全文获取类型
收费全文 | 5965篇 |
免费 | 318篇 |
国内免费 | 41篇 |
专业分类
耳鼻咽喉 | 72篇 |
儿科学 | 151篇 |
妇产科学 | 147篇 |
基础医学 | 748篇 |
口腔科学 | 126篇 |
临床医学 | 403篇 |
内科学 | 1676篇 |
皮肤病学 | 130篇 |
神经病学 | 547篇 |
特种医学 | 127篇 |
外国民族医学 | 1篇 |
外科学 | 524篇 |
综合类 | 27篇 |
预防医学 | 467篇 |
眼科学 | 140篇 |
药学 | 459篇 |
中国医学 | 38篇 |
肿瘤学 | 541篇 |
出版年
2023年 | 45篇 |
2022年 | 101篇 |
2021年 | 174篇 |
2020年 | 116篇 |
2019年 | 147篇 |
2018年 | 195篇 |
2017年 | 112篇 |
2016年 | 122篇 |
2015年 | 159篇 |
2014年 | 200篇 |
2013年 | 252篇 |
2012年 | 450篇 |
2011年 | 436篇 |
2010年 | 239篇 |
2009年 | 232篇 |
2008年 | 415篇 |
2007年 | 391篇 |
2006年 | 379篇 |
2005年 | 335篇 |
2004年 | 318篇 |
2003年 | 271篇 |
2002年 | 290篇 |
2001年 | 95篇 |
2000年 | 77篇 |
1999年 | 90篇 |
1998年 | 48篇 |
1997年 | 47篇 |
1996年 | 50篇 |
1995年 | 40篇 |
1994年 | 35篇 |
1993年 | 29篇 |
1992年 | 45篇 |
1991年 | 33篇 |
1990年 | 40篇 |
1989年 | 33篇 |
1988年 | 31篇 |
1987年 | 24篇 |
1986年 | 19篇 |
1985年 | 30篇 |
1984年 | 20篇 |
1983年 | 14篇 |
1982年 | 7篇 |
1981年 | 11篇 |
1980年 | 11篇 |
1979年 | 13篇 |
1978年 | 11篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1974年 | 11篇 |
1966年 | 8篇 |
排序方式: 共有6324条查询结果,搜索用时 15 毫秒
41.
Central precocious puberty and abnormal chromosomal patterns 总被引:1,自引:0,他引:1
Central precocious puberty (PP) can be caused by chromosomal aberrations. We report three patients presenting with central
PP in whom karyotype analysis demonstrated abnormal chromosomal patterns. The first patient was affected by the triple-X syndrome,
commonly characterized by premature ovarian failure. The second patient, a girl with inv dup(15)(pter→q12::q12→pter), had
a chromosomal aberration involving an imprinted region of the human genome, whose deletion is commonly associated with Prader-Willi
syndrome (PWS) and hypogonadotrophic hypogonadism. The third patient was a boy carrying a rare chromosome abnormality, the
duplication of chromosome 9 (q22→qter). All patients had mental retardation, which was mild in patient 1, moderate in patient
2, and severe in case 3. They underwent treatment with luteinizing hormone releasing hormone (LHRH) analogs, which were able
to stop the progression of the sexual development. We confirm that chromosomal aberrations are an important cause of central
PP, and that karyotype analysis in patients with PP and mental retardation, even if mild, is necessary because chromosomal
abnormalities can be present. 相似文献
42.
Luis Gandía Baldomero Lara Julita S. Imperial Mercedes Villarroya Almudena Albillos Rosario Maroto A. G. García Baldomero M. Olivera 《Pflügers Archiv : European journal of physiology》1997,435(1):55-64
The characteristics of the binding sites for the Conus magus toxins ω-conotoxin MVIIC and ω-conotoxin MVIID, as well as their effects on K+-evoked 45Ca2+ entry and whole-cell Ba2+ currents (I
Ba), and K+-evoked catecholamine secretion have been studied in bovine adrenal chromaffin cells. Binding of [125I] ω-conotoxin GVIA to bovine adrenal medullary membranes was displaced by ω-conotoxins GVIA, MVIIC and MVIID with IC50 values of around 0.1, 4 and 100 nM, respectively. The reverse was true for the binding of [125I] ω-conotoxin MVIIC, which was displaced by ω-conotoxins MVIIC, MVIID and GVIA with IC50 values of around 30, 80 and 1.200 nM, respectively. The sites recognized by ω-conotoxins MVIIC and MVIID in bovine brain
exhibited higher affinities (IC50 values of around 1 nM). Both ω-conotoxin MVIIC and MVIID blocked I
Ba by 70–80%; the higher the [Ba2+]o of the extracellular solution the lower the blockade induced by ω-conotoxin MVIIC. This was not the case for ω-conotoxin
MVIID; high Ba2+ (10 mM) slowed down the development of blockade but the maximum blockade achieved was similar to that obtained in 2 mM Ba2+. A further difference between the two toxins concerns their reversibility; washout of ω-conotoxin MVIIC did not reverse the
blockade of I
Ba while in the case of ω-conotoxin MVIID a partial, quick recovery of current was produced. This component was irreversibly
blocked by ω-conotoxin GVIA, suggesting that it is associated with N-type Ca2+ channels. Blockade of K+-evoked 45Ca2+ entry produced results which paralleled those obtained by measuring I
Ba. Thus, 1 μM of each of ω-conotoxin GVIA and MVIIA inhibited Ca2+ uptake by 25%, while 1 μM of each of ω-conotoxin MVIIC and MVIID caused a 70% blockade. K+-evoked catecholamine secretory responses were not reduced by ω-conotoxin GVIA (1 μM). In contrast, at 1 μM both ω-conotoxin
MVIIC and MVIID reduced the exocytotic response by 70%. These data strengthen the previously established conclusion that Q-type
Ca2+ channels that contribute to the regulation of secretion and are sensitive to ω-conotoxins MVIIC and MVIID are present in
bovine chromaffin cells. These channels, however, seem to possess binding sites for ω-conotoxins MVIIC and MVIID whose characteristics
differ considerably from those described to occur in the brain; they might represent a subset of Q-type Ca2+ channels or an entirely new subtype of voltage-dependent high-threshold Ca2+ channel.
Received: 16 April 1997 / Received after revision: 10 July 1997 / Accepted: 23 July 1997 相似文献
43.
Grosso S Vivarelli R Muraca MC Berardi R Marconcini S Morgese G Balestri P 《American journal of medical genetics. Part A》2004,(3):300-302
Craniofacial dyssynostosis (CFD) is a rare disorder related to premature closure of the lambdoid suture and the posterior part of the sagittal suture. Epilepsy, mental retardation, abnormalities of the corpus callosum, and short stature have been reported. We studied a patient with CFD, hydronephrosis, and partially empty sella turcica; the latter two features are reported for the first time. We discuss the brain anomalies and their neurologic sequelae, which are part of the CFD phenotype. 相似文献
44.
Budipitojo T Sasaki M Matsuzaki S Cruzana MB Iwanaga T Kitamura N Yamada J 《Archives of histology and cytology》2003,66(4):337-346
Gastrin-releasing peptide (GRP) has been proposed as a novel regulatory peptide in the reproductive tract. We previously demonstrated that GRP immunoreactivities are found predominantly in the uterine gland epithelial cells of nonpregnant and pregnant cows. The present study focused on the distribution of GRP immunoreactivity and the expression of GRP mRNA in the bovine endometrium during the estrous cycle. Tissues were collected from 21 uterine horns and bodies during the estrous cycle. RT-PCR showed the expected GRP mRNA fragments (284 bp) in the tissues from all stages of the cycle. In situ hybridization results ascertained the expression of the GRP mRNA in the uterine gland epithelial cells and superficial epithelial cells of the endometrium. Positive staining of GRP immunoreactivity in the uterine gland epithelial cells was detected in both the uterine horn and body from all stages of the cycle. In metestrus and diestrus stages, GRP was also detected in the superficial epithelial cells of horn, but not in the body. The degrees of GRP mRNA expression and intensities of GRP immunoreactivity in the endometrium increased from proestrus to diestrus stages. These findings suggest that GRP may be important both in the endometrial remodeling during the estrous cycle and in the implantation and development of blastocysts. 相似文献
45.
Bessler M Rosti V Peng Y Cattoretti G Notaro R Ohsako S Elkon KB Luzzatto L 《European journal of immunology》2002,32(9):2607-2616
Surface proteins tethered to the membrane through a glycosylphosphatidylinositol (GPI) anchor are deficient in the blood cells of patients with paroxysmal nocturnal hemoglobinuria (PNH) as result of a somatic mutation, in a hematopoietic stem cell, of the X-linked phosphatidylinositolglycan complementation group A (PIG-A) gene. In PNH patients, compared to the large numbers of GPI-deficient myeloid cells, the proportion of GPI-deficient lymphocytes tends to be low, and therefore the impact of GPI deficiency on immune function has been unclear. We have obtained complementation by Pig-a(-) embryonic stem (ES) cells of Rag(-/-) blastocysts, and we show that Pig-a(-) ES cells are able to reconstitute the T cell and B cell compartments of Rag(-/-) mice. Although these mice were immunologically competent, by comparison with appropriate controls we detected several abnormalities: (1) increased levels of IgG; (2) high frequency/titers of anti-nuclear antibodies; (3) markedly reduced delayed hypersensitivity; and (4) impaired activation-induced lymphocyte death in vitro. In some cases, aging Pig-a(-)/Rag(-/-) chimeric mice developed lymphadenopathy and polyclonal T cell and B cell expansion. Thus, GPI-linked proteins are not required for lymphocyte development but they are required for normal lymphocyte function and for maintaining normal peripheral lymphoid homeostasis. 相似文献
46.
Ernesto Falcidia Agata Grillo Piero Pavone Nunzio Cutuli Haruo Takabayashi Rosario R. Trifiletti Conrad T. Gilliam 《American journal of medical genetics. Part A》2001,101(3):262-267
The isolation and analysis of nucleated fetal cells (NFCs) from maternal blood may represent a new approach to noninvasive prenatal diagnosis. Although promising, these techniques require highly accurate separation of NFCs from nucleated cells of maternal origin; the two major problems limiting these techniques are the relative rarity of fetal cells in maternal blood and the need to establish their fetal origin. We now report a novel procedure that has allowed accurate separation of NFCs from maternal cells. The technique reported involves direct micromanipulator isolation of histochemically identified hemoglobin F‐positive nucleated cells to obtain fetal nucleated red blood cells (FNRBCs) of high yield and purity. Using this technique, followed by cell‐by‐cell multicolor fluorescence in situ hybridization (FISH) analysis of purified FNRBCs, we were able to detect some of the most common human aneuploidies (including Down syndrome, Klinefelter syndrome, and trisomy 13) in 33 pregnant women referred for amniocentesis. The procedure used, which can be completed in <72 hrs, produced complete concordance with the results of amniocentesis. We also confirm findings of prior studies suggesting that the number of FNRBCs in maternal circulation is remarkably higher in abnormal pregnancies than in normal pregnancies, especially in women carrying a fetus with trisomy 21. © 2001 Wiley‐Liss, Inc. 相似文献
47.
Giuseppe Giuffrè Rosario Alberto Caruso Gaetano Barresi G. Tuccari 《Virchows Archiv : an international journal of pathology》1998,432(3):261-266
To assess the prognostic significance of silver-stained nucleolar organizer region (AgNOR) proteins, a standardized AgNOR
analysis was performed on 78 patients affected by early (EGC, n=24) or advanced (AGC, n=54) gastric carcinomas. The histopathological diagnosis, grading and staging were done according to WHO and UICC recommendations;
the mean follow-up time was 56.9 months. Visualization and quantification of AgNORs were made in formalin-fixed, paraffin-embedded
sections as specified in the guidelines of the Committee on AgNOR Quantification (1995). Statistical analysis was performed
on the mean AgNOR area values (NORA). Highly significant differences (P<0.001) were found in NORA values between EGC and AGC, between low- and high-grade gastric carcinomas and between patients
dead from gastric cancer and living patients. In addition, significant P values were found on comparison of NORA values relating to pT status, pN status and stage. Comparison of Kaplan-Meier survival
curves revealed that patients affected by gastric carcinomas with higher NORA values (>5.213 μm2) had a worse prognosis. Finally, using Cox multiple regression analysis, the AgNOR quantity emerged as a useful independent
prognostic variable to predict the final outcome of patients affected by EGC or AGC.
Received: 26 September 1997 / Accepted: 26 January 1998 相似文献
48.
Begoa Pea Marcelo Aroca Ernesto Prez Antonio Bello Evaristo Riande Rosario Benavente 《Macromolecular chemistry and physics.》1997,198(5):1691-1699
The characteristic ratios of three samples of poly(1-hexadecene) with different tacticities were evaluated from intrinsic viscosity and molecular weight data obtained with a size exclusion chromatograph with dual (concentration plus viscosity) detector. No significant differences were found for the characteristic ratio in the studied range of tacticities. Theoretical calculations for the unperturbed dimensions were also performed for these samples by using the rotational isomeric state model, and compared with the experimental results. 相似文献
49.
We report the first case of acquired immunodeficiency syndrome (AIDS)-related primary hepatic leiomyosarcoma in a 9-year-old girl. The pathologic diagnosis was made on a partial hepatectomy specimen and was confirmed by immunohistochemistry and electron microscopy. No human immunodeficiency virus-related nucleic acid was identified in tumor cells by in situ hybridization. Review of the AIDS-related literature reveals a rising incidence of tumors of smooth muscle origin in human immunodeficiency virus-infected patients. This case study details the eighth pediatric AIDS patient with a tumor of smooth muscle origin and represents the 20th and the youngest patient with primary hepatic leiomyosarcoma to be reported in the world literature. 相似文献
50.
Itziar Benito-Sánchez Melissa M. Ertl Rosario Ferrer-Cascales Javier Oltra-Cucarella Joaquín A. Ibáñez-Alfonso Mahia Saracostti Schwartzman 《Developmental neuropsychology》2020,45(4):189-199
ABSTRACT To determine the prevalence of low scores on two neuropsychological tests commonly used to evaluate learning and memory in children. 6,030 healthy children from 10 countries in Latin America and Spain were administered Rey–Osterrieth Complex Figure (ROCF) and the Test de Aprendizaje y Memoria Verbal–Infantil (TAMV-I). Results showed that low scores are common when multiple neuropsychological outcomes (tests and/or scores) are evaluated in healthy individuals. Clinicians should consider the higher probability of low scores in a given individual when evaluating learning and memory using various sets of scores to reduce false-positive diagnoses of cognitive deficits in pediatric populations. 相似文献