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   3361篇
  免费   191篇
  国内免费   7篇
耳鼻咽喉   24篇
儿科学   216篇
妇产科学   75篇
基础医学   381篇
口腔科学   41篇
临床医学   231篇
内科学   542篇
皮肤病学   47篇
神经病学   137篇
特种医学   161篇
外科学   439篇
综合类   163篇
预防医学   397篇
眼科学   171篇
药学   235篇
中国医学   14篇
肿瘤学   285篇
  2023年   21篇
  2022年   39篇
  2021年   70篇
  2020年   60篇
  2019年   63篇
  2018年   79篇
  2017年   43篇
  2016年   62篇
  2015年   68篇
  2014年   123篇
  2013年   136篇
  2012年   201篇
  2011年   252篇
  2010年   137篇
  2009年   125篇
  2008年   211篇
  2007年   191篇
  2006年   139篇
  2005年   155篇
  2004年   152篇
  2003年   116篇
  2002年   93篇
  2001年   70篇
  2000年   64篇
  1999年   58篇
  1998年   24篇
  1997年   21篇
  1995年   16篇
  1992年   37篇
  1991年   33篇
  1990年   25篇
  1989年   38篇
  1988年   34篇
  1987年   29篇
  1986年   27篇
  1985年   26篇
  1984年   23篇
  1983年   19篇
  1982年   14篇
  1979年   40篇
  1978年   31篇
  1977年   18篇
  1975年   14篇
  1974年   26篇
  1973年   21篇
  1972年   16篇
  1971年   20篇
  1970年   26篇
  1969年   15篇
  1966年   17篇
排序方式: 共有3559条查询结果,搜索用时 15 毫秒
21.
MUC1 (CD227) is a large transmembrane epithelial mucin glycoprotein, which is aberrantly overexpressed in most adenocarcinomas and is a target for immune therapy for epithelial tumors. Recently, MUC1 has been detected in a variety of hematopoietic cell malignancies including T and B cell lymphomas and myelomas; however, its function in these cells is not clearly defined. Using the Jurkat T cell lymphoma cell line and normal human T cells, we demonstrate that MUC1 is not only expressed in these cells but is also phosphorylated upon T cell receptor (TCR) ligation and associates with the Src-related T cell tyrosine kinase, p56lck. Upon TCR-mediated activation of Jurkat cells, MUC1 is found in the low-density membrane fractions, where linker of T cell activation is contained. Abrogation of MUC1 expression in Jurkat cells by MUC1-specific small interfering RNA resulted in defects in TCR-mediated downstream signaling events associated with T cell activation. These include reduction in Ca2+ influx and extracellular signal-regulated kinase 1/2 phosphorylation, leading to a decrease in CD69 expression, proliferation, and interleukin-2 production. These results suggest a regulatory role of MUC1 in modulating proximal signal transduction events through its interaction with proteins of the activation complex.  相似文献   
22.
Vignesh  Pandiarajan  Barman  Prabal  Basu  Suprit  Mondal  Sanjib  Ishran  Bhoomika  Kumrah  Rajni  Dod  Aditya  Garg  Ravinder  Rawat  Amit  Singh  Surjit 《Immunologic research》2023,71(1):112-120
Immunologic Research - Juvenile dermatomyositis (JDM) is the commonest inflammatory myositis in children. The clinical phenotype is often characterized by the presence of myositis-specific...  相似文献   
23.
Voles (Microtus pennsylvanicus) were trapped in the immediate area of Love Canal (I), in an area very close to Love Canal (II), and in a reference area (III) about one km from Love Canal. The population densities were low in I, intermediate in II, and high in III. Using ages estimated on the basis of dry lens weights, mean life expectancy from weaning was 23.6 days in I, 29.2 days in II, and 48.8 days in III. Survivorship curves had significantly steeper slopes in I and II than in III. Thus, voles in I and II experienced a higher mortality rate than those in III. Liver and adrenal weights in females and seminal vesicle weights in males were significantly reduced in I compared to III. A fat pool from voles from I and II contained hexachlorocyclohexane and other chlorinated hydrocarbons that were not found in voles from III. These results suggest that relatively sedentary small native mammals may be of use in assessing environments with hazardous contamination.  相似文献   
24.
The greater risks of death faced by females in India are discussed in terms of the differences between the norther and southern regions of India, culture compounding inequality, and intervention strategies. When the assumption of a sex ratio of equality of 950/1000 is make, every region in the north is below (ranging from 874-913), and every region in the south above (ranging from 960-1040). The same north/south division remains for the male probability of dying by age 5 as a proportion of female probability (rural) in 1981. 2 explanations are given for female's greater survival changes in the south. 1) Marriage and kinship systems are different. Girls in the north typically marry earlier; many times marriage is to a stranger in a distant area so that family contact is reduced. The consequence is a reduction in female autonomy and status in both her father's and her husband's home. 2) Economic roles are different. Research has revealed that male/female survival equality occurs in states with high female labor force participation rates. At the micro level, working women's children tend to have more equal death rates. Physical devaluation is not only evidenced in death and survival, but also in the disparity in schooling. The states with the greatest gender differentials in mortality also have the greatest differences in literacy. This has been interpreted as household resources are disproportionately invested in males. Cultural inhibitions about the physical freedoms of girls also are involuntary reasons for the sex differential. The example is given of the apprehension generated for a male doctor's examination of a girl, a coeducational school environment, or a school located a distance from the home. There is the tradition of female seclusion and inhibition. In combination with the dependence on sons to limit the choices open to women, and to limit the growth and development, the product is inequality. Amniocentesis has lead to the increase in numbers of sex determination and abortion clinics. There is evidence that aborted fetuses are primarily female. Without change in these practices, there will not be a reversal in the sex ratio. Interventions suggested include increasing the number of facilities for the equal development of girls and women. There must be increases in female medical staff, more girl's schools in villages, and more nutrition programs for girls, Women's economic independence must be enhanced.  相似文献   
25.
Otitis media with effusion is one of the commonest otological problems in paediatric age group. The condition occurs in childhood as overt or covert hearing loss presenting as an educational or behavioural problem. As there is widespread controversy regarding its precise aetiology, natural history and pathogenesis a treatment dilemma still persists. The main goal of this study is to compare the efficacy of different modalities of medical and surgical treatment designed for this condition and analysis of the results statistical.  相似文献   
26.
27.

Background:

Though adequate literature is present depicting the results of pedicle screw-rod instrumentation using top loading systems for correction of adolescent idiopathic scoliosis (AIS), using the rod rotation technique, few published data is available regarding side loading systems used for a similar purpose. We report a retrospective study of a cohort of patients with strict inclusion criteria who underwent surgical correction of AIS with side-opening pedicle screw-rod posterior instrumentation using the axial translation technique of curve correction to assess the efficacy of side opening system for scoliosis correction with regards to patient satisfaction, Cobb''s angle correction and spinal balance.

Materials and Methods:

Clinical and radiological outcomes were measured in 14 consecutive patients (3 males, 11 females) with an average age of 14.0 years (range 9 to 23 years). They were followed up for an average period of 13.0 months (range – 2.2 to 28.5). All patients underwent posterior instrumentation only with pedicle screws used as anchor points. Hybrid constructs using hooks/wires or curves requiring anterior release were excluded from the study. All levels were not instrumented – more screws were put on the concavity and in the peri-apical region. Radiological evaluation was done by whole spine standing AP, lateral radiograms preoperatively and 1, 3, 6 and12 months after surgery. Cobb''s angles were measured and the spinal balance was noted. Clinical evaluation was done by SRS questionnaire. The complications were documented.

Results:

The mean preoperative Cobb''s angle was 58.35° (range – 44 to 72°), which came down postoperatively to 23.45° (range – 10 to 38°) signifying a mean correction of 59.57% (range – 26.92 to 76.17%). Clinical outcomes were evaluated using the SRS – 30 questionnaires. The values of mean pre- and postoperative scores are 3.68 and 4.18, showing an improvement of 0.5 points. Other than one patient of superficial wound infection, which healed with antibiotics, there was no major complication. No patient had neurological deterioration.

Conclusion:

Side-opening spinal instrumentation systems, using the axial translation technique, achieved good clinical and radiological outcome for patients of AIS.  相似文献   
28.
A male patient of 60 years presented with a swelling in the left groin of 10 months duration. Past records showed bilateral lumbar sympathectomy and omentopexy done 20 and 6 years back, respectively, for Buerger’s disease. Abdominal examination revealed a huge hernial swelling in the left groin extending from the symphysis pubis to anterior superior iliac spine measuring 25 × 18 cm. On exploration, the contents were intestines and omentum, which were coming out through a defect of 5 × 3 cm in the lower fibers of the conjoint muscle 4 cm cephalad to the deep ring, a finding which made the final diagnosis as an incisional hernia. We present this interesting case as a very rare complication of omentopexy, probably not reported previously, and an unusual case of an incisional hernia presenting as an inguinal hernia which is very difficult to diagnose unless encountered before. Its rarity and clinical challenge is highlighted.  相似文献   
29.
Multiple primary malignant neoplasm is the occurrence of a second primary malignancy in the same patient within 6 months of the detection of first primary (synchronous), or 6 months or more after primary detection (metachronous). Multiple primary malignant neoplasms are not very frequently encountered in clinical practice. The relative risk for a second primary malignancy increases by 1.111-fold every month from the detection of the first primary malignancy in any individual. We present 2 patients treated for carcinoma of the breast who developed a metachronous primary malignancy in the stomach to highlight the rare occurrence of multiple primary malignant neoplasms. These tumors were histologically dissimilar, with distinct immunohistochemical parameters. The importance lies in carefully identifying the second primary malignancies, not dismissing them as metastases, and treating them accordingly.Key words: Breast neoplasms, Stomach neoplasms, Neoplasms, Second primaryBreast cancer is the most common malignancy among women worldwide. With proper screening, earlier detection, and improved treatment, survival has greatly increased, with the result that there is now a large population of women with a present or past history of breast cancer. This has led to an increased detection of second primary malignancies among these women. The relative risk for a second primary malignancy increases by 1.111-fold every month from the detection of the first primary malignancy in any individual.1 Several authors have reported on a lesion in the stomach being labeled as a second primary malignancy and subsequently found to be metastasis. When the primary breast tumor is positive for estrogen and progesterone receptors (ER/PRs) and the stomach tumor is ER/PR negative, the diagnosis is established easily.2 However, studies have shown that some primary gastric cancers can have ER/PR positivity. Further, if the primary breast lesion is ER/PR negative, the same cannot be used as a marker. Here, we present 2 breast cancer patients who developed second primary malignancies in the stomach and the final diagnosis was established based on histopathology and immunohistochemistry.  相似文献   
30.
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