全文获取类型
收费全文 | 859篇 |
免费 | 46篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 67篇 |
儿科学 | 34篇 |
妇产科学 | 31篇 |
基础医学 | 99篇 |
口腔科学 | 17篇 |
临床医学 | 132篇 |
内科学 | 97篇 |
皮肤病学 | 34篇 |
神经病学 | 29篇 |
特种医学 | 141篇 |
外科学 | 85篇 |
综合类 | 20篇 |
预防医学 | 23篇 |
眼科学 | 44篇 |
药学 | 30篇 |
肿瘤学 | 35篇 |
出版年
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 11篇 |
2015年 | 18篇 |
2014年 | 16篇 |
2013年 | 23篇 |
2012年 | 19篇 |
2011年 | 25篇 |
2010年 | 35篇 |
2009年 | 37篇 |
2008年 | 29篇 |
2007年 | 44篇 |
2006年 | 33篇 |
2005年 | 47篇 |
2004年 | 34篇 |
2003年 | 27篇 |
2002年 | 27篇 |
2001年 | 35篇 |
2000年 | 21篇 |
1999年 | 14篇 |
1998年 | 22篇 |
1997年 | 43篇 |
1996年 | 25篇 |
1995年 | 23篇 |
1994年 | 18篇 |
1993年 | 6篇 |
1992年 | 16篇 |
1991年 | 14篇 |
1990年 | 14篇 |
1989年 | 23篇 |
1988年 | 22篇 |
1987年 | 27篇 |
1986年 | 14篇 |
1985年 | 19篇 |
1984年 | 14篇 |
1983年 | 13篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 12篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1971年 | 1篇 |
排序方式: 共有918条查询结果,搜索用时 0 毫秒
91.
Demonstration of reversible priming of human neutrophils using platelet- activating factor 总被引:3,自引:1,他引:3
Exposure of neutrophils to agents such as lipopolysaccharide, tumor necrosis factor-alpha (TNF-alpha), and the granulocyte-macrophage colony-stimulating factor causes a major upregulation of subsequent agonist-induced NADPH oxidase activation. This priming effect is a prerequisite for neutrophil-mediated tissue damage and has been widely considered to be an irreversible process. We have investigated the potential for neutrophils to recover from a priming stimulus by studying the effects of platelet-activating factor (PAF). PAF did not stimulate respiratory burst activity directly, but caused a rapid (maximal at 10 minutes) and concentration-dependent (EC50 50.2 nmol/L) increase in N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated superoxide anion release. At time-points > 10 minutes, this priming effect spontaneously declined, with return to basal levels of fMLP- stimulated superoxide anion generation by 120 minutes. An identical priming time-course was observed with N-methyl carbamyl PAF, a nonmetabolizable analogue of PAF, indicating that the transient nature of PAF-induced priming was not secondary to PAF metabolism. Two structurally diverse PAF receptor antagonists (UK-74,505 and WEB 2086), added 10 minutes after PAF addition, increased the rate of decay of the priming effect. In contrast, TNF-alpha-induced priming, which was of a similar magnitude to that observed for PAF, was slower to evolve (maximal at 30 minutes) and remained constant for at least 120 minutes. The reversible nature of PAF-induced priming was confirmed by demonstrating that PAF-, but not TNF-alpha-, induced cell polarization (shape change) and CD11b-dependent neutrophil binding of albumin-coated latex beads was also transient, with return to basal, unstimulated levels by 120 minutes. Furthermore, cells that had spontaneously deprimed following PAF exposure retained their capacity to be fully reprimed by a subsequent addition of either PAF or TNF-alpha. These data imply that neutrophil priming is not an irreversible event: the demonstration of a cycle of complete priming, depriming, and repriming offers the potential for functional recycling of neutrophils at sites of inflammation. 相似文献
92.
Biochemical markers of bone turnover in seronegative spondylarthropathy: relationship to disease activity 总被引:1,自引:0,他引:1
MacDonald AG; Birkinshaw G; Durham B; Bucknall RC; Fraser WD 《Rheumatology (Oxford, England)》1997,36(1):50-53
To investigate bone turnover in patients with seronegative
spondylarthropathy, a bone formation marker, type 1 procollagen carboxy-
terminal propeptide (P1CP), and resorption markers, the pyridinium
cross-links of collagen [urinary free (f) PYR and DPYR], were measured. The
median f-PYR, f-DPYR and P1CP (+/-interquartile range) were 15.8 (6.00)
nmol/mmol creatinine, 3.8 (2.2) nmol/mmol creatinine and 101.5 (38)
micrograms/1, respectively. There was a positive correlation between
resorption markers and acute-phase reactants such as C-reactive protein (r
= 0.42 for PYR, r = 0.42 for DPYR, P < 0.05), and a negative correlation
observed between P1CP and the erythrocyte sedimentation rate (r = -0.64, P
< 0.05). In the subgroup of patients with an elevated CRP concentration,
the concentration of PYR and DPYR was significantly increased (f-PYR 25.7
vs 15.8 and f-DPYR 6.6 vs 3.8, P < 0.01 for f-PYR, P < 0.05 for
f-DPYR). This study suggests than an elevation in acute-phase response in
patients with seronegative spondylarthropathy is associated with increased
concentration of bone resorption markers with a tendency for reduction in
bone formation markers. This may represent uncoupling of bone formation and
resorption, leading to bone loss in such patients.
相似文献
93.
94.
S Khotaba M Volfson L Tarazova M Odeh R Barenboym V Fait E Ophir M Oettinger 《Acta obstetricia et gynecologica Scandinavica》2001,80(11):1041-1042
BACKGROUND AND METHODS: To evaluate the efficacy and safety of labor induction by the double balloon device in women with previous cesarean section. Induction of labor was carried out in 37 women with previous cesarean section for various indications. All the inductions of labor were performed using the Atad double balloon device (ARD). RESULTS: Cervical ripening (Bishop scores above 5) was achieved in 82.3% of the induced women with subsequent vaginal delivery in 78.6% and repeat cesarean section in 22.3%. An important observation of the results was the chances to achieve a vaginal delivery according to the second Bishop score that was recorded 12 hours following the insertion of the device. When the second was above 5 the chances for vaginal delivery were 79.4%. The mean time from removal of the device to delivery was 10.8 hours. No complications were noted using the device. CONCLUSIONS: The double balloon device appears to be a safe and effective method of inducing labor in women with a previous lower segment cesarean section. Wide scale studies and further use of the device for induction of labor in women who have had previous cesarean sections are warranted. 相似文献
95.
Monoclonal antibodies were produced against isolated frog olfactory cilia, a preparation enriched in dendritic extensions of the chemosensory neurons. Two antibodies, 18.1 and 35.6, were found to react against specific glycoproteins of the sensory organelles. These glycoproteins were identified by their differential binding to the lectins wheat germ agglutinin and Concanavalin A. The antibodies fluorescently labeled isolated olfactory cilia, as well as the ciliary surface layer of olfactory epithelium, whose extent was defined by anti-tubulin and anti-keratin antibodies. Respiratory epithelium (or other tissues) as well as isolated respiratory cilia were not labeled by antibodies 18.1 and 35.6, indicating tissue specificity. The olfactory-specific antibodies can be used as markers of the sensory epithelium and of the sensory regions of olfactory dendritic membranes. Antibody 18.1 recognized gp95, a specific and major integral membrane glycoprotein of frog olfactory cilia. Since gp95 has been suggested as candidate olfactory receptor protein (Chen, Z. and Lancet, D., Proc. Natl. Acad. Sci. U.S.A., 81 (1984) 1859-1863), antibody 18.1 could also be useful for functional studies. 相似文献
96.
Postappendectomy fluid collections in children: incidence, nature, and evolution evaluated using US 总被引:1,自引:0,他引:1
At the authors' medical center, most patients with postappendectomy fluid collections are treated conservatively. Thirty-two (15%) of 216 children underwent postoperative sonography following appendectomies. In ten patients (31%), a total of 16 fluid collections were found on the initial postoperative sonogram. In the seven patients (70%) whose fluid collections were confined to the pelvis, the condition was treated conservatively and it resolved in 2-9 weeks. In three patients, fluid collections required surgical drainage and proved to be abscesses. In two of the three patients, abscesses were multiple and widely distributed in the abdomen, and the patients were clinically ill. The authors conclude that clinically symptomatic fluid collections develop postoperatively in approximately 5% of children who have undergone appendectomy for acute appendicitis and that the size and course of the fluid collection can be objectively monitored using sonography. Such fluid collections confined to the pelvis ultimately resolve with conservative, nonoperative therapy, although resolution may take up to 2 months. 相似文献
97.
98.
99.
AG Meldorf 《MedR Medizinrecht》2004,22(5):274-275
Ohne Zusammenfassung 相似文献
100.
AG Affleck SM Littlewood 《Journal of the European Academy of Dermatology and Venereology》2005,19(3):360-363
INTRODUCTION: The diagnosis of adult-onset Still's disease (AOSD) can be very difficult. There are no specific tests and reliance is usually placed on a symptom complex and the well described typical rash seen in most patients. In recent years, however, other cutaneous manifestations of AOSD have been reported but these are not so well known. OBSERVATIONS: We report a patient with urticaria and fixed plaques and review the other 'atypical' cutaneous findings associated with AOSD. CONCLUSIONS: The diagnosis of AOSD can be made in the absence of the typical Still's rash but in the presence of other atypical cutaneous features. 相似文献