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   23317篇
  免费   1746篇
  国内免费   143篇
耳鼻咽喉   200篇
儿科学   840篇
妇产科学   634篇
基础医学   3136篇
口腔科学   384篇
临床医学   2459篇
内科学   4807篇
皮肤病学   496篇
神经病学   2641篇
特种医学   509篇
外科学   2090篇
综合类   150篇
一般理论   37篇
预防医学   3045篇
眼科学   290篇
药学   1465篇
  1篇
中国医学   39篇
肿瘤学   1983篇
  2024年   32篇
  2023年   378篇
  2022年   686篇
  2021年   1205篇
  2020年   756篇
  2019年   996篇
  2018年   1070篇
  2017年   809篇
  2016年   872篇
  2015年   915篇
  2014年   1190篇
  2013年   1436篇
  2012年   2117篇
  2011年   2142篇
  2010年   1109篇
  2009年   935篇
  2008年   1375篇
  2007年   1298篇
  2006年   1209篇
  2005年   1052篇
  2004年   896篇
  2003年   762篇
  2002年   654篇
  2001年   108篇
  2000年   83篇
  1999年   90篇
  1998年   104篇
  1997年   94篇
  1996年   71篇
  1995年   79篇
  1994年   52篇
  1993年   58篇
  1992年   50篇
  1991年   44篇
  1990年   37篇
  1989年   34篇
  1988年   46篇
  1987年   33篇
  1986年   26篇
  1985年   21篇
  1984年   34篇
  1983年   22篇
  1982年   27篇
  1981年   34篇
  1980年   24篇
  1979年   11篇
  1978年   13篇
  1977年   11篇
  1974年   15篇
  1973年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
Pietro Rubegni  MD    Sara Poggiali  MD    Aldo Cuccia  MD    Maurizio Biagioli  MD    Michele Fimiani  MD 《Dermatologic surgery》2004,30(12P2):1539-1542
Background. Striated palmoplantar keratoderma or Brunauer-Fohs-Siemens syndrome is a very rare, focal, nonepidermolytic palmoplantar keratoderma with autosomal inheritance. Unlike other palmoplantar keratodermas, no association with visceral or skin cancer has ever been reported.
Objective. We report a case of malignant melanoma arising in the hyperkeratotic lesions on the right heel of a patient with striated palmoplantar keratoderma. The lesion was completely excised; our patient also underwent sentinel lymph node biopsy and then was treated with high-dose interferon adjuvant therapy.
Methods. Sentinel lymph node biopsy incision was made in elliptical fashion, long enough to harvest a full-thickness skin graft to cover the wide local excision defect. The skin graft was defatted by sharp dissection. Several perforations were made in graft and it was secured in place with sutures and bolster dressing.
Results. At follow-up, the grafted skin showed hyperkeratotic changes but no local or systemic signs of the disease was observed.
Conclusion. The association between striated palmoplantar keratoderma and acral melanoma is discussed.  相似文献   
44.
Compulsory health insurance schemes have received attention recently as a means of creating a reliable extra-budgetary source of health care funding. Yet, the full implications of such schemes in a developing country context are unclear; in particular, the impact on and relationship with private sector providers has infrequently been explored. This study examines patterns of public and private sector utilization under the Civil Servants' Medical Benefit Scheme (CSMBS) in Bangkok, Thailand. The CSMBS currently provides limited reimbursement for private inpatient care, but recent proposals suggest increasing benefit levels for care sought in the private sector. The study shows that despite high level of cost recovery in the public sector, charges were much lower than those in the private sector. Different patterns of diagnosis in the two sectors were found with private hospitals tending to treat a less complex case mix. Within the private sector, there was a limited tendency to specialize in certain types of care. It is concluded that under the current payment mechanism of fee-for-service reimbursement, measures to enhance access to private sector care should be approached with caution. In the long run, the scheme should merge with the recently established social security scheme.  相似文献   
45.
A detailed study comparing the distribution of D2 receptors and tyrosine hydroxylase-immunoreactive fibers in the hippocampus and parahippocampal cortices of the rat, cat, and human was conducted. The distribution of [125I]epidepride binding to D2 receptors along the transverse and longitudinal axes of the hippocampus and parahippocampus differed among the species. In rat hippocampus, the number of sites was highest in septal portions of lacunosum-moleculare of CA1 and stratum moleculare of the subiculum. Virtually no binding to D2 receptors existed in the temporal hippocamps. For the cat hippocampus, the highest binding existed in the inner one-third of the molecular layer of the dentate gyrus (DG). There were also significant numbers of D2 receptors in strata radiatum and oriens of the CA subfields, with almost undetectable levels in lacunosum moleculare and subiculum. The number of sites was higher in the septal than temporal hippocampus. In the human hippocampus, highest binding was observed in the molecular layer of DG and the subiculum, with lower levels in strata oriens and lacunosum-moleculare of CA3, and very low binding in CA1. The histochemical demonstration of the pattern of mossy fibers revealed an organization complementary to that of D2 receptors in cat and human. In none of the species was there significant expression of D2 receptors in the entorhinal cortex, except in the caudal extreme of this region in the rat. In that region a trilaminar pattern was exhibited that continued into the perirhinal cortex. A trilaminar pattern of D2 receptor expression was observed in the perirhinal cortex of all species, with the highest values in the external and deep laminae and low expression in the middle laminae. The organization of dopamine fibers was assessed by comparing the distribution of tyrosine hydroxylase-positive and dopamine β-hydroxylase-immunoreactive fibers in these same regions. It revealed consistent mismatches between the pattern of D2 receptor expression and dopaminergic innervation in all three species. The implications for this mismatch are discussed. It is hypothesized that the distribution of D2 receptors, and not of dopamine fibers, determines what neural systems dopamine influences in the hippocampal complex. © 1994 Wiley-Liss, Inc.  相似文献   
46.
47.
The principles of promoting autonomy and independence underpin many approaches to improving the quality of nursing care for older people in whatever setting, and are in line with wider developments in health care such as the Patient's Charter. However, these concepts require careful definition if nursing practices which might promote autonomy and independence are to be identified. Although the generalizability of the research-based literature in this field is limited by a focus upon older people in continuing-care settings, a review of the literature found a number of indicators associated with attempts to promote patient autonomy and independence. These were grouped into the following categories: systems of care delivery which promote comprehensive individualized assessment and multidisciplinary care planning; attempts to encourage patients/clients to participate in decisions about their care; patterns of communication which avoid exerting power and control over patients/clients and attempts to modify the environment to promote independence and minimize risk. It is suggested that the review identifies a number of principles for nursing practice which can be applied in a range of care settings in order to promote the autonomy and independence of older people.  相似文献   
48.
The usefulness of serum DU-PAN-2 in diagnosing pancreatic cancer and in distinguishing between this cancer and other benign and malignant diseases, and to assess the role of liver dysfunction in altering the serum levels of this marker were investigated. DU-PAN-2 was measured in the sera of 31 patients with pancreatic cancer, 32 with chronic pancreatitis, 20 with benign and 21 with malignant extra-pancreatic diseases. DU-PAN-2 was found to be above 300 U ml-1 in 21/31 patients with pancreatic cancer (sensitivity 68%). Only 3/32 patients with chronic pancreatitis had abnormal values. A substantial number of patients with both benign and malignant extra-pancreatic diseases had an elevated serum DU-PAN-2 (9/20 and 15/21, respectively). Correlations were found between DU-PAN-2 and (1) total bilirubin, (2) alanine-amino-transferase and (3) alkaline phosphatase. Of the patients with high DU-PAN-2 values, jaundice was found in: 2/3 with chronic pancreatitis, 9/10 with benign and 12/14 with malignant extra-pancreatic diseases. In conclusion, the serum DU-PAN-2 test for pancreatic malignancy is not completely satisfactory, because it is not sensitive enough. While the test for chronic pancreatitis has an acceptable specificity, the assay cannot distinguish between pancreatic cancer and other extra-pancreatic diseases, mainly of the liver and biliary tract. Liver dysfunction as well as jaundice seem to considerable affect the levels of this marker, as reported elsewhere for CA 19-9.  相似文献   
49.
50.
We report on a 26-year-old female affected by Noonan syndrome (NS), a congenital disorder characterized by various phenotypic features and congenital anomalies) associated with a variety of autoimmune diseases, including systemic lupus erythematosus, celiac disease, and Hashimoto thyroiditis. Autoimmunity is seldom described in NS and the association between this congenital disease and three autoimmune disorders has not been previously reported. Should the occurrence of autoimmune disorders in NS be confirmed, a relevant clinical and laboratory evaluation of NS patients should be performed in order to clarify whether the immune system involvement represents only an occasional event or is a feature of the disease.  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