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   28158篇
  免费   1884篇
  国内免费   98篇
耳鼻咽喉   216篇
儿科学   796篇
妇产科学   608篇
基础医学   4739篇
口腔科学   754篇
临床医学   2730篇
内科学   5352篇
皮肤病学   563篇
神经病学   2795篇
特种医学   727篇
外国民族医学   2篇
外科学   2844篇
综合类   149篇
一般理论   28篇
预防医学   2836篇
眼科学   415篇
药学   1798篇
中国医学   48篇
肿瘤学   2740篇
  2023年   204篇
  2022年   371篇
  2021年   688篇
  2020年   495篇
  2019年   685篇
  2018年   789篇
  2017年   645篇
  2016年   726篇
  2015年   812篇
  2014年   1003篇
  2013年   1422篇
  2012年   1967篇
  2011年   1963篇
  2010年   1134篇
  2009年   1051篇
  2008年   1771篇
  2007年   1718篇
  2006年   1628篇
  2005年   1546篇
  2004年   1344篇
  2003年   1377篇
  2002年   1240篇
  2001年   373篇
  2000年   330篇
  1999年   340篇
  1998年   258篇
  1997年   258篇
  1996年   200篇
  1995年   213篇
  1994年   176篇
  1993年   168篇
  1992年   223篇
  1991年   237篇
  1990年   197篇
  1989年   183篇
  1988年   175篇
  1987年   165篇
  1986年   167篇
  1985年   141篇
  1984年   162篇
  1983年   116篇
  1982年   126篇
  1981年   103篇
  1980年   93篇
  1979年   95篇
  1978年   103篇
  1976年   77篇
  1975年   96篇
  1974年   95篇
  1973年   77篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
The biodistribution of two recently developed tumour markers, trimethylated (CP(Me)3) and trimethoxylated (CP(OMe)3) carotenoporphyrin, was investigated by means of laser-induced fluorescence (LIF) after i.v. injection into 38 tumour-bearing (MS-2 fibrosarcoma) female Balb/c mice. At 3, 24, 48 or 96 h after administration, the carotenoporphyrin fluorescence was measured in tumoral and peritumoral tissue, as well as in the abdominal, thoracic and cranial cavities. The fluorescence was induced by a nitrogen laser-pumped dye laser, emitting light at 425 nm, and analysed by a polychromator equipped with an image-intensified CCD camera. The fluorescence was evaluated at 490, 655 and 720 nm: the second and third wavelengths represent the carotenoporphyrin (CP)-related peaks, whereas the first one is close to the peak of the tissue autofluorescence. The tumour and the liver were the two tissue types showing the strongest carotenoporphyrin-related fluorescence, whereas the cerebral cortex and muscle consistently exhibited weak substance-related fluorescence. In most tissue types, the fluorescence intensities decreased over time. A few exceptions were observed, notably the liver, in which the intensity remained remarkably constant over the time period investigated.  相似文献   
4.
5.
6.
7.
Nonconvulsive Status Epilepticus: High Incidence of Complex Partial Status   总被引:14,自引:6,他引:8  
Nonconvulsive status epilepticus may be subdivided into generalized (absence) status and complex partial status. The latter is regarded as a rarity, whereas the former constitutes the dominant part of the hitherto reported cases. We report 10 consecutive cases of adult patients with nonconvulsive status epilepticus, all documented by ictal electroencephalographic (EEG) recordings. Five had a complex partial status; the origin of the complex partial status appeared to be frontal in four of these patients. Three had recurrent complex partial seizures with incomplete recovery between seizures, and two had more continuous symptoms. One of the latter exhibited neither motor phenomena nor automatisms. The effect of diazepam or clonazepam was immediate in all 10 cases though transient in eight. A lasting control of the status was not achieved in six patients until i.v. phenytoin was added. The difficulties in the differentiation between complex partial status and absence status despite ictal EEG recordings are discussed, illustrated by a case with seizure discharges of a focal onset which rapidly generalized. The study indicates that complex partial status may be more common and the clinical expressions of absence status more variable than hitherto recognized.  相似文献   
8.
To determine whether polymorphisms of platelet surface glycoprotein associated with arterial thrombosis are risk factors for branch retinal vein occlusion. A case-control study in which 69 patients with branch retinal vein occlusion and 147 controls who attended the eye clinic for nonvascular complications participated. DNA was extracted from whole blood and analyzed for genotyping of platelet glycoprotein polymorphisms by polymerase chain reactions and specific restricted enzymes. No relationship was found between the four platelet glycoprotein polymorphisms i.e. GPIa C807T, VNTR and Kozak of glycoprotein Ibalpha, the HPA-1 of glycoprotein IIIa and the occurrence of branch retinal vein occlusion. The HPA-2 polymorphism was found in 18 out 60 (30%) patients with branch retinal vein occlusion in comparison with 27 out 142 (19%) of controls, with an estimated odds ratio of 1.8 (95% confidence interval, 0.91-3.65). The four platelet glycoprotein polymorphisms are not risk factors for branch retinal vein occlusion and therefore it seems unnecessary to screen those patients for it. A larger study is required, however, to determine whether HPA-2 is a novel risk factor for branch retinal vein occlusion.  相似文献   
9.
Cationic block copolymers spontaneously assemble via electrostatic interactions with DNA molecules in aqueous solution giving rise to micellar structures that protect the DNA from enzymatic degradation both in vitro and in vivo. In addition, we have previously shown that they are safe, not immunogenic and greatly increased antigen-specific CTL responses following six intramuscular inoculations of a very low dose (1 μg) of the vaccine DNA as compared to naked DNA. Nevertheless, they failed to elicit detectable humoral responses against the antigen. To gain further insight in the potential application of this technology, here we show that a shorter immunization protocol based on two DNA intramuscular inoculations of 1 μg of DNA delivered by these copolymers and a protein boost elicits in mice broad (both humoral and cellular) and long-lasting responses and increases the antigen-specific Th1-type T cell responses and CTLs as compared to priming with naked DNA. These results indicate that cationic block copolymers represent a promising adjuvant and delivery technology for DNA vaccination strategies aimed at combating intracellular pathogens.  相似文献   
10.
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