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991.
乙型肝炎病毒基因组中前-X-编码基因启动子序列的确定及转录活性的鉴定 总被引:17,自引:1,他引:16
利用长距离精确聚合酶链反应 (LA PCR)扩增慢性乙型肝炎患者血清来源的 5个全长的HBV基因组DNA ,在分析不同克隆之间的序列变异程度时 ,发现所获得的 5个克隆在X区之前可能还存在一个开放读码框架 (ORF) ,长度 16 8bp ,编码 5 6个氨基酸残基(aa) ,并将其暂时命名为前 X(pre X)。为了解前 X编码区上游DNA序列是否具有启动子活性 ,选取翻译起始密码子ATG上游 2 2 5bp的基因片段 ,将其克隆至报告基因表达载体pCAT3中 ,构建pCAT3 前 X promoter表达载体 ,以该质粒转染HepG2细胞 ,用ELISA法检测报告基因编码产物氯霉素乙酰转移酶 (CAT)的表达活性。结果发现 ,质粒 pCAT3 前 X promoter能够指导CAT的表达 ,吸光度 (A值 )是pCAT3的 3 5倍 ,提示pCAT3 前 X promoter中插入的DNA序列具有启动子活性 ,说明这一段基因序列中存在新的启动子区 ,为研究、界定前 X的ORF的存在提供了直接的依据。 相似文献
992.
J. E. Desmond J. W. Moore 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1986,65(1):59-74
Summary Previous investigations have suggested that the dorsolateral pontine tegmentum (DLP) may be part of a system essential for classical conditioning of the nictitating membrane response. The present study examined CR-related firing patterns of extracellularly-recorded single units in the DLP. Differential conditioning, using tonal CSs and periocular electrostimulation as the US, was employed so that firing patterns on CR and non-CR trials could be compared. Cells that exhibited CR-related increases in firing (excitatory cells) were found in reticular formation surrounding the motor trigeminal nucleus (zone h), including the supratrigeminal region, and in a region dorsal and dorsomedial to the brachium conjunctivum. Cells that exhibited CR-related decreases in firing (inhibitory cells) were observed in subcoeruleus/medial parabrachial regions and dorsal nucleus reticularis pontis oralis and caudalis. A third class of cells (temporal cells) exhibited CR-related shifts in the temporal distribution of spikes; these cells were located in various brain stem regions. The firing of many of the excitatory, inhibitory, and temporal cells preceded the behavioral CR by an amount of time sufficient for causal involvement. In light of evidence indicating that the cerebellum is critically involved in conditioning, the present study suggests that two systems, the cerebellum and the DLP, may be in control of CRs. The relationship of the two systems and their possible roles in conditioning are discussed. 相似文献
993.
A comparison of the hemodynamic effects produced by electrical stimulation of subnuclei of the paraventricular nucleus 总被引:5,自引:0,他引:5
The paraventricular nucleus of the hypothalamus (PVN) is composed of magnocellular and parvocellular subdivisions. Magnocellular neurosecretory neurons project to the neurohypophysis while parvocellular neurons send monosynaptic axonal projections to autonomic regulatory areas in the brainstem and spinal cord. In the present study, we investigated the hemodynamic effects produced by selective magnocellular or parvocellular stimulation. In urethane anesthetized rats with intact baroreflexes, magnocellular and parvocellular stimulation produced only slight differences in hemodynamic responses, however, following acute sinoaortic denervation a clear difference was observed. Parvocellular stimulation produced an increase in arterial pressure and vasoconstriction in gut, kidney and skeletal muscle. Magnocellular stimulation produced little effect on arterial pressure and marked vasodilation in the hindquarters. Blockade of peripheral vasopressin vascular receptors did not affect the vasoconstrictor response produced by stimulation of PVN. These data are consistent with the hypothesis that the long descending neural projections of the parvocellular PVN subserve a selective vasoconstrictor function. 相似文献
994.
临床上引起腹胀的原因很多,常见于消化系统功能障碍,轻者表现为食欲下降,睡眠紊乱,严重的可引起烦躁不安、呼吸困难、呻吟不止,甚至发生腹腔间室综合症,影响呼吸循环功能.临床上常单用三香散外敷脐部或常规的肛管排气,效果并不明显.我科自2008年~2009年对腹胀病人采用了三香散外敷脐部加一次性肛管外接一次性负压引流器进行肛管排气,取得了满意的效果,现报告如下. 相似文献
995.
996.
Skinner S Chiri CA Wroblewski J Transfeldt EE 《Journal of clinical monitoring and computing》2007,21(1):31-40
OBJECTIVE: Electrophysiological bulbocavernosus reflex (BCR) testing, during surgeries in which the constituent neural components are at risk, might supplement other low sacral (S2-4) stimulation/recording techniques. However, intraoperative BCR is not always reliably implemented. We proposed to analyze BCR signals in five surgical patients monitored with the novel application of double train stimulation (DTS) to determine if the potential could be enhanced. METHODS: We prospectively planned a regime of DTS BCR with a series of intertrain delays in five monitored patients at risk for low sacral neural injury. Patients were maintained with propofol, opiate infusion, and low inhalant anesthesia without muscle relaxant. Cutaneous sensory nerves of the penis (or clitoris) were stimulated using two consecutive pulse trains (DTS). Intertrain delays were 75, 100, 125, 150, 175, 200, and 250 ms. For BCR recording, uncoated paired wires were inserted into the external anal sphincter (EAS) bilaterally. For each trial, waveform amplitude, duration, and turn count measures for the first (single train) and second (double train) response were recorded. Percent increase/decrease of the second train response compared to the first train response was calculated. RESULTS: There was at least a 30% increase in measures of amplitude, turn count, and duration of the second train response in 22/28, 22/28, and 14/28 of the total trials respectively. There was an insufficient number of independent observations to determine statistical significance. CONCLUSIONS: Intraoperative BCR is currently obtained with some difficulty using pulse train stimulation. Our preliminary evidence has identified BCR waveform enhancement using DTS and suggests that the reliability of intraoperative BCR acquisition may be further improved by the addition of this technique. Our data are insufficient to define the best intertrain interval. 相似文献
997.
BACKGROUND: BK virus is an increasingly recognized pathogen in transplanted patients. DNA sequencing of this virus shows considerable genomic variability. METHODS: To understand the clinical significance of rearrangements in the non-coding control region (NCCR) of BK virus (BKV), we report a meta-analysis of 507 sequences, including 40 sequences generated in our own laboratory, for associations between rearrangements and disease, tissue tropism, geographic origin, and viral genotype. RESULTS: NCCR rearrangements were less frequent in (a) asymptomatic BKV viruria compared to patients viral nephropathy (1.7% vs. 22.5%), and (b) viral genotype 1 compared to other genotypes (2.4% vs. 11.2%). Rearrangements were commoner in malignancy (78.6%), and Norwegians (45.7%), and less common in East Indians (0%), and Japanese (4.3%). A surprising number of rearranged sequences were reported from mononuclear cells of healthy subjects, whereas most plasma sequences were archetypal. This difference could not be related to potential recombinase activity in lymphocytes, as consensus recombination signal sequences could not be found in the NCCR region. CONCLUSIONS: NCCR rearrangements are neither required nor a sufficient condition to produce clinical disease. BKV nephropathy and hemorrhagic cystitis are not associated with any unique NCCR configuration or nucleotide sequence. 相似文献
998.
Thomas F Nicot F Sandres-Sauné K Dubois M Legrand-Abravanel F Alric L Peron JM Pasquier C Izopet J 《Journal of medical virology》2007,79(1):26-34
Hepatitis C virus (HCV) is a major cause of chronic hepatitis and liver disease worldwide. The genetic heterogeneity of HCV and its spread among infected patients can be examined accurately by nucleotide sequencing. The diversity of HCV genotype 2 strains (HCV-2) was studied in a large cohort of patients in the Midi Pyrénées area of southern France. Phylogenetic analysis was performed on 344 NS5B sequences from patients infected with HCV-2. These included 145 strains whose E2 region was also analyzed, and epidemiological data were collected for the corresponding patients. HCV-2 accounts for 11.3% of HCV infections in this area. Phylogenetic analysis of NS5B sequences revealed eight subtypes, while that of the E2 region provided congruent results for 100% of strains. The most frequent subtypes were 2i (24.7%), 2k (22.4%) 2c (17.4%), and 2a (10.8%). The mean age of HCV-2-infected patients was 55.5 years. Epidemiological data showed that blood transfusion is the major route of infection, but it was not associated with any particular subtype. By contrast, intravenous drug users were infected predominantly with genotype 2a. HCV-2a-infected patients were younger than patients infected with other subtypes (48 vs. 56.5 years, P < 0.01). This study shows substantial genetic diversity of HCV-2 subtypes in the south of France and the spread of 2a strains via intravenous drug users. 相似文献
999.
Wang E 《Ageing research reviews》2007,6(1):1-11
In a society experiencing an accelerating increase in the middle- and old-age population, there is an urgent need to address age-dependent frailties by a paradigm shift, i.e. a new medical strategy to combat middle-age decline at the stage before incipient old-age problems develop into full-blown diseases. We suggest that a decline in cellular health status occurs at mid-life, and that this decline may involve a universal or system-specific programmatic shift of signaling control. This decline, although sub-clinical and asymptomatic, may precipitate increased risk of late-life diseases. The putative control for this mid-life cellular decline may be governed by a recently discovered group of molecular species, the microRNAs, small RNAs of approximately 22 nucleotide bases. In general microRNAs, while themselves not coding for any protein product, negatively regulate the expression of target genes by either degrading their message or inhibiting translation by binding to their 3'-untranslated region (UTR). Thus, possible derailment of these negative regulators for gene expression in mid-life may be the putative force inducing molecular frailty in individual cell signaling, and in time leading to tissue-wide dysfunction. A challenge for future research is then to identify these dysfunctional microRNAs, in order to develop advance diagnosis and therapy to combat mid-life decline, a preventive medicine approach to block, delay or reduce the risk of old-age diseases. 相似文献
1000.
Ten isolates belonging to different BVDV-1 subtypes and three BVDV-2 isolates were studied in 3′-nontranslated region (3′-NTR)
by sequencing of PCR products and comparative computer-assisted nucleotide sequence analysis. The alignment of nucleotide
sequences revealed that all BVDV-1 isolates except BVDV-1a isolates represented by NADL strain were characterised with a deletion
of 38 nucleotides in the variable region located after the stop codon. For all BVDV-1 subtypes, a constant region at the end
of viral genome was highly conserved. The variable and constant regions with no significant insertions or deletions were also
identified in BVDV-2 isolates. The poly AT reach region was situated at different locations in both pestiviruses. 相似文献