全文获取类型
收费全文 | 125425篇 |
免费 | 10168篇 |
国内免费 | 3240篇 |
专业分类
耳鼻咽喉 | 1286篇 |
儿科学 | 7221篇 |
妇产科学 | 3818篇 |
基础医学 | 14184篇 |
口腔科学 | 1713篇 |
临床医学 | 13691篇 |
内科学 | 21041篇 |
皮肤病学 | 2401篇 |
神经病学 | 11139篇 |
特种医学 | 2821篇 |
外国民族医学 | 5篇 |
外科学 | 11790篇 |
综合类 | 18083篇 |
现状与发展 | 17篇 |
一般理论 | 1篇 |
预防医学 | 7535篇 |
眼科学 | 2380篇 |
药学 | 6457篇 |
73篇 | |
中国医学 | 11289篇 |
肿瘤学 | 1888篇 |
出版年
2024年 | 309篇 |
2023年 | 2102篇 |
2022年 | 4240篇 |
2021年 | 6060篇 |
2020年 | 5548篇 |
2019年 | 4371篇 |
2018年 | 4433篇 |
2017年 | 4598篇 |
2016年 | 4683篇 |
2015年 | 4444篇 |
2014年 | 8606篇 |
2013年 | 9000篇 |
2012年 | 7078篇 |
2011年 | 8268篇 |
2010年 | 6373篇 |
2009年 | 6162篇 |
2008年 | 6002篇 |
2007年 | 6142篇 |
2006年 | 5555篇 |
2005年 | 4638篇 |
2004年 | 3969篇 |
2003年 | 3534篇 |
2002年 | 2469篇 |
2001年 | 2208篇 |
2000年 | 1923篇 |
1999年 | 1764篇 |
1998年 | 1454篇 |
1997年 | 1369篇 |
1996年 | 1307篇 |
1995年 | 1254篇 |
1994年 | 1061篇 |
1993年 | 959篇 |
1992年 | 856篇 |
1991年 | 671篇 |
1990年 | 628篇 |
1989年 | 507篇 |
1988年 | 514篇 |
1987年 | 464篇 |
1986年 | 411篇 |
1985年 | 525篇 |
1984年 | 437篇 |
1983年 | 282篇 |
1982年 | 354篇 |
1981年 | 322篇 |
1980年 | 260篇 |
1979年 | 212篇 |
1978年 | 133篇 |
1977年 | 104篇 |
1976年 | 86篇 |
1975年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
Sonia Ehrlich Tania Bustos Inder J. Paika Aubrey Milunsky John M. Opitz 《American journal of medical genetics. Part A》1983,15(2):261-263
Some variation in the phenotype of patients with dup(18q) is recognized. Our patient has the phenotype described for dup(18qter). 相似文献
972.
经颅磁刺激安全性的实验研究 总被引:4,自引:0,他引:4
目的 :探讨重复经颅磁刺激的安全性。方法 :选用 3 6只健康Wistar大鼠 ,随机分为对照组 ,低频刺激组和高频刺激组 ,对低频组和高频组分别给予不同频率和强度的经颅磁刺激 ,然后对各组大鼠的行为、组织病理形态学、血清髓鞘碱性蛋白 (MBP)及神经元特异性烯醇化酶 (NSE)含量进行观察。结果 :低频刺激组 (5Hz)和高频刺激组 (2 0Hz)在刺激过程中均未出现异常活动 ,无肢体强直、阵挛等 ,脑组织形态学包括大体观察、普通光镜及电镜改变不明显 ,其血清MBP和NSE含量与正常对照组比较 ,差异无显著性意义 (P >0 0 5 )。结论 :在一定强度和频率内经颅磁刺激是一种比较安全的方法 相似文献
973.
Theodore Kushnick Thomas G. Irons John E. Wiley Elizabeth A. Gettig Kathleen W. Rao Susan Bowyer John M. Opitz James F. Reynolds 《American journal of medical genetics. Part A》1987,28(3):567-574
Two white females, age 2 1/2 and 33 years, respectively, were investigated because of severe mental retardation associated with neurologic abnormalities, coarse face, and soft tissue syndactyly involving upper and lower limbs. Each had cytogenetic findings of a mosaic variant of Ullrich-Turner syndrome with X ring chromosome in peripheral lymphocyte and skin fibroblasts. Early X replication occurred in one-third of the X ring chromosomes; there was no evidence for X-autosome translocation involving either X and an autosomal duplication; results of studies for fragility of the X chromosomes were unremarkable. In situ hybridization with an X centromere probe was positive for the ring. To our knowledge, the unusual constellation of cytogenetic, physical, and mental findings seen in these 2 individuals has not been reported previously. 相似文献
974.
J.W. Coleman 《Immunology letters》1982,5(4):197-201
Two types of inhibition of basic peptide-induced rat mast cell secretion are reported. Pretreatment of rat peritoneal mast cells with Vibrio comma neuraminidase, an enzyme which cleaves sialic acid from oligosaccharides, led to inhibition of 5-hydroxytryptamine release induced by the basic peptides polylysine, corticotropin1–24 and a decapeptide sequence of human IgE. Inhibition was similarly observed when mast cells were challenged in the presence of the cationic cell membrane-active substance benzalkonium chloride. It is postulated that both of these experimental procedures inhibit basic peptide-induced secretion by depletion of cell surface negative charge. Sialic acid itself does not act as a specific receptor for basic peptides, since a molar excess of sialic acid in free solution failed to inhibit secretion by binding to basic peptides in the fluid phase. 相似文献
975.
对33例初诊骨髓增生异常综合征病人的骨髓涂片及骨髓活检进行分析,表明涂片在初诊筛选中能对MDS作出诊断,而骨髓活检对判断增生度,显示各系病态造血,提供预后信息及确诊MDS合并骨髓纤维化中意义重大,后者对前者起补充、修正的作用. 相似文献
976.
In this study, the relationship between physiological arousal, as indexed by heart rate variability, was examined in boys with fragile X syndrome (FXS) and typically developing boys matched on chronological age. In addition, the relationship of heart activity to clinical and molecular factors in the group of boys with FXS was examined. Results suggest that boys with FXS have higher levels of heart activity during the passive phases, as reflected in shorter heart periods. This high level of heart activity appears to be due to increased sympathetic activity and reduced parasympathetic activity. Boys with FXS did not display the expected patterns of heart activity in response to phases of increasing challenge, and sympathetic and parasympathetic systems did not appear coordinated in these boys with FXS. Clinical factors may be related to neural regulation of heart activity while molecular factors do not appear to be. 相似文献
977.
Life expectancy in British Marfan syndrome populations 总被引:2,自引:0,他引:2
JR Gray AB Bridges RR West L. McLeish AG Stuart JCS Dean MEM Porteous M. Boxer SJ Davies 《Clinical genetics》1998,54(2):124-128
A total of 206 patients with Marfan syndrome were ascertained throughout genetic clinics in Wales and Scotland during the period 1970–1990. There were 45 deaths representing 22% of the cohort. Mean age at death was 45.3 ± 16.5 years. 50% median cumulative survival in the total cohort (n = 206) was 53 years for males and 72 years for females. Multivariate analysis confirmed severity as the best independent indicator of survival. These findings and survival curves will assist in the counselling of British families and individuals with Marfan syndrome. 相似文献
978.
Ken Onodera Hironobu Sasano Ryo Ichinohasama Kiyoshi Ooya 《Pathology international》1998,48(10):786-790
The enzyme aromatase Is Involved In the conversion of androgens to estrogens and in the modulation of various androgenlc and estrogenlc actions. Abnormalities of estrogen metabolism have been postulated to play roles in the development and/or pathophyslology of Sjdgren's syndrome. In the present study, aromatase was immunolocal-ized In 75 cases of Inflammatory disorders of human minor salivary glands of the lower lip. These included cases of primary Sjögren's syndrome (19 cases), of chronic slaladenitis (34 cases) and of mucous extravasation cysts (22 cases), in order to clarify the possible involvement of in situ estrogen production in primary Sjögren's syndrome. Aromatase Immunoreactlvlty was detected In myoepithelial cells of acini and in interstitial cells adjacent to acini and ducts In 13/19 (68%) cases of primary Sjögren's syndrome. In contrast, aromatase expression was detected In only six of 34 (18%) cases of chronic sialadenttis and in seven of 22 (32%) cases of mucous extravasation cyst. These results suggest that Increased aromatase expression in minor salivary glands with primary Sjogren's syndrome in premenopausal women may be involved in the biological features of primary Sjogren's syndrome through the production of estrogens in situ and possibly through the aggravation of the inflammatory reaction. 相似文献
979.
Brice Poreau Francis Ramond Radu Harbuz Véronique Satre Claire Barro Claire Vettier Véronique Adouard Julien Thevenon Pierre‐Simon Jouk Charles Coutton Klaus Dieterich 《American journal of medical genetics. Part A》2019,179(4):650-654
The AMME syndrome defined as the combination of Alport syndrome, intellectual disability, midface hypoplasia, and elliptocytosis (AMME) is known to be a contiguous gene syndrome associated with microdeletions in the region Xq22.3q23. Recently, using exome sequencing, missense pathogenic variants in AMMECR1 have been associated with intellectual disability, midface hypoplasia, and elliptocytosis. In these cases, AMMECR1 gene appears to be responsible for most of the clinical features of the AMME syndrome except for Alport syndrome. In this article, we present two unrelated male patients with short stature, mild intellectual disability or neurodevelopmental delay, sensorineural hearing loss, and elliptocytosis harboring small microdeletions identified by array‐CGH involving TMEM164 and AMMECR1 genes and SNORD96B small nucleolar RNA for one patient, inherited from their mothers. These original cases further confirm that most specific AMME features are ascribed to AMMECR1 haploinsufficiency. These cases reporting the smallest microdeletions encompassing AMMECR1 gene provide new evidence for involvement of AMMECR1 in the AMME phenotype and permit to discuss a phenotype related to AMMECR1 haploinsufficiency: developmental delay/intellectual deficiency, midface hypoplasia, midline defect, deafness, and short stature. 相似文献
980.
Danielle K. Bourque Mireille Cloutier Kristin D. Kernohan Eric Bareke David Grynspan Jean Michaud CareRare Canada Consortium Kym M. Boycott 《American journal of medical genetics. Part A》2019,179(5):813-816
Neu–Laxova syndrome (NLS) is a lethal autosomal recessive microcephaly syndrome associated with intrauterine growth restriction (IUGR) and multiple congenital anomalies. Clinical features include central nervous system malformations, joint contractures, ichthyosis, edema, and dysmorphic facial features. Biallelic pathogenic variants in either the PHGDH or PSAT1 genes have been shown to cause NLS. Using exome sequencing, we aimed to identify the underlying genetic diagnosis in three fetuses (from one family) with prenatal skin edema, severe IUGR, micrognathia, renal anomalies, and arthrogryposis and identified a homozygous c.1A>C (p.Met1?, NM_006623.3) variant in the PHGDH gene. Loss of the translation start codon is a novel genetic mechanism for the development of NLS. Prenatal diagnosis of NLS is challenging and few reports describe the fetal pathology. Fetal neuropathologic examination revealed: delayed brain development, congenital agenesis of the corticospinal tracts, and hypoplasia of the hippocampus, cerebellum and brainstem. Each pregnancy also showed increased nuchal translucency (NT) or cystic hygroma. While NLS is rare, it may be a cause of recurrent increased NT/cystic hygroma. This finding provides further support that cystic hygroma has many different genetic causes and that exome sequencing may shed light on the underlying genetic diagnoses in this group of prenatal patients. 相似文献