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   26293篇
  免费   2567篇
  国内免费   2133篇
耳鼻咽喉   215篇
儿科学   268篇
妇产科学   367篇
基础医学   3289篇
口腔科学   518篇
临床医学   3631篇
内科学   4061篇
皮肤病学   199篇
神经病学   1536篇
特种医学   980篇
外国民族医学   14篇
外科学   2769篇
综合类   4139篇
现状与发展   8篇
一般理论   4篇
预防医学   1631篇
眼科学   616篇
药学   2897篇
  21篇
中国医学   1532篇
肿瘤学   2298篇
  2025年   10篇
  2024年   366篇
  2023年   562篇
  2022年   1118篇
  2021年   1387篇
  2020年   1072篇
  2019年   923篇
  2018年   877篇
  2017年   886篇
  2016年   773篇
  2015年   1175篇
  2014年   1544篇
  2013年   1272篇
  2012年   1877篇
  2011年   1947篇
  2010年   1278篇
  2009年   989篇
  2008年   1399篇
  2007年   1390篇
  2006年   1271篇
  2005年   1401篇
  2004年   928篇
  2003年   913篇
  2002年   733篇
  2001年   592篇
  2000年   654篇
  1999年   658篇
  1998年   432篇
  1997年   388篇
  1996年   335篇
  1995年   315篇
  1994年   281篇
  1993年   183篇
  1992年   208篇
  1991年   178篇
  1990年   142篇
  1989年   104篇
  1988年   110篇
  1987年   76篇
  1986年   77篇
  1985年   52篇
  1984年   34篇
  1983年   27篇
  1982年   12篇
  1981年   9篇
  1980年   8篇
  1979年   10篇
  1978年   3篇
  1977年   4篇
  1929年   2篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
This paper investigates the acute effects of carbofuran in workers of two pesticide-formulating plants. Mean airborne carbofuran concentrations ranged from 0.025 to 1.115 mg/m3 in plant A and from 0.018 to 0.067 mg/m3 in plant B, respectively. In workers of plant A the post-shift blood cholinesterase activity was significantly reduced, compared to pre-shift values. No difference in blood cholinesterase activity was found between pre- and post-shift values in workers of plant B. During the investigation, 25 cases of acute carbofuran poisoning were diagnosed by their clinical picture and depressed cholinesterase activity in blood. Usual symptoms included dizziness, weakness, blurred vision, nausea and sweating. Pallor, epigastric pain, vomiting and chest tightness occurred only in a few cases. Myosis was recorded in 24 cases. Fasciculation of muscle gastrocnemius induced by percussion was found in 6 cases, and four of them had also fasciculation of muscle orbicularis oculi. Inhibition of cholinesterase activity in the blood was related with the clinical features; however, the inhibition was rapidly reversible. In most cases, recovery was complete within 2-3 hours, with or without atropine treatment, after the subjects were removed from exposure. Rapid onset, mild illness and quick recovery are typical characteristics of occupational acute carbofuran poisoning.  相似文献   
992.
丁长囡  沈耕荣等 《上海医学》1993,16(1):14-16,F004
本文分析35例亚急性重症肝炎(简称亚重肝)的超微结构改变。其中病因有HBV 32例(91.4%),NANB1例(2.9%),HBV合并HDV1例(2.9%),未定2例,早期4例(11.4%),中期24例(68.6%),后期7例(20%),电镜下见大片肝细胞坏死,为炎症细胞取代,残存及再生肝细胞均呈不同程度的变性,浆内出现灶性及融合性液化区,细胞器严重损害,尤以线粒体及内质网为甚。作者认为光镜和电镜结合观察,是研究亚重肝形态改变的重要手段。  相似文献   
993.
994.
The main goal of brain tumor surgery is to maximize tumor resection while minimizing the risk of irreversible postoperative functional sequelae. Eloquent functional areas should be delineated preoperatively, particularly for patients with tumors near eloquent areas. Functional magnetic resonance imaging (fMRI) is a noninvasive technique that demonstrates great promise for presurgical planning. However, specialized data processing toolkits for presurgical planning remain lacking. Based on several functions in open-source software such as Statistical Parametric Mapping (SPM), Resting-State fMRI Data Analysis Toolkit (REST), Data Processing Assistant for Resting-State fMRI (DPARSF) and Multiple Independent Component Analysis (MICA), here, we introduce an open-source MATLAB toolbox named PreSurgMapp. This toolbox can reveal eloquent areas using comprehensive methods and various complementary fMRI modalities. For example, PreSurgMapp supports both model-based (general linear model, GLM, and seed correlation) and data-driven (independent component analysis, ICA) methods and processes both task-based and resting-state fMRI data. PreSurgMapp is designed for highly automatic and individualized functional mapping with a user-friendly graphical user interface (GUI) for time-saving pipeline processing. For example, sensorimotor and language-related components can be automatically identified without human input interference using an effective, accurate component identification algorithm using discriminability index. All the results generated can be further evaluated and compared by neuro-radiologists or neurosurgeons. This software has substantial value for clinical neuro-radiology and neuro-oncology, including application to patients with low- and high-grade brain tumors and those with epilepsy foci in the dominant language hemisphere who are planning to undergo a temporal lobectomy.  相似文献   
995.
BackgroundTo evaluate the safety and efficacy of single incision plus one (SI+1) port three-dimensional (3D) laparoscopic minimally invasive esophagectomy (MIE).MethodsClinical data of patients who underwent 3D thoracic laparoscopic MIE in our department from September 2020 to March 2021 were analyzed retrospectively. According to the different methods of laparoscopic surgery, the patients were divided into 2 groups: SI+1 port 3D laparoscopy group and multiportal 3D laparoscopy group. The operation time of the 3D laparoscopy component, amount of intraoperative blood loss, number of celiac lymph node dissections, postoperative abdominal drainage days, postoperative total abdominal drainage, postoperative complications, and length of hospital stay were analyzed.ResultsThere was no significant difference between the 2 methods in laparoscopic operation time (30.11±5.86 vs. 28.45±4.72 min, P=0.49), intraoperative blood loss (34.44±9.82 vs. 35.91±6.25 mL, P=0.69), number of celiac lymph node dissections (8.44±3.13 vs. 7.09±2.12, P=0.27), postoperative abdominal drainage days (3.11±0.33 vs. 3.00±0.00 days, P=0.28), postoperative total abdominal drainage (95.00±23.33 vs. 92.27±11.26 mL, P=0.74), postoperative complications (22.2% vs. 27.3%, P=0.33), and hospital stay (9.67±0.71 vs. 10.18±0.87 days, P=0.17). None of the patients enrolled in the study had recurrence or death to date.ConclusionsThe application of SI+1 port 3D laparoscopy in minimally invasive resection of esophageal carcinoma is safe and feasible.  相似文献   
996.
997.
The Chlamydia-secreted protease/proteasome-like activity factor (CPAF) is synthesized as a proenzyme (proCPAF) and requires processing for proteolytic activity. Recent structural studies have further demonstrated that CPAF is a serine protease that can undergo autoprocessing and self-activation in a concentration-dependent manner in vitro. However, it is not known how CPAF is processed and activated during chlamydial infection. In the current study, we used a mutant CPAF designated as CPAF(E558A) that is deficient in processing by itself as a substrate to search for putative CPAF activation factor(s) in Chlamydia-infected cells. CPAF(E558A) was processed by the lysates made from Chlamydia-infected cells and the processing activity correlated with the presence of endogenous active CPAF in the fractionated lysate samples. CPAF produced in the Chlamydia-infected cells is required for processing the mutant CPAF(E558A) since the processing activity was removed by depletion with anti-CPAF but not control antibodies. Furthermore, a purified and activated wild type CPAF alone was sufficient for processing CPAF(E558A) and no other chlamydial proteases are required. Finally, fusion tag-induced oligomerization can lead to autoprocessing and self-activation of the wild type CPAF in mammalian cells. These observations together have demonstrated that CPAF undergoes autoprocessing and self-activation during chlamydial infection.  相似文献   
998.
本文旨在建立压力负荷过重心表模型,并且通过无创性心功能的动态检测及常规病理等指标的观察,探讨毛冬青甲素(IA)对心衰模型的强心效应。结果表明:毛冬青甲素能提高心脏每搏排血量(SV)和心脏指数(CI),延缓毛冬青甲素组(毛甲组)兔心功SV、CI的下降:即时效应显示,IA给药后SV和CD逐渐升高,给药2小时后SV和CI达到最高峰,并接近术前正常值水平;在病理变化方面,由于IA的应用,毛甲组病理变化较对照组减轻,毛甲组心衰症候群得到不同程度的改善。提示毛冬青甲素有较好的强心作用。  相似文献   
999.
Zhu W  Zhao L  Zhang J  Ding X  Liu H  Ni E  Ma Y  Zhou C 《Neuroscience letters》2008,434(1):35-40
In the present study, the effects of Mozart's sonata K.448 on voluntary and involuntary attention were investigated by recording and analyzing behavioral and event-related potentials (ERPs) data in a three-stimulus visual oddball task. P3a (related to involuntary attention) and P3b (related to voluntary attention) were analyzed. The "Mozart effect" was showed on ERP but not on behavioral data. This study replicated the previous results of Mozart effect on voluntary attention: the P3b latency was influenced by Mozart's sonata K.448. But no change of P3a latency was induced by this music. At the same time, decreased P3a and P3b amplitudes in music condition were found. We interpret this change as positive "Mozart effect" on involuntary attention (P3a) and negative "Mozart effect" on voluntary attention (P3b). We conclude that Mozart's sonata K.448 has shown certain effects on both involuntary attention and voluntary attention in our study, but their effects work on different mechanisms.  相似文献   
1000.
Hui Ding  Zhongyun Ning 《Renal failure》2016,38(9):1311-1319
To evaluate the efficacy of Silodosin as a medical expulsive therapy of ureteral stones, we searched PubMed, EMBASE, the Cochrane Library, and CBM up to June 2015. All randomized controlled trials (RCTs) were identified in which patients were randomized to receive Silodosin versus placebo or other therapies for ureteral stones. Outcome measures assessed were overall stone expulsion rate (primary) and expulsion time, analgesics times, and the incidence of additional treatment and regarding treatment complications (secondary). Two authors independently assessed study quality and extracted data. All data were analyzed using RevMan 5.3. Seven RCTs with a total of 1035 patients met the inclusion criteria. The pooled meta-analysis showed a significant improvement in stone clearance with Silodosin (Silodosin versus placebo, OR?=1.69, 95% CI [1.19–2.40], p?=?0.003; Silodosin versus tamsulosin, OR?=2.82, 95% CI [1.79–4.44], p?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