全文获取类型
收费全文 | 16258篇 |
免费 | 969篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 223篇 |
儿科学 | 353篇 |
妇产科学 | 227篇 |
基础医学 | 2034篇 |
口腔科学 | 220篇 |
临床医学 | 1752篇 |
内科学 | 3430篇 |
皮肤病学 | 389篇 |
神经病学 | 973篇 |
特种医学 | 662篇 |
外科学 | 2598篇 |
综合类 | 123篇 |
现状与发展 | 1篇 |
一般理论 | 4篇 |
预防医学 | 1318篇 |
眼科学 | 527篇 |
药学 | 1158篇 |
5篇 | |
中国医学 | 83篇 |
肿瘤学 | 1202篇 |
出版年
2024年 | 155篇 |
2023年 | 209篇 |
2022年 | 451篇 |
2021年 | 869篇 |
2020年 | 484篇 |
2019年 | 575篇 |
2018年 | 644篇 |
2017年 | 427篇 |
2016年 | 505篇 |
2015年 | 522篇 |
2014年 | 660篇 |
2013年 | 710篇 |
2012年 | 1119篇 |
2011年 | 1086篇 |
2010年 | 648篇 |
2009年 | 521篇 |
2008年 | 898篇 |
2007年 | 881篇 |
2006年 | 749篇 |
2005年 | 698篇 |
2004年 | 617篇 |
2003年 | 542篇 |
2002年 | 493篇 |
2001年 | 493篇 |
2000年 | 451篇 |
1999年 | 371篇 |
1998年 | 122篇 |
1997年 | 104篇 |
1996年 | 92篇 |
1995年 | 78篇 |
1994年 | 68篇 |
1993年 | 61篇 |
1992年 | 150篇 |
1991年 | 105篇 |
1990年 | 118篇 |
1989年 | 109篇 |
1988年 | 93篇 |
1987年 | 81篇 |
1986年 | 67篇 |
1985年 | 54篇 |
1984年 | 48篇 |
1983年 | 33篇 |
1982年 | 19篇 |
1981年 | 12篇 |
1980年 | 14篇 |
1979年 | 15篇 |
1978年 | 6篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Han XY Pham AS Nguyen KU Smythe WR Ordonez NG Jacobson KL Tarrand JJ 《American journal of clinical pathology》2001,116(3):347-353
Pulmonary granuloma is a common lesion for which gram-negative bacteria are rarely implicated as a cause. Hence, most physicians are unaware of this etiology. We isolated a gram-negative bacterium from a surgically resected pulmonary granuloma in a 42-year-old, nonimmunocompromised woman. Within the necrotizing granuloma, numerous organisms also were demonstrated by Gram stain, suggesting a cause-disease relationship. Characterization of the bacterium by sequence analysis of the 16S ribosomal gene, cellular fatty acid profiling, and microbiologic studies revealed a novel bacterium with a close relationship to Pseudomonas. We propose a new species for the bacterium, Pseudomonas andersonii. These results suggest that the differential diagnosis of a lung granuloma also should include this gram-negative bacterium as a potential causative agent, in addition to the more common infections caused by acid-fast bacilli and fungi. This bacterium was shown to be susceptible to most antibiotics that are active against gram-negative bacteria. 相似文献
22.
The regional distribution and cellular localization of mRNA coding for the serotonin 1C receptor were investigated in tissue sections of mouse and rat brain by in situ hybridization histochemistry. Several 32P-labelled riboprobes derived from mouse genomic clones were used. The serotonin 1C receptor binding sites were visualized autoradiographically and quantified using [3H]mesulergine as ligand, in the presence of spiperone to block serotonin 1C receptors. Strong hybridization signal was observed in the choroid plexus of all brain ventricles. High levels of hybridization were also seen in the anterior olfactory nucleus, pyriform cortex, amygdala, some thalamic nuclei, especially the lateral habenula, the CA3 area of the hippocampal formation, the cingulate cortex, some components of the basal ganglia and associated areas, particularly the nucleus subthalamicus and the substantia nigra. The midbrain and brainstem showed moderate levels of hybridization. The distribution of the serotonin 1C receptor mRNA corresponded well to that of the serotonin 1C receptors. The highest levels of serotonin 1C receptor binding were observed in the choroid plexus. In addition, significant levels of the serotonin 1C receptor binding were seen in the anterior olfactory nucleus, pyriform cortex, nucleus accumbens, ventral aspects of the striatum, paratenial and paracentral thalamic nuclei, amygdaloid body and substantia nigra pars reticulata. The cingulate and retrosplenial cortices as well as the caudal aspects of the hippocampus (CA3) were also labelled. Binding in brainstem and medulla was low and homogeneously distributed. No significant binding was seen in the habenular and subthalamic nuclei. Similar findings were obtained in rat brain. These results demonstrate that, in addition to their enrichment in the choroid plexus, the serotonin 1C receptor mRNA and binding sites are heterogeneously distributed in the rodent brain and thus could be involved in the regulation of many different brain functions. The combination of in situ hybridization histochemistry with receptor autoradiography opens the possibility of examining the regulation of the serotonin 1C receptor synthesis after pharmacological or physiological alterations. 相似文献
23.
24.
25.
Myotonic dystrophy (DM) is a multisystemic disorder caused by an inherited CTG repeat expansion which affects three genes encoding the DM protein kinase (DMPK), a homeobox protein Six5 and a protein containing WD repeats. Using a panel of 16 monoclonal antibodies against several different DMPK epitopes we detected DMPK, as a single protein of approximately 80 kDa, only in skeletal muscle, cardiac muscle and, to a lesser extent, smooth muscle. Many earlier reports of DMPK with different sizes and tissue distributions appear to be due to antibody cross-reactions with more abundant proteins. One such antibody, MANDM1, was used to isolate two related protein kinases, MRCK alpha and beta, from a human brain cDNA library and the shared epitope was located at the catalytic site of DMPK using a phage-displayed random peptide library. The peptide library also identified an epitope shared between DMPK and a 55 kDa muscle-specific protein. The results suggest that effects of the repeat expansion on the DMPK gene may be responsible for muscle and heart features of DM, whereas clinical changes in other tissues may be due to effects on the other two genes. 相似文献
26.
Transgenic rat model of Huntington's disease 总被引:12,自引:0,他引:12
von Hörsten S Schmitt I Nguyen HP Holzmann C Schmidt T Walther T Bader M Pabst R Kobbe P Krotova J Stiller D Kask A Vaarmann A Rathke-Hartlieb S Schulz JB Grasshoff U Bauer I Vieira-Saecker AM Paul M Jones L Lindenberg KS Landwehrmeyer B Bauer A Li XJ Riess O 《Human molecular genetics》2003,12(6):617-624
Huntington's disease (HD) is a late manifesting neurodegenerative disorder in humans caused by an expansion of a CAG trinucleotide repeat of more than 39 units in a gene of unknown function. Several mouse models have been reported which show rapid progression of a phenotype leading to death within 3-5 months (transgenic models) resembling the rare juvenile course of HD (Westphal variant) or which do not present with any symptoms (knock-in mice). Owing to the small size of the brain, mice are not suitable for repetitive in vivo imaging studies. Also, rapid progression of the disease in the transgenic models limits their usefulness for neurotransplantation. We therefore generated a rat model transgenic of HD, which carries a truncated huntingtin cDNA fragment with 51 CAG repeats under control of the native rat huntingtin promoter. This is the first transgenic rat model of a neurodegenerative disorder of the brain. These rats exhibit adult-onset neurological phenotypes with reduced anxiety, cognitive impairments, and slowly progressive motor dysfunction as well as typical histopathological alterations in the form of neuronal nuclear inclusions in the brain. As in HD patients, in vivo imaging demonstrates striatal shrinkage in magnetic resonance images and a reduced brain glucose metabolism in high-resolution fluor-deoxy-glucose positron emission tomography studies. This model allows longitudinal in vivo imaging studies and is therefore ideally suited for the evaluation of novel therapeutic approaches such as neurotransplantation. 相似文献
27.
Phenylethylidenehydrazine, a novel GABA-transaminase inhibitor, reduces epileptiform activity in rat hippocampal slices 总被引:1,自引:0,他引:1
Phenylethylidenehydrazine (PEH), an analog of the monoamine oxidase inhibitor, beta-phenylethylhydrazine (phenelzine), inhibits the gamma-aminobutyric acid (GABA) catabolic enzyme GABA-transaminase and increases brain levels of GABA. GABA is the predominant fast inhibitory transmitter counteracting glutamatergic excitation, and increased neural GABA could influence a wide range of synaptic and circuit properties under both physiologic and pathophysiologic conditions. To examine the scope of these effects, we applied PEH (or vehicle) to rat hippocampal slices and measured basal glutamatergic transmission, synaptic plasticity, and epileptiform activity using extracellular field and whole cell patch clamp recordings. In vitro pre-treatment with PEH (100 microM) increased the GABA content of hippocampal slices by approximately 60% over vehicle-treated controls, but it had no effect on basal field excitatory postsynaptic potentials, tonic GABA currents, paired-pulse facilitation, or long-term potentiation. In contrast, pre-incubation with PEH caused a dose- and time-dependent reduction in epileptiform burst frequency induced by superfusion with Mg2+-free or high-K+ artificial cerebrospinal fluid. Thus, the inhibitory effects of PEH are state-dependent: hyper-excitation during epileptiform bursting was reduced, whereas synaptic transmission and plasticity were unaffected. 相似文献
28.
D Nguyen D A Reilly J J Reilly 《JPEN. Journal of parenteral and enteral nutrition》1987,11(3):255-258
Determining an individual's "ideal" body weight is fundamental in nutritional therapy. A simulation of the human body to a cylindrical volumetric model permits the calculation of the ideal body weight from the measured height, interacromioclavicular distance, and humeral length. A group of 189 healthy normal volunteers were assessed. The calculated "Pitt" ideal body weight correlated closely (r = 0.88 for males, r = 0.72 for women) with values obtained from the Metropolitan tables. The technique provides an estimate of ideal body weight based upon reproducible, easily obtained measurements of fixed bony landmarks. 相似文献
29.
Nguyen Tuyen Trat Tiffany Tieu Ngoc Thanh Vu Linda Sokal-Gutierrez Karen 《Maternal and child health journal》2022,26(9):1811-1819
Maternal and Child Health Journal - Vietnam’s post-war globalization, economic development, and urbanization have contributed to a nutrition transition from traditional diets to... 相似文献
30.
Basnet Sulochana Frongillo Edward A. Nguyen Phuong Hong Moore Spencer Arabi Mandana 《Maternal and child health journal》2021,25(6):946-946
Maternal and Child Health Journal - The article “Factor Structure and Equivalence of Maternal Resources for Care in Bangladesh, Vietnam, and Ethiopia”, written by Sulochana Basnet,... 相似文献