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   3531篇
  免费   183篇
  国内免费   10篇
耳鼻咽喉   37篇
儿科学   70篇
妇产科学   44篇
基础医学   396篇
口腔科学   136篇
临床医学   263篇
内科学   858篇
皮肤病学   36篇
神经病学   461篇
特种医学   72篇
外科学   614篇
综合类   18篇
一般理论   1篇
预防医学   272篇
眼科学   63篇
药学   187篇
中国医学   5篇
肿瘤学   191篇
  2024年   5篇
  2023年   30篇
  2022年   67篇
  2021年   122篇
  2020年   75篇
  2019年   104篇
  2018年   107篇
  2017年   69篇
  2016年   110篇
  2015年   82篇
  2014年   154篇
  2013年   153篇
  2012年   278篇
  2011年   286篇
  2010年   154篇
  2009年   146篇
  2008年   211篇
  2007年   225篇
  2006年   211篇
  2005年   221篇
  2004年   166篇
  2003年   152篇
  2002年   148篇
  2001年   67篇
  2000年   39篇
  1999年   41篇
  1998年   20篇
  1997年   28篇
  1996年   24篇
  1995年   9篇
  1994年   8篇
  1993年   9篇
  1992年   15篇
  1991年   16篇
  1990年   17篇
  1989年   13篇
  1988年   16篇
  1987年   7篇
  1986年   19篇
  1985年   6篇
  1984年   10篇
  1983年   10篇
  1982年   9篇
  1980年   6篇
  1979年   6篇
  1978年   12篇
  1977年   7篇
  1976年   8篇
  1969年   5篇
  1965年   3篇
排序方式: 共有3724条查询结果,搜索用时 0 毫秒
21.
Simultaneous measurements of skin potential (SP) and skin resistance (SR) obtained from 20 male and 20 female adult subjects during 2 sessions held 2 to 9 days apart were used in studying (1) the correlation of change measurements and prestimulus level in the two measures, and (2) the amount of correlation between SP and SR using both simple difference and residual change scores in which the regression of poststimulus values on initial level (prestimulus) has been controlled. Correlations within Ss and correlations among Ss showed large individual variability, correlation differences between males and females, and high correlation between SP and SR change scores. Although the law of initial value (LIV) seemed to have little applicability to the measurement of electrodermal responses, the results underscored the need to control for contamination of change measures by initial level regardless of direction.  相似文献   
22.
Patients infected with HIV-1 develop a potent humoral immune response against the virus, but HIV-1 primary isolates are remarkably resistant to neutralizing antibodies. Considering that the envelope glycoprotein of HIV-1 (gp120/41) is heavily glycosylated, we investigated whether anti-carbohydrate antibodies could inhibit HIV-1 infection in vitro. We studied the neutralizing activity of three monoclonal antibodies (mAbs) raised to carbohydrates of Schistosoma mansoni, against seven primary isolates of HIV-1. Assays were performed infecting peripheral blood mononuclear cells from normal donors with viral isolates previously treated with mAbs. Viral strains used were tropic for the coreceptors CCR5, CXCR4, and dual-tropic ones. We found that the anti-glycan mAbs vigorously inhibited HIV-1 infection, regardless of the preferential coreceptor usage of the isolate, in a dose-response manner. Importantly, five isolates were resistant to neutralization by two HIV-1 antibody-positive human sera endowed with potent anti-HIV-1 inhibitory activity. Our findings suggest that carbohydrates of the HIV-1 viral envelope may be a target of an effective humoral immune response elicited by vaccination.The first two authors contributed equally to this work  相似文献   
23.
Obesity and diet are associated with colorectal cancer (CRC) risk, and microbiome could mediate this risk factor. To investigate this interaction, we performed a case–control study (34 CRC cases and 32 controls) and analyzed fecal microbiota composition using 16S rRNA metabarcoding and sub-sequential shotgun analyses of genomic bacterial DNA to evaluate the role of microbiome and diet in CRC etiology, taking into account vitamin D and other risk biomarkers. Dietary habits were evaluated using a short questionnaire. Multivariate methods for data integration and mediation analysis models were used to investigate causal relationships. CRC cases were significantly more often deficient in vitamin D than controls (p = 0.04); FokI and CYP24A1 polymorphism frequency were different between cases and controls (p = 0.03 and p = 0.02, respectively). A diet poor in fatty fish and rich in carbohydrates was found to be significantly associated with CRC risk (p = 0.011). The mediation analysis confirmed the significant role of the microbiome in mediating CRC risk—increasing levels of Bifidobacteria/Escherichia genera ratio, an indicator of “healthy” intestinal microbiome, can overcome the effect of diet on CRC risk (p = 0.03). This study suggests that microbiome mediates the diet effect on CRC risk, and that vitamin D, markers of inflammation, and adipokines are other factors to consider in order to achieve a better knowledge of the whole carcinogenic process.  相似文献   
24.
Acute poststreptococcal GN (APSGN) is the prototype of immune complex GN and is associated with manifestations of autoimmune reactivity that have been neglected as epiphenomena. Recently, studies have demonstrated transient antifactor B autoantibodies that activate the alternative complement pathway, bringing self-immunity to a central position in the pathogenesis of APSGN. Therefore, examining other manifestations of autoimmunity that have been reported in association with poststreptococcal GN is of interest. This article reviews the renal and extrarenal manifestations of autoimmune reactivity in APSGN and considers their potential relevance in modifying the usually benign clinical course of the disease. It also discusses related aspects of the nephritogenic antigens, complement activation, and genetic elements associated with immune reactivity and their potential relevance to the familial incidence of the disease.  相似文献   
25.
26.
27.
Thirty-one patients with metastatic breast cancer not responding or progressing after initial response to adriamycin + cyclophosphamide (AC) treatment entered a phase 11 study with oral lonidamine in association to AC. Objective clinical responses were observed in 10 patients (32%) and consisted of 1 complete + 9 partial remissions. Disease stability and progression were observed in 8 and 13 cases, respectively. These results were obtained with a marginal toxicity in addition to that already reported for AC therapy, the main additional side effect being myalgia, which was easily manageable in most cases.  相似文献   
28.
29.
Propofol provokes a slight hypotensive effect that could mitigate the cardiovascular response to electroconvulsive therapy (ECT). In this study we compared the effects of propofol and thiopental for ECT anesthesia in seven women (22-67 years of age). Anesthesia was induced with either thiopental or propofol, and with atropine and suxamethonium for each treatment. The first anesthesia was assigned to thiopental or propofol at random; the next anesthesia was induced with the other drug, and alternated thereafter. Systolic blood pressure, diastolic blood pressure (DBP), and heart rate (HR) were recorded before anesthesia, after anesthetic induction, and 1 and 5 min after ECT. ECT-induced increases in DBP and HR were less marked with propofol than with thiopental. Seizure durations were decreased with propofol compared with thiopental.  相似文献   
30.
Although electrical seizure activity in response to opioids such as fentanyl has been well described in animals, scalp electroencephalographic (EEG) recordings have failed to demonstrate epileptiform activity following narcotic administration in humans. The purpose of this study was to determine whether fentanyl is capable of evoking electrical seizure activity in patients with complex partial (temporal lobe) seizures. Nine patients were studied in whom recording electrode arrays had been placed in the bitemporal epidural space several days earlier to determine which temporal lobe gave rise to their seizures. The symptomatic temporal lobe was localized by correlating clinical and electrical seizure activity obtained during continuous simultaneous videotape and epidural EEG monitoring. In each patient, clinical seizures and electrical seizure activity were consistently demonstrated to arise unilaterally from one temporal lobe (four on the right, five on the left). During fentanyl induction of anesthesia in preparation for secondary craniotomy for anterior temporal lobectomy, eight of the nine patients exhibited electrical seizure activity at fentanyl doses ranging from 17.7 to 35.71 micrograms.kg-1 (mean 25.75 micrograms.kg-1). More importantly, four of these eight seizures occurred initially in the "healthy" temporal lobe contralateral to the surgically resected lobe from which the clinical seizures had been shown to arise. These findings indicate that, in patients with complex partial seizures, moderate doses of fentanyl can evoke electrical seizure activity. The results of this study could have important implications for neurosurgical centers where electrocorticography is used during surgery for the purpose of determining the extent of the resection.  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