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   517篇
  免费   29篇
  国内免费   1篇
儿科学   6篇
妇产科学   16篇
基础医学   41篇
口腔科学   2篇
临床医学   85篇
内科学   63篇
皮肤病学   2篇
神经病学   55篇
特种医学   22篇
外科学   50篇
综合类   5篇
预防医学   60篇
药学   38篇
肿瘤学   102篇
  2023年   2篇
  2022年   2篇
  2021年   5篇
  2020年   4篇
  2019年   6篇
  2018年   8篇
  2017年   4篇
  2016年   12篇
  2015年   4篇
  2014年   16篇
  2013年   41篇
  2012年   34篇
  2011年   31篇
  2010年   14篇
  2009年   19篇
  2008年   32篇
  2007年   44篇
  2006年   26篇
  2005年   31篇
  2004年   28篇
  2003年   26篇
  2002年   21篇
  2001年   8篇
  2000年   9篇
  1999年   10篇
  1998年   4篇
  1997年   8篇
  1996年   4篇
  1995年   2篇
  1994年   5篇
  1993年   4篇
  1992年   3篇
  1991年   7篇
  1990年   5篇
  1989年   4篇
  1988年   6篇
  1987年   4篇
  1986年   11篇
  1985年   7篇
  1984年   4篇
  1983年   5篇
  1982年   4篇
  1981年   5篇
  1980年   4篇
  1976年   3篇
  1970年   1篇
  1969年   1篇
  1968年   4篇
  1966年   1篇
  1965年   1篇
排序方式: 共有547条查询结果,搜索用时 15 毫秒
1.
PURPOSE: This study describes the prevalence of probable major depressive disorder (MDD) as well as other depressive disorders (ODD) and severity of depressive symptoms in a national sample of women with spinal cord injury (SCI) and compares them with a case-matched sample of men with SCI. METHODS: A sample of 585 women was drawn and case-matched with men from the SCI Model System National SCI Database according to level/completeness of injury, follow-up year, and age. The outcome measure of depression was the Patient Health Questionnaire. MAIN FINDINGS: Prevalence rates for women were 7.9% for probable MDD and 9.7% for ODD; rates for men were 9.9% and 10.3%, respectively. Logistic regression revealed that women who were divorced or at year 1 follow-up had a higher odds of having probable MDD (odds ratio [OR], 3.4 and 2.9, respectively). Employed women and men had significantly lower odds of probable MDD (OR, 0.274 and 0.358, respectively). Statistically significant differences were not found in gender comparisons for either probable MDD or symptom severity, which also were not associated with injury characteristics. CONCLUSION: The most significant, and unexpected, research finding is the absence of gender differences in probable MDD and symptom severity. Results challenge notions that depression will necessarily follow SCI; that injury characteristics determine the development and severity of depression; and that women experience a greater burden of depression than men. The main clinical implication is that depression screening and referral should be a routine feature of health care for women living with SCI, as well as for their male counterparts. Furthermore, nearly one fourth of women and men reported experiencing some or greater difficulty in daily life and relationships in the absence of probable depressive disorder, warranting monitoring of subsyndromal depression as well.  相似文献   
2.
Carbamazepine, diuretics, and hyponatremia: a possible interaction   总被引:1,自引:0,他引:1  
Although carbamazepine is known to cause hyponatremia, no previous reports have indicated an interaction between carbamazepine and a diuretic. Two patients are described who were treated with this combination and developed symptomatic hyponatremia, which cleared when both drugs were discontinued in one patient and when the diuretic was discontinued in the second patient. The possible mechanisms of action of carbamazepine-induced hyponatremia are discussed.  相似文献   
3.
This study examined the types of stress experienced by maternal and paternal caretakers of children with Neural Tube Defects (NTD) and examined child and family characteristics that correlated with stress. Participants were 71 two-parent families of a child with spina bifida. Parents completed the Parenting Stress Index-Short Form to measure types of stress. Additional measures were completed to investigate variables potentially related to reported stress. Fathers reported significantly higher levels of stress from “dysfunctional parent-child interaction.” Mothers' personal stress correlated with disability and medical characteristics of the child. Fathers reported more stress when the child had maladaptive behaviors and when experiencing fewer social supports and resources. Mothers and fathers coparenting a child with NTD have both common and unique stresses. It is important that both be included in parent support and education initiatives.  相似文献   
4.
5.
Liver homogenates from rats fed tamoxifen (TAM) in the diet were shared among four different laboratories. TAM-DNA adducts were assayed by high pressure liquid chromatography-electrospray tandem mass spectrometry (HPLC-ES-MS/MS), TAM-DNA chemiluminescence immunoassay (TAM-DNA CIA), and (32)P-postlabeling with either thin layer ((32)P-P-TLC) or liquid chromatography ((32)P-P-HPLC) separation. In the first study, rats were fed a diet containing 500 p.p.m. TAM for 2 months, and the values for measurements of the (E)-alpha-(deoxyguanosin-N(2)-yl)-tamoxifen (dG-N(2)-TAM) adduct in replicate rat livers varied by 3.5-fold when quantified using 'in house' TAM-DNA standards, or other approaches where appropriate. In the second study, rats were fed 0, 50, 250 or 500 p.p.m. TAM for 2 months, and TAM-DNA values were quantified using both 'in house' approaches as well as a newly synthesized [N-methyl-(3)H]TAM-DNA standard that was shared among all the participating groups. In the second study, the total TAM-DNA adduct values varied by 2-fold, while values for the dG-N(2)-TAM varied by 2.5-fold. Ratios of dG-N(2)-TAM:(E)-alpha-(deoxyguanosin-N(2)-yl)-N-desmethyltamoxifen (dG-N(2)-N-desmethyl-TAM) in the second study were approximately 1:1 over the range of doses examined. The study demonstrated a remarkably good agreement for TAM-DNA adduct measurements among the diverse methods employed.  相似文献   
6.
N-Hydroxy-2-acetylaminofluorene (N-OH-AAF) is the proximate carcinogenic metabolite of the powerful rat liver carcinogen 2-acetylaminofluorene. In this study, transgenic Big Blue(R) rats were used to examine the relationship between in vivo mutagenicity and DNA adduct formation by N-OH-AAF in the target liver compared with that in nontarget tissues. Male rats were given one, two, or four doses of 25 mg N-OH-AAF/kg body weight by i.p. injection at 4-day intervals, and groups of treated and control rats were euthanized up to 10 weeks after beginning the dosing. Mutant frequencies were measured in the spleen lymphocyte hprt gene, and lacI mutant frequencies were determined in the liver and spleen lymphocytes. At 6 weeks after beginning the dosing, the hprt mutant frequency in spleen lymphocytes from the four-dose group was 16.5 x 10(-6) compared with 3.2 x 10(-6) in control animals. Also at 6 weeks, rats given one, two, or four doses of N-OH-AAF had lacI mutant frequencies in the liver of 97.6, 155.6, and 406.8 x 10(-6), respectively, compared with a control frequency of 25.7 x 10(-6); rats given four doses had lacI mutant frequencies in spleen lymphocytes of 55.8 x 10(-6) compared with a control frequency of 20.4 x 10(-6). Additional rats were evaluated for DNA adduct formation in the liver, spleen lymphocytes, and bone marrow by (32)P-postlabeling. Adduct analysis was conducted 1 day after one, two, and four treatments with N-OH-AAF, 5 days after one treatment, and 9 days after two treatments. N-(Deoxyguanosin-8-yl)-2-aminofluorene was the major DNA adduct identified in all the tissues examined. Adduct concentrations increased with total dose to maximum values in samples taken 1 day after two doses, and remained essentially the same after four doses. In samples taken after four doses, adduct levels were 103, 28, and 7 fmol/microg of DNA in liver, spleen lymphocytes, and bone marrow, respectively. The results indicate that the extent of both DNA adduct formation and mutant induction correlates with the organ specificity for N-OH-AAF carcinogenesis in the rat. Environ. Mol. Mutagen. 37:195-202, 2001. Published 2001 Wiley-Liss, Inc.  相似文献   
7.
Hepatitis C infection is associated with autoimmune disorders, such as the production of autoantibodies. Anti-LKM1 and anti-LC1, immunomarkers of type 2 autoimmune hepatitis, have been previously associated with a HCV infection. Anti-Soluble-Liver-Antigen autoantibodies (SLA) are specifically associated with type 1 and type 2 autoimmune hepatitis and more closely related to patients who relapse after steroid therapy. The recent molecular cloning of the soluble liver antigen provides the opportunity to develop more specific tests for the detection of antibodies against it. The aim of this work is to characterize anti-soluble-liver autoantibodies in sera from patients chronically infected by HCV. A recombinant cDNA from activated Jurkat cells coding for the full length tRNP(Ser)Sec/SLA antigen was obtained. ELISA, Western Blot and immunoprecipitation tests were developed and used to search for linear and conformational epitopes recognized by anti-SLA antibodies in sera from patients chronically infected by HCV. Anti-soluble liver antigen antibodies were found in sera from 10.4% of HCV-infected patients. The prevalence was significantly increased to 27% when anti-LKM1 was also present. Most anti-SLA reactivity was directed against conformational epitopes on the antigen. The means titers by ELISA were lower than those obtained in type 2 AIH. The result of autoantibody isotyping showed a subclass restriction to IgG1 and also IgG4. This study shows the presence of anti-SLA antibodies in approximately 10% of HCV infected patients. The prevalence of SLA autoantibodies in HCV infected patients increases when LKM1 autoantibodies are also present. The relationship between the prevalence of this characteristic autoimmune hepatitis autoantibody and the implication of an autoimmune phenomenon in the liver injury of patients chronically infected by HCV needs further investigation.  相似文献   
8.
The presence of relatively high levels of prostaglandin H synthase(PHS) in the dog urinary bladder and its ability to mediatethe activation of carcinogenic arylamines to DNA-bound productsin vitro suggests the involvement of this enzyme in arylamine-inducedbladder carcinogenesis. Since the PHS-dependent metabolism of2-naphthylamine (2-NA) had been shown to yield both ring- andN-oxidation products in vitro, we compared the reactivity of3H-labeled N-hydroxy-2-naphthylamine (N-OH-2-NA), 2-nitrosonaphthalene,and 2-amino-1-naphthol (2-AN) toward DNA and protein. In thePHS-incubation system, all three derivatives bound at high levelsto protein, but only N-OH-2-NA and 2-AN bound appreciably toDNA. Though ring-oxidation has usually been considered a detoxificationpathway, the covalent binding of [3H]2-AN to DNA was found tooccur readily under aerobic conditions and was enhanced at acidicpH. At pH 5 in air, the reactivity of [3H]2-AN with nucleicacids and protein was in the order: serum albumin > tRNA> poly G > poly C > DNA > poly A > rRNA >poly U. Enzymatic hydrolysis of DNA reacted with [3H]2-AN andsubsequent analysis by h.p.l.c. indicated the presence of severalcarcinogen-nucleoside adducts. The major product was characterizedas N4-(deoxyguanosin-N2-yl)-2-amino-1,4-naphthoquinoneimine;and two minor products were tentatively identified as N4-(deoxyadenosin-N6-yl)-2-amino-1,4-naphthoquinoneimineand a deoxyguanosin-N2-yl adduct of a naphthoquinoneimine dimer.These adducts accounted for 60% of the total DNA binding obtainedby incubation of [3H]2-NA with PHS in vitro and for 20% of the[3H]2-NA bound to dog urothelial DNA in vivo. The remainingadducts were identical to those previously reported as productsof the reaction of N-OH-2-NA with DNA. These results suggestthat a minor proportion of the DNA adducts found in vivo maybe formed by PHS-activation of 2-NA in the target tissue. Furthermore,the reactivity of 2-AN with cellular nucleophiles, presumablythrough formation of 2-imino-1-naphthoquinone or a protonated4-naphthocarbenium ion, indicates that ring-oxidation productsof arylamines and of other carcinogenic aryl compounds shouldbe evaluated as proximate carcinogenic metabolites.  相似文献   
9.
Older gay men experience an elevated prevalence of adverse health conditions that may be compounded by age-related deterioration. Some of these conditions may be ameliorated by regular adherence to physical activity (PA). However, many gay men participate in less PA than their age-matched heterosexual counterparts. With a focus on gay men aged 60 and over, the aims of this review were to examine the evidence for older gay men's engagement with PA and the research approaches used to describe this group. A systematic search of six academic databases (Academic Search Premier, Cinahl, PubMed, Sport Discus, APA PsychInfo and APA PsychArticles) generated 23 papers from 1970 to 2020 that focused on older gay men's engagement with PA. Although surveys were well represented in the literature, further studies utilising qualitative methodological frameworks have the potential to inform targeted interventional programs aimed at reducing less health disparities. The value of PA in older adults lies principally in improved performance of activities of daily living, independent living, increased longevity, decreased cognitive decline and improved mental well-being.  相似文献   
10.
Fu PP  Beland FA  Yang SK 《Carcinogenesis》1980,1(8):725-727
Cyclopenta-polycyclic aromatic hydrocarbons (cyclopenta-PAHs) are a group of compounds that have been detected as environmental pollutants. Perturbation molecular orbital (PMO) calculations on their presumed ultimate carcinogenic metabolites, the cyclopenta-PAH expoxides, predict that they may have a greater biological hazard than the classic PAHs.  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