全文获取类型
收费全文 | 1986754篇 |
免费 | 142859篇 |
国内免费 | 3675篇 |
专业分类
耳鼻咽喉 | 26902篇 |
儿科学 | 64114篇 |
妇产科学 | 56129篇 |
基础医学 | 289912篇 |
口腔科学 | 55478篇 |
临床医学 | 178360篇 |
内科学 | 390709篇 |
皮肤病学 | 42620篇 |
神经病学 | 158828篇 |
特种医学 | 76371篇 |
外国民族医学 | 584篇 |
外科学 | 293741篇 |
综合类 | 41910篇 |
现状与发展 | 3篇 |
一般理论 | 788篇 |
预防医学 | 157046篇 |
眼科学 | 45210篇 |
药学 | 144081篇 |
6篇 | |
中国医学 | 3568篇 |
肿瘤学 | 106928篇 |
出版年
2018年 | 20573篇 |
2016年 | 17348篇 |
2015年 | 19928篇 |
2014年 | 27877篇 |
2013年 | 42885篇 |
2012年 | 57977篇 |
2011年 | 61780篇 |
2010年 | 36508篇 |
2009年 | 34829篇 |
2008年 | 58587篇 |
2007年 | 62412篇 |
2006年 | 62215篇 |
2005年 | 61092篇 |
2004年 | 58664篇 |
2003年 | 56407篇 |
2002年 | 54962篇 |
2001年 | 87569篇 |
2000年 | 89579篇 |
1999年 | 76026篇 |
1998年 | 21391篇 |
1997年 | 19480篇 |
1996年 | 19858篇 |
1995年 | 18577篇 |
1994年 | 17517篇 |
1993年 | 16449篇 |
1992年 | 60328篇 |
1991年 | 58823篇 |
1990年 | 57418篇 |
1989年 | 55367篇 |
1988年 | 51453篇 |
1987年 | 50403篇 |
1986年 | 48256篇 |
1985年 | 45762篇 |
1984年 | 34633篇 |
1983年 | 29900篇 |
1982年 | 17954篇 |
1981年 | 16093篇 |
1979年 | 32888篇 |
1978年 | 23710篇 |
1977年 | 19961篇 |
1976年 | 18587篇 |
1975年 | 20279篇 |
1974年 | 24469篇 |
1973年 | 23839篇 |
1972年 | 22543篇 |
1971年 | 20928篇 |
1970年 | 19923篇 |
1969年 | 18802篇 |
1968年 | 17681篇 |
1967年 | 16014篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Tarentola annularis is a climbing gecko with a wide distribution in Africa north of the equator. In the present paper, we describe the development of the osteocranium of this lizard, from the first appearance of the cranial elements up to the point of hatching. This is based on a combination of histology and cleared and stained specimens. This is the first comprehensive account of gekkotan pre-hatching skull development based on a comprehensive series of embryos, rather than a few selected stages. Given that Gekkota is now widely regarded as representing the sister group to other squamates, this account helps to fill a significant gap in the literature. Moreover, as many authors have considered features of the gekkotan skull and skeleton to be indicative of paedomorphosis, it is important to know whether this hypothesis is supported by delays in the onset of cranial ossification. In fact, we found the sequence of cranial bone ossification to be broadly comparable to that of other squamates studied to date, with no significant lags in development. 相似文献
93.
Toidi Adekambi Chris C. Ibegbu Stephanie Cagle Ameeta S. Kalokhe Yun F. Wang Yijuan Hu Cheryl L. Day Susan M. Ray Jyothi Rengarajan 《The Journal of clinical investigation》2015,125(5):1827-1838
BACKGROUND. The identification and treatment of individuals with tuberculosis (TB) is a global public health priority. Accurate diagnosis of pulmonary active TB (ATB) disease remains challenging and relies on extensive medical evaluation and detection of Mycobacterium tuberculosis (Mtb) in the patient’s sputum. Further, the response to treatment is monitored by sputum culture conversion, which takes several weeks for results. Here, we sought to identify blood-based host biomarkers associated with ATB and hypothesized that immune activation markers on Mtb-specific CD4+ T cells would be associated with Mtb load in vivo and could thus provide a gauge of Mtb infection.METHODS. Using polychromatic flow cytometry, we evaluated the expression of immune activation markers on Mtb-specific CD4+ T cells from individuals with asymptomatic latent Mtb infection (LTBI) and ATB as well as from ATB patients undergoing anti-TB treatment.RESULTS. Frequencies of Mtb-specific IFN-γ+CD4+ T cells that expressed immune activation markers CD38 and HLA-DR as well as intracellular proliferation marker Ki-67 were substantially higher in subjects with ATB compared with those with LTBI. These markers accurately classified ATB and LTBI status, with cutoff values of 18%, 60%, and 5% for CD38+IFN-γ+, HLA-DR+IFN-γ+, and Ki-67+IFN-γ+, respectively, with 100% specificity and greater than 96% sensitivity. These markers also distinguished individuals with untreated ATB from those who had successfully completed anti-TB treatment and correlated with decreasing mycobacterial loads during treatment.CONCLUSION. We have identified host blood-based biomarkers on Mtb-specific CD4+ T cells that discriminate between ATB and LTBI and provide a set of tools for monitoring treatment response and cure.TRIAL REGISTRATION. Registration is not required for observational studies.FUNDING. This study was funded by Emory University, the NIH, and the Yerkes National Primate Center. 相似文献
94.
More than just crushing: a prospective pre‐post intervention study to reduce drug preparation errors in patients with feeding tubes 下载免费PDF全文
95.
Adilson Cunha Ferreira Edward Araujo Júnior Wellington P. Martins João Francisco Jordão Antônio Hélio Oliani Simon E. Meagher 《The journal of maternal-fetal & neonatal medicine》2015,28(14):1706-1710
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality. 相似文献
96.
Patients have become increasingly well informed with higher expectations to be involved in decision-making processes regarding their care and treatment. However, few studies have examined the impact of patient involvement on health care providers’ partnership-building communication. The aim of this study was to measure and explore the self-reported effects of patient involvement on the work of physicians and nurses. A questionnaire survey was distributed among cardiology staff in 12 Swedish hospitals (N = 488, response rate 67%). The sample was comprised of registered nurses (RNs, n = 303), licensed practical nurses (LPNs, n = 132), and physicians (MDs, n = 53). Confirmatory factor analysis was used to examine seven questionnaire statements concerning implications of patient involvement for one’s clinical work. Regression analyses were used to examine factors associated with staff’s partnership-building communication. Analysis confirmed two distinct factors accounting for 57% of the total variance, representing both negative—“Hassles”—and positive—“Uplifts”—aspects of patient involvement. Regression analyses revealed that only positive aspects (i.e., uplifts) of patient involvement predicted staff behavior aimed at involving patients. Working with actively involved patients may be a source of stress, both negative and positive, for health care professionals. By developing work routines for involving patients in their care, health care workplaces may help health care professionals to buffer the negative effects, and enhance the positive effects, of that stress. 相似文献
97.
98.
L. Misery E. Weisshaar E. Brenaut A.W.M. Evers F. Huet S. Ständer A. Reich E. Berardesca E. Serra-Baldrich J. Wallengren D. Linder J.W. Fluhr J.C. Szepietowski H. Maibach for the Special Interest Group on sensitive skin of the International Forum for the Study of Itch 《Journal of the European Academy of Dermatology and Venereology》2020,34(2):222-229
The special interest group on sensitive skin of the International Forum for the Study of Itch previously defined sensitive skin as a syndrome defined by the occurrence of unpleasant sensations (stinging, burning, pain, pruritus and tingling sensations) in response to stimuli that normally should not provoke such sensations. This additional paper focuses on the pathophysiology and the management of sensitive skin. Sensitive skin is not an immunological disorder but is related to alterations of the skin nervous system. Skin barrier abnormalities are frequently associated, but there is no cause and direct relationship. Further studies are needed to better understand the pathophysiology of sensitive skin – as well as the inducing factors. Avoidance of possible triggering factors and the use of well-tolerated cosmetics, especially those containing inhibitors of unpleasant sensations, might be suggested for patients with sensitive skin. The role of psychosocial factors, such as stress or negative expectations, might be relevant for subgroups of patients. To date, there is no clinical trial supporting the use of topical or systemic drugs in sensitive skin. The published data are not sufficient to reach a consensus on sensitive skin management. In general, patients with sensitive skin require a personalized approach, taking into account various biomedical, neural and psychosocial factors affecting sensitive skin. 相似文献
99.
100.
Frédéric Janvier Deborah Delaune Thomas Poyot Eric Valade Audrey Mérens Pierre E. Rollin Vincent Foissaud 《Emerging infectious diseases》2016,22(2):292-294
We evaluated RNA stability of Ebola virus in EDTA blood and urine samples collected from infected patients and stored in West Africa’s environmental conditions. In blood, RNA was stable for at least 18 days when initial cycle threshold values were <30, but in urine, RNA degradation occurred more quickly. 相似文献