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   450篇
  免费   41篇
  国内免费   105篇
耳鼻咽喉   10篇
儿科学   13篇
妇产科学   27篇
基础医学   42篇
口腔科学   19篇
临床医学   88篇
内科学   88篇
皮肤病学   65篇
神经病学   19篇
特种医学   3篇
外科学   47篇
综合类   30篇
预防医学   52篇
眼科学   4篇
药学   78篇
肿瘤学   11篇
  2022年   1篇
  2021年   3篇
  2020年   6篇
  2019年   6篇
  2018年   7篇
  2017年   4篇
  2016年   10篇
  2015年   8篇
  2014年   7篇
  2013年   15篇
  2012年   21篇
  2011年   26篇
  2010年   19篇
  2009年   15篇
  2008年   27篇
  2007年   92篇
  2006年   23篇
  2005年   41篇
  2004年   26篇
  2003年   23篇
  2002年   23篇
  2001年   23篇
  2000年   15篇
  1999年   11篇
  1998年   11篇
  1997年   10篇
  1996年   7篇
  1995年   3篇
  1994年   8篇
  1993年   15篇
  1992年   21篇
  1991年   11篇
  1990年   10篇
  1989年   14篇
  1988年   13篇
  1987年   3篇
  1986年   1篇
  1985年   4篇
  1983年   2篇
  1981年   1篇
  1980年   1篇
  1978年   1篇
  1976年   2篇
  1975年   1篇
  1970年   3篇
  1969年   1篇
  1968年   1篇
排序方式: 共有596条查询结果,搜索用时 31 毫秒
1.
An examination was made of neurogenesis in the anteroventral periventricular nucleus (AVPv) of the preoptic area of the rat using bromodeoxyuridine (BrdU), a thymidine analog, and a BrdU-specific antibody. Cells in the AVPv of adult rats were labeled with the antibody when BrdU was injected into pregnant rats once during day 13 to 18 of gestation, but not during day 10 to 12 nor 19 to 20 of gestation nor on postnatal day 1, indicating that neurogenesis of the AVPv occurs during a limited period from day 13 to 18 of gestation. Next, to examine the effects of androgen on neurogenesis, BrdU was injected once on day 15 into pregnant rats that also received injections of testosterone propionate (TP). The number of BrdU-labeled cells in the AVPv was similar in control female and male fetuses and female fetuses from pregnant rats that received daily injections of TP during days 14 to 16, when fetuses were examined on day 17 of gestation. These results suggest that the neurogenesis that was recognized by labeling with BrdU was not affected by the treatment with TP. On day 21 of gestation, BrdU-labeled cells in the AVPv of control male fetuses and female fetuses that received TP during days 14 to 18 were fewer in number than those in female fetuses of the control group, whereas treatments with TP during days 14 to 16 and during days 17 to 18 did not cause any significant decrease in number of BrdU-labeled cells. These findings support the hypothesis that elimination of a population of cells, for example, by cell death as described previously, is enhanced in male fetuses and in female fetuses treated with TP repetitively.  相似文献   
2.
We investigated the effects of activated protein C resistance (APCR), Factor V Leiden (FVL) mutation, and high lipoprotein (a) levels in 32 young patients with branch retinal vein occlusion (BRVO) vs 30 controls. No difference between patients with BRVO and controls was found with regard to APCR, FVL mutation, or lipoprotein (a) levels. These factors do not seem important in the etiology of BRVO. The authors have stated that they do not have a significant financial interest or other relationship with any product manufacturer or provider of services discussed in this article. The authors also do not discuss the use of off-label products, which includes unlabeled, unapproved, or investigative products or devices.  相似文献   
3.
OBJECTIVE: Polycystic ovary syndrome (PCOS) is frequently associated with insulin resistance and a consequent increased risk of metabolic diseases. The aim of the present study was to investigate the role of adiponectin in insulin resistance in PCOS women. MATERIALS AND METHODS: Forty-seven patients with PCOS and 23 control subjects, matched for age and body mass index (BMI), were enrolled in the study. Clinical, metabolic and hormonal parameters and adiponectin levels were measured, and HOMA-IR score (homeostasis model assessment-insulin resistance index) was calculated for each subject. RESULTS: There was no difference in adiponectin levels between PCOS patients and the control group. However, adiponectin levels were negatively correlated with obesity-associated parameters and HOMA-IR score in PCOS patients and controls. As adiponectin is modulated by BMI we adjusted for BMI among the PCOS patients, and found a negative correlation between adiponectin levels and HOMA-IR score (r = -0.51, p < 0.001). Adiponectin and BMI were independent determinants of insulin resistance in PCOS patients (adjusted R2 = 0.66, p < 0.001). CONCLUSION: Adiponectin did not seem to be actively involved in the pathogenesis of PCOS. However, adiponectin levels were independently associated with insulin resistance in PCOS patients, suggesting that adiponectin might play a role in the complicated metabolic abnormalities of PCOS.  相似文献   
4.
To evaluate the association of HLA types with Turkish patients with Graves' disease, HLA typing, clinical findings, and thyroid antibodies were correlated. The HLA types, clinical findings (ophthalmopathy and age at onset), and thyroid stimulating hormone (TSH) receptor (TRAb) and antithyroid microsomal antibodies (MAb) were analyzed. Seventy Turkish patients with Graves' disease and 306 control subjects were assessed. Serological HLA typing was performed in HLA A, B, C, DR, and DQ loci. There was a significantly increased prevalence of HLA B8, B49, DR3, DR4, and DR10 in Graves' disease. The association of Graves' disease with HLA DR3 was found to be less strong than previously described. The HLA DR4 antigen may contribute to the predisposition of Graves' disease in Turkey. The results suggest that HLA B7, B13, DR7, DQw2, and DQw3 may confer a protective effect for Graves' disease in Turkey. Patients carrying HLA B12, B18, and B44 haplotypes had a tendency to develop the disease at a later age. The difference from the other studies may be the result of the selection of the controls; in part, of the variability in serological typing reagents; and, also, of the rather weak HLA associations with the disease.This study was presented in part at the Annual Meeting of the National Endocrinology and Diabetes Association, Bursa, Turkey, May 25–28, 1992.  相似文献   
5.
In the present study, we tried to determine whether IUD insertion related PID and febrile complications could, be prevented by prophylactic use of antibiotics. We studied 300 patients who were admitted to our family planning clinic for IUD contraception. Of these, 150 patients received prophylactic Doxycycline (group 1) and the second 150 received no therapy (group 2). Five cases experienced fever with or without leucocytosis and none required hospitalization. PID was observed in one woman in each group.Positive culture (gonorrhea) was obtained in one woman who was then treated by relevant, antibiotics; the other woman required hospitalization for two days. The overall infection rates for group 1 and 2 were 2.1% and 2.9%, respectively and this difference was not significant. The incidence of PID infection and febrile complications was found to be very low for both groups when compared to other studies, suggesting that aseptic conditions with proper insertion reduce the risk of infection.
Resumen En el presente estudio, intentamos determinar si la inflamación pélvica y las complicationes febriles relacionadas con la inserción, de DIU podían evitarse mediante la administración profiláctica de antibióticos. Estudiamos a 300 pacientes de nuestra clínica de planificación familiar que recibieron DIU. Se administró un tratamiento profiláctico de doxicilina a 150 pacientes (Grupo 1) mientras que las restantes no recibieron ningún tratamiento (Grupo 2). Hubo cinco casos de fiebre con o sin leucocitosis pero ninguno requirió hospitalización. La inflamación pélvica se observó en dos casos, uno de cada grupo. Se obtuvo un cultivo positivo (gonorrea) en uno de los casos, que fue tratado con antibióticos apropiados, y el segundo caso debió ser hospitalizado durante dos días. Las tasas generales de infección fueron para el Grupo 1 y el Grupo 2, respectivamente, del 2,1% y del 2,9%, diferencia que no es significativa. Una comparación con otros estudios permitió verificar que la incidencia de infección pélvica inflamatoria y complicaciones febriles era muy baja en los dos grupos, lo cual hace pensar que las condiciones de asepsia y la inserción correcta reducen el riesgo de infección.

Resumé Dans la présente étude, nous avons tenté de déterminer si l'inflammation pelvienne et les complications fébriles liées à l'insertion de DIU pouvaient être évitées par une administration prophylactique d'antibiotiques. Nous avons suivi 300 patientes de notre clinique de planning familial, admises pour l'insertion, de DIU. Un traitement prophylactique de doxycycline a été administré à 150 de ces patientes (Groupe 1) et les autres n'ont reçu aucune, thérapie (Groupe 2). Nous avons eu cinq cas de fièvre avec ou sans leucocytose mais aucune de ces femmes n'a d être hospitalisée. L'inflammation pelvienne s'est manifestée dans deux cas, un dans chaque groupe. Une culture positive (gonorrhée) a été obtenue chez une de ces patientes, à laquelle un traitement aux antibiotiques appropriés a été administré, et la seconde a d être hospitalisée pendant deux jours. Les taux globaux d'infection ont été, respectivement pour le groupe 1 et le groupe 2, de 2,1% et 2,9%, ce qui ne représente pas une différence significative. Une comparaison avec d'autres études a permis, de constater que l'incidence d'infection pelvienne inflammatoire et de complications fébriles était très faible dans les deux groupes, ce qui laisse penser que les conditions d'asepsie et une insertion correcte réduisent le risque d'infection.
  相似文献   
6.
This molecular epidemiologic case-control study of lung cancer incorporated three complementary biomarkers: the glutathione S- transferase M1 (GSTM1) null genotype, a potential marker of susceptibility, and polycyclic aromatic hydrocarbon-DNA adducts (PAH- DNA) and sister chromatid exchanges (SCE), both indicators of environmentally induced genetic damage. Associations between biomarkers and lung cancer were investigated, as were possible gene-environment interactions between the GSTM1 null genotype and tobacco smoke exposure. Subjects included 136 primary non-small cell lung cancer surgical patients and 115 controls at the Columbia Presbyterian Medical Center. Questionnaire and Tumor Registry data, pre-treatment blood samples and biomarker measurements on blood were obtained. Overall, GSTM1 null genotype was significantly associated with lung cancer [odds ratio (OR) = 2.04, 95% confidence interval (CI) = 1.13-3.68]. ORs for GSTM1 and lung cancer were significant in females (2.50, 1.09-5.72) and smokers (2.25, 1.11-4.54) and not significant in males (1.4, 0.58-3.38) and non-smokers (0.88, 0.18-4.33). However, ORs for males versus females and smokers versus non-smokers did not differ significantly. The OR for GSTM1 and lung cancer in female smokers was 3.03 (1.09- 8.40), compared with 1.42 (0.53-4.06) in male smokers. In contrast to PAH-DNA adducts in leukocytes, SCE did not differ between cases and controls. Neither biomarker differed significantly between the two GSTM1 genotypes. The combined effect of elevated PAH-DNA adducts and GSTM1 genotype on case-control status (16.19, 1.2-115) appeared multiplicative. Results suggest that the effect of the GSTM1 null genotype is greatest in female smokers, which is consistent with other evidence that indicates that women are at higher risk of lung cancer than males, given equal smoking. Persons with both the GSTM1 deletion and elevated PAH-DNA adducts may represent a sensitive subpopulation with respect to carcinogens in tobacco smoke and other environmental media.   相似文献   
7.
In addition to the reproductive consequences, polycystic ovary syndrome (PCOS) is characterized by a metabolic disorder in which hyperinsulinemia and insulin resistance are central features. The effects and possible benefits from insulin-sensitizing drugs are not well known, especially in non-obese women with PCOS. This study was designed to evaluate the effects of metformin and flutamide on metabolic parameters and insulin resistance in non-obese women with PCOS. Thirty non-obese women newly diagnosed with PCOS and 15 age- and weight-matched healthy volunteers as controls were included in the study. Patients were assigned randomly to receive flutamide 250 mg daily or metformin 850 mg three times daily. Glucose, insulin, insulin resistance, androgen levels and glucose and insulin responses to an oral glucose tolerance tests (OGTT) were assessed before and after a 4-week therapy period. A positive correlation was found between body mass index and insulin level in patients with PCOS and controls. Follicle stimulating hormone, luteinizing hormone, free testosterone and dehydroepiandrosterone sulfate levels decreased significantly, but insulin resistance levels were not changed after flutamide therapy. Body weight, free testosterone, insulin and insulin resistance levels decreased significantly after metformin therapy. In conclusion, metformin treatment improved insulin sensitivity and decreased androgen levels, and flutamide decreased androgen levels but failed to improve insulin sensitivity in the non-obese women with PCOS.  相似文献   
8.
1-取代吡唑烷酮类抗惊构效关系的研究   总被引:5,自引:0,他引:5  
1-正癸基吡唑烷-3-酮(Ⅱ结构式见表1)是欧洲专利报道的一种新型减肥剂。White等报道该化合物可通过血脑屏障,并对γ-氨基丁酸氨基转移酶(GABA-T)有强烈的抑制活性,但对谷氨酸脱羧酶的抑制作用较弱,因此可引起脑内γ-氨基丁酸(GABA)水平的升高,故我们相信应有抗惊活性。经我们合成后,发现Ⅱ确有良好的抗癲痫活性,抗小鼠最大电  相似文献   
9.
Objective To explore the characteristics of arrhythmogenic right ventricular cardiomyopathy (ARVC). Methods Seven patients with arrhythmogenic right ventricular cardiomyopathy and 34 members of three families were studied. All patients and family members underwent history collection, clinical examination, electrocardiogram (ECG), two-dimensional echocardiography (2-DE) and a signal averaging electrocardiogram. Programmed ventricular stimulation was performed in five patients. Results All patients and family members had normal morphologic characteristics and normal function of the left ventricular by 2-DE. Fourteen persons had abnormal findings indicating ARVC. Five had enlargement of the right ventricular with diffused hypocontractility, eight had thin and systolic bulging in the focal anterior wall with hypokinesia and one had bulging of the inferior wall. Twenty-five persons (seven patients and 18 family members) had abnormal findings in ECG. Positive ventricular late potential was recorded in 13 persons (six patients). Two to three monomorphic ventricular tachycardia (VT) with left bundle branch block (LBBB) configurations were induced in five patients. Ventricular fibrillation was induced in two patients during the electrophysiologic study (EPS). Five patients had very high pacing threshold and/or ineffective pacing in one or many regions of the right ventricle. Two members of one family died suddenly. One member was a dwarf with ARVC. Spontaneous VT with a left bundle branch block (LBBB) configuration was recorded in five patients, polymorphic VT with extremely short coupling interval in one, and premature ventricular complexes with LBBB configuration in 12 (six patients). Conclusion Our familial study strongly suggests that ARVC may be a hereditary disease and it is helpful in the diagnosis and detection of ARVC. The most common manifestations were abnormal structure and function of the right ventricle and abnormal ECG of repolarization and ventricular arrhythmia which originates from the right ventricle.  相似文献   
10.
0 引言 手术切除椎管内肿瘤是唯一有效的治疗方法 .由于病变部位的特殊性 ,手术难度大、危险性大 ,术后易出现神经损伤、脊髓缺血、水肿 ,发生呼吸障碍、高热、消化道出血、四肢瘫痪或截瘫等严重并发症 .其护理工作也具有一定的复杂性和特殊性 .1 临床资料 我院 2 0 0 0 - 0 5 / 11收治椎管内肿瘤患者 2 6 (男19,女 7)例 ,年龄 9~ 6 1岁 .颈椎段 14例 ,胸椎段 6例 ,腰椎段 5例 ,骶管内 1例 . 7例为转移瘤 ,2例为原发性胶质瘤 ,其余均为良性肿瘤 .本组患者以颈段椎管内肿瘤居多 (5 4% ) .2 讨论 为使患者安全渡过围手术期 ,术前健康教…  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