全文获取类型
收费全文 | 112007篇 |
免费 | 10262篇 |
国内免费 | 6501篇 |
专业分类
耳鼻咽喉 | 1036篇 |
儿科学 | 2095篇 |
妇产科学 | 795篇 |
基础医学 | 8366篇 |
口腔科学 | 1842篇 |
临床医学 | 14000篇 |
内科学 | 11733篇 |
皮肤病学 | 1409篇 |
神经病学 | 3182篇 |
特种医学 | 4417篇 |
外国民族医学 | 7篇 |
外科学 | 9923篇 |
综合类 | 27892篇 |
现状与发展 | 42篇 |
一般理论 | 2篇 |
预防医学 | 11999篇 |
眼科学 | 1679篇 |
药学 | 13163篇 |
138篇 | |
中国医学 | 9325篇 |
肿瘤学 | 5725篇 |
出版年
2024年 | 442篇 |
2023年 | 1290篇 |
2022年 | 3290篇 |
2021年 | 4354篇 |
2020年 | 3687篇 |
2019年 | 2301篇 |
2018年 | 2508篇 |
2017年 | 2990篇 |
2016年 | 2506篇 |
2015年 | 4263篇 |
2014年 | 5569篇 |
2013年 | 6852篇 |
2012年 | 10018篇 |
2011年 | 10540篇 |
2010年 | 9023篇 |
2009年 | 8063篇 |
2008年 | 8634篇 |
2007年 | 8501篇 |
2006年 | 7499篇 |
2005年 | 6242篇 |
2004年 | 4611篇 |
2003年 | 4075篇 |
2002年 | 3274篇 |
2001年 | 2922篇 |
2000年 | 2135篇 |
1999年 | 973篇 |
1998年 | 367篇 |
1997年 | 340篇 |
1996年 | 287篇 |
1995年 | 213篇 |
1994年 | 202篇 |
1993年 | 126篇 |
1992年 | 129篇 |
1991年 | 96篇 |
1990年 | 69篇 |
1989年 | 56篇 |
1988年 | 39篇 |
1987年 | 41篇 |
1986年 | 37篇 |
1985年 | 23篇 |
1984年 | 21篇 |
1983年 | 20篇 |
1982年 | 15篇 |
1981年 | 6篇 |
1979年 | 22篇 |
1969年 | 6篇 |
1964年 | 8篇 |
1959年 | 10篇 |
1958年 | 11篇 |
1957年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Lymphoproliferative disorders comprise a heterogeneous group of neoplasms whose behaviors range from indolent to very aggressive. The increased incidence seen in the context of immunodeficiency provides evidence that the host immune system plays a vital role in their pathogenesis. We believe that T-helper (Th)-2 dominant states favor development of lymphoproliferative disorders, including lymphoma, and conversely T-helper (Th)-1 immunity protects against lymphoproliferative disease. The age distribution of lymphomas favors childhood and post-reproductive senescence, suggesting that exposure to these periods of Th-2 bias constitutes a key risk factor for developing the disease. The tendency of lymphomas to arise in Th-2 biased locations such as mucosal interfaces, immunoprivileged sites, and regions of B-cell differentiation may likewise reflect a corresponding spatial predilection. Various clinical conditions or treatments that shift Th1/Th2 balance, including HIV infection, transplant-related immune suppression, and autoimmune disorders, can also influence the status of lymphoproliferative diseases. 相似文献
62.
目的:探讨HIE患者血中6-keto-PGF1α、NSE水平变化及临床意义.方法:用RIA检测89例HIE患者和32例正常新生儿血中6-keto-PGF1α、NSE水平变化.结果:HIE轻、中、重度组6-keto-PGF1α水平与正常对照组比较,均存在显著性差异(p<0.01),HIE患者轻度组NSE水平与对照组比较无显著性差异(p>0.05),中、重度组NSE水平与对照组比较存在显著性差异(p<0.01),6-keto-PGF1α、NSE二组血中浓度上升与HIE程度呈正相关.结论:HIE患者中6-keto-PGF1α、NSE水平检测,对判断HIE的脑损伤程度、治疗、预后观察,具有重要临床意义和应用价值. 相似文献
63.
Maeda A Ohguro H Nabeta Y Hirohashi Y Sahara H Maeda T Wada Y Sato T Yun C Nishimura Y Torigoe T Kuroki Y Sato N 《European journal of immunology》2001,31(2):563-572
Cancer-associated retinopathy (CAR) is a rare paraneoplastic syndrome, and the recoverin-specific autoantibody is suggested to contribute to the pathogenesis of retinopathy, including apoptosis of retinal cells. Because it is known that CAR(+) cancer patients have a preferable prognosis, we hypothesized that aberrantly expressed recoverin in cancer cells can become a target of cytotoxic T lymphocytes (CTL). Here we tested nine recoverin-derived HLA-A24-binding peptides for their capacity to elicit antitumor CTL. We observed recoverin-specific CTL responses in two HLA-A24(+) CAR(+) cancer patients. In addition, the CTL responses were obtained from three of ten CAR(-) cancer patients and two of six healthy individuals. The CTL precursor frequency of CAR(+) cancer patients and that of CAR(-) cancer patients was higher than that of healthy individuals. Of nine recoverin peptides, R49 (QFQSIYAKF), R49.2 (QFQSIYAKFF), and R64 (AYAQHVFRSF) were discovered to induce the peptide-specific CTL. Taken together, our present data suggest that peripheral activation of recoverin-specific antitumor CTL is likely to contribute to the preferable prognosis of CAR(+) cancer patients. Moreover, in cases other than CAR(+) cancer patients, recoverin may offer the opportunity to design epitope-based immunotherapeutic approaches for treating HLA-A24(+) cancer patients with a recoverin-expressing tumor. 相似文献
64.
In most cases, while schwannoma is sporadically manifested as a single benign neoplasm, the presence of multiple schwannomas in one patient is usually indicative of neurofibromatosis 2. However, several recent reports have suggested that schwannomatosis itself may also be a distinct clinical entity. This study examines an extremely rare case of probable schwannomatosis associated with intracranial, intraspinal and peripheral involvements. A 63-year-old woman presented with a seven-year history of palpable lumps on both sides of the supraclavicular area and hearing impairment in both ears. On physical examination, no skin manifestations were evident. Facial sensory change, deafness in the left ear and decreased gag reflex were revealed by neurological examination. Magnetic resonance imaging revealed multiple lesions of the trigeminal nerves, acoustic nerves, lower cranial nerves, spinal accessory nerve, brachial plexuses, and spinal nerves. Pathological examination of tumors from the bilateral brachial plexuses, the spinal nerve in the T8 spinal position and the neck mass revealed benign schwannomas. Following is this patient case report of multiple schwannomas presenting with no skin manifestations of neurofibromatosis. 相似文献
65.
We investigated the effect of beta-adrenergic stimulation on the heart rate and QT interval in syncope children with or without coexisting ventricular arrhythmias (VA). Of the 24 children who presented with syncope or presyncope and showed negative tilt test, 13 were classified into a group with VA and the remaining 11 without VA. The provocative test was performed in bolus infusion and continuous infusion. RR, QT, and QTc intervals on routine 12-lead surface electrocardiogram were obtained during each stage of isoproterenol infusion. In all cases, malignant ventricular arrhythmia and syncope were not induced by isoproterenol provocative test. RR and QT intervals were shortened and QTc intervals were prolonged as the isoproterenol dose was increased in both groups and methods. The QTc interval reached its peak level after the bolus injection of 1.0 microgram and during the continuous infusion of 0.03 microgram/kg/min. The two groups showed no significant difference in the QTc interval change according to the infusion methods. This study indicates that changes in the heart rate and QT interval by beta-adrenergic stimulation were not different according to the coexisting ventricular arrhythmias in syncope children with negative head-up tilt test. 相似文献
66.
.The aim of this study is to estimate the chaos phenomenon in temporomandibular joints (TMJ) sound using fractal dimension (FD), and to examine the diagnostic value of the FD in comparing TMJ sounds produced by 6 asymptomatic and 25 symptomatic TMJ. Multiple mandibular opening and closing cycles recorded were used to calculate the waveform dimension and correlation dimension in the FD. Chaos in the TMJ sounds was estimated by the FD that was saturated with some constant value to an increase of embedding dimension. Results reveal that fractal analysis produces a high degree of reproducibility within, and similarity across subjects, and indicate that both FD values of the asymptomatic TMJ sounds are significantly higher than those of the symptomatic. These findings suggest that chaos is present in TMJ sounds and the difference in the FD is of diagnostic value in evaluation of pathological change in TMJ sound signals. 相似文献
67.
本文研究丁敌枯双对BALB/C雄性小鼠生殖细胞分裂比率及精原细胞染色体畸变的影响。将实验小鼠随机分为三组,即实验组(敌枯双组),阳性对照组(环磷酰胺组)和阴性对照组(双蒸水组)。结果发现:敌枯双能明显诱发精原细胞多倍体率和裂隙率增加,抑制终变期/中期Ⅰ和中期Ⅱ细胞的减数分裂比率,促进精原细胞有丝分裂比率。实验结果还提示:在遗传毒理检测中亚急性实验是必要的,并对实验结果进行了初步讨论。 相似文献
68.
69.
Brazilin and haematoxylin, plant pigments, were examined for their effects on the Bovine-Lens aldose reductase (LAR)-activity. About 50% inhibition was observed in a concentration of 10 (-4) M-brazilin and 10 (-4) M-haematoxylin, and above 95% inhibition was observed in a concentration of 10 (-3) M-brazilin and 10 (-3)M-haematoxylin. In order to determine the type of inhibition, kinetic studies were also conducted with brazilin and haematoxylin, in which both were found to be noncompetitive inhibitors. 相似文献
70.
目的 :研究肾综合征出血热 (HFRS)多尿期肾图的变化及其意义。方法 :静脉注射 1 31 I-邻碘马尿酸钠 (1 31 I- OIH) 3.7×10 9Bq(10 μCi) ,用闪烁照相法描记 15 min,通过电子计算机自动处理 ,得出肾图的各项参数。结果 :2 0例受检者均已进入多尿期 ,2 4h尿量在 2 0 0 0 ml以上 ,血尿素氮 (BUN)已正常或接近正常 ,但肾图却明显异常 ,表现为半排时间 (TC1 /2 )延长 (>8min) ,15min残留率 (C1 5 /b)超过 5 0 % ,肾脏指数大多低于 45 % ;同期作尿β2 -微球蛋白 (β2 - m )测定 ,也明显高于正常 ;8例作发射型电子计算机扫描 (ECT)检查 ,肾小球滤过率 (GFR)和有效肾血浆流量 (ERPF)分别为 (4 0 .8± 2 1.2 ) ml/min和 (35 0 .8± 10 2 .1) ml/min,均明显低于正常 (P<0 .0 1)。结论 :HFRS患者多尿期肾图大多呈排出不良和功能受损的图形 ,表明该期肾功能以及肾血流量尚未恢复正常 ,对症治疗仍需继续。 相似文献