全文获取类型
收费全文 | 861530篇 |
免费 | 71566篇 |
国内免费 | 1838篇 |
专业分类
耳鼻咽喉 | 12806篇 |
儿科学 | 24634篇 |
妇产科学 | 25101篇 |
基础医学 | 124277篇 |
口腔科学 | 25492篇 |
临床医学 | 75326篇 |
内科学 | 164602篇 |
皮肤病学 | 16991篇 |
神经病学 | 70213篇 |
特种医学 | 35194篇 |
外国民族医学 | 171篇 |
外科学 | 136159篇 |
综合类 | 24611篇 |
现状与发展 | 2篇 |
一般理论 | 264篇 |
预防医学 | 66946篇 |
眼科学 | 20519篇 |
药学 | 64763篇 |
中国医学 | 1593篇 |
肿瘤学 | 45270篇 |
出版年
2018年 | 7341篇 |
2015年 | 7735篇 |
2014年 | 11119篇 |
2013年 | 16789篇 |
2012年 | 22727篇 |
2011年 | 23851篇 |
2010年 | 13881篇 |
2009年 | 13079篇 |
2008年 | 22600篇 |
2007年 | 24642篇 |
2006年 | 24513篇 |
2005年 | 24160篇 |
2004年 | 23722篇 |
2003年 | 22853篇 |
2002年 | 21938篇 |
2001年 | 35841篇 |
2000年 | 36489篇 |
1999年 | 30907篇 |
1998年 | 9226篇 |
1997年 | 8548篇 |
1996年 | 8477篇 |
1995年 | 8008篇 |
1994年 | 7726篇 |
1992年 | 26668篇 |
1991年 | 26108篇 |
1990年 | 25626篇 |
1989年 | 24686篇 |
1988年 | 23224篇 |
1987年 | 22887篇 |
1986年 | 21749篇 |
1985年 | 21102篇 |
1984年 | 16386篇 |
1983年 | 13997篇 |
1982年 | 8860篇 |
1981年 | 8204篇 |
1980年 | 7672篇 |
1979年 | 16739篇 |
1978年 | 12119篇 |
1977年 | 10182篇 |
1976年 | 9336篇 |
1975年 | 10148篇 |
1974年 | 12646篇 |
1973年 | 12139篇 |
1972年 | 11540篇 |
1971年 | 10691篇 |
1970年 | 10219篇 |
1969年 | 9911篇 |
1968年 | 8901篇 |
1967年 | 8232篇 |
1966年 | 7657篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
162.
Marlene L Hauck Susan M LaRue William P Petros Jean M Poulson Daohai Yu Ivan Spasojevic Amy F Pruitt Allison Klein Beth Case Donald E Thrall David Needham Mark W Dewhirst 《Clinical cancer research》2006,12(13):4004-4010
PURPOSE: To determine the maximum tolerated dose, dose-limiting toxicities, and pharmacokinetic characteristics of doxorubicin encapsulated in a low temperature sensitive liposome (LTSL) when given concurrently with local hyperthermia to canine solid tumors. EXPERIMENTAL DESIGN: Privately owned dogs with solid tumors (carcinomas or sarcomas) were treated. The tumors did not involve bone and were located at sites amenable to local hyperthermia. LTSL-doxorubicin was given (0.7-1.0 mg/kg i.v.) over 30 minutes during local tumor hyperthermia in a standard phase I dose escalation study. Three treatments, given 3 weeks apart, were scheduled. Toxicity was monitored for an additional month. Pharmacokinetics were evaluated during the first treatment cycle. RESULTS: Twenty-one patients were enrolled: 18 with sarcomas and 3 with carcinomas. Grade 4 neutropenia and acute death secondary to liver failure, possibly drug related, were the dose-limiting toxicities. The maximum tolerated dose was 0.93 mg/kg. Other toxicities, with the possible exception of renal damage, were consistent with those observed following free doxorubicin administration. Of the 20 dogs that received > or = 2 doses of LTSL-doxorubicin, 12 had stable disease, and 6 had a partial response to treatment. Pharmacokinetic variables were more similar to those of free doxorubicin than the marketed liposomal product. Tumor drug concentrations at a dose of 1.0 mg/kg averaged 9.12 +/- 6.17 ng/mg tissue. CONCLUSION: LTSL-doxorubicin offers a novel approach to improving drug delivery to solid tumors. It was well tolerated and resulted in favorable response profiles in these patients. Additional evaluation in human patients is warranted. 相似文献
163.
H J Kim C H Kang Y T Kim S-W Sung J H Kim S M Lee C-G Yoo C-T Lee Y W Kim S K Han Y-S Shim J-J Yim 《The European respiratory journal》2006,28(3):576-580
Although surgical lung resection could improve prognosis in some patients with multidrug-resistant tuberculosis (MDR-TB), there are no reports on the optimal candidates for this surgery. The aim of the present study was to elucidate the prognostic factors for surgery in patients with MDR-TB. Patients who underwent lung resection for the treatment of MDR-TB between March 1993 and December 2004 were included in the present study. Treatment failure was defined as greater than or equal to two of the five cultures recorded in the final 12 months of treatment being positive, any one of the final three cultures being positive, or the patient having died during treatment. The variables that affected treatment outcomes were identified through univariate and multivariate logistic regression analysis. In total, 79 patients with MDR-TB were included in the present study. The treatment outcomes of 22 (27.8%) patients were classified as failure. A body mass index <18.5 kg x m(-2), primary resistance, resistance to ofloxacin and the presence of a cavitary lesion beyond the range of the surgical resection were associated with treatment failure. Low body mass index, primary resistance, resistance to ofloxacin and cavitary lesions beyond the range of resection are possible poor prognostic factors for surgical lung resection in multidrug-resistant tuberculosis patients. 相似文献
164.
165.
Background
In meningitis, the cerebrospinal fluid contains high levels of innate immune molecules (e.g. complement) which are essential to ward off the infectious challenge and to promote the infiltration of phagocytes (neutrophils, monocytes). However, epithelial cells of either the ependymal layer, one of the established niche for adult neural stem cells, or of the choroid plexus may be extremely vulnerable to bystander attack by cytotoxic and cytolytic complement components. 相似文献166.
167.
168.
169.
J Vandevoorde S Verbanck D Schuermans J Kartounian W Vincken 《The European respiratory journal》2006,27(2):378-383
The purpose of this study was to determine fixed cut-off points for forced expiratory volume in one second (FEV(1))/FEV(6) and FEV(6) as an alternative for FEV(1)/forced vital capacity (FVC) and FVC in the detection of obstructive and restrictive spirometric patterns, respectively. For the study, a total of 11,676 spirometric examinations, which took place on Caucasian subjects aged between 20-80 yrs, were analysed. Receiver-operator characteristic curves were used to determine the FEV(1)/FEV(6) ratio and FEV(6) value that corresponded to the optimal combination of sensitivity and specificity, compared with the commonly used fixed cut-off term for FEV(1)/FVC and FVC. The data from the current study indicate that FEV(1)/ FEV(6) <73% and FEV(6) <82% predicted can be used as a valid alternative for the FEV(1)/FVC <70% and FVC <80% pred cut-off points for the detection of obstruction and restriction, respectively. The statistical analysis demonstrated very good, overall, agreement between the two categorisation schemes. For the spirometric diagnosis of airway obstruction (prevalence of 45.9%), FEV(1)/FEV(6) sensitivity and specificity were 94.4 and 93.3%, respectively; the positive and negative predictive values were 92.2 and 95.2%, respectively. For the spirometric detection of a restrictive pattern (prevalence of 14.9%), FEV(6) sensitivity and specificity were 95.9 and 98.6%, respectively; the positive and negative predictive values were 92.2 and 99.3%, respectively. This study demonstrates that forced expiratory volume in one second/forced expiratory volume in six seconds <73% and forced expiratory volume in six seconds <82% predicted, can be used as valid alternatives to forced expiratory volume in one second/forced vital capacity <70% and forced vital capacity <80% predicted, as fixed cut-off terms for the detection of an obstructive or restrictive spirometric pattern in adults. 相似文献
170.
Christine E. Marx William T. Trost Lawrence J. Shampine Robert D. Stevens Christine M. Hulette David C. Steffens John F. Ervin Marian I. Butterfield Daniel G. Blazer Mark W. Massing Jeffrey A. Lieberman 《Neuropsychopharmacology》2006,60(12):1287-1294
BACKGROUND: Few data are currently available investigating neurosteroids (NS) in Alzheimer's disease (AD). The NS allopregnanolone may be decreased in serum and plasma in patients with AD, but it is unclear if allopregnanolone is also reduced in brain. Because a number of NS exhibit neuroprotective effects and impact cognitive performance in rodent models, these molecules may be relevant to the pathophysiology of neurodegenerative disorders. We therefore investigated prefrontal cortex (PFC) NS levels in AD. METHODS: Neurosteroid levels (allopregnanolone, pregnenolone, dehydroepiandrosterone [DHEA]) were determined in postmortem PFC in 14 male subjects with AD and 15 cognitively intact male control subjects by gas chromatography/mass spectrometry preceded by high-performance liquid chromatography purification. RESULTS: Subjects with AD exhibit significant reductions in allopregnanolone compared with cognitively intact control subjects (median levels = 2.50 ng/g vs. 5.59 ng/g, respectively; p = .02). Allopregnanolone levels are inversely correlated with neuropathological disease stage (Braak), r = -.49, p = .007. Median DHEA levels are elevated in subjects with AD (p = .01). CONCLUSIONS: Subjects with AD demonstrate significant reductions in PFC allopregnanolone levels, a finding that may be relevant to neuropathological disease stage severity. Neurosteroids may have utility as candidate biomarkers in AD. 相似文献