首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   916950篇
  免费   75604篇
  国内免费   5896篇
耳鼻咽喉   13136篇
儿科学   25092篇
妇产科学   25654篇
基础医学   130423篇
口腔科学   26459篇
临床医学   82975篇
内科学   172315篇
皮肤病学   17436篇
神经病学   72774篇
特种医学   37172篇
外国民族医学   213篇
外科学   141290篇
综合类   34868篇
现状与发展   21篇
一般理论   264篇
预防医学   70537篇
眼科学   22263篇
药学   70684篇
  39篇
中国医学   5069篇
肿瘤学   49766篇
  2021年   8211篇
  2018年   9385篇
  2016年   8248篇
  2015年   10394篇
  2014年   14412篇
  2013年   19479篇
  2012年   26770篇
  2011年   28388篇
  2010年   16500篇
  2009年   15248篇
  2008年   25315篇
  2007年   27401篇
  2006年   27267篇
  2005年   26928篇
  2004年   25516篇
  2003年   24540篇
  2002年   23385篇
  2001年   36936篇
  2000年   37650篇
  1999年   32153篇
  1998年   10089篇
  1997年   9362篇
  1996年   9111篇
  1995年   8604篇
  1994年   8228篇
  1992年   27021篇
  1991年   26388篇
  1990年   25889篇
  1989年   24890篇
  1988年   23427篇
  1987年   23037篇
  1986年   21876篇
  1985年   21191篇
  1984年   16428篇
  1983年   14031篇
  1982年   8871篇
  1981年   8219篇
  1979年   16748篇
  1978年   12114篇
  1977年   10183篇
  1976年   9328篇
  1975年   10147篇
  1974年   12642篇
  1973年   12137篇
  1972年   11538篇
  1971年   10685篇
  1970年   10218篇
  1969年   9910篇
  1968年   8900篇
  1967年   8230篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
目的探讨脉冲微波治疗前列腺炎的效果。方法收治前列腺炎病人532例。用南京亿高ECO—100型电脑微波前列腺炎治疗仪,经肛门途径发射脉冲微波,前列腺部位温度控制在41℃~42℃,每次持续45~60min,共七次。以显效、有效为判断疗效标准。结果17~25岁组显效47.93%,有效52.07%,26~45岁组显效52.06%,有效47.94%,两组有效率100%。结论脉冲微波经肛门途径治疗前列腺炎效果明显,有推广价值。  相似文献   
92.
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   
93.
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   
94.
95.

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   
96.
97.
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   
98.
阿格雷(Peter Agre)博士,美国杜克大学医学院细胞生物学系教授,约翰斯霍普金斯大学医学院生物化学系客座教授。阿格雷教授其研究成果在于分离出了长期以来所搜寻的特定输送水分子的通道。这一发现开启了针对细菌、植物和哺乳动物水通道的系列生化、生理和遗传研究之门,从而使得研究人员可以仔细跟踪水分子通过细胞膜的过程,并了解为何只有水分子而不是其他小分子能够通过细胞膜,阿格雷博士也因此获得了2003年诺贝尔化学奖。  相似文献   
99.
The aim of the current study was to investigate whether alterations in N-terminal pro brain natriuretic peptide (NT-proBNP) reflect changes in right ventricular structure and function in pulmonary hypertension patients during treatment. The study consisted of 30 pulmonary hypertension patients; 15 newly diagnosed and 15 on long-term treatment. NT-proBNP, right heart catheterisation and cardiac magnetic resonance imaging measurements were performed, at baseline and follow-up. There were no significant differences between newly diagnosed patients and those on treatment at baseline or follow-up with respect to NT-proBNP, haemodynamics and right ventricular parameters. Relative changes in NT-proBNP during treatment were correlated to the relative changes in right ventricular end-diastolic volume index (r = 0.59), right ventricular mass index (r = 0.62) and right ventricular ejection fraction (r = -0.81). N-terminal pro brain natriuretic peptide measurements reflect changes in magnetic resonance imaging-measured right ventricular structure and function in pulmonary hypertension patients. An increase in N-terminal pro brain natriuretic peptide over time reflects right ventricular dilatation concomitant to hypertrophy and deterioration of systolic function.  相似文献   
100.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号