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   530篇
  免费   44篇
  国内免费   2篇
儿科学   32篇
妇产科学   68篇
基础医学   62篇
口腔科学   5篇
临床医学   68篇
内科学   73篇
皮肤病学   12篇
神经病学   43篇
特种医学   54篇
外科学   46篇
综合类   5篇
预防医学   61篇
眼科学   2篇
药学   18篇
肿瘤学   27篇
  2023年   1篇
  2022年   8篇
  2021年   10篇
  2020年   9篇
  2019年   9篇
  2018年   11篇
  2017年   6篇
  2016年   8篇
  2015年   15篇
  2014年   13篇
  2013年   24篇
  2012年   15篇
  2011年   16篇
  2010年   14篇
  2009年   20篇
  2008年   20篇
  2007年   29篇
  2006年   30篇
  2005年   16篇
  2004年   20篇
  2003年   19篇
  2002年   15篇
  2001年   14篇
  2000年   14篇
  1999年   14篇
  1998年   18篇
  1997年   11篇
  1996年   14篇
  1995年   19篇
  1994年   12篇
  1993年   7篇
  1992年   12篇
  1991年   7篇
  1990年   13篇
  1989年   4篇
  1988年   8篇
  1987年   11篇
  1986年   11篇
  1985年   15篇
  1984年   14篇
  1983年   5篇
  1982年   6篇
  1981年   3篇
  1980年   3篇
  1978年   3篇
  1977年   2篇
  1976年   6篇
  1975年   1篇
  1962年   1篇
排序方式: 共有576条查询结果,搜索用时 343 毫秒
111.
112.
113.
This study investigates the difference in cancer mortality rates between migrant groups and the native Dutch population, and determines the extent of convergence of cancer mortality rates according to migrants' generation, age at migration and duration of residence. Data were obtained from the national cause of death and population registries in the period 1995-2000. We used Poisson regression to compare the cancer mortality rates of migrants originating from Turkey, Morocco, Surinam, Netherlands Antilles and Aruba to the rates for the native Dutch. All-cancer mortality among all migrant groups combined was significantly lower when compared to that of the native Dutch population (RR = 0.55, CI: 0.52-0.58). For a large number of cancers, migrants had more than 50% lower risk of death, while elevated risks were found for stomach and liver cancers. Mortality rates for all cancers combined were higher among second generation migrants, among those with younger age at migration, and those with longer duration of residence. This effect was particularly pronounced in lung cancer and colorectal cancer. For most cancers, mortality among second generation migrants remained lower compared to the native Dutch population. Surinamese migrants showed the most consistent pattern of convergence of cancer mortality. The generally low cancer mortality rates among migrants showed some degree of convergence but did not yet reach the levels of the native Dutch population. This convergence implies that current levels of cancer mortality among migrants will gradually increase in future years if no specific preventive measurements are taken.  相似文献   
114.
115.
OBJECTIVES: Testing of fetal habituation to repeated vibroacoustic stimulation might give additional information concerning the fetal condition and central nervous system (CNS) functioning in postterm pregnancies. This study is designed to investigate whether healthy postterm fetuses are able to habituate and if so, if the habituation pattern of postterm fetuses differs from that of term fetuses. STUDY DESIGN: Twenty women with an uncomplicated pregnancy beyond 41 weeks gestational age (GA) participated, and 37 women with a GA between 37 and 40 weeks served as controls. The vibroacoustic stimulus was repeatedly applied to the maternal abdomen above the fetal legs for a period of 1s every 30s. A fetal trunk movement within 1s of stimulus application was considered a positive response. Lack of response to four consecutive stimuli indicated habituation. The habituation rate is defined as the number of stimuli applied before the fetus stopped responding. Data were compared using Mann-Whitney U test. RESULTS: Of the 18 postterm fetuses in which the presence or absence of habituation could be established, 14 habituated and four persisted in responding. Twenty-six of the 32 term fetuses, in which the presence or absence of habituation could be established, habituated and six persisted in responding. The habituation rate varied widely in postterm (median of eight stimuli, quartile ranges of 6 and 18) as well as in term fetuses (median of 9.5 stimuli, quartile ranges of 6 and 15). There was no difference in median habituation rate between postterm and term fetuses. CONCLUSION: The ongoing maturation of the CNS in the last weeks of pregnancy appears not to be reflected in the fetal habituation pattern. Furthermore, the interfetal variability in habituation of healthy postterm fetuses is such that testing of habituation appears not to be suitable for the identification of the fetus at risk for an adverse neonatal outcome.  相似文献   
116.
OBJECTIVES: To determine fetal growth in low risk pregnancies at the beginning of the third trimester and to assess the relative importance of fetal gender and maternal parity. SETTING: Dutch primary care midwifery practice. STUDY DESIGN: Retrospective cohort study on 3641 singleton pregnancies seen at a primary care midwifery center in the Netherlands. Parameters used for analysis were fetal abdominal circumference (AC), fetal head circumference (HC), gestational age, fetal gender and maternal parity. Regression analysis was applied to describe variation in AC and HC with gestational age. Means and standard deviations in the present population were compared with commonly used reference charts. Multiple regression analysis was applied to examine whether gender and parity should be taken into account. RESULTS: The fetal AC and HC increased significantly between the 27th and the 33rd week of pregnancy (AC r2=0.3652, P<0.0001; HC r2=0.3301, P<0.0001). Compared to some curves, our means and standard deviations were significantly smaller (at 30+0 weeks AC mean=258+/-13 mm; HC mean=281+/-14 mm), but corresponded well with other curves. Fetal gender was a significant determinant for both AC (P<0.0001) and HC (P<0.0001). Parity contributed significantly to AC only but the difference was small (beta=0.00464). CONCLUSION: At the beginning of the third trimester, fetal size is associated with fetal gender and, to a lesser extent, with parity. Some fetal growth charts (e.g., Chitty et al.) are more suitable for the low-risk population in the Netherlands than others.  相似文献   
117.
PURPOSE: To investigate the feasibility of withholding antibiotics and early discharge for patients with chemotherapy-induced neutropenia and fever at low risk of bacterial infection by a new risk assessment model. PATIENTS AND METHODS: Outpatients with febrile neutropenia were allocated to one of three groups by a risk assessment model combining objective clinical parameters and plasma interleukin 8 level. Patients with signs of a bacterial infection and/or abnormal vital signs indicating sepsis were considered high risk. Based on their interleukin-8 level, remaining patients were allocated to low or medium risk for bacterial infection. Medium-risk and high-risk patients received standard antibiotic therapy, whereas low-risk patients did not receive antibiotics and were discharged from hospital after 12 hours of a febrile observation. End points were the feasibility of the treatment protocol. RESULTS: Of 196 assessable episodes, 76 (39%) were classified as high risk, 84 (43%) as medium risk, and 36 (18%) as low risk. There were no treatment failures in the low-risk group (95% CI, 0% to 10%). Therefore, sensitivity of our risk assessment model was 100% (95% CI, 90% to 100%), the specificity, positive, and negative predictive values were 21%, 13%, and 100%, respectively. Median duration of hospitalization was 3 days in the low-risk group versus 7 days in the medium- and high-risk groups (P < .0001). The incremental costs of the experimental treatment protocol amounted to a saving of 471 (US $572) for every potentially low-risk patient. CONCLUSION: This risk assessment model appears to identify febrile neutropenic patients at low risk for bacterial infection. Antibiotics can be withheld in well-defined neutropenic patients with fever.  相似文献   
118.
We detected a highly divergent SARS-CoV-2 Alpha variant in an immunocompromised person several months after the latest detection of the Alpha variant in the Netherlands. The patient was infected for 42 weeks despite several treatment regimens and disappearance of most clinical symptoms. We identified several potential immune escape mutations in the spike protein.  相似文献   
119.
120.
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