全文获取类型
收费全文 | 14758篇 |
免费 | 938篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 96篇 |
儿科学 | 512篇 |
妇产科学 | 471篇 |
基础医学 | 1871篇 |
口腔科学 | 218篇 |
临床医学 | 2094篇 |
内科学 | 2652篇 |
皮肤病学 | 276篇 |
神经病学 | 1585篇 |
特种医学 | 301篇 |
外科学 | 1300篇 |
综合类 | 122篇 |
现状与发展 | 1篇 |
一般理论 | 16篇 |
预防医学 | 2027篇 |
眼科学 | 335篇 |
药学 | 948篇 |
中国医学 | 15篇 |
肿瘤学 | 907篇 |
出版年
2023年 | 93篇 |
2022年 | 154篇 |
2021年 | 348篇 |
2020年 | 199篇 |
2019年 | 363篇 |
2018年 | 417篇 |
2017年 | 273篇 |
2016年 | 318篇 |
2015年 | 388篇 |
2014年 | 516篇 |
2013年 | 791篇 |
2012年 | 1103篇 |
2011年 | 1170篇 |
2010年 | 641篇 |
2009年 | 521篇 |
2008年 | 1036篇 |
2007年 | 1045篇 |
2006年 | 1047篇 |
2005年 | 1018篇 |
2004年 | 953篇 |
2003年 | 907篇 |
2002年 | 863篇 |
2001年 | 97篇 |
2000年 | 70篇 |
1999年 | 101篇 |
1998年 | 142篇 |
1997年 | 134篇 |
1996年 | 124篇 |
1995年 | 121篇 |
1994年 | 68篇 |
1993年 | 91篇 |
1992年 | 59篇 |
1991年 | 54篇 |
1990年 | 46篇 |
1989年 | 40篇 |
1988年 | 47篇 |
1987年 | 31篇 |
1986年 | 31篇 |
1985年 | 31篇 |
1984年 | 45篇 |
1983年 | 38篇 |
1982年 | 45篇 |
1981年 | 44篇 |
1980年 | 33篇 |
1979年 | 13篇 |
1978年 | 18篇 |
1977年 | 9篇 |
1976年 | 8篇 |
1973年 | 6篇 |
1972年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
Conway F. Saylor PhD Cynthia Cupit Swenson Ph.D. Paige Powell Ph.D. 《Child psychiatry and human development》1992,22(3):139-149
This article reports highlights from over 200 parents' observations of their preschoolers' play and verbalizations in the year following Hurricane Hugo. Commonly reported activities included reenactment and discussion of the event in multiple mediums, personification of Hugo, and expression of fears related to storms. Precocious concern for others, insight, and vocabulary were also noted. In these intact, relatively high functioning families, parents seemed able to facilitate their youngsters' adjustment without outside intervention.Portions of this report were presented in earlier form at the 1991 Society for Research in Child Development meeting in Seattle, Washington. 相似文献
73.
Wijkstrom-Frei C El-Chemaly S Ali-Rachedi R Gerson C Cobas MA Forteza R Salathe M Conner GE 《American journal of respiratory cell and molecular biology》2003,29(2):206-212
The lactoperoxidase (LPO) antibiotic system is a well-characterized component of mammary and salivary gland secretions. Because LPO has been shown to function in ovine airways, human airway tissue and secretions were examined for the presence of LPO and its substrate, the anion thiocyanate (SCN-). In addition, human airway secretions were tested for LPO-mediated antibacterial activity, and LPO's activity was assessed against some human airway pathogens. The data showed that normal human airway secretions contained LPO enzyme activity (0.65 +/- 0.09 microg/mg secreted protein; n = 17), and Western blots of secretions demonstrated bands of the expected sizes for LPO. LPO mRNA was detected in trachea by sequencing PCR-amplified cDNA. SCN-, LPO's substrate, was present in undiluted airway secretions at concentrations sufficient for LPO catalysis (0.46 +/- 0.19 mM; n = 8), and diluted secretions contained antibacterial activity with LPO-like properties. Immunocytochemistry localized LPO to submucosal glands in human bronchi. Finally, as expected based on the known antibacterial spectrum of the LPO system, airway secretions showed LPO-dependent activity against Pseudomonas aeruginosa. In addition, the airway LPO system was shown to be effective against Burkholderia cepacia and Haemophilus influenzae. Thus, a functional LPO system exists in human airways and may contribute to airway host defense against infection. 相似文献
74.
Specific antibody responses to three schistosome-related carbohydrate structures in recently exposed immigrants and established residents in an area of Schistosoma mansoni endemicity
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)
Naus CW van Remoortere A Ouma JH Kimani G Dunne DW Kamerling JP Deelder AM Hokke CH 《Infection and immunity》2003,71(10):5676-5681
By the use of surface plasmon resonance spectroscopy, immunoglobulin G (IgG) subclass and IgM antibodies against three schistosome-derived carbohydrate structures, FLDN (Fucalpha1-3GalNAcbeta1-4GlcNAcbeta1-3Galalpha1), LDN-DF [GalNAcbeta1-4(Fucalpha1-2Fucalpha1-3)GlcNAcbeta1], and LDNF [GalNAcbeta1-4(Fucalpha1-3)GlcNAcbeta1-3Galalpha1], were measured in 184 previously unexposed Kenyan immigrants who moved into the Masongaleni area, where Schistosoma mansoni is endemic. They were sampled within their first year of exposure and again 2 years later. A cohort selected out of the original residents of the area, who had been exposed for many years, served as controls. Associations with responses to S. mansoni worm, egg (SEA), and cercarial (CERC) antigens were examined. In addition, we measured responses to keyhole limpet hemocyanin, a glycoprotein which carries glycan epitopes that are also expressed by schistosomes. Specific IgG1 responses were most pronounced against FLDN and LDN-DF and strongly associated with those previously measured to SEA and CERC. Similarly to previously published age profiles of IgG1 and IgG2 responses to SEA, levels of IgG1 against LDN-DF decreased with age. In contrast, specific IgM responses against the three schistosome-derived carbohydrate structures were most marked against LDNF. Our results indicate that, of the three glycan structures tested, the acute response against schistosome glycoconjugate antigens in young children is mainly directed against the LDN-DF epitope. The response to LDN-DF in older individuals and the responses to the two other epitopes were similar in the two cohorts, suggesting that these antigens are recognized in the early stages of infection and that the immune response persists. The biological significance of these observations needs further elucidation. 相似文献
75.
Gerhardt CA Vannatta K McKellop JM Taylor J Passo M Reiter-Purtill J Zeller M Noll RB 《Journal of pediatric psychology》2003,28(4):275-279
OBJECTIVE: To evaluate predictions from professionals in pediatric rheumatology regarding the child-rearing practices of caregivers of children with juvenile rheumatoid arthritis (JRA) and healthy classmates. METHODS: Sixteen professionals identified items from the Child-Rearing Practices Report (CRPR) that were expected to differentiate between caregivers of children with JRA (64 mothers, 45 fathers) and caregivers of healthy classmates (64 mothers, 40 fathers). Families were interviewed, and physician ratings of disease severity were obtained. RESULTS: Experts predicted difficulties in protectiveness, discipline, and worry. Ratings from parents of children with JRA showed modest agreement with the professionals, surprising similarity to controls, and a limited association with disease factors. CONCLUSIONS: Contrary to expert opinion, JRA has only a modest influence on some child-rearing practices. Educating health care providers may minimize misperceptions about caring for children with JRA, and screening parents of children with more severe disease may assist in allocating education and services for families. 相似文献
76.
The Complete Set of Predicted Genes from Saccharomyces cerevisiae in a Readily Usable Form
下载免费PDF全文
![点击此处可从《Genome research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
James R. Hudson Jr. Elliott P. Dawson Kimberly L. Rushing Cynthia H. Jackson Daniel Lockshon Diana Conover Christian Lanciault James R. Harris Steven J. Simmons Rodney Rothstein Stanley Fields 《Genome research》1997,7(12):1169-1173
Nearly all of the open reading frames (ORFs) of the yeast Saccharomyces cerevisiae have been synthesized by PCR using a set of ~6000 primer pairs. Each of the forward primers has a common 22-base sequence at its 5′ end, and each of the back primers has a common 20-base sequence at its 5′ end. These common termini allow reamplification of the entire set of original PCR products using a single pair of longer primers—in our case, 70 bases. The resulting 70-base elements that flank each ORF can be used for rapid and efficient cloning into a linearized yeast vector that contains these same elements at its termini. This cloning by genetic recombination obviates the need for ligations or bacterial manipulations and should permit convenient global approaches to gene function that require the assay of each putative yeast gene. 相似文献
77.
McNeilly MD Robinson EL Anderson NB Pieper CF Shah A Toth PS Martin P Jackson D Saulter TD White C Kuchibatla M Collado SM Gerin W 《International journal of behavioral medicine》1995,2(4):321-338
It has been speculated that exposure to the chronic stress of racism contributes to the high rates of hypertension among African Americans. Social support may buffer the effects of stress on cardiovascular (CV) health by attenuating stress-induced CV responses that have been linked to hypertension. In this study we investigated the effects of racism and social support on CV reactivity in African American women. Participants showed greater increases in CV and emotional responses while responding and listening to racist provocation. Augmented blood pressure (BP) persisted through recovery following racial stress. Participants receiving no support showed the greatest increases in anger during racist provocation. No significant effects were seen for support on CV reactivity. These results provide some of the first evidence that interactive confrontation with racism elicits significant increases in CV reactivity and emotional distress. Furthermore, individuals receiving less support may be at greater risk for the potentially health-damaging effects of racial stress. These findings may have significant implications for the health of African Americans. 相似文献
78.
Elliott AM Graham JM Curry CJ Pal T Rimoin DL Lachman RS 《American journal of medical genetics》2002,113(4):351-361
Dolichospondylic dysplasia (DD) is a rare skeletal dysplasia primarily characterized by tall vertebral bodies and disproportionate short stature. Radiographic manifestations include tall vertebral bodies and gracile bones of the hands. Patients usually have eye and ear findings in addition to borderline mental retardation; however, tall vertebral bodies and slender tubular bones are also seen in the 3-M syndrome. Patients with the 3-M syndrome have a characteristic face with a triangular shape, frontal bossing, a flattened malar region, full eyebrows, a short nose with a bulbous tip, upturned nares, and full lips. We present two unrelated patients who share a distinct phenotype and have tall vertebral bodies, overtubulation of long bones, and short tubular bones of the hands and feet. We discuss the overlapping and distinguishing features between DD and the 3-M syndrome. Patient 1 was a 13-year-old female, and patient 2 was an unrelated adult female. These patients had normocephaly and short stature. They shared a common phenotype consisting of mild malar hypoplasia, a narrowed nasal body with a fleshy tip, full lips, and normal intelligence. In addition, they showed mild hand and foot abnormalities. These two patients lack many of the typical clinical features of both DD and the 3-M syndrome. They share a common phenotype and likely represent a distinct disorder. The spectrum of disorders with tall vertebral bodies as a key feature may include different entities that may be further defined with the characterization of the molecular defect(s). 相似文献
79.
Shieh WJ Hsiao CH Paddock CD Guarner J Goldsmith CS Tatti K Packard M Mueller L Wu MZ Rollin P Su IJ Zaki SR 《Human pathology》2005,36(3):303-309
This article describes the pathological studies of fatal severe acute respiratory syndrome (SARS) in a 73-year-old man during an outbreak of SARS in Taiwan, 2003. Eight days before onset of symptoms, he visited a municipal hospital that was later identified as the epicenter of a large outbreak of SARS. On admission to National Taiwan University Hospital in Taipei, the patient experienced chest tightness, progressive dyspnea, and low-grade fever. His condition rapidly deteriorated with increasing respiratory difficulty, and he died 7 days after admission. The most prominent histopathologic finding was diffuse alveolar damage of the lung. Immunohistochemical and in situ hybridization assays demonstrated evidence of SARS-associated coronavirus (SARS-CoV) infection in various respiratory epithelial cells, predominantly type II pneumocytes, and in alveolar macrophages in the lung. Electron microscopic examination also revealed coronavirus particles in the pneumocytes, and their identity was confirmed as SARS-CoV by immunogold labeling electron microscopy. This report is the first to describe the cellular localization of SARS-CoV in human lung tissue by using a combination of immunohistochemistry, double-stain immunohistochemistry, in situ hybridization, electron microscopy, and immunogold labeling electron microscopy. These techniques represent valuable laboratory diagnostic modalities and provide insights into the pathogenesis of this emerging infection. 相似文献
80.