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   752篇
  免费   47篇
  国内免费   8篇
耳鼻咽喉   1篇
儿科学   16篇
妇产科学   10篇
基础医学   75篇
口腔科学   41篇
临床医学   109篇
内科学   175篇
皮肤病学   10篇
神经病学   29篇
特种医学   82篇
外科学   105篇
综合类   6篇
一般理论   2篇
预防医学   70篇
眼科学   3篇
药学   32篇
肿瘤学   41篇
  2023年   2篇
  2022年   5篇
  2021年   7篇
  2020年   8篇
  2019年   9篇
  2018年   19篇
  2017年   9篇
  2016年   11篇
  2015年   20篇
  2014年   11篇
  2013年   26篇
  2012年   30篇
  2011年   37篇
  2010年   22篇
  2009年   22篇
  2008年   30篇
  2007年   37篇
  2006年   35篇
  2005年   38篇
  2004年   30篇
  2003年   19篇
  2002年   26篇
  2001年   15篇
  2000年   22篇
  1999年   21篇
  1998年   26篇
  1997年   24篇
  1996年   20篇
  1995年   16篇
  1994年   14篇
  1993年   14篇
  1992年   11篇
  1991年   11篇
  1990年   7篇
  1989年   21篇
  1988年   17篇
  1987年   11篇
  1986年   12篇
  1985年   10篇
  1984年   7篇
  1983年   9篇
  1982年   6篇
  1981年   12篇
  1980年   11篇
  1979年   4篇
  1978年   6篇
  1977年   6篇
  1976年   5篇
  1975年   6篇
  1968年   2篇
排序方式: 共有807条查询结果,搜索用时 15 毫秒
51.
52.
53.
Goals The objective of this study was to assess the knowledge possessed and the attitudes held by Italian radiotherapists regarding evaluation and treatment of pain.Methods One hundred and twenty-six radiotherapists completed a 16-item questionnaire that was specifically designed to investigate three main topics: the attention paid to pain, the use of analgesics, and pain in children. Chi-square or Fishers exact text was employed to evaluate differences based on position (staff/resident), age (<35/>35 years old), availability of consultants in pain therapy and/or palliative care, colleagues with main interest in palliative care among their own staff, and region of residence (north/center/south of Italy).Results Overall percentage of correct answers was 76.6% (range 34.9–94.4%). Correct answers by groups of items were: attention paid to pain 77.3%, use of analgesics 81.5%, and pain in children 63.7%.Conclusion Results of the survey demonstrate that knowledge and attitudes of Italian radiotherapists towards the approach to and treatment of pain can be considered satisfactory.  相似文献   
54.
Interferon treatment of hepatitis C virus (HCV) infection after liver transplantation (LT) can result in immune‐mediated graft dysfunction (IGD). The occurrence of, risk factors for, and outcomes of IGD with direct‐acting antiviral (DAA) therapy have not been reported. We conducted a multicenter study of HCV+LT recipients who did or did not develop DAA‐IGD (1 case: 2 controls—33 vs 66). Among all treated between 2014 and 2016, DAA‐IGD occurred in 3.4% (33/978). IGD occurred only after treatment completion (76.0 [IQR, 47.0;176]). Among those treated, 48% had plasma cell hepatitis, 36% acute cellular rejection, 6% chronic rejection, and 9% combined findings. Median time to liver enzyme resolution was 77.5 days (IQR, 31.5;126). After diagnosis, hospitalizations, steroid‐induced hyperglycemia, and infection occurred in a higher percentage of cases vs controls (33% vs 7.5%, 21% vs 1.5%, 9% vs 0%; all P < .05). Only one IGD patient died and none required retransplant. A multivariate regression analysis found that liver enzyme elevations during and soon after DAA therapy completion correlated with subsequent IGD. In conclusion, while DAA‐IGD is uncommon, liver enzyme elevations during or after DAA therapy may be a sign of impending IGD. These indicators should guide clinicians to diagnose and treat IGD early before the more deleterious later clinical presentation.  相似文献   
55.
BACKGROUND: The present study evaluated the role of the PON1 L55M polymorphism independently and in conjunction with the Q192R polymorphism on the risk of coronary atherosclerosis in an Italian population. MATERIALS AND METHODS: Three hundred and ninety-one subjects with significant coronary stenosis (> 50%) (coronary artery disease-positive; CAD+), 196 subjects with normal coronary arteries (< 10% stenosis) (CAD-) and 178 healthy controls were screened using a combination of polymerase chain reaction and restriction enzyme digestion. RESULTS: In the pooled population, the frequencies of L and M alleles were 0.63 and 0.37, respectively; the most common haplotypes were QQ/LM (24.2%) and QR/LL (21.8%) and a strong linkage disequilibrium between L/55 and R/192 alleles was observed (D' = -0.91; P < 0.0001). CAD+ subjects did not show any significant differences in the distribution of PON1-55 genotypes as compared to CAD- subjects and population controls (chi2 = 1.5, P = 0.8). After controlling for other risk factors, the low-concentration M allele was not associated with a significant change of CAD risk (OR 1.02; 95% CI 0.80-1.29; P = 0.87). Moreover, the L55M polymorphism did not show any interaction with other risk factors such as smoking, diabetes, hypertension, low levels of high-density lipoprotein (HDL) or high ratios of low-density to high-density lipoproteins. The combination of L55M with the Q192R polymorphism did not show any effect on CAD risk. However, a marginal decrease in myocardial infarction risk was detected when QQ/MM carriers (OR 0.51; 95% CI 0.26-0.99; P = 0.048), but not LL/RR carriers, were compared with subjects not homozygous for an L or R allele. CONCLUSIONS: These findings did not indicate a major effect of the PON1 L55M polymorphism, either alone or in combination with the Q192R polymorphism, on CAD risk. Additional studies are needed for a better evaluation of the role of the 55/192 PON1 genotypes in combination on myocardial infarction risk.  相似文献   
56.
Cell-mediated lympholysis (CML) to trinitrophenyl (TNP)-modified autologous splenic lymphocytes has been recently reported in the mouse (1). Both the sensitization and effector phases of this phenomenon were shown to be T-cell mediated. Effector cell specificity studies indicated that modification of the target cells is a necessary but insufficient requirement for cytolysis, and suggested that altered cell surface components controlled by genes mapping in the mouse major histocompatibility H-2 complex (MHC) are important in the specificity of the cytotoxic reaction (1). In allogeneic models the generation of cytotoxic effector cells has been shown to be preceded or accompanied by immunogen- induced proliferation of responding lymphocytes, i.e. a mixed lymphocyte reaction (MLR) (2-5), although the generation of effectors may not necessarily always be the consequence of extensive cell proliferation (5). If the induction of cytotoxic effector lymphocytes by modified syngeneic spleen cells is characteristic of sensitization with cellular alloantigens, one would expect to find that sensitization with TNP-modified autologous cells would also induce thymidine incorporation by the responding cells in the culture. The present report demonstrates that both stimulation of thymidine incorporation and generation of cytotoxic effector cells are part of the in vitro response to TNP-modified autologous lymphocytes. However, the MLR to TNP- modified autologous cells consistently appeared to be less pronounced when compared with an allogeneic MLR, whereas the cytotoxic activity of the effector cells generated by sensitization against TNP-modified autologous cells was frequently as high as that detected against H-2 alloantigens. These two components of reactivity to “modified self” are verified in several C57BL/10 congenic and B10.A recombinant mouse strains.  相似文献   
57.
Background: Recruitment of progenitors during a large-volume collection, as defined by increasing relative and absolute numbers of progenitors (colony-forming units-granulocyte-macrophage [CFU-GM] of CD34+ cells), has been reported previously. Study Design and Methods: To ascertain whether intra-apheresis recruitment occurs in pediatric patients who have undergone mobilization with chemotherapy and granulocyte-colony-stimulating factor (G-CSF), each hour's portion of a 4-hour leukapheresis was collected into separate bags, and assessed by complete blood count, CFU-GM, and CD34+ cell assays. Seven pediatric patients (median age, 7; range, 2–19) were studied in connection with 2 to 4 collections each, for a total of 21 collections (with hourly samples). The collections lasted for 4 hours, at an inlet rate of 1 to 3 mL per kg per minute, for daily processing totals of 5 to 12 blood volumes. (One blood volume [mL] is estimated by the patient's weight in kg × 70 mL/kg.) Smaller (younger) patients had inlet rates exceeding 2 mL per kg per minute, and larger (older) patients had rates of 1 to 1.5 mL per kg per minute. CFU-GM and CD34+ cell counts obtained each hour of the collection and divided by the first hour's value were compared by nonparametric repeated-measures ANOVA. Results: Second-, third- and fourth-hour CD34+ progenitor cell counts were arithmetically higher than first-hour counts, but the trend did not reach significance (p = 0.1561). Second-hour counts were higher than first-hour counts in the overall analysis (mean ± standard error [SE], 1.00 and 1.39 ± 0.1, respectively; p = 0.0525) and in children older than 5 years (1.00 vs. 1.70 ± 0.30, respectively; p = 0.0259), but not in children younger than 5 years (p = 0.8125). CFU-GM counts did not differ among the 4 hours of collection (p = 0.1717) or between the first and second hour (p = 0.9587). Conclusion: In larger (older) patients, from whom fewer blood volumes were collected, there is a trend toward intra-apheresis recruitment, although less than reported previously. In the smaller (younger) patients, from whom more blood volumes were collected, no trend was observed. Lack of (or submaximal) prior mobilization in previously reported studies may have facilitated intracollection recruitment. Alternatively, the larger number of blood volumes collected from the smaller (younger) patients may have masked intra-apheresis recruitment. The study documents the feasibility of large-volume, 4-hour leukapheresis in pediatric patients.  相似文献   
58.
59.
60.
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