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   409篇
  免费   16篇
  国内免费   12篇
儿科学   14篇
妇产科学   5篇
基础医学   35篇
口腔科学   5篇
临床医学   39篇
内科学   83篇
皮肤病学   22篇
神经病学   8篇
特种医学   155篇
外科学   21篇
综合类   3篇
预防医学   20篇
眼科学   2篇
药学   4篇
中国医学   1篇
肿瘤学   20篇
  2024年   1篇
  2023年   4篇
  2022年   7篇
  2021年   7篇
  2020年   6篇
  2019年   2篇
  2018年   17篇
  2017年   7篇
  2016年   9篇
  2015年   7篇
  2014年   8篇
  2013年   13篇
  2012年   15篇
  2011年   13篇
  2010年   10篇
  2009年   12篇
  2008年   6篇
  2007年   20篇
  2006年   5篇
  2005年   1篇
  2004年   5篇
  2003年   3篇
  2002年   3篇
  2001年   1篇
  2000年   1篇
  1999年   4篇
  1998年   13篇
  1997年   22篇
  1996年   24篇
  1995年   15篇
  1994年   17篇
  1993年   11篇
  1992年   3篇
  1991年   3篇
  1990年   5篇
  1989年   22篇
  1988年   13篇
  1987年   18篇
  1986年   17篇
  1985年   20篇
  1984年   13篇
  1983年   7篇
  1982年   5篇
  1981年   3篇
  1980年   3篇
  1979年   3篇
  1978年   1篇
  1977年   3篇
  1976年   3篇
  1975年   6篇
排序方式: 共有437条查询结果,搜索用时 15 毫秒
1.
Bonfanti  R; Furie  BC; Furie  B; Wagner  DD 《Blood》1989,73(5):1109-1112
PADGEM protein (PADGEM), also known as GMP140, is a platelet alpha- granule membrane protein that is translocated to the external membrane after platelet activation. Although the biosynthesis of this protein was originally thought to be confined to megakaryocytes, the synthesis of PADGEM in endothelial cells was recently demonstrated (McEver et al: Blood 70:1974a, 1987). We now describe the subcellular localization of this protein in endothelial cells. Immunofluorescence staining of permeabilized human umbilical vein endothelial cells with KC4, a well characterized monoclonal antibody to PADGEM, showed positively stained elongated structures similar in distribution and shape to Weibel-Palade bodies. Their identity as Weibel-Palade bodies was confirmed by double label immunofluorescence using KC4 and a polyclonal antiserum to von Willebrand factor (vWf), a protein known to be specifically stored in these organelles. All Weibel-Palade bodies were found to contain PADGEM. In contrast to strong perinuclear staining produced with anti- vWf antibodies, no significant perinuclear staining was obtained with KC4, indicating that relatively little PADGEM is present in the endoplasmic reticulum and in the Golgi apparatus. In endothelial cells treated with secretagogues that stimulate vWf release the elongated structures positive for PADGEM disappeared, further identifying these structures as Weibel-Palade bodies. This observation extends the parallels between Weibel-Palade bodies and alpha-granules and suggests a possible functional association between vWf and PADGEM.  相似文献   
2.
Segel  MC; Paulus  DD; Hortobagyi  GN 《Radiology》1988,169(1):49-54
The response to induction chemotherapy is an important prognostic factor in patients with nonmetastatic, locally advanced breast carcinomas. Assessment at mammography of the response of 60 breast cancers in 59 women was performed between 1974 and 1986. Responses were excellent in 13 tumors, moderate in 34, and poor in 13 (excellent moderate = 78%). Assessment of response of discrete masses in a fatty breast was easiest; assessment of response of tumor areas that were poorly defined-such as a focal area of architectural distortion or mass in dense breast parenchyma-was more difficult. Of 17 patients with excellent pathologic responses-that is, minimal or no residual tumor-15 (88%) had complete responses (no residual tumor) as determined with mammography, physical examination, or both. Mammography provides information complementary to physical examination and is essential in the accurate assessment of the response to chemotherapy of locally advanced breast cancer.  相似文献   
3.
4.
In a human in-vitro fertilization (IVF) programme, the effect of co- culture of embryos with human fibroblasts was evaluated with respect to pregnancy rate and embryo development. Patients were included in the study after giving informed written consent. The IVF treatments were randomly assigned by stratification of both age (<36 versus > or =36 years) and previous IVF attempts (yes versus no). After fertilization was established, the zygotes were transferred to a 4-well dish with or without fibroblasts and cultured for 2 days. On the third day after ovum pick-up (OPU), cell number and quality [5 (good) to 1 (poor)] of the embryos were scored and a maximum of three embryos was transferred. Supernumerary embryos of good quality were cryopreserved. The design of this study was a group sequential trial with the objective of detecting differences between pregnancy rates following IVF with conventional incubation or incubation in co-culture with fibroblasts. This design included one evaluation at half-way data collection. In the study, 148 patients had an OPU, of whom 77 were allocated to the co-culture group. There was no statistically significant difference in pregnancy rate, cell number and embryo quality between the two groups. The ongoing pregnancy rate per embryo transfer was 27% in co-culture and 30% in the conventional culture group. The implantation rates per transferred embryo were 17 and 18% respectively. Using a multivariate logistic regression model for the probability of ongoing pregnancies, the odds ratio of co-culture, adjusted for age and previous IVF attempts, was not statistically significant. In conclusion, co-culture with human fibroblasts does not contribute to an improvement of embryo quality nor to a higher pregnancy rate after IVF in an unselected group of patients.   相似文献   
5.
Male genital tract obstructions may result from infections, previous inguinal and scrotal surgery (vasectomy) and congenital bilateral absence of the vas deferens (CBAVD). Microsurgery can sometimes be successful in treating the obstruction. In other cases and in cases of failed surgical intervention, the patient can be treated by microsurgical or percutaneous epididymal sperm aspiration (MESA, PESA) or testicular sperm extraction (TESE) and intracytoplasmic sperm injection (ICSI). We present the results of 39 ICSI procedures for obstructive azoospermia in 24 couples. The aetiology of the obstruction was failed microsurgery in 11 patients, CBAVD in nine and genital infections in four. Sperm retrieval was accomplished via MESA in four cases, PESA in 18 cases and via TESE in 11 cases. TESE was only applied when PESA failed to produce enough spermatozoa for simultaneous ICSI. In six patients, the ICSI procedure was performed with cryopreserved spermatozoa after an initial PESA procedure. Fertilization occurred in 47% of the metaphase II oocytes; embryo transfer was performed in 92% of procedures and resulted in a clinical pregnancy in 13/39 procedures. Ongoing pregnancy was achieved in 10/39 procedures. One pregnancy was terminated early after prenatal investigation showed a cytogenetic abnormality (47,XX+18, Edwards syndrome). The other nine pregnancies resulted in the live birth of 10 children, without any congenital abnormalities. Epididymal and testicular retrieved spermatozoa were successfully used for ICSI to treat obstructive azoospermia, and resulted in an ongoing pregnancy in 10 of 24 couples (41.6%) after 39 ICSI procedures, a success rate of 25.6% per treatment cycle and of 27.7% per embryo transfer.   相似文献   
6.
7.
Davis  GD; Fulton  RE; Ritter  DG; Mair  DD; McGoon  DC 《Radiology》1978,128(1):133-144
Of 181 patients with severe congenital pulmonary atresia and ventricular septal defect or "type IV truncus" (an obsolete term), all but 11% had true central pulmonary arteries. These arteries were demonstrable by large serial biplane angiograms using multiple selective injections into collateral vessels, frequent photographic subtraction, and occasional pulmonary vein-wedge angiograms. These techniques are extremely important for accurate diagnosis and in planning corrective or palliative surgery, which was done in 77% of patients with pulmonary arteries.  相似文献   
8.
Vaccines protect cats from serious diseases by inducing antibodies and cellular immune responses. Primary vaccinations and boosters are given according to vaccination guidelines provided by industry and veterinary organizations, based on minimal duration of immunity (DOI). For certain diseases, particularly feline panleukopenia, antibody titres correlate with protection. For feline calicivirus and feline herpesvirus, a similar correlation is absent, or less clear. In this review, the European Advisory Board on Cat Diseases (ABCD) presents current knowledge and expert opinion on the use of antibody testing in different situations. Antibody testing can be performed either in diagnostic laboratories, or in veterinary practice using point of care (POC) tests, and can be applied for several purposes, such as to provide evidence that a successful immune response was induced following vaccination. In adult cats, antibody test results can inform the appropriate re-vaccination interval. In shelters, antibody testing can support the control of FPV outbreaks by identifying potentially unprotected cats. Antibody testing has also been proposed to support decisions on optimal vaccination schedules for the individual kitten. However, such testing is still expensive and it is considered impractical to monitor the decline of maternally derived antibodies.  相似文献   
9.
Policy drives practice, and health services research (HSR) is at the intersection of policy, practice, and patient outcomes. HSR specific to rehabilitation and disability is particularly needed. As rehabilitation researchers and providers, we are uniquely positioned to provide the evidence that guides reforms targeting rehabilitative care. We have the expertise to define the value of rehabilitation in a policy-relevant context. HSR is a powerful tool for providing this evidence. We need to continue building capacity for conducting rigorous, timely rehabilitation-related HSR. Fostering stakeholder engagement in these research efforts will ensure we maintain a patient-centered focus as we address the “Triple Aim” of better care, better health, and better value. In this Special Communication we discuss the role of rehabilitation researchers in HSR. We also provide information on current resources available in our field for conducting HSR and identify gaps for capacity building and future research. Health care reforms are a reality, and through HSR we can give rehabilitation a strong voice during these transformative times.  相似文献   
10.

Objectives

The objectives of this study were to determine the association between patients’ functional status at discharge from skilled nursing facility (SNF) care and 30-day potentially preventable hospital readmissions, and to examine common reasons for potentially preventable readmissions.

Design

Retrospective cohort study.

Setting

SNFs and acute care hospitals submitting claims to Medicare.

Participants

National cohort of Medicare fee-for-service beneficiaries discharged from SNF care between July 15, 2013, and July 15, 2014 (n = 693,808). Average age was 81.4 (SD 8.1) years, 67.1% were women, and 86.3% were non-Hispanic white.

Measurements

Functional items from the Minimum Data Set 3.0 were categorized into self-care, mobility, and cognition domains. We used specifications for the SNF potentially preventable 30-day postdischarge readmission quality metric to identify potentially preventable readmissions.

Results

The overall observed rate of 30-day potentially preventable readmissions following SNF discharge was 5.7% (n = 39,318). All 3 functional domains were independently associated with potentially preventable readmissions in the multivariable models. Odds ratios for the most dependent category versus the least dependent category from multilevel models adjusted for patients’ sociodemographic and clinical characteristics were as follows: mobility, 1.54 (95% confidence interval [CI] 1.49–1.59); self-care, 1.50 (95% CI 1.44–1.55); and cognition, 1.12 (95% CI 1.04–1.20). The 5 most common conditions were congestive heart failure (n = 7654, 19.5%), septicemia (n = 7412, 18.9%), urinary tract infection/kidney infection (n = 4297, 10.9%), bacterial pneumonia (n = 3663, 9.3%), and renal failure (n = 3587, 9.1%). Across all 3 functional domains, septicemia was the most common condition among the most dependent patients and congestive heart failure among the least dependent.

Conclusions

Patients with functional limitations at SNF discharge are at increased risk of hospital readmissions considered potentially preventable. Future research is needed to determine whether improving functional status reduces risk of potentially preventable readmissions among this vulnerable population.  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