全文获取类型
收费全文 | 324498篇 |
免费 | 29148篇 |
国内免费 | 22893篇 |
专业分类
耳鼻咽喉 | 2986篇 |
儿科学 | 3454篇 |
妇产科学 | 4928篇 |
基础医学 | 39966篇 |
口腔科学 | 5493篇 |
临床医学 | 45313篇 |
内科学 | 49749篇 |
皮肤病学 | 3091篇 |
神经病学 | 18370篇 |
特种医学 | 11993篇 |
外国民族医学 | 213篇 |
外科学 | 33240篇 |
综合类 | 49922篇 |
现状与发展 | 76篇 |
一般理论 | 20篇 |
预防医学 | 19632篇 |
眼科学 | 9569篇 |
药学 | 32852篇 |
334篇 | |
中国医学 | 17434篇 |
肿瘤学 | 27904篇 |
出版年
2024年 | 1010篇 |
2023年 | 5033篇 |
2022年 | 13063篇 |
2021年 | 16410篇 |
2020年 | 12057篇 |
2019年 | 10865篇 |
2018年 | 11428篇 |
2017年 | 9928篇 |
2016年 | 9376篇 |
2015年 | 14381篇 |
2014年 | 17831篇 |
2013年 | 15365篇 |
2012年 | 22841篇 |
2011年 | 25834篇 |
2010年 | 15923篇 |
2009年 | 12261篇 |
2008年 | 17030篇 |
2007年 | 17025篇 |
2006年 | 17062篇 |
2005年 | 16781篇 |
2004年 | 10665篇 |
2003年 | 9762篇 |
2002年 | 8443篇 |
2001年 | 7473篇 |
2000年 | 8285篇 |
1999年 | 9021篇 |
1998年 | 5478篇 |
1997年 | 5505篇 |
1996年 | 4335篇 |
1995年 | 3924篇 |
1994年 | 3213篇 |
1993年 | 2098篇 |
1992年 | 2827篇 |
1991年 | 2415篇 |
1990年 | 2118篇 |
1989年 | 1862篇 |
1988年 | 1563篇 |
1987年 | 1353篇 |
1986年 | 1107篇 |
1985年 | 912篇 |
1984年 | 526篇 |
1983年 | 373篇 |
1982年 | 242篇 |
1981年 | 238篇 |
1980年 | 188篇 |
1979年 | 221篇 |
1978年 | 82篇 |
1977年 | 89篇 |
1974年 | 102篇 |
1973年 | 83篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
142.
N Wang 《中华结核和呼吸杂志》1991,14(2):79-82, 126
A prospective study was conducted with patients with pulmonary infections who were consecutively admitted to the three community hospitals in Benghu from July 1986 to May 1987, and to the children's hospital in Nanjing from September 1986 to January 1987. Antibodies to Lpi-8, Lm, Ld, and Lg were measured by the micro-agglutination test. During the study period, 150 adult patients (100 pairs sera) and 212 control healthy people and 110 pairs sera of childhood patients and 173 children without respiratory tract infections were investigated. The diagnosis of legionellosis was based on seroconversion (fourfold rise in titer to greater than 1:32 or static titer of greater than 1:32) and clinical and radiographic features of legionnaires' disease. About 11% legionella infection in hospitalized adult patients with pulmonary infections, and about 5.45% in children with atypical pneumonias. 相似文献
143.
几种手性药物对映体的HPLC分离与生物样品分析 总被引:2,自引:0,他引:2
使用CHIRAL-AGP柱,通过优化色谱条件,以HPLC法对3种手性药物SFZ-47〔(±)-3H-1,2-二氢-2-(4-甲基苯胺基)-甲基-1-吡咯里嗪酮〕,KMBZ-009〔(±)-反式-4-苯基-5-(邻氯苄基)-吡咯烷酮-2〕和地丙苯酮〔(±)-2′-(2-羟基-3-(特戊胺基)丙氧基)-3-苯基苯丙基酮〕进行了对映体的直接分离,达到良好的分离效果.在此基础上测试了动物血浆样品中SFZ-47的对映体,对其药物动力学的对映体选择性进行了初步研究. 相似文献
144.
145.
磁共振成像对颅内脑膜瘤水肿分析 总被引:1,自引:0,他引:1
目的:探讨脑膜瘤周围脑水肿的程度和肿瘤的生长部位.质地.组织学亚型的相关性.研究其瘤周水肿的形成原因.材料和方法:使用经手术和病理证实的65例脑膜瘤MRI和临床病理资料.观察分析脑膜瘤的瘤周水肿的程度.肿瘤的质地,组织学亚型等.结果:发生于大脑颅盖部或/和有矢状窦受累的脑膜瘤有明显的脑水肿.而发生于其它部位(颅底,丘脑、小脑、脑池等)无或只有轻度脑水肿.结论:轻度脑水肿主要是脑膜瘤对脑组织的直接压迫,而中,重度脑水肿主要是脑膜瘤对大脑表面引流静脉尤其是矢状窦的压迫或阻塞.脑水肿和肿瘤的发生部位有关,面和肿瘤的质地、组织学亚型无关. 相似文献
146.
四氧嘧啶诱发糖尿病大鼠血管紧张素的变化 总被引:1,自引:0,他引:1
实验观察了四氧嘧啶诱发糖尿病大鼠连续饲养110d后体内肾素一血管紧张素系统的变化。结果表明,血浆和心脏的血管紧张素Ⅱ含量无明显变化,而肾脏的AngⅡ含量却明显低于正常对照组。另外,心脏的心钠素(ANP)含量在糖尿病大鼠与正常对照组之间无差别,血中的糖化血红蛋白含量基本无变化。上述结果表明,糖尿病大鼠早期心脏可能无明显损伤,而肾脏的肾素一血管紧张素系统活性降低。 相似文献
147.
P. K. C. Wang 《Optimal control applications & methods.》1995,16(5):305-320
The problem of controlling the temperature distribution in a solid cylinder whose length varies with time and with one end in contact with a constant temperature medium is considered. This problem is motivated from that of controlling the temperature and thermal gradient inside a crystal pulled from a melt by the Czochralski method. Boundary feedback controls are derived by considering the time rate of change of a cost functional involving the deviations of both the solid temperature and its gradient from their desired values. The derived feedback controls consist of spatially distributed proportional-plus-rate and lag compensators and a non-linear feedback control involving the temperature gradient at the cylinder surface and the velocity of the spatial domain boundary. The resulting feedback-controlled system has the property that the cost functional along any motion decreases monotonically to zero with time. A numerical scheme for solving the partial differential equation of the feedback-controlled system is proposed. Typical numerical results on the dynamic behaviour of the feedback-controlled system obtained by means of the proposed scheme are presented. 相似文献
148.
Abstract: A pulsatile impeller assist heart and a total heart were tested as a chronic left ventricular assist device in 5 calves and an acute biventricular assist device in 4 pigs respectively, to evaluate their blood compatibility. During the left ventricular assist experiments, the indicators for hemolysis, thrombogenesis, renal dysfunction, and hepatic dysfunction were measured preoperatively, at the beginning of the pumping, 6 h postoperatively, and every following day. The results demonstrated that the impeller assist heart causes no severe blood damage nor organ dysfunction in the experiments lasting up to 11 days. In biventricular assist experiments, the number of red blood cells, white blood cells, platelets, and the he-matocrit, hemoglobin, free hemoglobin, and lactate dehy-drogenase levels were tested preoperatively at the beginning of the pumping and every 2 h postoperatively. The data remained in acceptable ranges during experiments lasting 6 h. It is confirmed that the authors' impeller assist heart and total heart have the advantages of simplicity, implantability, and pulsatility with good blood compatibility. 相似文献
149.
枢复宁在肺癌患者体内的药物动力学和生物利用度 总被引:3,自引:1,他引:2
9名接受顺铂化疗的原发性肺癌患者单次口服和静脉注射枢复宁8mg后,用反相高效液相色谱法测定血浆药物浓度。经用PKBP-N1程序在计算机上拟合计算表明,枢复宁在人体内表现为二房室模型。口服后主要药动学参数:T1/2Ka=0.41±0.30h,T1/2α=0.9±0.43h,T1/2β=3.3±1.2h,Cmax=28.6±9.5ng/ml,Tmax=1.7±0.9h,AUC=158±73ng·h/ml,绝对生物利用度为55%。 相似文献
150.
Y Taki T Morimoto A Tanaka M Noguchi W Y Wang T Nishihira K Nishikawa K Mori K Ozawa 《The Journal of surgical research》1990,48(1):56-60
Ketogenic capacity of mitochondria from the remnant liver of 70% hepatectomized rats was studied in relation to mitochondrial phosphorylative activity. Ketogenic capacity increased to a maximum of 6.04 +/- 0.39 from 3.84 +/- 0.13 of control, with an enhancement of mitochondrial phosphorylative activity 6 hr after hepatectomy, and then decreased to normal levels within 24 hr. Adenylate energy charge, (ATP + 1/2ADP)/(ATP + ADP + AMP), of the remnant liver decreased to 0.825 +/- 0.006 as compared to 0.849 +/- 0.002 of control 6 hr after operation. At 12 hr, total ketone body concentrations of the arterial blood increased concomitant with a fall in ketone body ratio (acetoacetate/3-hydroxybutyrate) which reflects the decreased liver mitochondrial redox (NAD+/NADH) state. These findings suggest that an enhancement of mitochondrial fatty acid oxidation and ketogenesis occurs concomitant with an enhancement of mitochondrial phosphorylative activity in the remnant liver in response to a decreased energy charge after 70% hepatectomy. 相似文献