全文获取类型
收费全文 | 2180篇 |
免费 | 165篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 117篇 |
妇产科学 | 116篇 |
基础医学 | 198篇 |
口腔科学 | 57篇 |
临床医学 | 259篇 |
内科学 | 468篇 |
皮肤病学 | 72篇 |
神经病学 | 54篇 |
特种医学 | 167篇 |
外科学 | 256篇 |
综合类 | 161篇 |
预防医学 | 139篇 |
眼科学 | 12篇 |
药学 | 117篇 |
1篇 | |
中国医学 | 74篇 |
肿瘤学 | 77篇 |
出版年
2021年 | 25篇 |
2020年 | 17篇 |
2018年 | 29篇 |
2017年 | 26篇 |
2016年 | 19篇 |
2015年 | 42篇 |
2014年 | 62篇 |
2013年 | 68篇 |
2012年 | 78篇 |
2011年 | 91篇 |
2010年 | 70篇 |
2009年 | 66篇 |
2008年 | 73篇 |
2007年 | 61篇 |
2006年 | 58篇 |
2005年 | 39篇 |
2004年 | 47篇 |
2003年 | 44篇 |
2002年 | 38篇 |
2001年 | 45篇 |
2000年 | 37篇 |
1999年 | 49篇 |
1998年 | 51篇 |
1997年 | 63篇 |
1996年 | 54篇 |
1995年 | 50篇 |
1994年 | 57篇 |
1993年 | 37篇 |
1992年 | 33篇 |
1991年 | 27篇 |
1990年 | 28篇 |
1989年 | 37篇 |
1988年 | 38篇 |
1987年 | 43篇 |
1986年 | 35篇 |
1985年 | 30篇 |
1984年 | 30篇 |
1983年 | 26篇 |
1982年 | 20篇 |
1981年 | 27篇 |
1980年 | 19篇 |
1977年 | 14篇 |
1959年 | 35篇 |
1958年 | 61篇 |
1957年 | 87篇 |
1956年 | 45篇 |
1955年 | 75篇 |
1954年 | 67篇 |
1953年 | 17篇 |
1952年 | 14篇 |
排序方式: 共有2359条查询结果,搜索用时 15 毫秒
1.
Abstract: This paper dicusses the use of esophageal dilatation with a Rigiflex TTS balloon. This method was used 45 times on 11 patients affected by anastomotic or a severe grade peptic esophageal stenosis. Fluoroscopic guidance was used in 36 procedures (80%) without effecting the mean duration of the treatment (12 minutes). The results were considered satisfactory when these goals had been achieved: a) dilatation of the stenosis over 15 mm; b) a dysphagia free-time of more than 6 months. A satisfactory result was achieved in 10 patients (90.9%), without deaths and major complications. 5 patients received 1 dilatation and the other 5 needed, 3-3-4-7–11 procedures respectively to obtain a satisfactory result. On these basis we consider that its great efficacy, security and tolerability depend on the following characteristics of the Rigiflex TTS balloon: 1) “radial” dilatation; 2) the possibility of introducing the balloon through the operative channel of the fiberscope; 3) direct visualization of the stenosis during dilatation. The following disadvantages with this method are: the absence of a tactile sensation of dilatation and the elevated cost of the instrument. We conclude that the Rigiflex TTS balloon is an important alternative to guide-wire techniques, especially for the treatment of severe esophageal strictures. 相似文献
2.
Integrin stimulation regulates polymorphonuclear leukocytes inflammatory cytokine expression. 总被引:1,自引:0,他引:1 下载免费PDF全文
OBJECTIVE: The purpose of these studies is to investigate the role of integrin binding on the regulation of polymorphonuclear leukocyte (PMN) cytokine receptor expression. SUMMARY BACKGROUND DATA: Current knowledge in this area revolves around the ability of beta 2 integrins to mediate PMN adherence and chemotaxis. The role of alpha 1-6/beta 1 integrins in regulating cytokine receptor expression has not been probed. METHODS: Purified human PMN were adhered on plastic, fibronectin, or laminin-coated surfaces followed by the addition of iodine 125 (125I) monoclonal antibodies (mAbs) directed against tumor necrosis factor-alpha R (TNF-alpha R) p60, p80, or interleukin-1 beta R (IL-1 beta R) types I, II. Receptor expression was calculated based on the counts per minute (cpm) bound. The role of individual beta 1 integrins was assessed using mAbs directed against the alpha 1-6 subunit of the beta 1 complex, and integrin cross-linkage was achieved using secondary goat antimouse F(ab')2 antibodies. Polymorphonuclear leukocytes were pretreated with herbimycin A to determine the role of protein tyrosine kinase in mediating the effect of the beta 1 integrins. RESULTS: Adherence of PMN to Ln decreased IL-1 beta types I, II receptor expression, whereas adherence to Fn increased TNF-alpha R p60 and p80 expression. Anti-VLA-5 (CD49e) but not anti-VLA-1 through VLA-4 and VLA-6, blocked the effect of Fn on TNF-alpha receptors, whereas anti-VLA-6 but not anti-VLA-1 through VLA-5 blocked the effect of Ln on IL-1 beta receptors. Modulation of IL-1 beta and TNF-alpha receptors by VLA-5 and VLA-6 required protein tyrosine kinase activation as herbimycin A (10 micrograms/mL) blocked the affect of Fn and Ln. Changes in PMN cytokine receptor expression led to parallel changes in functional activity as assessed by the binding of 125I IL-1 beta and TNF-alpha. CONCLUSIONS: Integrin stimulation regulates the cell surface expression of PMN cytokine receptors. Ligation of CD49e upregulates TNF-alpha receptor expression, whereas binding of CD49f downregulates IL-1 beta receptor expression. Both processes are protein tyrosine kinase dependent. Changes in PMN cytokine receptor expression led to corresponding changes in functional activity. These results provide the first demonstration that chemotaxis of PMN into the interstitium provides a mechanism for ongoing participation in the local inflammatory response and is regulated by matrix protein integrin receptors. 相似文献
3.
This exploratory study has examined the effect of selected characteristics on the career advancement patterns of nurse executives in service and educational settings. The findings are not consistently in agreement with those of other researchers. For example, Hall et al. found that nearly two-thirds of nursing deans had planned their careers to attain that position. In this study, however, eighty-three percent of the respondents indicated that they had not planned their career advancement, but had simply taken opportunities that had come their way. The influence of others was important in the career advancement of these administrators. Many individuals, including faculty and nursing service colleagues, nursing directors, deans, and non-nursing administrators supported the respondents' personal and professional development through role modeling, teaching skills, and encouragement. Deliberate career planning and education in administration were, for the most part, lacking. Although the sample is too small to generate general conclusions about the universe of nurse executives, this does suggest that it is not uncommon for deans and service administrators to learn necessary skills on the job. 相似文献
4.
5.
This paper describes a case of recurrent aorto-duodenal fistula treated successfully by re-sitting the duodenum in an ante-colic position. Secondary aorto-duodenal fistula affects less than 1% of patients who have received a prosthetic abdominal aortic graft. However following correction of such a fistula the incidence of recurrent fistulation or aortic stump blow-out is reported as high as 47%. we describe an alternative approach to management of this difficult problem. 相似文献
6.
Anulus fibrosus in bulging intervertebral disks 总被引:1,自引:0,他引:1
In this investigation the association of radial tears of the anulus fibrosus and bulging of the intervertebral disk was studied. An index of disk bulging was measured in sagittal anatomic sections in 149 lumbar disks from 31 cadavers. The indexes of disk bulging were correlated with stages of disk development and the presence of an annular tear. The largest disk-bulging indexes were always associated with radial tears of the anulus. Eighty-four percent of the disks with radial tears had disk-bulging indexes greater than 2.5 mm. Most normal adult disks had an index of less than 2.5 mm. The results challenge the concept that the anulus fibrosus is intact in bulging disks, although ruptured in herniated disks. 相似文献
7.
H A Liebman M K Carfagno I C Weitz P Berard J M Diiorio E Vosburgh R W Simms 《American journal of clinical pathology》1992,98(5):534-541
Severe bleeding resulting from excessive fibrinolysis has been observed in patients with primary amyloidosis. The authors studied a patient with this hemostatic disorder before and during therapy with epsilon-aminocaproic acid. Excessive fibrinolysis was associated with depressed plasma concentrations of coagulation Factors XII, XI, high-molecular-weight kininogen, and Factors VIII and V; and plasminogen and alpha-2-plasmin inhibitor. These deficiencies were corrected with treatment. The functional and antigenic concentrations of tissue plasminogen activator and plasminogen activator inhibitor in the patient's plasma were normal. Urokinase-type activator activity and antigen were three to five times elevated in the patient's plasma. Results of immunoprecipitation showed that single-chain urokinase-type activator was the primary urokinase-type activator species in the patient's plasma. Excessive fibrinolysis in patients with amyloidosis results from increased plasma single-chain urokinase-type activator activity. 相似文献
8.
9.
10.