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   4534篇
  免费   294篇
  国内免费   22篇
耳鼻咽喉   96篇
儿科学   122篇
妇产科学   77篇
基础医学   608篇
口腔科学   614篇
临床医学   323篇
内科学   845篇
皮肤病学   100篇
神经病学   317篇
特种医学   234篇
外科学   455篇
综合类   52篇
一般理论   3篇
预防医学   448篇
眼科学   123篇
药学   290篇
中国医学   37篇
肿瘤学   106篇
  2023年   26篇
  2022年   71篇
  2021年   166篇
  2020年   107篇
  2019年   134篇
  2018年   167篇
  2017年   120篇
  2016年   121篇
  2015年   153篇
  2014年   180篇
  2013年   255篇
  2012年   327篇
  2011年   354篇
  2010年   234篇
  2009年   189篇
  2008年   235篇
  2007年   289篇
  2006年   214篇
  2005年   191篇
  2004年   139篇
  2003年   115篇
  2002年   100篇
  2001年   86篇
  2000年   68篇
  1999年   58篇
  1998年   57篇
  1997年   56篇
  1996年   51篇
  1995年   49篇
  1994年   35篇
  1993年   34篇
  1992年   32篇
  1991年   47篇
  1990年   38篇
  1989年   45篇
  1988年   32篇
  1987年   22篇
  1986年   29篇
  1985年   34篇
  1984年   16篇
  1983年   19篇
  1982年   12篇
  1981年   19篇
  1980年   12篇
  1979年   23篇
  1978年   13篇
  1977年   14篇
  1976年   17篇
  1975年   7篇
  1969年   6篇
排序方式: 共有4850条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
OBJECTIVES: To determine whether aromatase expression in the eutopic endometrium and adenomyotic foci is affected by previous use of oral contraceptives containing gestodene, and to determine whether changes in cyclooxygenase-2 (COX-2) expression occur in adenomyosis during the menstrual cycle. PATIENT AND METHODS: This was a retrospective cohort study carried out in paraffin-embedded endometrial tissue obtained from patients with a histological diagnosis of adenomyosis obtained during the proliferative (n = 25) and luteal (n = 10) phases of the menstrual cycle and following the use of continuous oral contraception with gestodene/ethinyl estradiol (n = 7). COX-2 and aromatase expression were measured in both eutopic endometrium and adenomyotic foci using immunohistochemical methods. RESULTS: Aromatase expression was detected in 80% of the endometrial slices by immunohistochemistry. In positive cases, aromatase was mainly detected in the stromal cells of the eutopic endometrium, whereas in the adenomyotic foci this expression was negative in the majority of the cases. Oral contraceptives containing gestodene, on the other hand, were effective in suppressing aromatase expression in both eutopic and ectopic endometrium. COX-2 expression was detected by immunohistochemistry in the glandular epithelium of both eutopic endometrium and adenomyotic foci and there were no significant changes in its intensity throughout the menstrual cycle. CONCLUSION: Aromatase expression in the eutopic endometrium and adenomyotic foci is suppressed by oral contraceptives containing gestodene. Increased aromatase activity may be responsible for the persistent COX-2 expression during the luteal phase.  相似文献   
5.
Paracoccidioidomycosis of the central nervous system presents either as meningeal or pseudotumoral lesions. Although occurring more frequently in the brain and meninges, they can occasionally involve the spinal cord. A case of paracoccidioidomycosis in the cervical spinal cord is reported in this paper. Difficulties in establishing the etiologic diagnosis, the importance of radiologic examination of the thorax, and the treatment of the patient are commented. In an extensive review of the literature on the subject, only three other cases have been found, which are also discussed.  相似文献   
6.
Thirty cases of phyllodes tumour (cystosarcoma phyllodes) of the breast that presented to the Clinical Oncology Unit at Guy's Hospital were reviewed. Tumours were classified as benign, malignant or borderline according to the following histological criteria: mitotic rate, nuclear pleomorphism, stromal overgrowth and tumour margins. In 14 (46.5%) cases the tumours were considered histologically benign, in 11 (36.5%) malignant, and in five (17%) borderline. Recurrence was seen in a similar proportion of patients with tumours classified as benign (21 %) and malignant (18 %) according to histological criteria. Malignant lesions tended to recur earlier. Infiltrating tumour margins were noted in all patients and stromal overgrowth in all hut one in whom recurrence was observed. Risk of recurrence also appeared to he related to tumour size. Only one patient developed distant metastases and died of her disease. Because of treatment variation no conclusion can he made regarding optimal therapy but the importance of adequate clearance, either through wide excision or mastectomy, is emphasized for all phyllodes tumours irrespective of histological features.  相似文献   
7.
Primary pregnancy in the liver. A case report   总被引:1,自引:0,他引:1  
A case of intra-hepatic pregnancy is reported. The patient was 32 years old and presented with an acute intra-abdominal hemorrhage. At surgery a spongy 3 x 2 x 1.5 cm mass was removed from the right liver lobe. Microscopically, well developed chorionic villi appeared invading the liver tissue. The patient had a relatively uneventful recovery.  相似文献   
8.
We report the case of a 75-year-old-woman who presented with bilateral scalp ulcerations and blindness, accompanied by severe headache and scalp tenderness, due to bilateral temporal arteritis without systemic involvement. A biopsy taken from the border of an ulceration showed evidence of giant cell arteritis. She was treated with oral prednisone, 60 mg per day. The ulcerations healed in a few weeks but the vision loss was irreversible. This case highlights for temporal arteritis the importance of accurate and timely diagnosis as well as the need for prompt therapy with systemic steroids in order to avoid major complications, namely loss of vision. It also demonstrates that scalp necrosis and ulcerations are skin signs associated with a poor prognosis.  相似文献   
9.
Fine needle aspiration cytology is a safe diagnostic technique for breast cancer and can identify certain benign lesions, which can be excised without affecting surrounding tissue. The combination of experienced operator and cytologist can yield high sensitivity and specificity, together with important prognostic information.  相似文献   
10.
Thirty-eight nontoxigenic strains ofCorynebacterium diphtheriae isolated between 1987 and 1992 from clinical specimens of French patients were typed by biotyping, antibiograms, bacteriophage typing, ribotyping, and restriction analysis by pulsed-field gel electrophoresis (PFGE). Excellent correlation occurred between the genotypes defined by PFGESfil profiles or by ribotypeBstEll profiles. Genotyping revealed seven genotype patterns among the 26 biotype mitis isolates, five among the nine biotype gravis isolates, and three among the three biotype belfanti isolates. Phage typing was nonreactive for nine of the 38 isolates. A combination of all the typing methods led to the identification of 19 different types ofCorynebacterium diphtheriae.  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