全文获取类型
收费全文 | 49204篇 |
免费 | 2492篇 |
国内免费 | 1139篇 |
专业分类
耳鼻咽喉 | 269篇 |
儿科学 | 1402篇 |
妇产科学 | 227篇 |
基础医学 | 2465篇 |
口腔科学 | 93篇 |
临床医学 | 7535篇 |
内科学 | 9283篇 |
皮肤病学 | 263篇 |
神经病学 | 2258篇 |
特种医学 | 1453篇 |
外科学 | 4548篇 |
综合类 | 9887篇 |
预防医学 | 3313篇 |
眼科学 | 238篇 |
药学 | 5862篇 |
48篇 | |
中国医学 | 2213篇 |
肿瘤学 | 1478篇 |
出版年
2024年 | 68篇 |
2023年 | 597篇 |
2022年 | 1505篇 |
2021年 | 1988篇 |
2020年 | 1747篇 |
2019年 | 1352篇 |
2018年 | 1424篇 |
2017年 | 1554篇 |
2016年 | 1810篇 |
2015年 | 1724篇 |
2014年 | 4228篇 |
2013年 | 4013篇 |
2012年 | 3582篇 |
2011年 | 3668篇 |
2010年 | 2872篇 |
2009年 | 2489篇 |
2008年 | 2389篇 |
2007年 | 2425篇 |
2006年 | 2147篇 |
2005年 | 1771篇 |
2004年 | 1398篇 |
2003年 | 1148篇 |
2002年 | 872篇 |
2001年 | 821篇 |
2000年 | 687篇 |
1999年 | 590篇 |
1998年 | 472篇 |
1997年 | 446篇 |
1996年 | 376篇 |
1995年 | 323篇 |
1994年 | 316篇 |
1993年 | 222篇 |
1992年 | 198篇 |
1991年 | 196篇 |
1990年 | 183篇 |
1989年 | 148篇 |
1988年 | 138篇 |
1987年 | 96篇 |
1986年 | 90篇 |
1985年 | 124篇 |
1984年 | 108篇 |
1983年 | 53篇 |
1982年 | 80篇 |
1981年 | 69篇 |
1980年 | 62篇 |
1979年 | 51篇 |
1978年 | 43篇 |
1977年 | 36篇 |
1976年 | 28篇 |
1975年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Eran Maman David M. Steinberg Batia Stark Shai Izraeli Shlomo Wientroub 《Journal of children's orthopaedics》2007,1(1):63-68
Purpose Studies on musculoskeletal manifestations (MSM) of childhood acute lymphoblastic leukemia (ALL) have yielded variable findings
with regard to their clinical impact. We investigated the significance for differential diagnosis, treatment and outcome of
musculoskeletal complaints as presenting symptoms of ALL, and their correlation with leukemia immunophenotypes, for which
data is lacking.
Methods Data on 783 children in the national study for childhood ALL between 1984 and 2003 were reviewed retrospectively. Statistical
analysis examined possible relationships between MSM at the time of diagnosis and demographic and clinical data, biological
features of leukemia (peripheral blood counts, immunophenotype and main cytogenetic aberration), response to initial prednisone
treatment, and outcome.
Results Of 765 children with data on orthopaedic complaints, 240 presented with MSM (31.4%). Among these children, B cell precursor
(BCP) was much more common (209/576, 36.3%) than T cell ALL (25/176, 14.2%). Patients with MSM had lower white blood cell
counts (WBC) (median of 9 vs. 20 × 109/L, P < 0.001) and percentage of blast cells in the peripheral blood at diagnosis compared to those without (median of 27 vs. 53%,
P < 0.001). Hepatomegaly and splenomegaly were less common in MSM group (67 vs. 53% <3 cm, P < 0.001, and 63 vs. 50% <3 cm, P < 0.001, respectively). Poor response to initial treatment with prednisone was recorded in 7.1% of patients with MSM versus
11.5% of those without (P = 0.086). The analysis revealed no independent effect of MSM on event-free survival (EFS), after correcting for differences
in EFS related to immunophenotype or initial WBC.
Conclusions MSM occur mostly in children with BCP ALL who present with less involvement of extramedullary organs, low peripheral blood
blasts and white blood cells counts. These findings highlight the importance of including ALL in the differential diagnosis
of MSM even in the presence of an apparently normal peripheral blood count. Our study also suggests that MSM are caused by
leukemic cells with enhanced biological propensity to remain relatively confined within the intramedullary bone-marrow space. 相似文献
82.
The Hemodynamic Mechanisms of Lung Injury and Systemic Inflammatory Response Following Brain Death in the Transplant Donor 总被引:7,自引:2,他引:5
Vassilios S. Avlonitis Christopher H. Wigfield John A. Kirby John H. Dark 《American journal of transplantation》2005,5(4):684-693
Brain-dead donors are the major source of lungs for transplantation. Brain death is characterized by two hemodynamic phases. Initially, massive sympathetic discharge results in a hypertensive crisis. This is followed by neurogenic hypotension. Up-regulation of pro-inflammatory mediators occurs in all organs and lung injury develops; this can adversely affect graft function post-transplantation. The mechanisms of the systemic and lung inflammation are unknown. We hypothesized that the hemodynamic changes are responsible for these inflammatory phenomena. Brain death was induced by intra-cranial balloon inflation in rats. This resulted in hypertensive crisis, followed by hypotension. There was a significant increase in blood neutrophil CD11b/CD18 expression and pro-inflammatory cytokine levels in serum and bronchoalveolar lavage, compared with control animals. Rupture of the capillary-alveolar membrane was demonstrated by electron microscopy. Elimination of the hypertensive response by α-adrenergic antagonist pre-treatment prevented inflammatory lung injury, reduced the systemic inflammatory markers and preserved capillary-alveolar membrane integrity. Correction of the neurogenic hypotension with noradrenaline ameliorated the systemic inflammatory response and improved oxygenation. We conclude that the sympathetic discharge triggers systemic and lung inflammation, which can be further enhanced by neurogenic hypotension. Management of the brain-dead donor with early anti-inflammatory treatment and vasoconstrictors is warranted. 相似文献
83.
Andr ia Kist Fernandes Felipe Mallmann Ana Maria Pasquali Steinhorst Fernando Lopes Nogueira Eduardo Mü ller vila Dumitriu Zunino Saucedo Francisco Juchem Machado Marcelo Greg rio Raymundi S rgio Saldanha Menna Barreto Paulo de Tarso Roth Dalcin 《The Journal of asthma》2003,40(6):683-690
Asthma patients that depend on emergency department (ED) services are generally considered to have extremely poor disease control and prognosis. It is important to identify characteristics related to poor disease control and frequent visits to the ED to apply appropriate clinical management. This study comprised a cross-sectional survey of consecutive patients with asthma exacerbation (age ≥12 years) presenting at the adult ED of a large, tertiary care, university-affiliated hospital over a 2-month period. The frequent visitors (FV) were defined by ≥3 visits to the ED in the preceding year, and the occasional visitors (OV) by ≤2 visits. Eighty-six patients (61 females and 25 males) were included in the study (mean age 38 ± 18 years). Of these patients, 51.2% were FV and 48.8% were OV. Sixty-nine percent had annual income lower than A$3000 and 66.3% had ≤8 years of the formal education. Only 18.6% had used inhaled corticosteroids, 79.1% identified the asthma attack severity, 70.9% increased or initiated inhaled β-agonist, 20.9% increased or initiated steroid therapy, and 55.8% had an asthma action plan for attack. The number of hospital admissions in past year (OR 4.3, P = .02), use of home nebulizer (OR 3.6, P = .05) and the lack of a written asthma action plan (OR 3.3, P = .03) were independently associated with frequent visits to the ED. We conclude that a substantial proportion of the patients that visit the ED are FV. These patients are more likely to have hospital admission in the past year, to use a home nebulizer, and to lack a written asthma action plan. They should be considered the most important target for asthma education. 相似文献
84.
Fas和mdr-1在急性白血病的表达及其相关性研究 总被引:1,自引:0,他引:1
本研究应用流式细胞仪 (FCM)直接免疫荧光法和半定量RT PCR方法分别测定 5 9例初发急性白血病(AL)患者治疗前及完全缓解 (completeremission ,CR)后骨髓Fas和mdr 1mRNA表达情况 ,旨在探讨Fas和mdr 1在AL的表达及二者在多药耐药 (multidrugresistance ,MDR)中的相关性。结果显示 :Fas在初发AML阳性表达率比ALL高 ,两表达率间有差异 (P <0 .0 5 ) ,mdr 1在AML和ALL阳性表达率间无差异 (P >0 .0 5 ) ,Fas 与mdr 1 有负相关性 (r =- 0 .2 82 ,P <0 .0 5 ) ;经单因素及多因素COX分析 ,Fas和mdr 1独立于其他参数 ,更具判断预后价值 ;在Fas 与Fas-的AML和AL ,CR率均有显著性差异 (P <0 .0 1) ,在mdr 1 、mdr 1-的AML和AL中的CR率有显著性差异 (P <0 .0 1) ;经Logrank检验 ,Fas 与Fas-组CR率及中数缓解时间有显著性差异 (χ2 =7.35 ,P =0 .0 0 6 7) ,mdr 1 与mdr 1-组CR率及中数缓解时间有显著性差异 (χ2 =10 .71,P =0 .0 0 11)。结论 :Fas、mdr 1与疗效高度相关 ;Fas阳性表达可能是AL预后良好因素 ;mdr 1为疗效差、预后不良的重要因素。 相似文献
85.
86.
早期肠内营养及其输注方式对大鼠重症急性胰腺炎病理和肠道功能的影响 总被引:4,自引:0,他引:4
目的:观察早期肠内营养及其不同输注方式对重症急性胰腺炎的影响。方法:采用胰管逆行注射建立大鼠重症急性胰腺炎(SAP)模型,假手术组用生理盐水,SAP组随机分为持续、间隙和未行肠内营养3个亚组(每组12只),假手术组同样分为3个亚组(每组8只)。各组于48 h后启动肠内营养,72 h后再次麻醉大鼠,收集组织及血液标本;检测指标包括肠道转运系数、血淀粉酶、器官细菌移位率、血清细胞因子TNF-α、胰腺病理评分及血浆D-乳酸等。结果:①、SAP后48h进行肠内营养并未加重胰腺炎;肠内营养组与未行肠内营养组在血淀粉酶、胰腺病理评分方面,差异无统计学意义(P>0.05);然而早期肠内营养可以促进肠蠕动,减少肠道细菌移位率,两组间在肠道转运系数、脏器细菌移位率及血清TNF-α水平方面,差异有统计学意义(P<0.05)。②、SAP行肠内营养的两种方式间,各项指标比较无显著差异。结论:SAP大鼠在早期行肠内营养是可行的,其可保持肠道生理的完整性、减少了脏器细菌移位率,但未改善预后;持续和间隙二种肠内营养输注方式间无显著差异。 相似文献
87.
综合医院医务人员感染SARS情况对比分析 总被引:3,自引:1,他引:2
目的:分析在防治SARS工作初期、后期医务人员感染SARS的差异和采取的对策,为减少综合医院内医务人员SARS的感染提供参考。方甚:对本院自2003年3月24日至6月2日SARS诊断治疗任务中发生的医务人员的感染原因和采取的对策进行回顾性分析。结果:防治SARS工作初期,急诊科交叉感染和在SARS隔离病房等与SARS患者密切接触的工作岗位,共有17名医务人员感染,及时隔离治疗,均已痊愈,未造成医护人员的进一步交叉感染:经加强防护培训,改善工作条件,在防治SARS工作后期,仅发生2名护工感染,亦已痊愈,派出非典医疗队实现零感染。结论:综合医院内医务人员感染SARS的问题严峻,加强医院内的全员防护培训,按岗分区管理,改善医务人员的工作条件和病人的隔离观察环境,做好监督检查,积极应对,可以减少医务人员的SARS感染。 相似文献
88.
沾染液体火箭推进剂时的个人洗消技术进展 总被引:3,自引:0,他引:3
岳茂兴 《中华航空航天医学杂志》2003,14(3):189-192
目的 回顾与分析国内外有关沾染液体火箭推进剂时个人洗消技术和方法的研究资料,提出有效的个人洗消技术和方法,以尽可能地避免染毒或减轻染毒伤员的伤害程度。资料来源与选择 结合我们已进行的有关研究和参加抢救的临床救治体会,并引用国内外公开发表的相关论文及著作。资料引用 论文28篇及3部专著。资料综合主要针对个人洗消技术的有效性与安全性对文献作者采用的方法和指标进行分析和综合。结论 迅速及时地进行有效的洗消,以尽早彻底清除沾染的毒物,是防治液体火箭推进剂中毒的首要措施,可以明显避免或减轻染毒伤员的伤害程度。 相似文献
89.
A. Zielke C. Hasse Th. Bandorski H. Sitter P. Wachsmuth R. Grobholz M. Rothmund 《Surgical endoscopy》1997,11(12):1194-1197
Background: Recent studies have documented the feasibility of ultrasonography (US) to diagnose acute colonic diverticulitis (ACD). This
prospective observational trial determined the sonomorphology of ACD and evaluated the diagnostic accuracy of routine US performed
on admission by surgeons in training.
Methods: Fifty-seven consecutive patients with a confirmed episode of ACD were entered into this study, and the sonomorphology of
the involved colon was assessed. US findings were compared to the results of the clinical evaluation and correlated to the
clinicopathological outcome.
Results: The sonomorphology of ACD was characterized by segmental inflammatory transformation of the colon averaging 9.9 ± 3.2 cm
(range, 6–20) in length and visualized as target phenomena of a mean 3.5 ± 0.8 cm (range, 2.4–4.8) width. Targets were caused
by hypoechogenic thickening of the colonic wall of an average 7.7 ± 2.6 mm (range, 4–18). In 40% of cases, a hyperechogenic
halo representing peridiverticulitis (average width, 2.3 ± 0.6; range, 1.2–3 cm) was noted. Diverticula were seen in almost
half of the cases. Of the 57 cases with confirmed ACD, the diagnosis was made by US in 48, for a global accuracy of 84.2%.
US was false negative in nine patients, suggesting perforated appendicitis in five cases and acute appendicitis in one (the
final diagnoses were perforated sigmoid diverticulitis in five cases and cecal diverticulitis in one case). In three patients,
US was nondiagnostic.
Conclusion: In the hands of sonographically trained surgeons, ultrasound is a useful modality to image acute colonic diverticulitis.
US reveals diagnostic sonomorphology in most cases of ACD and therefore facilitates early confirmation of the diagnosis and
assessment of severity.
Received: 3 October 1996/Accepted: 9 May 1997 相似文献
90.
应用不同浓度TPA诱发血小板聚集,观察20名正常人血小板的聚集率。结果显示:TPA从5ng/ml到10ng/ml之间,随着浓度的增加,血小板聚集率逐渐增加,最佳浓度为10ng/ml。当TPA浓度〉10mg/ml时,继续增加TPA浓度,血小板聚集率将不再升高,且于20mg/ml时出现明显的解聚现象。 相似文献