全文获取类型
收费全文 | 381篇 |
免费 | 24篇 |
国内免费 | 52篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 13篇 |
基础医学 | 37篇 |
口腔科学 | 6篇 |
临床医学 | 78篇 |
内科学 | 78篇 |
皮肤病学 | 4篇 |
神经病学 | 15篇 |
特种医学 | 68篇 |
外科学 | 41篇 |
综合类 | 16篇 |
预防医学 | 24篇 |
眼科学 | 24篇 |
药学 | 30篇 |
肿瘤学 | 22篇 |
出版年
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 12篇 |
2012年 | 4篇 |
2011年 | 10篇 |
2010年 | 14篇 |
2009年 | 13篇 |
2008年 | 11篇 |
2007年 | 49篇 |
2006年 | 16篇 |
2005年 | 19篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 8篇 |
2001年 | 9篇 |
2000年 | 9篇 |
1999年 | 2篇 |
1998年 | 20篇 |
1997年 | 12篇 |
1996年 | 21篇 |
1995年 | 13篇 |
1994年 | 19篇 |
1993年 | 10篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 13篇 |
1988年 | 8篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1982年 | 3篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 4篇 |
1969年 | 4篇 |
1947年 | 2篇 |
排序方式: 共有457条查询结果,搜索用时 640 毫秒
1.
2.
F W Doane 《Ultrastructural pathology》1987,11(5-6):681-685
3.
Abstract This paper explores the integral relationship between philosophy and nursing practice. The discussion begins by suggesting that philosophy is more than a set of abstract ideas or an intellectual activity; that it is a way of living and being in practice. The author contends that philosophical inquiry can improve the adequacy and relevance of family and nursing theories by promoting the examination and expansion of those theories in light of the experiences and intuitions of nurses. Offering a personal example the author exemplifies how philosophical activity can directly and experientially enhance everyday nursing practice. 相似文献
4.
Uroscopy in the 21st century: high-field NMR spectroscopy 总被引:1,自引:1,他引:0
Neild GH; Foxall PJ; Lindon JC; Holmes EC; Nicholson JK 《Nephrology, dialysis, transplantation》1997,12(3):404-417
From the experiments described, it can be seen that there are different
research approaches that can be taken and these are summarized in Table 1.
Whereas much scientific research is principally hypothesis led, there
remains, nevertheless, an important place for exploratory research. High
resolution NMR can measure, directly and simultaneously, a wide range of
endogenous metabolites in biological fluids and has the unique capability
of providing structural information on the metabolites detected. It has
proved to be a powerful research tool with which to study inherited
metabolic diseases, renal disease, drug metabolism, and toxicity, and can
be used to monitor the effects of drug therapy. For instance, by using a
library of experimental toxins one can map the metabolic profile of
site-specific nephron injury. With this approach in man one could
eventually take an unknown disease such as Balkan nephropathy and predict
the initial site of tubular injury, the mode of injury and therefore the
kind of toxin capable of producing that injury. NMR spectroscopic
techniques are still advancing rapidly, with ever increasing sensitivity
and sophistication of NMR pulse sequences to enhance structural elucidation
in complex mixtures. Given the advances in directly coupled HPLC-NMR and
even HPLC-NMR-mass spectroscopy it is likely that these technologies in
conjunction with pattern recognition will make major contribution to our
understanding of renal processes and provide new diagnostic insights in the
21st century.
相似文献
5.
Background
Correct diagnosis in psychiatry may be improved by novel diagnostic procedures. Computerized Decision Support Systems (CDSS) are suggested to be able to improve diagnostic procedures, but some studies indicate possible problems. Therefore, it could be important to investigate CDSS systems with regard to their feasibility to improve diagnostic procedures as well as to save time. 相似文献6.
Cystic hypersecretory carcinoma (CHC) is a rare variant of intraductal carcinoma. A CHC in a 50-year-old woman was excised and processed for light and electron microscopy and immunohistochemistry. The tumor had a marked cystic appearance. The walls of the cysts consisted of epithelial and myoepithelial cells and a well-developed basement membrane. The epithelial cells contained well-developed rough-surfaced endoplasmatic reticulum and Golgi apparatus. Secretory granules were not detected, with the exception of a few mucus-producing cells. The secretion was predominantly homogenous, reminiscent of thyroid colloid, and demonstrated distinct PAS positivity. The cells displayed a strong labeling with epithelial membrane antigen (EMA) and EMA-positive structures were observed within the intraluminal secretion, too. Some of these were stained by alcian blue. In addition, the colloid-like material was admixed with mucus showing a filamentous internal structure and lipid droplets resulting in some heterogenity of the secretion. Intraductal micropapillary proliferation in some of the cysts and adjacent nondistended ducts was a further defining feature of the tumor. Steroid hormone receptor and Ki-67 proliferation marker immuno his Tochemistry showed scattered positivity among the tumor cells. These results are in agreement with previous observations and further clarify the nature of this low-grade in situ cancer. 相似文献
7.
Philip W. Westerman Maria Jo?o Vaz Lawrence M. Strenk J. William Doane 《Proceedings of the National Academy of Sciences of the United States of America》1982,79(9):2890-2894
The 2H NMR spectrum of a multilamellar dispersion of 1-myristoyl-2-[14,14,14-2H3]myristoyl-sn-glycero-3-phosphocholine with 1 mol% cholesterol in excess water has been recorded at temperatures between -15°C and 36°C. Motionally averaged quadrupole coupling constants νQ and motionally induced asymmetry parameters η are obtained by spectral analysis. Values of these quantities indicate that, at temperatures below -4°C, any rotational motion of the molecules about their molecular long axis is slow on the NMR time scale. At temperatures immediately above the pretransition these same parameters show that a fast-rotational motion is occurring about the molecular long axis. This rotational motion is hindered in that the molecules flip about a twofold symmetry axis. Between -4°C and the pretransition, spectra appear as the superposition of two powder patterns, one corresponding to the pattern observed below -4°C and the other to the pattern above the pretransition. The relative contribution of the latter increases with temperature until the pretransition is reached. These data have been interpreted in two ways: either the sample between -4°C and the pretransition contains two populations of rapidly and slowly rotating molecules, or there is only a single population of molecules undergoing a 180° flipping motion on the time scale of the NMR measurement. The latter interpretation is more consistent with other experimental findings. At the temperature of the main transition the hydrocarbon chains melt. In the absence of cholesterol, spectra are more complex in that the line shape is reproduced by the superposition of three spectral powder patterns between -4°C and the pretransition and by the superposition of two spectral patterns above the pretransition. It is postulated that these two patterns observed above the pretransition are in direct correspondence to the two ripple structures observed by freeze-fracture electron microscopy in the absence of cholesterol. 相似文献
8.
BACKGROUND:
Flavonoids are polyphenolic substances with antioxidant properties, and they are found in different vegetables and fruits. Epidemiological studies have shown that the consumption of flavonoids reduces the prevalence of cardiovascular diseases. The use of synthetic antioxidants, however, has been limited because of their toxicity. Therefore, medical researchers have intensified their quest to find natural antioxidants.OBJECTIVES:
To investigate the effect of several pure flavonoids, such as kaempferol, quercetin, morin and rutin, on red blood cell hemolysis and evaluate their -SH capacity as an indicator of membrane protection.METHODS:
The rate of hemolysis and cell membrane -SH capacity were determined by spectrophotometry. Red blood cell peroxidation was induced using 2,2′-azo-bis-(2-amidinopropane) dihydrochloride. The effect of each flavonoid on hemolysis was examined at three concentrations (0.5 μg/mL, 5 μg/mL and 10 μg/mL), however, only the greatest concentration (10 μg/mL) of each flavonoid was used to study the effect on -SH groups.RESULTS:
In all cases, the antioxidant activity was dose-dependent. Rutin showed the highest inhibitory effect on hemolysis among flavonoids (42.5%). The protective effect of kaempferol, rutin and morin against -SH group oxidation measured 7.7%, 23.3% and 26.4%, respectively.CONCLUSIONS:
Results showed that flavonoids and flavonoid-containing plants can be used as natural antioxidants for the treatment and prevention of disease conditions, the pathogenesis of which is mediated by lipid peroxidation. 相似文献9.
Effective pain control enhances patient recovery after surgery. Laparoscopic techniques for major abdominal surgery are increasingly utilised to reduce surgical trauma. Intrathecal morphine is an attractive analgesic option that is gaining popularity. However, limited evidence guides its use in the setting of laparoscopic surgery. In addition, enhanced recovery after surgery pathways advocate opioid-sparing techniques. We conducted a feasibility trial to compare intrathecal morphine with non-neuraxial analgesia in laparoscopic or laparoscopic-assisted major abdominal surgery to inform the design of a future large clinical trial. This multicentre, double-blind, randomised controlled trial was conducted at two tertiary hospitals in Australia. Fifty-one patients were randomly allocated to receive either intrathecal morphine (intervention group) or a sham subcutaneous injection of normal saline in the lumbar area (control group) immediately before the induction of general anaesthesia. Co-primary outcomes were patient recruitment and successful adherence to treatment allocation as per the study protocol. The primary endpoints of feasibility and protocol adherence were met with a 46% recruitment rate (51 of 110 eligible patients) and 96% protocol adherence. There was only one patient with failed access to the intrathecal space. For secondary endpoints, fewer patients in the intrathecal morphine group required opioids in the post-anaesthesia care unit, their postoperative pain scores at rest were lower across the four time-points measured (p = 0.007), but not dynamic pain scores (p = 0.061), and pruritus was more common following intrathecal morphine (p = 0.007). Total oral morphine equivalents until postoperative day 3 were less in the intrathecal morphine group (median (95%CI) difference 82 (−13 to 168) mg), but this reduction was not statistically significant (p = 0.10). These findings support conducting a definitive clinical trial. 相似文献
10.
A Konski C Poulter H Keys P Rubin J Beecham K Doane 《International journal of radiation oncology, biology, physics》1988,14(1):49-55
Peritoneal cytology has been shown to be one of the prognostic factors in endometrial cancer. A series of 134 patients was seen between January 1977 and March 1985 with clinical Stage I (or treated as a clinical Stage I) endometrial adenocarcinoma at the University of Rochester Cancer Center. The majority of patients underwent extrafascial hysterectomy with the majority of washings obtained at the time of surgery. Fourteen percent (19/134) of the patients were found to have positive cytology. Eleven patients with positive cytology (11/19) were treated with local-regional pelvic treatment; the other eight patients received whole abdominal therapy. The recurrence rates were less with the local treatment than with the whole abdominal treatment groups (9.1% vs. 25%) in those patients having positive cytology. There was no statistical difference in recurrence rates between the pathologic Stage I patients with positive cytology (10%) versus those patients having negative cytology (5%), nor was there statistical difference in survival between pathologic Stage I positive or negative cytology patients. It is suggestive from this non-randomized study that positive cytology in endometrial cancer is not an independent prognostic factor and that whole abdominal irradiation did not influence outcome. 相似文献