首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   29708篇
  免费   2723篇
  国内免费   1787篇
耳鼻咽喉   282篇
儿科学   324篇
妇产科学   382篇
基础医学   3684篇
口腔科学   466篇
临床医学   3847篇
内科学   4786篇
皮肤病学   229篇
神经病学   1868篇
特种医学   1156篇
外国民族医学   24篇
外科学   3153篇
综合类   4267篇
现状与发展   5篇
一般理论   16篇
预防医学   2104篇
眼科学   696篇
药学   2973篇
  13篇
中国医学   1341篇
肿瘤学   2602篇
  2024年   85篇
  2023年   390篇
  2022年   1006篇
  2021年   1332篇
  2020年   977篇
  2019年   879篇
  2018年   1012篇
  2017年   881篇
  2016年   908篇
  2015年   1326篇
  2014年   1537篇
  2013年   1394篇
  2012年   2240篇
  2011年   2324篇
  2010年   1483篇
  2009年   1217篇
  2008年   1669篇
  2007年   1721篇
  2006年   1713篇
  2005年   1595篇
  2004年   1307篇
  2003年   1394篇
  2002年   1191篇
  2001年   672篇
  2000年   559篇
  1999年   528篇
  1998年   324篇
  1997年   360篇
  1996年   286篇
  1995年   271篇
  1994年   231篇
  1993年   167篇
  1992年   199篇
  1991年   162篇
  1990年   152篇
  1989年   95篇
  1988年   98篇
  1987年   80篇
  1986年   64篇
  1985年   61篇
  1984年   59篇
  1983年   27篇
  1982年   29篇
  1981年   25篇
  1980年   16篇
  1979年   14篇
  1978年   11篇
  1977年   11篇
  1974年   9篇
  1973年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Ghrelin, one of the brain-gut peptides, stimulates food-intake. Recently, ghrelin has also shown to play an important role in depression treatment. However, the mechanism of ghrelin’s antidepressant-like actions is unknown. On the other hand, sex differences in depression, and the fluctuation of estrogens secretion have been proved to play a key role in depression. It has been reported that women have higher level of ghrelin expression, and ghrelin can stimulate estrogen secretion while estrogen acts as a positive feedback mechanism to up-regulate ghrelin level. Ghrelin may be a potential regulator of reproductive function, and estrogen may have additional effect in ghrelin’s antidepressantlike actions. In this review, we summarize antidepressant-like effects of ghrelin and estrogen in basic and clinical studies, and provide new insight on ghrelin’s effect in depression.  相似文献   
992.

Aim:

To develop a population pharmacokinetic (PopPK) model of tacrolimus in healthy Chinese volunteers and liver transplant recipients for investigating the difference between the populations, and for potential individualized medication.

Methods:

A set of 1100 sparse trough concentration data points from 112 orthotopic liver transplant recipients, as well as 851 dense data points from 40 healthy volunteers receiving a single dose of tacrolimus (2 mg, po) were collected. PopPK model of tacrolimus was constructed using the program NONMEM. Related covariates such as age, hepatic and renal functions that were potentially associated with tacrolimus disposition were evaluated. The final model was validated using bootstrapping and a visual predictive check.

Results:

A two-compartment model of tacrolimus could best describe the data from the two populations. The final model including two covariates, population (liver transplant recipients or volunteers) and serum ALT (alanine aminotransferase) level, was verified and adequately described the pharmacokinetic characteristics of tacrolimus. The estimates of V2/F, Q/F and V3/F were 22.7 L, 76.3 L/h and 916 L, respectively. The estimated CL/F in the volunteers and liver transplant recipients was 32.8 and 18.4 L/h, respectively. Serum ALT level was inversely related to CL/F, whereas age did not influence CL/F. Thus, the elderly (≥65 years) and adult (<65 years) groups in the liver transplant recipients showed no significant difference in the clearance of tacrolimus.

Conclusion:

Compared with using the sparse data only, the integrating modeling technique combining sparse data from the patients and dense data from the healthy volunteers improved the PopPK analysis of tacrolimus.  相似文献   
993.

Aim:

Interferon-γ inducible protein 16 (IFI16), a DNA sensor for DNA double-strand break (DSB), is expressed in most human hepatocellular carcinoma cell (HCC) lines. In this study we investigated the re-localization of chromatin-bound IFI16 by Nutlin-3, a DNA damage agent, in HCC cells in vitro, and the potential mechanisms.

Methods:

Human HCC SMMC-7721 (wild-type TP53), Huh-7 (mutant TP53), Hep3B (null TP53) and normal fetal liver L02 cell lines were examined. DSB damage in HCC cells was detected via γH2AX expression and foci formation assay. The expression of IFI16 and IFNB mRNA was measured using RT-PCR, and subcellular localization and expression of the IFI16 protein were detected using chromatin fractionation, Western blot analysis, and fluorescence microscopy.

Results:

Treatment of SMMC-7721 cells with Nutlin-3 (10 μmol/L) or etoposide (40 μmol/L) induced significant DSB damage. In SMMC-7721 cells, Nutlin-3 significantly increased the expression levels of IFI16 and IFNB mRNA, and partially redistributed chromatin-bound IFI16 protein to the cytoplasm. These effects were blocked by pretreatment with pifithrin-α, a p53 inhibitor. Furthermore, Nutlin-3 did not induce ectopic expression of IFI16 protein in Huh-7 and Hep3B cells. Moreover, the association of IFI16 with chromatin and Nutlin-3-induced changes in localization were not detected in L02 cells.

Conclusion:

Nutlin-3 regulates the subcellular localization of IFI16 in HCC cells in vitro in a p53-dependent manner.  相似文献   
994.
This study aimed to investigate the effects of the basic treatment for heart failure and sequential treatment with rh-brain natriuretic peptide (rhBNP) alone or the combination of rhBNP and sacubitril/valsartan. Cardiac structure, pulmonary artery pressure, inflammation and oxidative stress in patients with acute heart failure were evaluated.Three hundred patients with acute heart failure were included. According to the random number table method, the patients were divided into 3 groups of 100 patients per group: the standard treatment group (treated with an angiotensin-converting enzyme inhibitor, β receptor blocker, and corticosteroid antagonist), rhBNP group (basic treatment combined with rhBNP) and sequential treatment group (basic treatment for heart failure combined with rhBNP followed by sacubitril/valsartan). The changes in NT-probrain natriuretic peptide (BNP) levels, cardiac troponin T (cTnT) levels, cardiac structure, pulmonary artery pressure, and the levels inflammatory factors and oxidative stress factors were compared among the 3 groups at 1, 4, 12, and 36 weeks after treatment.The sequential treatment group displayed superior outcomes than the standard treatment group and the rhBNP group in terms of left atrium diameter, left ventricular end diastolic volume, left ventricular ejection fraction, pulmonary artery pressure, NT-proBNP levels, and cTnT levels, which respond to damage to the heart structure and myocardium. This result may be related to the decreased levels of inflammatory factors and the correction of oxidative stress imbalance.Sacubitril/valsartan significantly reduce the serum levels of inflammatory factors in patients with acute heart failure while decreasing the levels of oxidizing factors and increasing the levels of antioxidant factors. These changes may be one of the explanations for the better cardiac structure and better pulmonary artery pressure observed in the sequential treatment group.  相似文献   
995.
Rationale:Endogenous fungal endophthalmitis (EFE) is a sight-threatening complication of systemic fungemia. As the prevalence rises, treatment remains a challenge especially when there is a failure in first-line treatment or drug-resistant fungus. This case report studies a case of chronic EFE, focusing on the diagnostic procedures, treatment options, monitoring parameters and the treatment outcomePatient concerns:A 64-year-old man with underlying well controlled diabetes mellitus was treated with 2 weeks’ course of intravenous antifungal fluconazole for pyelonephritis as his blood culture grew Candida albicans. Concurrently, he complained of 3 months of bilateral painless progressive blurring of vision. At presentation, his visual acuity (VA) was light perception both eyes. Ocular examination revealed non granulomatous inflammation with dense vitritis of both eyes.Diagnosis:He was diagnosed with EFE but the condition responded poorly with the medications.Interventions:He was treated with intravitreal (IVT) amphotericin B and fluconazole was continued. Vitrectomy was performed and intraoperative findings included bilateral fungal balls in the vitreous and retina with foveal traction in the left eye. Postoperatively, vision acuity was 6/24, N8 right eye and 2/60, N unable for left eye with extensive left macular scar and hole. Vitreous cultures were negative. He received multiple IVT amphotericin B and was started on topical steroid eye drops for persistent panuveitis with systemic fluconazole. Ocular improvement was seen after switching to IVT and topical voriconazole. Despite this, his ocular condition deteriorated and he developed neovascular glaucoma requiring 3 topical antiglaucoma agents. Panretinal photocoagulation was subsequently performed.Outcomes:At 3 months’ follow-up, his vision acuity remained at 6/24 for right eye and 2/60 for the left eye. There was no recurrence of inflammation or infection in both eyes.Lessons:Voriconazole could serve as a promising broad spectrum tri-azole agent in cases of failure in first-line treatment or drug-resistant fungus.  相似文献   
996.
Background:Spinal cord injury (SCI) is one of the most disabling and destructive neurological diseases. Neurogenic bladder dysfunction (NBD) is one of the serious complications after SCI, 80% of patients after SCI will have neurogenic bladder symptoms. NBD after SCI may lead to urinary retention, urinary incontinence, and urinary tract infection. In severe cases, it can lead to renal failure or even death. NBD after SCI not only seriously affects the patient''s quality of life but also physical and mental health. NBD after SCI is a social and medical problem. In recent years, more and more clinical studies prove that heat-sensitive can improve the clinical symptoms of NBD after SCI. Therefore, this article conducts a systematic evaluation and meta-analysis on the efficacy and safety of heat-sensitive moxibustion in treating NBD after SCI.Methods:Search 8 electronic databases including PubMed, Embase, Web of Science, The Cochrane Library, Clinical Trials, China National Knowledge Infrastructure, China Science and Technology Journal Database, Wanfang Database, and China Biomedical Literature Database. We will search above electronic databases from the inception to May 2021, without any language restriction. Clinical randomized controlled trials containing heat-sensitive moxibustion for NBD after SCI and eligible interventions(s) and outcome(s) were included, with no limitation of language and publication status. Two researchers will independently conduct literature search, screening, information extraction, quality assessment, and data analysis. Review Manager 5.3 software will be used for statistical analysis.Results:The findings will be submitted to a peer-reviewed publication.Conclusion:This systematic review and meta-analysis will provide a standard clinical decision-making guideline for heat-sensitive moxibustion treatment of NBD after SCI.INPLASY registration number:INPLASY202150071.  相似文献   
997.
998.
The retinoblastoma tumor suppressor protein pRb restricts cell growth through inhibition of cell cycle progression. Increasing evidence suggests that pRb also promotes differentiation, but the mechanisms are poorly understood, and the key question remains as to how differentiation in tumor cells can be enhanced in order to diminish their aggressive potential. Previously, we identified the histone demethylase KDM5A (lysine [K]-specific demethylase 5A), which demethylates histone H3 on Lys4 (H3K4), as a pRB-interacting protein counteracting pRB''s role in promoting differentiation. Here we show that loss of Kdm5a restores differentiation through increasing mitochondrial respiration. This metabolic effect is both necessary and sufficient to induce the expression of a network of cell type-specific signaling and structural genes. Importantly, the regulatory functions of pRB in the cell cycle and differentiation are distinct because although restoring differentiation requires intact mitochondrial function, it does not necessitate cell cycle exit. Cells lacking Rb1 exhibit defective mitochondria and decreased oxygen consumption. Kdm5a is a direct repressor of metabolic regulatory genes, thus explaining the compensatory role of Kdm5a deletion in restoring mitochondrial function and differentiation. Significantly, activation of mitochondrial function by the mitochondrial biogenesis regulator Pgc-1α (peroxisome proliferator-activated receptor γ-coactivator 1α; also called PPARGC1A) a coactivator of the Kdm5a target genes, is sufficient to override the differentiation block. Overexpression of Pgc-1α, like KDM5A deletion, inhibits cell growth in RB-negative human cancer cell lines. The rescue of differentiation by loss of KDM5A or by activation of mitochondrial biogenesis reveals the switch to oxidative phosphorylation as an essential step in restoring differentiation and a less aggressive cancer phenotype.  相似文献   
999.
Resistant starch, as a source of energy for the beneficial bacteria in intestine, may have beneficial health effects, limiting your risk for obesity and colon problems. This study evaluated the effects of sorghum resistant starch (SRS) on the changes of body weight, blood lipid and the population of intestinal flora in the colon of high-fat diet-induced (HFD) overweight and obese rats which contained 60 rats. Sixty male rats were divided into five groups of normal control group (NC), model control group (MC A), model control group (MC B), sorghum resistant starch A group (SRS A) and sorghum resistant starch B group (SRS B) which administrated standard diet, diets A and B. The results indicated that SRS helps the body prevent and treat obesity through mechanisms including synthesis and secretion of leptin (LP) and adiponcetin (ADP) and improvement in intestinal flora.  相似文献   
1000.
<正>解剖学图谱作为重要的辅助教学及医学学习工具,通过一幅幅图文并茂的图片向读者展示人体复杂的解剖学结构和形态学特点。纵观国内出版的各类解剖学图谱,大多以图片为主,基本甚少附文字注解,而国外的经典解剖图谱,尤其是目前全球公认的权威图谱Gray's解剖学图谱~([1])、Grant's解剖学图谱~([2])和Thieme解剖图谱系列~([3])都是图片与文字注解相结合,并越来越  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号