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   27913篇
  免费   3811篇
  国内免费   682篇
耳鼻咽喉   172篇
儿科学   196篇
妇产科学   626篇
基础医学   2896篇
口腔科学   683篇
临床医学   2266篇
内科学   3487篇
皮肤病学   262篇
神经病学   931篇
特种医学   1874篇
外国民族医学   48篇
外科学   2782篇
综合类   1537篇
现状与发展   7篇
预防医学   1168篇
眼科学   140篇
药学   1596篇
  23篇
中国医学   258篇
肿瘤学   11454篇
  2024年   55篇
  2023年   1945篇
  2022年   2908篇
  2021年   2824篇
  2020年   2837篇
  2019年   1697篇
  2018年   1264篇
  2017年   1272篇
  2016年   1366篇
  2015年   1408篇
  2014年   2600篇
  2013年   1708篇
  2012年   1574篇
  2011年   1320篇
  2010年   1563篇
  2009年   1410篇
  2008年   572篇
  2007年   812篇
  2006年   509篇
  2005年   400篇
  2004年   218篇
  2003年   198篇
  2002年   202篇
  2001年   242篇
  2000年   172篇
  1999年   202篇
  1998年   225篇
  1997年   142篇
  1996年   198篇
  1995年   159篇
  1994年   86篇
  1993年   82篇
  1992年   37篇
  1991年   54篇
  1990年   57篇
  1989年   66篇
  1988年   18篇
  1986年   2篇
  1984年   1篇
  1983年   1篇
排序方式: 共有10000条查询结果,搜索用时 307 毫秒
91.
BackgroundProstatic radiation therapy (RT) often causes erectile dysfunction (ED) and the mechanisms governing RT-induced ED are unclear with a lack of therapeutic strategies.AimTo determine the effects of ex vivo RT on major pelvic ganglion (MPG) neuron survival, and neurite growth in whole vs dissociated culture.MethodsMPGs were removed and irradiated (0 or 8 Gy) from male Sprague Dawley rats. For dissociated culture, MPG neurons were digested in collagenase/dispase and cultured on coverslips. Immunofluorescent staining for beta-tubulin III (TUBB3; neuron marker), neuronal nitric oxide synthase (nNOS; nitrergic marker), tyrosine hydroxylase (TH; sympathetic marker), and terminal deoxynucleotidyl transferase dUTP nick end labeling assessed neurite length, branching, autonomic neuron density, and apoptosis. For whole organ culture, MPGs were grown in Matrigel. Gene expression of apoptotic markers (caspase 1, 3), TUBB3, nNOS, TH, and Schwann cells (Sox10, Krox20, glial fibrillary acid protein) was measured in whole organ cultured MPGs by quantitative polymerase chain reaction.OutcomesAfter 72 hours, neurite length, branching, autonomic neuron density, and apoptosis were assessed, and gene expression was measured.ResultsRT increased apoptosis in dissociated neurons measured by terminal deoxynucleotidyl transferase dUTP nick end labeling (P < .001) and whole MPG culture via upregulation of caspase 3 gene expression (P < .05). Nitrergic neurons were markedly decreased in irradiated dissociated culture (P < .05), while nNOS gene expression was upregulated in irradiated whole organ culture (P < .05). The proportion of dissociated sympathetic neurons and whole organ TH gene expression remained unchanged after RT. Interestingly, RT dissociated neurites were 22% shorter than controls, while RT whole organ neurites were 15% longer than controls (P < .01). MPG Schwann cells markers (Sox10, Krox20) were elevated after RT in whole organ culture.Clinical TranslationProstatic RT leads to increased neuronal cell death and less erectogenic nitrergic neurons contributing to ED.Strengths & LimitationsThe advantages of dissociated neuron culture include distinct neurites which are easily measured for apoptosis, length/branching, and specific neuron types. In contrast, whole MPG culture is advantageous as it contains all the supporting cells present in vivo.ConclusionThe 2 different culture methods demonstrated opposing neurite growth after RT indicating the importance of supporting cell network to promote pelvic neuron neuritogenesis and survival following RT.Randolph JT, Pak ES, Koontz BF, et al. Ex Vivo Radiation Leads to Opposing Neurite Growth in Whole Ganglia vs Dissociated Cultured Pelvic Neurons. J Sex Med 2020;17:1423–1433.  相似文献   
92.
This study aimed to observe the therapeutic effects of magnesium lithospermate B on acute and chronic colitis induced by dextran sodiumsulfate (DSS) and the role of inflammasome complex (NOD-like receptor protein, NLRP; apoptosis-associated speck-like protein containing, ASC; caspase-1). Establishment of acute and chronic colitis models were by using 5% DSS oral administration in BALB/C male mice. Magnesium lithospermate B (240 mg/kg body weight) was given by subcutaneous injection. Samples were collected for biomarker assay, histological examination, immunohistochemical evaluation and western blot. There was obvious increase in TNF-α level and NLPR3, ASC, and caspase-1 expressions in acute and chronic colitis groups compared with the normal control. Significant decrease of the tumor necrosis factor-α level and the expressions of NLPR3, ASC, and caspase-1 were observed after treatment with magnesium lithospermate B. This study showed that magnesium lithospermate B could be used to treat acute and chronic colitis by inhibiting the activation of the NLRP3/ASC/Caspase-1 pathway.  相似文献   
93.
屈娜  王晓彬 《现代肿瘤医学》2020,(10):1744-1749
目的:研究D-二聚体(D-dimer,D-D)和中性粒细胞/淋巴细胞比值(neutrophil to lymphocyte ratio,NLR)与卵巢癌临床病理特征及预后的关系。方法:回顾性分析2012年1月至2015年12月于我院妇科行手术治疗的卵巢恶性肿瘤患者387例和卵巢良性肿瘤患者250例临床资料。比较血清D-D和外周血NLR在卵巢良、恶性肿瘤中的表达水平;确定D-D和NLR临界值,D-D+NLR=0(D-D≤0.555 mg/L和NLR≤2.792),D-D+NLR=1(D-D>0.555 mg/L或NLR>2.792),D-D+NLR=2(D-D>0.555 mg/L和NLR>2.792),分析两者联合的评分系统与卵巢癌临床病理特征和预后的关系。结果:血清D-D和外周血NLR在卵巢良、恶性肿瘤患者中的表达水平有统计学差异(P<0.001)。D-D高水平组与低水平组相比,患者的分期、分级、淋巴结转移、腹水、CA125水平、残余瘤大小有统计学差异(P<0.05)。NLR高水平组与低水平组相比,患者的年龄、分期、淋巴结转移、腹水、CA125水平、残余瘤大小有统计学差异(P<0.05)。D-D+NLR为0、1、2分的平均总生存期(OS)分别为70个月、58个月、40个月。D-D+NLR评分是影响OS的独立预后因素。结论:术前血清D-D和外周血NLR与卵巢癌临床病理特征和OS相关,D-D+NLR评分可以作为评估卵巢癌预后的指标。  相似文献   
94.
自噬是真核细胞通过溶酶体对其自身生物大分子和细胞器回收再利用的过程,其在维持细胞稳态中发挥重要作用,并参与多种病理生理过程。在肿瘤的发病过程中,自噬发挥“双面作用”,既可以抗癌也能促癌。前列腺癌是老年男性最常见的恶性肿瘤,研究表明前列腺癌的发生发展与自噬作用密切相关,放化疗、内分泌治疗等对肿瘤细胞造成的应激可通过自噬得以缓解,抵抗治疗,因而自噬抑制剂对于放化疗等具有协同促进作用。本文就自噬在前列腺癌中发病和治疗进行综述,以期为前列腺癌的诊治提供一些新的思路。  相似文献   
95.
96.
PurposeWe aim to develop and validate a new adaptive method for prostate cancer radiation therapy (RT), using an offline strategy to improve treatment personalization by modeling the internal target volume on individual basis and account for the residual set-up uncertainties by robust optimization.Methods and MaterialsTwenty patients with intermediate-high prostate cancer treated with radical radiation therapy were enrolled. The first step of the offline adaptive RT strategy is the identification of a patient-specific internal target volume based on the kV cone beam computed tomography (kV-CBCT) data sets acquired during the first 5 fractions. The deformable image registration algorithm ANACONDA was used to propagate the clinical target volumes (CTVs) from the reference-planning computed tomography to the CBCTs; these contours were assessed by a radiation oncologist. In the second step, the internal target volume was used to replan the treatment using a min-max robust algorithm based on the worst scenario optimization. The CTV coverage and organs-at-risk sparing achieved with the robust plan (RP) were analyzed and compared with the original standard plan, calculating the dose distributions on the residual CBCTs.ResultsThe RP was shown to achieve optimal coverage of the CTV even in the worst scenario, with significantly lower doses to the rectum and bladder. CTV coverage of the RP was statistically better than the standard plan in terms of D99 (P = .008) and D98 (P = .02). Statistically significant mean dose reduction and D2 reduction were noted for the rectum (P < .05) and bladder (P < .009). Moreover, the RP appeared to be less sensitive to bladder and rectal filling.ConclusionsThis adaptive strategy in prostate cancer radiation therapy is feasible and safe; it may be used to adapt the treatment with better target coverage and organs-at-risk sparing than standard planning target volume–based planning.  相似文献   
97.
98.
Recent meta-analyses on checkpoint inhibitors in cancer report conflicting data regarding the association of patient gender with inhibitor efficacy. In advanced kidney cancer, checkpoint inhibitors have shown improved outcomes in first- and second-line settings compared with standard of care, but the role of patient gender on treatment outcome is unclear. We aimed to assess the efficacy of immunotherapy according to patient gender in advanced kidney cancer.We performed a systematic review and meta-analysis according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A literature search was performed using PubMed, Scopus, Web of Science, and The Cochrane Library to identify eligible studies published through February 16, 2019. Studies were included if they reported on the differential outcomes of male and female patients with metastatic kidney cancer receiving immunotherapy. Our outcomes of interest were overall survival (OS) or progression-free survival (PFS).Four randomized controlled trials comprising a total of 3664 patients (2715 males and 949 females) met our inclusion criteria. Both men and women with metastatic kidney cancer had an OS and PFS advantage with immunotherapy compared with standard-of-care, but no statistically significant difference between the genders was observed (OS hazard ratio [HR] for men, 0.69; 95% confidence interval [CI], 0.59-0.8; P = .40; HR for women, 0.62; 95% CI, 0.48-0.81; P = .13; PFS HR for men, 0.7; 95% CI, 0.59-0.82; P = .24; HR for women, 0.68; 95% CI, 0.52-0.90; P = .105).In patients with advanced kidney cancer receiving checkpoint inhibitors, there seems to be no association of patient gender with treatment outcome.  相似文献   
99.
100.
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