全文获取类型
收费全文 | 121600篇 |
免费 | 9682篇 |
国内免费 | 3054篇 |
专业分类
耳鼻咽喉 | 1247篇 |
儿科学 | 7194篇 |
妇产科学 | 3802篇 |
基础医学 | 13708篇 |
口腔科学 | 1571篇 |
临床医学 | 13155篇 |
内科学 | 20741篇 |
皮肤病学 | 2365篇 |
神经病学 | 10691篇 |
特种医学 | 2816篇 |
外国民族医学 | 3篇 |
外科学 | 11412篇 |
综合类 | 17355篇 |
现状与发展 | 15篇 |
预防医学 | 6840篇 |
眼科学 | 2190篇 |
药学 | 6150篇 |
52篇 | |
中国医学 | 11244篇 |
肿瘤学 | 1785篇 |
出版年
2024年 | 231篇 |
2023年 | 2091篇 |
2022年 | 3377篇 |
2021年 | 5962篇 |
2020年 | 5427篇 |
2019年 | 4299篇 |
2018年 | 4341篇 |
2017年 | 4447篇 |
2016年 | 4564篇 |
2015年 | 4358篇 |
2014年 | 8515篇 |
2013年 | 8751篇 |
2012年 | 6892篇 |
2011年 | 8034篇 |
2010年 | 6224篇 |
2009年 | 6034篇 |
2008年 | 5852篇 |
2007年 | 5973篇 |
2006年 | 5400篇 |
2005年 | 4464篇 |
2004年 | 3803篇 |
2003年 | 3369篇 |
2002年 | 2319篇 |
2001年 | 2111篇 |
2000年 | 1824篇 |
1999年 | 1702篇 |
1998年 | 1402篇 |
1997年 | 1314篇 |
1996年 | 1261篇 |
1995年 | 1222篇 |
1994年 | 1039篇 |
1993年 | 927篇 |
1992年 | 845篇 |
1991年 | 652篇 |
1990年 | 597篇 |
1989年 | 505篇 |
1988年 | 505篇 |
1987年 | 457篇 |
1986年 | 401篇 |
1985年 | 515篇 |
1984年 | 432篇 |
1983年 | 266篇 |
1982年 | 346篇 |
1981年 | 319篇 |
1980年 | 257篇 |
1979年 | 209篇 |
1978年 | 131篇 |
1977年 | 101篇 |
1976年 | 88篇 |
1975年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
991.
主动脉弓畸形及其临床意义 总被引:5,自引:0,他引:5
目的研究主有及其临床意义。方法:在历时15年对320例主动脉弓的解剖中,发现4例主动脉弓畸形,并对此弓变形及其周围诸结构进行解剖和观察。结果:在4例主动脉弓畸形的病例,,2例为右食管后锁骨下动脉并存右非喉返神经,另2例为右主工存左食管后锁骨下一左背主动脉分离。食管后锁上动脉起始部形成憩中产生食管受压性咽下困难,左锁骨下动脉或左背主动脉经支汛管连接或发自左肺动脉,可形成先天性肺动脉一锁骨下动脉窃血症 相似文献
992.
Marta L. Tamayo Cesar Maldonado Silvia L. Plaza Gustavo M. Alvira Gustavo E. Tamayo Marta Zambrano Jaime L. Frias Jaime E. Bernal 《Clinical genetics》1996,50(3):126-132
We describe the neurological evaluation and MRI analysis of 30 patients, belonging to 16 families with Usher syndrome (US) type I and type II (US1 and US2). In addition to the classic visual and audiological abnormalities seen in these patients, we observed abnormal gait in 88.9% of US1 and in 66.7% of US2 patients and abnormal coordination in 33.4% of US1, and in 58.3% of US2. Borderline mental retardation, depression or bipolar affective disorder were observed in 16.7% of US1 and 33.3% of US2 patients. MRI analysis showed cerebellar abnormalities in 50% of US 1 and 75% of US2 patients, but no clear correlation was observed between structural abnormalities and clinical findings. A pattern for the MRI classification of US patients is suggested. 相似文献
993.
Zvi Borochowitz Lorenzo Pavone Galia Mazor Renata Rizzo Hanna Dar 《American journal of medical genetics. Part A》1992,43(4):678-685
Five unrelated patients (a male and 4 females) were affected with a previously undefined multiple congenital anomalies/mental retardation syndrome which has been designated the facio-cutaneous-skeletal (FCS) syndrome and which includes mental retardation with specific sociable, humorous behavior, characteristic facial appearance, excessive generalized skin, postnatal growth failure, and skeletal involvement. Consanguinity was noted in 2 patients, thus autosomal recessive inheritance is suggested. © 1992 Wiley-Liss, Inc. 相似文献
994.
Cushing's Syndrome Secondary to Olfactory Neuroblastoma 总被引:2,自引:0,他引:2
A case of olfactory neuroblastoma in a 36-year-old woman who presented with florid Cushing's syndrome is reported. A nasal polyp, which proved to be an olfactory neuroblastoma, was resected. The procedure was followed by complete remission from the endocrinologic abnormalities. Postoperatively, the patient was well for 5 years until recurrence of both Cushing's syndrome and the nasal polyp was noted. Following combined transnasal-transcranial resection of the tumor, which extended into the anterior cranial fossa, the patient again experienced complete remission of Cushing's syndrome. Immunohistochemistry showed the tumor to be positive for neuron-specific enolase, synaptophysin, chromogran-in, adrenocorticotropic hormone, (J-endorphin, and S-100 protein. Electron microscopy revealed neuritic processes containing microtubules and neurosecretory granules. This is the first reported case of Cushing's syndrome secondary to olfactory neuroblastoma. 相似文献
995.
Liliane Schanden Alina Ferster Franoise Mascart-Lemone Alain Crusiaux Catherine Grard Arnaud Marchant Myriam Lybin Thierry Velu Eric Sariban Michel Goldman 《European journal of immunology》1993,23(1):56-60
We characterized the defects of CD4+ cells in a 17-month-old girl suffering from combined immunodeficiency with hypereosinophilia (Omenn's syndrome). Because the vast majority of peripheral blood CD4+ cells expressed the CD45R0 isoform, we purified circulating CD4+ CD45R0+ cells from the patient and healthy individuals in order to compare their production of cytokines. The patient's CD4+ CD45R0+ cells spontaneously produced high levels of interleukin-5 (IL-5) in vitro (1600 pg/ml after 24 h of culture) and this was associated with the presence of IL-5 in serum (323 pg/ml). After stimulation with phorbol 12-myristate 13-acetate (PMA) and calcium ionophore A23187, they produced higher levels of IL-4 (306 vs. 55 ± 4 pg/ml) and IL-5 (2900 vs. 213 ± 72 pg/ml) and lower levels of IL-2 (17 vs. 63 ± 17 IU/ml) and interferon-γ (IFN-γ) (16 vs. 299 ± 70 IU/ml) than controls CD4+ CD45R0+ cells. This T helper type 2 (Th2) pattern was confirmed by the detection using reverse polymerase chain reaction of IL-4, IL-5 and IL-10 mRNA within peripheral blood mononuclear cells. During a therapeutic trial with human IFN-γ (40 μg/day) which ameliorated the clinical status of the patient, we observed a down-regulation of the in vivo expression of IL-5 and IL-10, a normalization of the eosinophil count and an improvement of the Tcell response to phytohemagglutinin. This observation indicates for the first time that Th2-like cells might be involved in certain forms of congenital immunodeficiency and that IFN-γ might down-regulate their activities in vivo. 相似文献
996.
Roberto T. Zori Brian A. Gray Angela Bent-Williams Daniel J. Driscoll Charles A. Williams Joleen L. Zackowski 《American journal of medical genetics. Part A》1993,46(4):379-383
We report on an infant with preaxial acrofacial dysostosis (Nager syndrome) who was diagnosed prenatally as having an apparently balanced X/autosome translocation [46,X,t(X;9)(p22.1;q32)mat] inherited from a previously diagnosed mosaic translocation carrier mother [46,XX/46,X,t(X;9)(p22.1;q32)]. Replication studies on amniocytes showed the normal X chromosome to be late replicating while the same studies repeated on the infant's lymphocytes showed the translocated X chromosome to be late replicating in most cells. Late replication studies of the mother's lymphocytes demonstrated that the normal X chromosome was late replicating in most cells. The presence of Nager syndrome in this infant may be the result of critical break-points and/or position effects on chromosome 9, inducing expression of a gene responsible for the syndrome. © 1993 Wiley-Liss, Inc. 相似文献
997.
Hvidtjørn D Grove J Schendel D Vaeth M Ernst E Nielsen L Thorsen P 《Human reproduction (Oxford, England)》2005,20(9):2550-2551
BACKGROUND: In a Danish population-based cohort study assessing the risk of cerebral palsy in children born after IVF, we made some interesting observations regarding 'vanishing co-embryos'. METHODS and RESULTS: All live-born children born in Denmark from 1 January 1995 to 31 December 2000 were included in this analysis. The children conceived by IVF/ICSI (9444) were identified through the IVF Register, the children conceived without IVF/ICSI (395 025) were identified through The Danish Medical Birth Register. Main outcome measure was the incidence of cerebral palsy. Within the IVF/ICSI children we found indications of an increased risk of cerebral palsy in those children resulting from pregnancies, where the number of embryos transferred was higher than the number of children born. CONCLUSIONS: The association between vanishing embryo syndrome and incidence of cerebral palsy following IVF requires further investigation in larger, adequately powered, studies. 相似文献
998.
Messinis IE 《Human reproduction (Oxford, England)》2005,20(10):2688-2697
Ovulation induction is the method for treating anovulatory infertility. For patients with hypogonadotrophic hypogonadism, the treatment involves administration of both FSH and LH, while HCG is injected for follicle rupture. Pulsatile GnRH has the same effectiveness as gonadotrophins and the advantage of the low multiple pregnancy rate. In polycystic ovary syndrome (PCOS), the first treatment choice is clomiphene citrate. With this drug, in properly selected patients, the cumulative pregnancy rate approaches that of normal women. Low-dose protocols of FSH are the second line of treatment, effective in inducing monofollicular development. Laparoscopic ovarian drilling can be an alternative but not as a first choice treatment in clomiphene-resistant patients. Other treatments, such as pulsatile GnRH and GnRH agonists, are hardly used today in PCOS. However, in obese women with PCOS, weight loss and exercise should be recommended as the first line of therapy. Newer agents including aromatase inhibitors and insulin sensitizers, although promising, need further evaluation. 相似文献
999.
The triple A or Allgrove syndrome is an autosomal-recessive disease (MIM*231550) characterized by the triad of achalasia, alacrima and adrenocorticotropic hormone (ACTH)-resistant adrenal insufficiency. Associated features of the syndrome are neurological and dermatological abnormalities. Until the discovery of the AAAS gene as the responsible gene in triple A syndrome, the diagnosis was based on characteristic clinical features. Here we present the clinical and molecular genetic data which demonstrated the marked phenotypic variability in three unrelated patients with triple A syndrome. The final diagnosis of triple A syndrome was confirmed by molecular analysis. In one patient with isolated achalasia, the diagnosis of triple A syndrome could only be made on the basis of the molecular genetic analysis of the AAAS gene. We therefore suggest that the diagnosis of triple A syndrome should be considered in patients who exhibit only one or two of the main symptoms (i.e. alacrima, achalasia or adrenal insufficiency). These patients require careful neurological investigation, and mutation analysis of the AAAS gene should be performed. 相似文献
1000.
目的:探讨了肾病综合征患者红细胞免疫功能与脂质过氧化的关系。方法:应用红细胞酵母花环法测定了31例肾病综合征患者的红细胞免疫功能和化学法测定血清丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)含量,并与35名正常健康人作比较。结果:肾病综合征患者RBC-ICR花环率和MDA水平明显升高(P〈0.01),而RBC-C3bR,SOD,GSH-PX水平则〈正常(P〈0.01),相关分析显示:RBC-C3b花环与MDA呈显著负相关(r=-0.4786,P〈0.01),RBC-ICR与MDA呈正相关(r=0.6702,P〈0.01)。结论:肾病综合征患者红细胞免疫黏附功能的降低与活性代谢紊乱密切相关。 相似文献