全文获取类型
收费全文 | 4011篇 |
免费 | 193篇 |
国内免费 | 58篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 137篇 |
妇产科学 | 28篇 |
基础医学 | 842篇 |
口腔科学 | 38篇 |
临床医学 | 746篇 |
内科学 | 362篇 |
皮肤病学 | 40篇 |
神经病学 | 618篇 |
特种医学 | 70篇 |
外科学 | 228篇 |
综合类 | 398篇 |
现状与发展 | 2篇 |
预防医学 | 281篇 |
眼科学 | 42篇 |
药学 | 235篇 |
1篇 | |
中国医学 | 68篇 |
肿瘤学 | 112篇 |
出版年
2023年 | 37篇 |
2022年 | 49篇 |
2021年 | 102篇 |
2020年 | 78篇 |
2019年 | 89篇 |
2018年 | 94篇 |
2017年 | 108篇 |
2016年 | 99篇 |
2015年 | 95篇 |
2014年 | 153篇 |
2013年 | 196篇 |
2012年 | 213篇 |
2011年 | 221篇 |
2010年 | 199篇 |
2009年 | 149篇 |
2008年 | 178篇 |
2007年 | 176篇 |
2006年 | 181篇 |
2005年 | 156篇 |
2004年 | 151篇 |
2003年 | 120篇 |
2002年 | 87篇 |
2001年 | 96篇 |
2000年 | 85篇 |
1999年 | 84篇 |
1998年 | 68篇 |
1997年 | 66篇 |
1996年 | 66篇 |
1995年 | 63篇 |
1994年 | 66篇 |
1993年 | 50篇 |
1992年 | 39篇 |
1991年 | 29篇 |
1990年 | 28篇 |
1989年 | 25篇 |
1988年 | 31篇 |
1987年 | 26篇 |
1986年 | 46篇 |
1985年 | 81篇 |
1984年 | 62篇 |
1983年 | 64篇 |
1982年 | 56篇 |
1981年 | 55篇 |
1980年 | 52篇 |
1979年 | 22篇 |
1978年 | 16篇 |
1977年 | 12篇 |
1975年 | 13篇 |
1974年 | 9篇 |
1973年 | 12篇 |
排序方式: 共有4262条查询结果,搜索用时 15 毫秒
21.
为探讨中枢去甲肾上腺素(NE)能神经元兴奋对脑水肿的影响,作者观察了刺激或损毁大鼠右侧蓝斑后,同侧大脑半球脑水含量的变化.结果,NE能神经元兴奋时,同侧半球脑皮质神经元也处于兴奋状态,脑内NE,肾上腺素(E)含量分别达正常组的307.46%和299.41%,脑水含量(79.21±0.28%)也较正常组(78.46±0.42%)明显增高(P<0.01).损毁蓝斑后,同侧半球脑内NE,E含量仅为正常组的12.80%和32.31%,脑水含量稍有下降,无统计学意义.提示中枢NE能神经元兴奋可能是脑水肿发生过程中的重要环节之一. 相似文献
22.
用电解损毁方法损毁Wistar成年雄性大鼠的双侧蓝斑区。结果出现膀胱扩张、尿液潴留和血尿等,膀胱和输尿管尿液有大量红细胞和血红蛋白,膀胱粘膜和肾脏充血.结果表明:损毁双侧蓝斑区后不仅有膀胱出血,还有肾脏出血。这个实验可用作研究“特发性”血尿的动物模型。 相似文献
23.
采用无抗凝作用剂量肝素皮下注射治疗小儿肾病综合征25例,观察了近期疗效与12~24月后对皮质激素或环磷酰胺(CTX)治疗反应的关系.结果表明,近期对肝素治疗显效但复发以及有效者,今后用激素或CTX治疗均可达完全缓解,无效者则效果较差.本文结果表明,肝素治疗的近期疗效可用于预测肾病患儿的远期预后. 相似文献
24.
25.
基于非标准协议的短距离无线通信,具有成本低、易开发、低功耗的优点,非常适用于小范围内的数据传输。提出一种基于非标准无线通信芯片nRF24L01的个人健康监护系统设计方案,并将其与现有的、基于标准协议无线通信的个人健康监护系统进行比较。结果表明:基于非标准协议无线通信的个人健康监护系统具有效率高、功耗低、通信性能好的特点。 相似文献
26.
Peter Christian Ruokonen Thomas Schwenteck Jörg Draeger 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2007,245(9):1259-1265
BACKGROUND: Two new tonometers have been introduced that are based on the impedance principle. Both the TGDc-01 (transpalpebral measurement) and the iCare (corneal measurement) do not require corneal anaesthesia. The present work presents an evaluation of both devices. METHODS: Comparative measurements using one of the new tonometers and applanation tonometry were performed by one investigator according to the international standard for ocular tonometer (ISO 8612). Measurements were performed on 445 eyes without corneal pathology from 243 patients. Six measurements were performed for iCare and 3 for TGDc, immediately followed by 3 applanation tonometry measurements. RESULTS: The correlation coefficient with respect to applanation tonometry was 0.81 for TGDc and 0.95 for iCare. TGDc-01 measurements showed an average deviation of 3.1 +/- 2.6 mmHg to those of Perkins applanation tonometry. The maximum difference was 28.7 mmHg below and 9.8 mmHg above the results of applanation tonometry. iCare showed an average deviation of 2.5 +/- 1.1 mmHg to Goldmann tonometry. The maximum difference was 14.5 mmHg below and 9.8 mmHg above. CONCLUSIONS: The results of both new tonometers showed a good correlation with the reference applanation tonometric methods, but the strict requirements of ISO 8612 are not fulfilled by either tonometer at present. Additionally, transpalpebral measurements with the TGDc-01 showed unacceptably high variability. 相似文献
27.
A. Alonso P. Martin C. Albarran M. Sancho 《International journal of legal medicine》1993,105(6):311-314
Summary The polymorphism of the D1S80 locus has been analyzed in a population sample of 203 unrelated individuals living in Madrid (central Spain) by PCR and subsequent semi-dry discontinuous polyacrylamide gel electrophoresis (Tris-chloride/Tris-glycine buffer system) followed by silver staining, The electrophoretic system described in this study offers high resolution in the separation of the different D1S80 alleles allowing the detection of microvariability around the allele T22 in the spanish population. Twenty different alleles containing 17–40 repeats of the basic 16bp unit were distinguished. The alleles T18 and T24 were found to be relatively common in Spain, as in other populations:, with frequencies of 0.224 and 0.372, respectively. No evidence of significant deviations from Hardy-Weinberg equilibrium was found in these preliminary population data. 相似文献
28.
Kazue Semba 《The Journal of comparative neurology》1993,330(4):543-556
Microinjection of cholinergic agonists in a dorsolateral part of the mesopontine tegmentum has been shown to induce a rapid eye movement (REM) sleep-like state. Physiological evidence indicates that not only acetylcholine but also various amine transmitters, including those implicated in behavioral state regulation, affect neuronal activity in this region of the pontine reticular formation. In the present study, sources of select aminergic and cholinergic inputs to this REM sleep induction zone were identified and quantitatively analyzed by using fluorescence retrograde tracing combined with immunofluorescence in the rat. In addition to previously demonstrated cholinergic projections from the pedunculopontine and laterodorsal tegmental nuclei, the REM sleep induction zone received various aminergic inputs that originated in widely distributed regions of the brainstem and hypothalamus. Serotoninergic afferents represented a mean of 44% of all aminergic/cholinergic source neurons projecting to the REM sleep induction zone, which was comparable to the mean percentage of 39% represented by cholinergic afferent neurons. The serotoninergic afferents originated from the raphe nuclei at all brainstem levels, with heavier projections from the pontine than from the medullary raphe nuclei. Unexpectedly, an additional major serotoninergic input was provided by serotoninergic neurons in the nucleus prosupralemniscus (B9). Noradrenergic afferent neurons represented a mean of 14% of all aminergic/cholinergic source neurons, which was only about one-third of the mean percentage of either cholinergic or serotoninergic source neurons. These noradrenergic projection neurons were located not only in the locus ceruleus (8%) but also in the lateral tegmentum, including the A5 (4%) and A7 (2%) cell groups. Histaminergic neurons in the tuberomammillary hypothalamic nucleus represented a minor group of afferent neurons (3%), and a still smaller input came from adrenegic C1 neurons. The pattern of these transmitter-specific afferent connections appeared to be similar regardless of the longitudinal level within the REM sleep induction zone. The present results are consistent with previous behavioral and physiological evidence for a role of the pontine REM sleep induction zone in triggering REM sleep. The regulation of REM sleep induction would be best understood in terms of a state-dependent interplay of cholinergic, serotoninergic, and other inputs all acting convergently upon neurons in the REM sleep-inducing region of the pontine reticular formation. 相似文献
29.
Petri S. Mattila Jan Schugk Hongyan Wu Olli Mkel 《European journal of immunology》1995,25(9):2578-2582
During the initial stages of B lymphocyte differentiation heavy chain variable (VH), diversity (DH) and joining (JH) gene segments recombine to form a functional heavy chain variable region (VDJ) gene. Evidence for genetic polymorphism of the human JH gene segments has been obtained from mature rearranged VDJ sequences. We conducted an analysis of the published rearranged JH gene sequences and found that the JH alleles present in the two published germ-line JH region sequences were rare (approx. 2%) in the rearranged sequences. As an attempt to explain this discrepancy a 2.5-kb strech of DNA containing all the six heavy chain JH region genes and the most 3' DH gene segment, DHQ52, was amplified by the polymerase chain reaction from 39 individuals and analyzed for restriction fragment length polymorphism. Five new JH region haplotypes were found and sequenced. These new haplotypes contained the coding segment alleles that were frequent in antibody genes. Surprisingly, a high number of interallelic differencies in the non-coding sequence was found between the new and the two previously published haplotypes implying that the haplotypes had been separated early in evolution. In this respect the JH locus resembles HLA loci. 相似文献
30.
Prospect for enzyme therapy in glycogenosis II variants: a study on cultured muscle cells 总被引:4,自引:0,他引:4
A. T. van der Ploeg P. A. Bolhuis R. A. Wolterman J. W. Visser M. C. B. Loonen H. F. M. Busch A. J. J. Reuser 《Journal of neurology》1988,235(7):392-396
Summary Impairment of skeletal muscle function is the common feature of distinct clinical forms of glycogenosis type II. In the present study, muscle cultures from different patients were used to investigate the cause of clinical heterogeneity and the feasibility of enzyme replacement therapy. The activity of acid -glucosidase appears to be the primary factor in determining the extent of lysosomal glycogen storage in muscle, and thereby the clinical severity of the disease. Neutral -glucosidases do not seem influencial. Correction of the enzymatic defect was achieved in skeletal muscle cultures from patients by administration of a high-uptake form of acid -glucosidase, purified from human urine. The enzyme reaches the lysosomes, including the glycogen storage vacuoles, and the lysosomal glycogen content is reduced to control level. In normal muscle cells 20% of the total cellular glycogen pool is segregated in lysosomal compartments. This percentage is higher than in fibroblasts, which may partly explain why muscles are more prone to store glycogen. The relevance of this study for enzyme therapy is discussed. 相似文献