全文获取类型
收费全文 | 16123篇 |
免费 | 1094篇 |
国内免费 | 43篇 |
专业分类
耳鼻咽喉 | 139篇 |
儿科学 | 474篇 |
妇产科学 | 552篇 |
基础医学 | 2232篇 |
口腔科学 | 138篇 |
临床医学 | 2777篇 |
内科学 | 2976篇 |
皮肤病学 | 431篇 |
神经病学 | 1294篇 |
特种医学 | 345篇 |
外国民族医学 | 2篇 |
外科学 | 1663篇 |
综合类 | 113篇 |
一般理论 | 17篇 |
预防医学 | 1822篇 |
眼科学 | 179篇 |
药学 | 972篇 |
中国医学 | 22篇 |
肿瘤学 | 1112篇 |
出版年
2023年 | 65篇 |
2022年 | 111篇 |
2021年 | 247篇 |
2020年 | 166篇 |
2019年 | 291篇 |
2018年 | 362篇 |
2017年 | 217篇 |
2016年 | 277篇 |
2015年 | 314篇 |
2014年 | 473篇 |
2013年 | 748篇 |
2012年 | 1101篇 |
2011年 | 1191篇 |
2010年 | 629篇 |
2009年 | 569篇 |
2008年 | 1152篇 |
2007年 | 1189篇 |
2006年 | 1150篇 |
2005年 | 1143篇 |
2004年 | 1063篇 |
2003年 | 982篇 |
2002年 | 1002篇 |
2001年 | 173篇 |
2000年 | 163篇 |
1999年 | 226篇 |
1998年 | 243篇 |
1997年 | 153篇 |
1996年 | 145篇 |
1995年 | 121篇 |
1994年 | 110篇 |
1993年 | 105篇 |
1992年 | 122篇 |
1991年 | 105篇 |
1990年 | 126篇 |
1989年 | 103篇 |
1988年 | 97篇 |
1987年 | 77篇 |
1986年 | 71篇 |
1985年 | 61篇 |
1984年 | 65篇 |
1983年 | 63篇 |
1982年 | 70篇 |
1981年 | 54篇 |
1980年 | 54篇 |
1979年 | 43篇 |
1978年 | 41篇 |
1977年 | 30篇 |
1976年 | 24篇 |
1975年 | 27篇 |
1974年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
Role of Eotaxin-1 (CCL11) and CC chemokine receptor 3 (CCR3) in bleomycin-induced lung injury and fibrosis
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Huaux F Gharaee-Kermani M Liu T Morel V McGarry B Ullenbruch M Kunkel SL Wang J Xing Z Phan SH 《The American journal of pathology》2005,167(6):1485-1496
Eotaxin-1/CCL11 and its receptor CCR3 are involved in recruitment of eosinophils to diverse tissues, but their role in eosinophil recruitment in pulmonary fibrosis is unclear. The present study examined the pulmonary expression of CCL11 and CCR3 during bleomycin (blm)-induced lung injury and determined their importance in the recruitment of inflammatory cells and the development of lung fibrosis. In mice, blm induced a marked pulmonary expression of CCL11 and CCR3. Immunostaining for CCR3 revealed that this receptor was not only expressed by eosinophils but also by neutrophils. CCL11-deficient (CCL11(-/-)) mice developed significantly reduced pulmonary fibrosis. Expression of profibrotic cytokines such as transforming growth factor-beta1 was diminished in the absence of CCL11. Furthermore, increased lung expression of CCL11 significantly enhanced blm-induced lung fibrosis and production of profibrotic cytokines. These effects were also associated with an increase of eosinophil and neutrophil pulmonary infiltration. In contrast, mice treated with neutralizing CCR3 antibodies developed significantly reduced pulmonary fibrosis, eosinophilia, neutrophilia, and expression of profibrotic cytokines. Together, these data suggest that CCL11 and CCR3 are important in the pulmonary recruitment of granulocytes and play significant pathogenic roles in blm-induced lung fibrosis. 相似文献
102.
103.
N. M. Griffiths D. Chabardès M. Imbert-Teboul S. Siaume-Perez F. Morel N. L. Simmons 《Pflügers Archiv : European journal of physiology》1988,412(4):363-368
The effect of vasoactive intestinal peptide (VIP) upon adenylate cyclase (AC) activity has been determined in defined microdissected renal tubules isolated from collagenase-treated rabbit kidneys. In the presence of 10 M GTP, 1 M VIP gave marked stimulations of AC over basal values in the bright portion of the distal convoluted tubule (DCTb) (10.1-fold), and in the collecting tubule isolated from the inner stripe of the outer medulla (OMCTi, 7.8-fold). Less pronounced effects of VIP were found in the medullary collecting tubule isolated from the outer stripe (2.5-fold) and in the granular portion of the distal convoluted tubule (2.0-fold). VIP stimulation of AC activity in these segments amounted to 25 to 40% of the effect elicited by other agonists (arginine vasopressin, calcitonin or parathyroid hormone) in their respective target segments. A low response to VIP was observed in the cortical thick ascending limb (1.8-fold) which represented less than 5% of the calcitonin-stimulated AC activity. In the thin descending limb VIP produced a slight and variable stimulation of AC. VIP was without effect upon AC in the convoluted and straight portions of the proximal tubule, the medullary thick ascending limb and the cortical collecting tubule. Halfmaximal stimulation of AC by VIP was observed at 26±10 nM (n=3) in OMCTi and at 19 nM (n=2) in DCTb. Related peptides glucagon, secretin and PHI gave lower stimulations of AC compared to VIP in OMCTi. Conversely for rat OMCTi, under identical conditions, glucagon was much more effective than VIP. 相似文献
104.
Fine-needle aspiration cytology remains a useful tool for preoperative diagnosis of breast lesions. We describe a case of adenoid cystic carcinoma (ACC) of the breast detected by ultrasound-guided fine-needle aspiration (FNA). Subsequent histopathology corroborated the diagnosis. ACC is a rare but distinctive neoplasm of the breast that can be accurately diagnosed by FNA. Its infrequent presentation, favorable prognosis, and relatively conservative management in the breast prompt us to reinforce its features. 相似文献
105.
Bastien N Ward D Van Caeseele P Brandt K Lee SH McNabb G Klisko B Chan E Li Y 《Journal of clinical microbiology》2003,41(10):4642-4646
106.
R. O. Jacoby P. N. Bhatt Diane J. Gaertner Abigail L. Smith Elizabeth A. Johnson 《Archives of virology》1987,95(3-4):251-270
Summary The pathogenesis of rat virus (RV) infection was studied in random-bred Sprague-Dawley rats after oronasal inoculation of a recent RV isolate designated RV-Yale (RV-Y). RV-Y was pathogenic for rats inoculated as infants (2 days) whereas rats inoculated as juveniles (4 weeks) had asymptomatic infection and no lesions. Rats inoculated as infants developed pantropic infection accompanied by hepatic necrosis, granuloprival cerebellar hypoplasia and hemorrhagic encephalopathy. Virological and serological studies showed that virus could persist in inoculated rats for at least 35 days and for at least 28 days after seroconversion was first detected. Immuno-histochemical results indicated that RV-Y infects tissues conducive to virus excretion including kidney and lung. RV-Y also was found in genital tissues of some rats. Athymic juvenile rats inoculated intraperitoneally with RV-Y had a poor humoral immune response and harbored infectious virus for at least 3 weeks, whereas infection in euthymic control rats was detected for 1 week. These studies indicate that RV-Y can persists in the presence of humoral immunity and suggest that transmission of infection could occur for a substantial period after seroconversion. They also suggest that immunodeficient rats have increased susceptibility to persistent infection. 相似文献
107.
Polymorphic membrane protein H has evolved in parallel with the three disease-causing groups of Chlamydia trachomatis
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Chlamydia trachomatis is a human pathogen causing trachoma, urogenital disease, and lymphogranuloma venereum (LGV). A family of nine polymorphic membrane protein genes (pmpA to pmpI), resembling autotransporter proteins, has recently been discovered in C. trachomatis. pmp genes are large and predicted to be outer membrane proteins. We hypothesized that they would contain useful nucleotide sequence variability for epidemiologic studies. Since sequence information is available only for serovars D and L2, we sought to determine the amount of diversity within an individual pmp gene among serovars. We used restriction fragment length polymorphism (RFLP) analysis as a primary screen to assess the amount of sequence divergence among the pmp genes for serovars A to L3 of C. trachomatis. RFLP analysis showed little variation for some of the genes, such as pmpA, but substantial variation in others, such as pmpI. pmpH and pmpE yielded RFLP patterns that clustered the 15 serovars into ocular, urogenital, and LGV groups, and both proteins have been localized to the outer membrane. Therefore, we chose to sequence pmpE, pmpH, and pmpI from each of the 15 serovars. Evolutionary analysis showed three distinct divergence patterns. PmpI was least variable, resulting in an ambiguous evolutionary pattern. PmpE showed a high degree of diversity in the ocular strains compared to the other strains. Finally, the evolution of PmpH shows three groups that reflect disease groups, suggesting this protein may play a role in pathogenesis. 相似文献
108.
Coulter P Lema C Flayhart D Linhardt AS Aucott JN Auwaerter PG Dumler JS 《Journal of clinical microbiology》2005,43(10):5080-5084
Lyme disease is usually diagnosed and treated based on clinical manifestations. However, laboratory testing is useful for patients with confusing presentations and for validation of disease in clinical studies. Although cultivation of Borrelia burgdorferi is definitive, prior investigations have shown that no single test is optimal for Lyme disease diagnosis. We applied high-volume blood culture, skin biopsy culture, PCR, and serodiagnosis to a cohort of patients with suspected Lyme disease acquired in Maryland and southern Pennsylvania. The study was performed to confirm the relative utility of culture and to identify laboratory testing algorithms that will supplement clinical diagnosis. Overall, 30 of 86 patients (35%) were culture positive, whereas an additional 15 of 84 (18%) were seropositive only (51% total sero- and culture positive), and PCR on skin biopsy identified 4 additional patients who were neither culture nor seropositive. Among 49 laboratory test-positive patients, the highest sensitivity (100%) for diagnosis was obtained when culture, skin PCR, and serologic tests were used, although serologic testing with skin PCR was almost as sensitive (92%). Plasma PCR was infrequently positive and provided no additional diagnostic value. Although culture is definitive and has a relatively high sensitivity, the results required a mean of 3.5 weeks to recovery. The combination of acute-phase serology and skin PCR was 75% sensitive, offering a practical and relatively rapid alternative for confirming clinical impression. The full battery of tests could be useful for patients with confusing clinical signs or for providing strong laboratory support for clinical studies of Lyme disease. 相似文献
109.
McLennan NF Brennan PM McNeill A Davies I Fotheringham A Rennison KA Ritchie D Brannan F Head MW Ironside JW Williams A Bell JE 《The American journal of pathology》2004,165(1):227-235
The function of the normal conformational isoform of prion protein, PrP(C), remains unclear although lines of research have suggested a role in the cellular response to oxidative stress. Here we investigate the expression of PrP(C) in hypoxic brain tissues to examine whether PrP(C) is in part regulated by neuronal stress. Cases of adult cerebral ischemia and perinatal hypoxic-ischemic injury in humans were compared with control tissues. PrP(C) immunoreactivity accumulates within neuronal processes in the penumbra of hypoxic damage in adult brain, and within neuronal soma in cases of perinatal hypoxic-ischemic injury, and in situ hybridization analysis suggests an up-regulation of PrP mRNA during hypoxia. Rodents also showed an accumulation of PrP(C) in neuronal soma within the penumbra of ischemic lesions. Furthermore, the infarct size in PrP-null mice was significantly greater than in the wild type, supporting the proposed role for PrP(C) in the neuroprotective adaptive cellular response to hypoxic injury. 相似文献
110.
Jamet D Marzin Y Douet-Guilbert N Morel F Le Bris MJ Herry A Banzakour S Bourquard P Morice P Abgrall JF Berthou C De Braekeleer M 《Cancer Genetics and Cytogenetics》2005,161(2):159-163
Jumping translocations (JT) have been defined as nonreciprocal translocations involving a same donor chromosome arm or chromosome segment onto two or more recipient chromosomes in different cell lines in the same patient, leading to a mosaic karyotype. This definition has been expanded to also include extra copies of a same donor segment on different recipient chromosomes in a single clone. Six patients with multiple myeloma and JT involving chromosome arm 1q were identified among 37 patients presenting with chromosome 1 abnormalities. All six patients had an advanced disease and a short survival. The literature review allowed us to identify 24 additional patients with JT. Chromosomes 16 and 19 were the recipients in 11 (45.8%) and 6 (25%) of these 24 patients, respectively. Breakpoints on the recipient chromosomes were pericentromeric in 46.2% and telomeric in 40.4% of the breakpoints recorded. Since telomeres are made of (TTAGGG)n tandem DNA repeats that are also found in the pericentromeric heterochromatic regions (interstital telomeric sequences), it is presumed that jumping translocations arise through illegimate recombination between telomere repeat sequences and interstitial telomeric sequences. 相似文献