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   959篇
  免费   86篇
  国内免费   2篇
耳鼻咽喉   6篇
儿科学   22篇
妇产科学   28篇
基础医学   84篇
口腔科学   13篇
临床医学   62篇
内科学   153篇
皮肤病学   45篇
神经病学   119篇
特种医学   27篇
外科学   83篇
综合类   1篇
预防医学   97篇
眼科学   3篇
药学   121篇
中国医学   2篇
肿瘤学   181篇
  2024年   1篇
  2023年   15篇
  2022年   22篇
  2021年   55篇
  2020年   47篇
  2019年   45篇
  2018年   75篇
  2017年   36篇
  2016年   42篇
  2015年   42篇
  2014年   33篇
  2013年   42篇
  2012年   95篇
  2011年   85篇
  2010年   40篇
  2009年   27篇
  2008年   43篇
  2007年   40篇
  2006年   52篇
  2005年   21篇
  2004年   18篇
  2003年   20篇
  2002年   9篇
  2001年   7篇
  2000年   8篇
  1999年   15篇
  1998年   4篇
  1997年   3篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1992年   9篇
  1991年   3篇
  1990年   9篇
  1989年   7篇
  1988年   12篇
  1987年   9篇
  1986年   3篇
  1985年   11篇
  1984年   6篇
  1983年   5篇
  1982年   5篇
  1981年   2篇
  1979年   6篇
  1977年   1篇
  1976年   3篇
  1975年   1篇
  1974年   4篇
  1973年   2篇
  1972年   3篇
排序方式: 共有1047条查询结果,搜索用时 15 毫秒
1.
Harinakshi Sanikini  David C. Muller  Marisa Sophiea  Sabina Rinaldi  Antonio Agudo  Eric J. Duell  Elisabete Weiderpass  Kim Overvad  Anne Tjønneland  Jytte Halkjær  Marie-Christine Boutron-Ruault  Franck Carbonnel  Iris Cervenka  Heiner Boeing  Rudolf Kaaks  Tilman Kühn  Antonia Trichopoulou  Georgia Martimianaki  Anna Karakatsani  Valeria Pala  Domenico Palli  Amalia Mattiello  Rosario Tumino  Carlotta Sacerdote  Guri Skeie  Charlotta Rylander  María-Dolores Chirlaque López  Maria-Jose Sánchez  Eva Ardanaz  Sara Regnér  Tanja Stocks  Bas Bueno-de-Mesquita  Roel C.H. Vermeulen  Dagfinn Aune  Tammy Y.N. Tong  Nathalie Kliemann  Neil Murphy  Marc Chadeau-Hyam  Marc J. Gunter  Amanda J. Cross 《International journal of cancer. Journal international du cancer》2020,146(4):929-942
Obesity has been associated with upper gastrointestinal cancers; however, there are limited prospective data on associations by subtype/subsite. Obesity can impact hormonal factors, which have been hypothesized to play a role in these cancers. We investigated anthropometric and reproductive factors in relation to esophageal and gastric cancer by subtype and subsite for 476,160 participants from the European Prospective Investigation into Cancer and Nutrition cohort. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox models. During a mean follow-up of 14 years, 220 esophageal adenocarcinomas (EA), 195 esophageal squamous cell carcinomas, 243 gastric cardia (GC) and 373 gastric noncardia (GNC) cancers were diagnosed. Body mass index (BMI) was associated with EA in men (BMI ≥30 vs. 18.5–25 kg/m2: HR = 1.94, 95% CI: 1.25–3.03) and women (HR = 2.66, 95% CI: 1.15–6.19); however, adjustment for waist-to-hip ratio (WHR) attenuated these associations. After mutual adjustment for BMI and HC, respectively, WHR and waist circumference (WC) were associated with EA in men (HR = 3.47, 95% CI: 1.99–6.06 for WHR >0.96 vs. <0.91; HR = 2.67, 95% CI: 1.52–4.72 for WC >98 vs. <90 cm) and women (HR = 4.40, 95% CI: 1.35–14.33 for WHR >0.82 vs. <0.76; HR = 5.67, 95% CI: 1.76–18.26 for WC >84 vs. <74 cm). WHR was also positively associated with GC in women, and WC was positively associated with GC in men. Inverse associations were observed between parity and EA (HR = 0.38, 95% CI: 0.14–0.99; >2 vs. 0) and age at first pregnancy and GNC (HR = 0.54, 95% CI: 0.32–0.91; >26 vs. <22 years); whereas bilateral ovariectomy was positively associated with GNC (HR = 1.87, 95% CI: 1.04–3.36). These findings support a role for hormonal pathways in upper gastrointestinal cancers.  相似文献   
2.
AIMS: To report clinical outcomes of a large series of cases with advanced thyroid cancer. STUDY DESIGN: Three hundred and eighty-five patients at the UICC stages III and IV were selected for the study with thyroid cancer. RESULTS: Papillary carcinoma and sclerosing carcinoma have better survival than the Hürthle cell and insular types. Lymphatic metastasis does not appear to worsen the prognosis. All the tumour forms offer the chance of long survival. CONCLUSIONS: Surgical treatment is the primary treatment of thyroid carcinoma. The combined treatments of surgery, metabolic beam therapy, suppressive hormone therapy, radiotherapy and chemotherapy cure a high percentage of patients with the tumour at an advanced stage.  相似文献   
3.
Introduction Amisulpride is a substituted benzamide that, at low doses, selectively blocks D2 and D3 presynaptic dopamine receptors, enhancing dopaminergic transmission in frontal cortex and limbic areas. Many clinical studies versus placebo, tricyclic antidepressants and selective serotonin reuptake inhibitors showed amisulpride antidepressant effect, supporting its safety and rapid onset of action. In oncological population, depression is quite frequent and difficult to treat because of the particular sensitivity of cancer patients to the antidepressants’ side effects. Goals of work The aims of this study were to evaluate efficacy, safety and tolerability of low doses of amisulpride (50 mg) in oncological, depressed patients during chemotheraphy. Materials and methods One hundred six consecutive cancer outpatients with depressive symptoms were treated in a prospective, intention to treat, 4-week study, and were evaluated in single-blind with Montgomery Asberg rating scale for depression (MADRS), clinical global impression (CGI) and dosage record treatment emergent symptom scale (DOTES) to assess side effects of treatment. Main results After 4 weeks of treatment, scores of MADRS and CGI significantly improved (p < 0.002; p < 0.001, respectively), with a reduction of depressive symptoms concerning both emotional (such as apparent sadness, reported sadness, inner tension, etc.) and physical cluster (such as lack of appetite, reduction in weight, tiredness and insomnia) with good tolerability (only two patients dropped out). Conclusions This study is the first trial on the use of amisulpride in a cohort of oncological, depressed patients during chemotherapy. Amisulpride demonstrated high efficacy and safety. Controlled studies are needed to confirm these preliminary data.  相似文献   
4.
In this study, skin-infiltrating cells were characterized in both the active and remission phases of post-burn hypertrophic scar biopstes. Immunohistochemistry examination of active phase samples showed an abundant presence of Langerhans cells, T cells, macrophages, a low presence of natural killer cells and the lack of B lymphocytes. In active hypertrophic scars T lymphocytes infiltrate deep into the superficial dermis and are also observed in the epidermis: CD3+ cells were present at about 222±107 per 0.25 mm2. In particular the analysis of lymphocyte subpopulations showed that CD4+ T cells predominate in the dermis as well as in the epidermis of active hypertrophic scars whereas CD8+ cells were less well represented (CD4/CD8 ratio is 2.06). This distribution was also shown in remission phase samples and in normotrophic scar specimens, although the lymphocyte number was significantly lower. Approximately 70 per cent of T lymphocytes present in the tissue involved in active phase hypertrophic scar samples were activated (positive with anti-HLA-DR and IL-2 receptor antibodies) which is significantly higher than remission phase hypertrophic and normotrophic scars, in which positivity was 40 and 38 per cent, respectively. Upon activation, the lesional lymphocytes release several cytokines, locally and transiently, that interact with specific receptors in response to different stimulation. Central to the immune hypothesis of hypertrophic scars is that some of the T-cell lymphokines act on keratinocytes, fibroblasts and other cell types to induce changes characteristic of these scars. The presence and close proximity of activated T lymphocytes and antigen-presenting cells of various phenotypes in both the epidermis and dermis of hypertrophic tissues provides strong circumstantial evidence of a local immune response. However, the manner in which T cells achieve and maintain their activated state in hypertrophic tissues in not yet known, and both antigen-dependent and independent mechanisms may contribute.  相似文献   
5.
Rabbit lung microsomes metabolize (S)-nicotine primarily to (S)-nicotine delta 1',5'-iminium ion, which is the precursor of (S)-cotinine, the major urinary metabolite of (S)-nicotine in mammals. (S)-Nicotine-N'-oxide and normicotine are also produced as minor metabolites. alpha-Methylbenzylaminobenzotriazole, a mechanism-based suicide inhibitor of rabbit lung cytochromes P-450 2 and 6, inhibited (S)-nicotine oxidation in parallel with inhibition of benzphetamine N-demethylation and ethoxyresorufin O-deethylation. Pretreatment of rabbits with TCDD or Aroclor 1260 had no effect and markedly inhibited (S)-nicotine oxidation, respectively, strongly suggesting that alpha-methylbenzylaminobenzotriazole inhibition was due to inactivation of rabbit lung P-450 2. Reconstitution with cytochromes P-450 2 and 5 demonstrated that only P-450 2 was active toward (S)-nicotine, yielding predominantly the iminium ion, with smaller amounts of nornicotine, (S)-nicotine N'-oxide, and an unknown metabolite also detected. The purified rabbit lung P-450 2-catalyzed oxidation of (S)-nicotine to (S)-nicotine delta 1',5'-iminium ion exhibited a Km of 70 microM and a Vmax of 1.5 min. Covalent binding of (S)-5-3H-nicotine to rabbit lung macromolecules was dependent upon rabbit lung P-450 2-catalyzed formation of the iminium ion. Antibodies raised against P-450 2 inhibited the rabbit lung microsomal metabolism of (S)-nicotine to (S)-nicotine delta 1',5'-iminium ion by almost 95%. Titration of reconstituted P-450 2 with cytochrome b5 produced a concentration-dependent inhibition of nicotine oxidase activity. Increasing the ratio of NADH to NADPH in incubations containing lung microsomes and (S)-nicotine decreased the yield of the iminium ion, confirming the inhibitory effect of cytochrome b5 on the P-450 2-catalyzed alpha-carbon oxidation reaction. NADH alone did not support the lung microsomal metabolism of (S)-nicotine. N'-oxidation of (S]-nicotine is catalyzed by purified pig liver flavin-containing monooxygenase. A number of experiments involving the use of P-450 inhibitors, titration with NADPH-cytochrome P-450 reductase antibodies, and determination of the pH-enzyme activity profile suggested that rabbit lung flavin-containing monooxygenase contributes to a small amount of the N'-oxide produced by rabbit lung microsomes. Further examination with purified flavin-containing monooxygenase isolated from rabbit lung microsomes demonstrated that (S)-nicotine is a poor substrate for this enzyme. The low yield of N'-oxide, relative to other metabolites, in rabbit lung is uncharacteristic for most mammalian tissues and presumably reflects the unusual substrate specificity of rabbit lung flavin-containing monooxygenase.  相似文献   
6.
Nineteen patients that had developed hypertrophic scars subsequent to thermal injury were typed for HLA class II allogenotypes with the restriction fragment length polymorphism technique. A significant association was found with DR beta 16 (pc = 1.45 x 10(-4); relative risk = 12.25). This finding adds evidence to other data suggesting that immunologic phenomena are involved in pathologic scarring. Moreover, the results presented here have allowed an identification of a genetically determined risk factor for hypertrophic scar formation located in the HLA region.  相似文献   
7.
The expression of HLA class I- like molecules was analyzed on human acute and chronic leukemic cells. The presence on leukemic cells of class I- like molecules, absent on the patient's normal lymphocytes, was examined by complement- dependent lymphocytotoxicity using platelet absorbed alloantisera that recognize HLA-linked, 45-12 kd, beta-2-microglobulin associated molecules, selectively expressed on PHA-activated cells. A positive reactivity of the anti- class I- like alloantisera was found in 50% of the acute leukemias (cALL, T-ALL and AML), independently of the lineage of differentiation, while chronic lymphocytic leukemias (B-CLL) were constantly negative. It is suggested that beta-2-microglobulin associated HLA molecules may represent markers of leukemic blast activation and/or maturation state.  相似文献   
8.
P5 (LILPKHSDAD) is a hypocholesterolemic peptide from lupin protein with a multi-target activity, since it inhibits both 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCoAR) and proprotein convertase subtilisin/kexin type-9 (PCSK9). This work shows that, during epithelial transport experiments, the metabolic transformation mediated by intestinal peptidases produces two main detected peptides, ILPKHSDAD (P5-frag) and LPKHSDAD (P5-met), and that both P5 and P5-met are linearly absorbed by differentiated human intestinal Caco-2 cells. Extensive comparative structural, biochemical, and cellular characterizations of P5-met and the parent peptide P5 demonstrate that both peptides have unique characteristics and share the same mechanisms of action. In fact, they exert an intrinsically multi-target behavior being able to regulate cholesterol metabolism by modulating different pathways. The results of this study also highlight the dynamic nature of bioactive peptides that may be modulated by the biological systems they get in contact with.  相似文献   
9.
10.
The cytokine profile of T cell clones (TCC) from the dermis and epidermis of burn patients with hypertrophic scars (HS) in active (AHS) and remission phases (RHS) was determined in this study. We found that AHS tissues are heavily infiltrated by Type 0-Type 1 polarized CD3+ lymphocytes producing high IFN-gamma and low IL-4 levels. Analysis of their surface marker phenotype showed that the high IFN-gamma production was shared equally between the CD4+ TCRalpha/beta and CD8+ TCRalpha/beta clones. The profile of TCC from RHS tissues revealed pronounced infiltration of Type 0-Type 1 polarized lymphocytes with an even more evident Type 1 profile. However, the levels of IFN-gamma produced by RHS-derived TCC were 4-6 times lower than those produced by AHS-derived TCC. These data show that high levels of IFN-gamma produced by Type 0-Type 1 lymphocytes infiltrating HS are a feature of AHS, whereas reduction of this ability to produce high levels of IFN-gamma, though without a shift towards a Type 0-Type 2 phenotype through an increase in IL-4, is characteristic of RHS.  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