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   10302篇
  免费   711篇
  国内免费   31篇
耳鼻咽喉   91篇
儿科学   327篇
妇产科学   247篇
基础医学   1299篇
口腔科学   738篇
临床医学   716篇
内科学   2198篇
皮肤病学   223篇
神经病学   1114篇
特种医学   201篇
外科学   1173篇
综合类   69篇
一般理论   9篇
预防医学   1059篇
眼科学   112篇
药学   716篇
中国医学   66篇
肿瘤学   686篇
  2024年   11篇
  2023年   142篇
  2022年   268篇
  2021年   457篇
  2020年   317篇
  2019年   428篇
  2018年   449篇
  2017年   322篇
  2016年   315篇
  2015年   376篇
  2014年   480篇
  2013年   585篇
  2012年   817篇
  2011年   808篇
  2010年   457篇
  2009年   415篇
  2008年   630篇
  2007年   598篇
  2006年   502篇
  2005年   485篇
  2004年   406篇
  2003年   359篇
  2002年   352篇
  2001年   162篇
  2000年   124篇
  1999年   110篇
  1998年   70篇
  1997年   32篇
  1996年   32篇
  1995年   22篇
  1994年   28篇
  1993年   15篇
  1992年   56篇
  1991年   44篇
  1990年   49篇
  1989年   30篇
  1988年   27篇
  1987年   31篇
  1986年   22篇
  1985年   18篇
  1984年   16篇
  1983年   17篇
  1978年   11篇
  1975年   9篇
  1974年   11篇
  1972年   12篇
  1969年   9篇
  1968年   10篇
  1967年   9篇
  1966年   14篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
141.
142.
143.
Clinical Rheumatology - Health informatics and biomedical computing have introduced the use of computer methods to analyze clinical information and provide tools to assist clinicians during the...  相似文献   
144.

Coronavirus 2019 disease (COVID-19) is associated with coagulation dysfunction that predisposes patients to an increased risk for both arterial (ATE) and venous thromboembolism (VTE) and consequent poor prognosis; in particular, the incidence of ATE and VTE in critically ill COVID-19 patients can reach 5% and 31%, respectively. The mechanism of thrombosis in COVID-19 patients is complex and still not completely clear. Recent literature suggests a link between the presence of antiphospholipid antibodies (aPLs) and thromboembolism in COVID-19 patients. However, it remains uncertain whether aPLs are an epiphenomenon or are involved in the pathogenesis of the disease.

  相似文献   
145.
Diabetes mellitus is the leading cause of end-stage renal disease, and uncontrolled hyperglycemia is directly related to the increased mortality in this setting. As kidney function decreases, it becomes more challenging to control blood glucose since the risk of hypoglycemia increases. Decreased appetite, changes in glycaemia homeostasis, along with reduced renal excretion of anti-hyperglycemic drugs tend to facilitate the occurrence of hypoglycemia, despite the paradoxical occurrence of insulin resistance in advanced kidney disease. Thus, in patients using insulin and/or oral anti-hyperglycemic agents, dynamic adjustments with drug dose reduction or drug switching are often necessary. Furthermore, in addition to consider these pharmacokinetics alterations, it is of utmost importance to choose drugs with proven cardio-renal benefits in this setting, such as sodium-glucose co-transporter 2 inhibitors and glucagon-like peptide 1 receptor agonists. In this review, we summarize the indications and contraindications, titration of doses and side effects of the available anti-hyperglycemic agents in the presence of advanced diabetic kidney disease (DKD) and dialysis, highlighting the risks and benefits of the different agents. Additionally, basic renal function assessment and monitoring of glycemic control in DKD will be evaluated in order to guide the use of drugs and define the glycemic targets to be achieved.  相似文献   
146.
147.
The records of 292 patients who were admitted to a teaching hospital from 1984 to 1990 in Uberlandia in southeastern Brazil after being bitten by snakes of the genus Bothrops were retrospectively surveyed. The patients were from 42 municipalities in three states of Brazil. Most (42%) bites occurred between 4:00 PM and 10:00 PM. Fourteen percent of the bites occurred in the month of April. In 54 (18%) of the cases, the snakes were captured and identified as belonging to the following species: B. moojeni (29), B. neuwiedi (18), and Bothrops species (7). A diagnosis was made based on clinical findings in 238 (82%) cases. The lower limbs were the commonest site of bite (74%). The median time interval between bite and admission to the hospital was 3 hr. Fang marks were recorded in 58% of the cases and swelling was recorded in 82%. Clotting time was greater than 15 min in (142 of 264) 54% of the cases. A tourniquet was used on 44 cases. The mean +/- SD dose of specific antivenom used was 187.48 +/- 93.44 mg. The complications that occurred included abscess formation in 18% of the cases, necrosis in 16%, and renal failure in 5%. Amputation was performed in three (1%) cases. The case fatality rate was also 1% (three cases). When all cases were analyzed, the chi-square test for trend showed an increased susceptibility of renal failure with age (P < 0.04). Clotting time greater than 15 min was associated with the development of abscesses (P < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
148.
The polymorphic merozoite surface protein-2 (MSP-2) of Plasmodium falciparum is a major malaria-vaccine candidate. In the present study, PCR and hybridization with allelic-specific probes were used to type the Msp-2 gene from isolates from hypo-endemic Brazil (N = 113), meso-endemic Vietnam (N = 208) and holo-endemic Tanzania (N = 67). The typing methods were designed to group isolates into the dimorphic allelic families FC27 and IC1 and to detect possible between-family recombination events. The analysis was complemented by a comparison of 156 Msp-2 sequences from the GenBank database with 12 additional sequences obtained during the present study. Statistically significant differences were detected in pair-wise comparisons of the distribution of Msp-2 allelic types in Brazil and Vietnam, and in Brazil and Tanzania, but not in Vietnam and Tanzania. The extent of allelic diversity in the Msp-2 gene, as estimated by the total number of different alleles found in a given parasite population and the mean multiplicity of infections, clearly paralleled the levels of malaria endemicity in the study areas. However, no correlation between age and multiplicity of infections was found in the subjects. The patterns of Msp-2 diversity in Brazil appeared to be temporally stable, since no significant difference was observed in the distribution of Msp-2 allelic types among isolates collected, 10--13 years apart, in the same area of Rond?nia. Despite the extensive sequence diversity found in Msp-2 alleles, especially in the central repetitive region of the molecule, several instances of identical or nearly identical alleles were found among isolates from different countries and regions, possibly as a result of extensive homoplasy. No recombinant allele was detected by molecular typing in any of the study sites, and the GenBank database included only 12 recombinant sequences (representing 7% of all reported Msp-2 sequences), all of them with an IC1-type 5' end and an FC27-type 3' end. A single, putative, crossover site was characterised for all recombinant alleles. Most of the allelic diversity observed was therefore attributable to variation in the repetitive region of the gene, instead of recombination between alleles of dimorphic families (as commonly found, for example, in the Msp-1 gene). The implications of these findings for studies on the genetic and antigenic diversity of malarial parasites are discussed.  相似文献   
149.
BACKGROUND: Although risk assessment charts have been proposed to identify patients at high cardiovascular risk, in everyday practice general practitioners (GPs) often use their knowledge of the patients to estimate the risk subjectively. DESIGN: A cross-sectional study aimed to describe how GPs perceive, qualify and grade cardiovascular risk in everyday practice. METHODS: General practitioners had to identify in a random sample of 10% of their contacts the first 20 consecutive patients perceived as being at cardiovascular risk. For each patient essential data were collected on clinical history, physical examination and laboratory tests, for the qualification of risk. At the end of the process GPs subjectively estimated the overall patient's level of risk. General practitioners grading was compared with the risk estimate from a reference chart. RESULTS: Over a mean time of 25 days 3120 patients perceived as being at cardiovascular risk were enrolled. According to the inclusion scheme each GP had contact with more than 200 patients at cardiovascular risk every month. Thirty percent of these patients had atherosclerotic diseases. Up to 72% of patients without any history of atherosclerotic diseases but perceived to be at risk could be classified according to a reference chart as being at moderate to very high risk. Comparing GPs' grading of risk with a chart estimate there was agreement in 42% of the cases. Major determinants of GPs' underestimation of risk were age, sex and smoking habits, while obesity and family history were independently associated with overestimation. CONCLUSIONS: On the basis of their perception GPs properly identify patients at cardiovascular risk in the majority of cases. General practitioners subjective grading of risk level only partially agreed with that given by a chart.  相似文献   
150.
Situs inversus, a condition in which the major visceral organs are reversed from their normal positions in the body, can be detected by prenatal ultrasonography. Often benign, it may be associated with primary ciliary dyskinesia, an autosomal recessive disorder characterized by chronic respiratory disease. Yet, prenatal diagnosis of primary ciliary dyskinesia has not been reported. We describe a pregnancy in which situs inversus was diagnosed by fetal ultrasound at 20 weeks gestation. Prenatal testing for primary ciliary dyskinesia led to the discovery that both parents were asymptomatic carriers of a pathogenic mutation in the CCDC103 gene, with an affected neonate.  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