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   681篇
  免费   35篇
  国内免费   4篇
耳鼻咽喉   16篇
儿科学   16篇
妇产科学   16篇
基础医学   130篇
口腔科学   18篇
临床医学   44篇
内科学   89篇
皮肤病学   19篇
神经病学   48篇
特种医学   96篇
外科学   72篇
综合类   7篇
预防医学   43篇
眼科学   5篇
药学   78篇
中国医学   4篇
肿瘤学   19篇
  2023年   2篇
  2022年   8篇
  2021年   14篇
  2020年   11篇
  2019年   15篇
  2018年   14篇
  2017年   14篇
  2016年   16篇
  2015年   21篇
  2014年   25篇
  2013年   42篇
  2012年   72篇
  2011年   54篇
  2010年   36篇
  2009年   26篇
  2008年   53篇
  2007年   55篇
  2006年   49篇
  2005年   32篇
  2004年   39篇
  2003年   27篇
  2002年   34篇
  2001年   4篇
  2000年   1篇
  1999年   3篇
  1998年   6篇
  1997年   5篇
  1996年   8篇
  1995年   5篇
  1994年   3篇
  1993年   2篇
  1992年   2篇
  1991年   2篇
  1990年   2篇
  1989年   3篇
  1988年   1篇
  1987年   2篇
  1986年   1篇
  1984年   1篇
  1983年   1篇
  1982年   2篇
  1981年   2篇
  1980年   1篇
  1976年   3篇
  1969年   1篇
排序方式: 共有720条查询结果,搜索用时 15 毫秒
101.
Protein-energy malnutrition and inflammation are among the leading causes of poor outcome in hemodialysis patients. Hepatitis C virus (HCV) infection is accompanied by elevated proinflammatory mediators, also found in dialysis patients with malnutrition–inflammation complex syndrome. We aimed to study the rate and characteristics of malnutrition–inflammation complex syndrome (MICS) in hemodialysis patients, especially those with hepatitis C. The study included 147 patients (mean age 55.1 ± 12.9 years), 24.5% of whom were HCV-positive, undergoing adequate hemodialysis three times a week for the last 52.7 ± 52.5 months. Parameters of nutrition and inflammation were investigated to evaluate MICS. HCV-positive vs. HCV-negative patients had significantly higher hematocrit (29.6 ± 4.5 g/dL vs. 28.1 ± 4.3, P < 0.05), uric acid (345.8 ± 96.5 vs. 321.3 ± 118.8 µmol/mL, P < 0.05), aspartate aminotransferase (AST, also known as serum glutamic oxaloacetic transaminase [SGOT]) (23.3 ± 14.9 vs. 17.8 ± 9 U/L, P < 0.008), alanine aminotransferase (ALT, also known as serum glutamic pyruvic transaminase [SGPT]) (41.2 ± 28.7 vs. 26.6 ± 17.1 U/L, P < 0.0003), serum creatinine (980.4 ± 219.1 vs. 888.4 ± 202.9 µmol/mL, P < 0.022), intact parathyroid hormone (329.7 ± 630.5 vs. 110.2 ± 145.3 pg/mL, P < 0.002), malnutrition–inflammation score (7.4 ± 5.2 vs. 5.6 ± 4.1, P < 0.038), and Charlson comorbidity index (4.5 ± 1.5 vs. 4 ± 1.4, P < 0.05). MICS had a prevalence of 20–40% in our study. HCV-positive patients had a significantly higher prevalence of MICS than HCV-negative patients (30–40% vs. 20–30%).  相似文献   
102.
In addition to producing antinociception, opioids exert profound effects on body temperature. This study aimed at comparing antinociceptive and hyperthermic responses between two groups of μ-opioid receptor agonists: fentanyl (4-anilinopiperidine-type) and morphine (phenanthrene-type) derivatives in rats. Analgesic activity was assessed by tail immersion test and the body temperature by insertion of a thermometer probe into the colon. Fentanyl (F), (±)-cis-3-methyl fentanyl (CM), (±)-cis-3-carbomethoxy fentanyl (C), (±)trans-3-carbomethoxy fentanyl (T) and (±)-cis-3 butyl fentanyl (B) produced dose-dependent increase in antinociception and hyperthermia. The relative order of analgesic potency was: CM(11.27)>F(1)>C(0.35)≥T(0.11)≥B(0.056). Similar to this, the relative order of hyperthermic potency was: CM(8.43)>F(1)>C(0.46)≥T(0.11)≥B(0.076). Morphine (M), oxycodone (O), thebacon (T) and 6,14-ethenomorphinan-7-methanol, 4,5-epoxy-6-fluoro-3-hydroxy-α,α,17-trimethyl-, (5α,7α) (E) also produced dose-dependent increase in antinociception and hyperthermia. Among morphine derivatives the relative order of analgesic potency was: E(56)>O(5)≥T(2.6)>M(1), and similar to this, the relative order of hyperthermic potency was: E(37)>O(3)≥T(2.3)>M(1). Morphine (phenanthrene-type) and fentanyl (4-anilinopiperidine-type) derivatives produced hyperthermia in rats at doses about 2 times lower, and 6–11 times higher, than their median antinociceptive doses, respectively. This study is first to identify difference between these two classes of opioid drugs in their potencies in producing hyperthermia. Further studies are needed to clarify the significance of these findings.  相似文献   
103.

Aim

To analyze cancer mortality trends in men in Central Serbia during 1985-2006 period.

Methods

Mortality rates and trends for the most frequent cancers in men (lung, stomach, colorectal, pancreatic, and prostate cancer) were calculated. Mortality rates for all cancers were adjusted by direct standardization. Percentage changes of the rates were calculated as the percentage difference between the rates of two successive years and then as a mean of these changes for the entire observed period. Trend lines were estimated using linear regression.

Results

Total cancer mortality in men increased, with mean percentage of annual changes being 1.53% (95% confidence interval [CI], -0.09-3.16). Lung, stomach, colorectal, pancreatic, and prostate cancers represented 58.1% and 61.6% of total cancer deaths in 1985 and 2006, respectively. Increasing trends were observed for all investigated cancers: mean annual percentage change for lung cancer was 2.31%(95% CI, 1.03-3.59), for colorectal cancer 2.23% (95% CI, -0.18-4.65), for prostate cancer 3.06% (95% CI, -2.07-8.18), and for pancreatic cancer 1.58% (95% CI, -2.17-5.32). Stomach cancer mortality significantly decreased in age groups 40-49 and 50-59 years.

Conclusion

The most frequent cancers in men in Central Serbia, ie, lung, colorectal, prostate, and pancreatic cancer, showed an increasing trend. Only stomach cancer mortality decreased over time.Cancer mortality in the European Union (EU) (1) and the United States (2) peaked in the late 1980s and has declined thereafter. Since 1988, the total cancer mortality in men from the EU has leveled off, and declined by an average 1.3% per year over the last 10 years due to the combined effect of early detection and improved treatment (3). The prevention of cancer in the EU was defined by the Code Against Cancer in 1987. The Code was revised in 1994 (4) and again in 2003 (5) as new member states entered the Union.There are geographic differences in cancer burden between Western and Eastern Europe. According to estimates from 2002, cancer mortality in men was higher in Central-Eastern European countries than in North-Western countries (6). In Serbia, neither prevention activities nor mass screening tests were applied, with the sole exception of the government’s effort to implement tobacco control.The aim of this study was to analyze recent changes in cancer mortality trends for men in Serbia, a country with approximately 5.5 million population (excluding the two autonomous provinces), in the period 1985-2006.  相似文献   
104.
The co-evolution of a wide range of helminth parasites and vertebrates represented a constant pressure on the host's immune system and a selective force for shaping the immune response. Modulation of the immune system by parasites is accomplished partly by dendritic cells. When exposed to helminth parasites or their products, dendritic cells do not become classically mature and are potent inducers of Th2 and regulatory responses. Treating animals with helminths (eggs, larvae, extracts) causes dampening or in some cases prevention of allergic or autoimmune diseases. Trichinella spiralis (T. spiralis) possess a capacity to retune the immune cell repertoire, acting as a moderator of the host response not only to itself but also to third party antigens. In this review, we will focus on the ability of T. spiralis-stimulated dendritic cells to polarize the immune response toward Th2 and regulatory mode in vitro and in vivo and also on the capacity of this parasite to modulate autoimmune disease--such as experimental autoimmune encephalomyelitis.  相似文献   
105.
106.
We investigated the association of CX3CR1 genotypes/haplotypes with MS and performed the prediction analysis of protein sequence variants' effects on CX3CL1/CX3CR1 interaction. We found no association of CX3CR1 with MS susceptibility. Frequency of I(249)T(280) haplotype was significantly lower in SP compared to RR patients (RR>10 years, OR=0.30, 95%CI=0.11-0.79, p=0.01; OR=0.53, 95%CI=0.18-1.56, p=0.2, in SP<10 years vs. RR>10 years). Prediction analysis showed that I249 T280 protein variant would significantly affect CX3CL1/CX3CR1 interaction. Our results suggest that CX3CR1 I???T??? haplotype could have protective effect for switch to SP MS. Further research is warranted to validate and replicate currently observed results.  相似文献   
107.
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease affecting upper and lower motor neurons. Dysfunction and death of motor neurons are closely related to the modified astrocytic environment. Astrocytic endfeet, lining the blood–brain barrier (BBB), are enriched in two proteins, aquaporin‐4 (AQP4) and inwardly rectifying potassium channel (Kir) 4.1. Both channels are important for the maintainance of a functional BBB astrocytic lining. In this study, expression levels of AQP4 and Kir4.1 were for the first time examined in the brainstem and cortex, along with the functional properties of Kir channels in cultured cortical astrocytes of the SOD1G93A rat model of ALS. Western blot analysis showed increased expression of AQP4 and decreased expression of Kir4.1 in the brainstem and cortex of the ALS rat. In addition, higher immunoreactivity of AQP4 and reduced immunolabeling of Kir4.1 in facial and trigeminal nuclei as well as in the motor cortex were also observed. Particularly, the observed changes in the expression of both channels were retained in cultured astrocytes. Furthermore, whole‐cell patch‐clamp recordings from cultured ALS cortical astrocytes showed a significantly lower Kir current density. Importantly, the potassium uptake current in ALS astrocytes was significantly reduced at all extracellular potassium concentrations. Consequently, the Kir‐specific Cs+‐ and Ba2+‐sensitive currents were also decreased. The changes in the studied channels, notably at the upper CNS level, could underline the hampered ability of astrocytes to maintain water and potassium homeostasis, thus affecting the BBB, disturbing the neuronal microenvironment, and causing motoneuronal dysfunction and death. © 2012 Wiley Periodicals, Inc.  相似文献   
108.
109.
BACKGROUND/AIM: Peripheral blood (PB) is used more frequently as a source of stem cells (SCs) for allogeneic transplantation. However, the influence of cell source on the clinical outcome of SC transplantation is not yet well established. The aim of this study was to compare the results of PBSC transplantation (PBSCT) with bone marrow transplantation (BMT) on the basis of engraftment, frequency and severity of immediate (mucositis, acute Graft versus Host Disease--aGvHD) and delayed (chronic GvHD--cGvHD) complications, as well as transplant-related mortality (TRM), transfusion needs, relapses and overall survival (OS). METHODS: We analyzed 158 patients, women/men ratio 64/94 median age 29 (range 9-57), who underwent allogeneic SC transplantation between 1989 and 2009. All included patients had diseases as follows: acute myeloid leukemia (AML)--39, acute lymphoblastic leukemia (ALL) 47, chronic myeloid leukemia (CML)--32, myelodysplastic syndrome (MDS)--10, Hodgkin's lymphoma (HL)- 2, multiple myeloma (MM) 3, granulocytic sarcoma (GrSa) 3, severe aplastic anemia (sAA)--22. The patients underwent transplantations were divided into two groups: BMT group (74 patients) and PBSCT group (84 patients). Each recipient had HLA identical sibling donor. SCs from bone marrow were collected by multiple aspirations of iliac bone and from PB by one "Large Volume Leukapheresis" (after recombinant human granulocyte colony stimulating factor, rHuG-CSF) application (5-12 microg/kgbm, 5 days). Conditioning regimens were applied according to primary disease, GvHD prophylaxis consisted of combination of a cyclosporine A and methotrexate. Results. Engraftment, according to the count of polymorphonuclear and platelets, were significantly (p < 0.001) faster in the PBSCT vs BMT group. The needs for transfusion support were significantly (P < 0.01) higher in the BMT group. Those patients had more frequently oropharingeal mucositis grade 3/4 (33.3% vs 10.0%, p < 0.05). There were no significant differences in the incidence of aGvHD and cGvHD between the two groups. The patients who underwent PBSCT had more frequently extensive cGvHD in comparison with the BMT group (29.1% vs 11.29%, p < 0.05). SC source (SCS) had no significant influence on the TRM (21.62% vs 23.8%, p = 0.64) and the incidence of relapses (21.6% vs 29.7%, p = 0.32). Finally, the patients treated by BMT hd a significantly better OS (logrank 2.33, p < 0.05). Conclusion. SCs harvesting from PB resulted in improved cell yield, faster engraftment, as well as in a decrease of immediate transplantation related complications with a reduced treatment cost. Allogeneic PBSCT were associated with more frequent extensive cGvHD, while the influence of SCS in TRM and relapses was not observed. Finally, the long-term OS was better in the patients treated by BMT. To verify impact of SC source on transplantation (PBSCT vs BMT) overall efficacy, more larger randomized clinical studies are needed.  相似文献   
110.
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