seriously injured children stayed significantly shorter on the intensive care
unit, required significantly less ventilator days. Furthermore, the incidence of single organ failure (SOF) and multiple organ
failure (MOF) was significantly lower in the children group. Mortality in the children group (29.6%) was lower than that in
the adult group (33.7%). There was no death due to MOF in the children group as compared to 2.4% (n = 6) in the adults.
Conclusion: The incidence of SOF and MOF was significantly lower in the children group although there was no difference in ISS, GCS and
injury patterns. The prognosis of severely injured children was found to be better than those of adults. Moreover, there was
no death due to MOF in the children group. 相似文献
56.
OBJECTIVE: This study employed EEG source localisation procedures to study the contribution of motor preparatory and attentional processing to foreperiod activity in an S1-S2 motor priming task. METHODS: Behavioural and high-density event-related potential (ERP) data were recorded in an S1-S2 priming task where participants responded to S2 with a left or right-hand button press. S1 either provided information about response hand (informative) or ambiguous information (uninformative). RESULTS: Responses were significantly faster in informative trials compared with uninformative trials. Dipole source analysis of foreperiod lateralized ERPs revealed sources of motor preparatory activity in the dorsolateral premotor cortex (PMd) in line with previous work. In addition, two spatial attention components (ADAN, LDAP) were identified with generators in the PMd and occipitotemporal visual areas in the middle temporal (MT) region, respectively. Separation of motor-related and attentional PMd source locations was reliable along the rostral-caudal axis. CONCLUSIONS: The presence of attentional components in a motor priming paradigm supports the premotor theory of attention which suggests a close link between attention and motor preparatory processes. Separation of components in the premotor cortex is in accord with a functional division of PMd into rostral (higher-order processing) and caudal (motor-related processing) areas as suggested by imaging work. SIGNIFICANCE: A prime for response preparation is a trigger for separate, but closely linked, attention-related activity in premotor areas. 相似文献
57.
58.
Anton H. Schwabegger Barbara DelFrari Christian Apprich 《European journal of plastic surgery》2006,28(8):534-536
Whereas decubitus ulcer in the back or hip region is a common entity in plegic or elderly patients, the occurrence in the lateral shoulder region is seldom seen. However, resulting from continuous lateral decubitus positioning or limited compliance by the patient, pressure sores may occur in almost any region of the body, but predominately, they arise in acral zones with underlying bone prominences. The deltoid area is such an anatomically critical region, especially if the underlying deltoid muscle is paralyzed. The transposition of a pedicled deltoid flap, slightly modified as a hatchet flap, is described for cover of a decubitus ulcer in the deltoid region in a paraplegic male. Although utilization of the deltoid flap as a free flap is an established procedure for selected indications [Russell et al. (1985) Extremity reconstruction using the free deltoid flap. Plast Reconstr Surg 76:586–595, Serafin D (1996) The deltoid flap. In: Serafin D (ed) Atlas of microsurgical composite tissue transplantation, chapter 19. Saunders, Philadelphia, PA, pp 153–159, Wang et al. (2003) The free deltoid flap: microscopic anatomy studies and clinical application to oral cavity reconstruction. Plast Reconstr Surg 112:404–411], transposition as a pedicled flap, to the best of our knowledge, has not been previously described in the available literature. 相似文献
59.
Nestin expression persists in astrocytes of organotypic slice cultures from rat cortex 总被引:11,自引:0,他引:11
Rainald Schmidt-Kastner Christian Humpel 《International journal of developmental neuroscience》2002,20(1):29-38
Nestin is an intermediate filament protein typical for neural precursor cells that is down-regulated in the post-natal rodent brain. Re-expression of nestin has been observed in reactive astrocytes after injury. In this study, organotypic slice cultures from rat cortex were examined for expression of nestin and glial fibrillary acidic protein between 2 and 8 weeks in culture. Immunoreactivity for nestin and glial fibrillary acidic protein was seen in astrocytes which persisted throughout the observation period. Immunofluorescence double labeling showed widespread co-localization of nestin and glial fibrillary acidic protein. Image analysis revealed that levels of nestin-immunoreactivity plateaued after 5 weeks in culture. By comparison nestin immunoreactivity was absent from glial cells of the cortex in mature rats. These immunohistochemical findings of a persistent expression of nestin in glial cells of organotypic slice culture of the rat cortex indicate a different time course of glial maturation in vitro. This difference could be related to the altered trophic stimulation in vitro; differences in neuronal maturation, activity or survival; slow degeneration of the vasculature; or intrinsic properties of astrocytes. 相似文献
60.
Brachial artery hemodynamic response to acute converting enzyme inhibition by enalaprilat in essential hypertension 总被引:1,自引:0,他引:1
To assess the vascular involvement of renin-angiotensin system inhibition in human hypertension, acute effects of intravenous enalaprilat on brachial artery diameter, blood flow, and blood velocity were investigated in hypertensive patients by pulsed Doppler technique and compared with effects of saline vehicle. Compared with saline vehicle, enalaprilat reduced blood pressure (P less than 0.001) and increased brachial arterial diameter (P less than 0.01) and brachial blood flow (P less than 0.01). Enalaprilat effect on arterial pulse pressure was dependent on preinjection pulse pressure (r = -0.76; P less than 0.001), but its effect on mean blood pressure was not dependent on preinjection mean blood pressure. On the other hand, enalaprilat effect on arterial blood flow was negatively correlated with preinjection blood pressure (r = -0.64; P less than 0.02). The findings point to different responses of large and small arteries to intravenous enalaprilat. 相似文献