全文获取类型
收费全文 | 8289篇 |
免费 | 565篇 |
国内免费 | 133篇 |
专业分类
耳鼻咽喉 | 39篇 |
儿科学 | 161篇 |
妇产科学 | 103篇 |
基础医学 | 1012篇 |
口腔科学 | 132篇 |
临床医学 | 724篇 |
内科学 | 1437篇 |
皮肤病学 | 122篇 |
神经病学 | 783篇 |
特种医学 | 466篇 |
外国民族医学 | 1篇 |
外科学 | 839篇 |
综合类 | 523篇 |
现状与发展 | 2篇 |
预防医学 | 356篇 |
眼科学 | 102篇 |
药学 | 1140篇 |
中国医学 | 334篇 |
肿瘤学 | 711篇 |
出版年
2023年 | 89篇 |
2022年 | 154篇 |
2021年 | 193篇 |
2020年 | 190篇 |
2019年 | 424篇 |
2018年 | 354篇 |
2017年 | 258篇 |
2016年 | 221篇 |
2015年 | 259篇 |
2014年 | 385篇 |
2013年 | 458篇 |
2012年 | 455篇 |
2011年 | 475篇 |
2010年 | 340篇 |
2009年 | 365篇 |
2008年 | 334篇 |
2007年 | 296篇 |
2006年 | 230篇 |
2005年 | 219篇 |
2004年 | 203篇 |
2003年 | 187篇 |
2002年 | 147篇 |
2001年 | 124篇 |
2000年 | 106篇 |
1999年 | 96篇 |
1998年 | 71篇 |
1997年 | 73篇 |
1996年 | 60篇 |
1995年 | 64篇 |
1994年 | 59篇 |
1993年 | 47篇 |
1992年 | 48篇 |
1991年 | 50篇 |
1990年 | 45篇 |
1989年 | 29篇 |
1988年 | 33篇 |
1987年 | 21篇 |
1985年 | 175篇 |
1984年 | 244篇 |
1983年 | 190篇 |
1982年 | 157篇 |
1981年 | 168篇 |
1980年 | 142篇 |
1979年 | 147篇 |
1978年 | 107篇 |
1977年 | 87篇 |
1976年 | 115篇 |
1975年 | 92篇 |
1974年 | 91篇 |
1973年 | 73篇 |
排序方式: 共有8987条查询结果,搜索用时 109 毫秒
101.
The stereotyped, episodic abnormal behaviour manifested by a child and her mother on exposure to a particular sort of sunlight is described in detail. The child is the first fully documented patient with this so-called "self-induced" form of photosensitive epilepsy in whom for several years no electroencephalographic sensitivity to flickering light could be demonstrated. The probability that the cingulate circuit may be the anatomical substrate involved in the pathogenesis of these patients' unusual response to sunlight is discussed. Both patients also exhibited remarkably persistent habit rhythmias--the one common to both being that of circling. 相似文献
102.
Among the 1,892 patients who underwent cerebrovascular digital subtraction angiography at our hospital over the past 18 months, there was a subgroup of 34 patients (65 carotid arteries) for whom noninvasive cerebrovascular test results and standard cerebral arteriograms were also available. These patients were reviewed retrospectively and the ability of both methods to detect hemodynamically significant lesions, defined as a greater than 50 percent reduction in the diameter of the carotid artery, was determined using the arteriograms as the "gold standard." Noninvasive cerebrovascular tests had a sensitivity of 81 percent, a specificity of 95 percent, a positive predictive value of 92 percent, a negative prediction value of 88 percent, and an overall accuracy of 89 percent. Digital subtraction angiography had a sensitivity of 84 percent, a specificity of 92 percent, a positive predictive value of 88 percent, a negative predictive value of 89 percent, and an overall accuracy of 89 percent. If the four cases of hemodynamically significant stenosis of the carotid siphon not detected by digital subtraction angiography had been considered as false-negatives, its sensitivity would have been reduced to 72 percent. In patients with hemispheric cerebral ischemia, we found noninvasive cerebrovascular tests neither necessary nor cost-effective. Digital subtraction angiography, on the other hand, often provided definitive diagnostic information in such patients if the intracranial circulation was well defined and the extracranial lesion corresponded to the patients' symptoms. Noninvasive cerebrovascular testing was the safest and most cost-effective technique for screening patients with asymptomatic bruits, atypical, nonhemispheric cerebral symptoms, and those who have undergone carotid endarterectomy. If the noninvasive cerebrovascular test result was positive or equivocal, digital subtraction angiography was performed to localize the responsible lesion and exclude carotid occlusion. 相似文献
103.
P.C. Waldmeier K. Stöcklin J.-J. Feldtrauer 《Naunyn-Schmiedeberg's archives of pharmacology》1992,345(5):544-547
Summary The effects of local and systemic administration of the potent GABA uptake inhibitor, SK&F 89976, on GABA overflow from the striatum of conscious rats were investigated in brain dialysis experiments. Administration of the compound via the dialysis probe at concentrations of 25 or 100 gmol/l significantly increased basal GABA overflow about 2-fold. Overflow evoked by 104 mmol/l K+ remained unaltered at the lower and was almost doubled at the higher concentration; this increase did, however, not reach statistical significance.Given systemically at 50 mg/kg i.p., a dose which is severalfold higher than those which exhibit anticonvulsant effects, SK&F 89976 caused a significant enhancement of K+-stimulated GABA overflow by about a factor of 2; the lower dose of 20 mg/kg i.p. was not effective. Basal GABA overflow was not significantly increased by either dose. These results suggest that the marked effects of nipecotic acid on basal GABA overflow reported by several authors seem to be related to GABA displacement rather than uptake inhibition, and that uptake inhibition does not improve the interpretability of measurements of GABA release by brain dialysis. They neither support the idea that the relative insensitivity of extracellular GABA to low Ca2+ and tetrodotoxin is indirectly due to very efficient removal of GABA by neuronal and/or glial uptake, leaving only residual amounts to be measured.
Send offprint requests to P. Waldmeier at the above address 相似文献
104.
Bone marrow biopsy instead of 'marrow juice' for cell kinetic analysis. Comparison of bone marrow biopsy and aspiration material 总被引:1,自引:0,他引:1
Wolfgang Hiddemann Thomas Büchner Michael Andreeff Bernhard Wörmann Myron R. Melamed Bayard D. Clarkson 《Leukemia research》1982,6(4):601-612
Since cell kinetic bone marrow studies have so far exclusively been carried out on aspiration material and have yielded inconsistent or even contradictory results, we investigated the adequacy and reliability of aspirates for cell kinetic analyses in comparison to biopsies. Paired samples of bone marrow (133) were taken simultaneously by aspiration and Jamshidi biopsy from 48 patients with acute leukemias and 67 patients with non-leukemic disorders. Cell kinetic analysis by (1) flow cytometry (FCM) of cellular DNA and RNA content, (2) autoradiography for [3H]TdR pulse labelling indices and (3) liquid scintillation counting of [3H]TdR uptake revealed significantly higher values in biopsies (p less than 0.001) exceeding the corresponding results from aspirates on average by factors of 1.65 for FCM S-phase index, 1.90 for G0/1 cells with high RNA content, 1.82 for [3H]TdR LI and 1.90 for [3H]TdR uptake. In more than 70% of all samples results from biopsies were 1.1-11.4 times higher, indicating that aspirates were equivalent to biopsies in fewer tan 30% of cases. Cell kinetic analysis in vitro blood/biopsy mixtures and measurements of DNA synthesis rate in corresponding aspirates and biopsies revealed that these discrepancies are due to the contamination of aspirates with non-proliferating nucleated blood cells. Biopsy, however, was found to provide representative and reproducible sampling of marrow for cell kinetic studies and should replace the presently used aspirate already characterized as "unreliable marrow juice" by Dameshek et al. in 1937 [18]. 相似文献
105.
F Feuilhade U Testa W Vainchenker A Henri H T That Y Beuzard F Galacteros B Dreyfus H Rochant 《Leukemia research》1981,5(3):203-213
Hb F, Hb A2 and i-antigen expression were investigated in adulthood acute leukemias. The study of i-antigen expression by immuno-agglutination and immunofluorescence showed that it is preferentially increased among AML patients. A similar result was obtained for F-cell frequency which was often increased in AML, while it was normal in ALL. Hb A2 level was significantly lower in AML than in ALL. These differences between AML and ALL red cell patterns further suggest that the leukemic clone involves the erythroid lineage in AML but not in ALL. 相似文献
106.
P C Leung 《The Journal of hand surgery》1979,4(5):409-411
Venous congestion in a replanted or transplanted digit can be detected, even before any obvious color changes, by the "throbbing" elicited by pinching the digit between the thumb and finger of the examiner until the skin blanches. Releasing the pressure slowly, a sensation of throbbing will be felt synchronous with the patient's pulse rate. The sign disappears when venous congestion is relieved or when swelling persists and increases enough to lessen the arterial inflow. 相似文献
107.
F波和面神经电图对早期周围性面瘫预后诊断的价值 总被引:4,自引:0,他引:4
目的 通过随访调查评价F波和面神经电图在早期周围性面瘫预后中的价值。方法 对发病21天内做过F波和面神经电图检查、病史已达3年的35例周围性面瘫患者进行了恢复结果随访,比较两种诊断方法预后判断的准确度。F波是否存在及面神经电图值是否大于90%分别作为两种方法的诊断界值。结果 用F波是否能引出判断周围性面瘫患者好坏的准确度为97.14%,高于面神经电图的88.57%,用F波是否消失判断患者有无并发症的准确度为94.29%,高于面神经电图的85.71%,两种方法经配对卡方检验,有显著性差异(x~2=17.72,P<0.01)。F波存在是较好预后的定性指标。结论 F波是早期周围性面瘫一种理想的判断预后的客观诊断指标。 相似文献
108.
109.
《Journal of labelled compounds & radiopharmaceuticals》2003,46(7):645-659
The neurotransmitter glutamate is thought to be crucially involved in a huge number of neurological and psychiatric disorders, such as Morbus Parkinson, Alzheimer's disease and schizophrenia. Aiming at an improved diagnostic tool for PET a new [18F]fluorine labelled NMDA receptor ligand was developed that may potentially allow the in vivo visualization of glutama‐tergic neurotransmission. The 19F‐analogue trans‐5,7‐dichloro‐4‐(3‐{4‐[4‐(2‐fluoroethyl)‐piperazin‐1‐yl]‐phenyl}‐ureido)‐1,2,3,4‐tetrahydro quinoline‐2‐carboxylic acid was synthesised to determine the binding affinity, lipophilicity and biodistribution of the ligand. This substance exhibits a Ki of 12 nM for the glycine binding site using [3H]MDL‐105,519 assays on pig cortical membranes. A logD of 1.3 was determined for this compound according to the OECD guidelines employing the HPLC method. Radiosynthesis of this ligand was achieved by labelling the precursor trans‐5,7‐dichloro‐4‐[3‐(4‐piperazin‐1‐yl‐phenyl)‐ureido]‐1,2,3,4‐tetrahydroquinoline‐2‐carboxylic acid methyl ester with 2‐[18F]fluoroethyltosylate and subsequent cleaving of the methyl ester moiety, resulting in an overall decay corrected yield of 35% of the final product trans‐5,7‐dichloro‐4‐(3‐{4‐[4‐(2‐[18F]fluoroethyl)‐piperazin‐1‐yl]‐phenyl}‐ureido)‐1,2,3,4‐tetrahydroquinoline‐2‐carboxylic acid. The biodistribution kinetics of this compound were determined with Sprague Dawley rats ex vivo for brain, liver, kidney, and bone. The ligand showed a maximum brain uptake 30 min.p.i. of about 0.1% ID/g. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
110.
F/LVO方案时辰化疗治疗ⅢA期胃癌的临床观察 总被引:3,自引:0,他引:3
目的观察F/LVO方案时辰化疗治疗ⅢA期胃癌患者的疗效。方法将46例行D2根治术后的ⅢA期胃癌患者随机分为A组(时辰化疗组)和B组(对照组常规化疗)。结果A组和B组的1年生存率(OS)分别为90.9%(20/22)和83.3%(20/24)(P>0.05);3年生存率分别为72.7%(16/22)和33.3%(8/24),2组比较有显著性差异(P<0.05)。A组和B组的1年病情无进展生存率(DFS)分别为81.8%(18/22)和50.0%(12/24);3年无进展生存率分别为54.5%(12/22)和16.7%(4/24),2组比较均有显著性差异(P<0.05)。结论时辰化疗是ⅢA期胃癌患者D2根治术后较为理想的辅助化疗模式。 相似文献