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   55562篇
  免费   3484篇
  国内免费   110篇
耳鼻咽喉   529篇
儿科学   2296篇
妇产科学   1514篇
基础医学   6945篇
口腔科学   539篇
临床医学   8544篇
内科学   9519篇
皮肤病学   756篇
神经病学   5329篇
特种医学   974篇
外科学   4603篇
综合类   589篇
一般理论   109篇
预防医学   7764篇
眼科学   760篇
药学   3632篇
中国医学   61篇
肿瘤学   4693篇
  2023年   290篇
  2022年   431篇
  2021年   1016篇
  2020年   693篇
  2019年   1050篇
  2018年   1202篇
  2017年   977篇
  2016年   1058篇
  2015年   1237篇
  2014年   1711篇
  2013年   2728篇
  2012年   3929篇
  2011年   4240篇
  2010年   2356篇
  2009年   2127篇
  2008年   3831篇
  2007年   4075篇
  2006年   3927篇
  2005年   4068篇
  2004年   3863篇
  2003年   3636篇
  2002年   3351篇
  2001年   469篇
  2000年   343篇
  1999年   470篇
  1998年   685篇
  1997年   608篇
  1996年   479篇
  1995年   481篇
  1994年   425篇
  1993年   338篇
  1992年   243篇
  1991年   207篇
  1990年   185篇
  1989年   196篇
  1988年   185篇
  1987年   169篇
  1986年   162篇
  1985年   163篇
  1984年   186篇
  1983年   169篇
  1982年   215篇
  1981年   207篇
  1980年   155篇
  1979年   94篇
  1978年   112篇
  1977年   52篇
  1976年   57篇
  1975年   45篇
  1974年   68篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
73.
74.
This report of the North American Pediatric Transplant Cooperative Study summarizes data contributed by 57 participating centers on 754 children with 761 transplants from 1 January 1989 to 16 February 1989. Data collection was initiated in October 1987 and follow-up of all patients is ongoing. Transplant frequency increased with age; 24% of the patients were less than 5 years, with 7% being under 2 years. Common frequent diagnoses were: aplastic/dysplastic kidneys (18%), obstructive uropathy (16%), and focal segmental glomerulosclerosis (12%). Preemptive transplant, i.e., transplantation without prior maintenance dialysis, was performed in 21% of the patients. Dialytic modalities pretransplant were peritoneal dialysis in 42% and hemodialysis in 25%. Bilateral nephrectomy was reported in 29%. Live-donor sources accounted for 42% of the transplants. Among cadaveric donors, 41% of the donors were under 11 years old. During the first post-transplant month, maintenance therapy was used similarly for live-donor and cadaver source transplants, with prednisone, cyclosporine, and azathioprine used in 93%, 83%, and 81%, respectively. Triple therapy with prednisone, cyclosporine, and azathioprine was used in 78%, 75%, and 75% of functioning cadaver source transplants at 6 months, 12 months, and 18 months as opposed to 60%, 63%, and 54% for live-donor procedures, with single-drug therapy being uncommon. Rehospitalization during months 1–5 occurred in 62% of the patients, with treatment of rejection and infection being the main causes. Additionally, 9% were hospitalized for hypertension. During months 6–12 and 12–17, 30% and 28% of the patients with functioning grafts were rehospitalized. Times to first rejection differed significantly for cadaver and live-donor transplants. The median time to the first rejection was 36 days for cadaver transplants and 156 days for live-donor transplants. Overall, 57% of treated rejections were completely reversible although the complete reversal rate decreased to 37% for four or more rejections. One hundred and fifty-two graft failures had occurred at the time of writing, with a 1-year graft survival estimate of 0.88 for live-donor and 0.71 for cadaver source transplants. In addition to donor source, recipient age is a significant prognostic factor for graft survival. Among cadaver donors, decreasing donor age is associated with a decreasing probability of graft survival. Thirty-five deaths have occurred; 16 attributed to infection and 19 to other causes. The current 1-year survival estimate is 0.94. There have been 9 malignancies.A list of all participating centers and the names of the investigators is printed on pages 552–553  相似文献   
75.
In summary, we have described two patients with CRMO and psoriasis, and have reviewed the musculoskeletal manifestations associated with pustular eruptions of the palms and soles. In view of the frequent occurrence of PPP in patients with CRMO, we suggest that the occurrence of psoriasis in our two patients is more than coincidence, and that noninfectious, inflammatory lesions of bone may be another musculoskeletal manifestation of psoriasis. This rare association, as well as the association of PPP with disorders associated with new bone formation, may shed new insights on the relatively common finding of periosteal elevation associated with psoriatic arthritis and the occasional severe juxta-articular osteolytic destructive bone lesions seen in psoriatic arthritis.  相似文献   
76.
77.
Federal regulations prescribe distinct protections for children participating in research studies. Procedures for collecting tissue specimens from children solely for research purposes must pose no more than a minor increase over minimum risk, thereby limiting the approvable correlative biologic studies to evaluate molecularly targeted agents in children with cancer. Ethical issues arise when approvable correlative studies are a mandatory component of an early-phase pediatric clinical trial of new anticancer agents. The National Cancer Institute Cancer Therapy Evaluation Program sponsored a workshop in 2002 to discuss tissue collection for correlative biologic studies in early-phase childhood cancer clinical studies of molecularly targeted agents. Workshop participants recommended the following: (1) tissue specimens for correlative studies should provide vital clinical and scientific results to qualify for early-phase pediatric study consideration; (2) parents should receive a realistic appraisal of the risks, requirements, and potential for benefit of phase I protocol participation; (3) investigators should clearly distinguish clinically necessary procedures from research procedures of no benefit to the child to improve correlative study informed consent; and (4) participation in correlative research studies included in clinical trials generally should be voluntary. The need to acquire important biologic data regarding new molecular agents will challenge the ingenuity of pediatric cancer researchers, necessitating the application of highly sensitive laboratory assay methods, new imaging procedures, and preclinical models of childhood cancer. Such innovative methods can allow necessary scientific information to be obtained while simultaneously respecting the protections appropriately afforded to children participating in research studies and minimizing the burden of research participation for children with cancer and their families.  相似文献   
78.
Germline mutations in the neurofibromatosis type 2 tumour suppressor gene   总被引:13,自引:2,他引:11  
The recent identification of the NF2 tumour suppressor genehas enabled large scale screening for pathological mutationsin the gene. We have sought germline mutations In the NF2 geneby SSCP and heteroduplex analysis of cDNA and genomic DNA samplesfollowed by cloning and sequencing of mutant alleles. In thepresent report we describe 11 putative pathological mutations,including five nonsense mutations, three short insertions ordeletions cauing frameshifts and three missense mutations. Moststop mutations and frameshift mutations were found In Individualsexpressing a severe phenotype while one of the three missensemutations was associated with a mild phenotype. Four unrelatedNF2 patients of the 93 tested were found to have identical nonsensemutations caused by a C to T transition (C169) in a CpG dinucleotide,which is a potential mutational hotspot in the NF2 tumour suppressorgene.  相似文献   
79.
A review of the history of fetal heart rate monitoring is followed by detailed analysis of eight randomized, controlled trials and of a recent prospective study of electronic fetal monitoring compared with intermittent auscultation. No significant differences between the methods were reported in perinatal mortality rates, neonatal infection rates, and Apgar scores. Mixed results were reported for length of labor, maternal analgesic use during labor, maternal genital tract infection rates, umbilical cord pH values, and admissions to neonatal intensive care units. Auscultation was associated in two trials with a significantly increased rate of neonatal seizures. Electronic fetal monitoring was correlated with a significantly increased cesarean delivery rate in the first four trials, and with a significantly increased rate of operative delivery (forceps plus cesarean delivery) in three later trials. A decision tree is presented to assist the clinician in selecting the appropriate fetal monitoring method for a given client.  相似文献   
80.
Dreams during pregnancy were collected from post-partum women on the maternity ward of an Israeli hospital. Our data indicate that primipara women and women with complicated obstetrical histories were more likely to report increased dreaming during pregnancy. The collected dream corpus suggests that dreams during pregnancy can be viewed as a distinct dream genre. This paper develops a tentative typology of that genre. In addition, the authors argue that the context of disclosure was highly relevant to the sorts of manifest contents that were reported.  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