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   4152篇
  免费   225篇
  国内免费   14篇
耳鼻咽喉   63篇
儿科学   296篇
妇产科学   87篇
基础医学   551篇
口腔科学   42篇
临床医学   241篇
内科学   687篇
皮肤病学   70篇
神经病学   255篇
特种医学   102篇
外科学   509篇
综合类   106篇
一般理论   1篇
预防医学   244篇
眼科学   190篇
药学   480篇
中国医学   50篇
肿瘤学   417篇
  2023年   27篇
  2022年   72篇
  2021年   150篇
  2020年   75篇
  2019年   96篇
  2018年   125篇
  2017年   88篇
  2016年   130篇
  2015年   115篇
  2014年   144篇
  2013年   199篇
  2012年   297篇
  2011年   315篇
  2010年   204篇
  2009年   152篇
  2008年   232篇
  2007年   202篇
  2006年   195篇
  2005年   199篇
  2004年   167篇
  2003年   136篇
  2002年   122篇
  2001年   55篇
  2000年   73篇
  1999年   56篇
  1998年   36篇
  1997年   26篇
  1996年   29篇
  1995年   24篇
  1994年   22篇
  1993年   20篇
  1992年   46篇
  1991年   44篇
  1990年   36篇
  1989年   55篇
  1988年   44篇
  1987年   38篇
  1986年   34篇
  1985年   31篇
  1984年   28篇
  1983年   28篇
  1982年   15篇
  1981年   16篇
  1979年   34篇
  1978年   15篇
  1976年   14篇
  1973年   17篇
  1972年   16篇
  1970年   13篇
  1968年   11篇
排序方式: 共有4391条查询结果,搜索用时 31 毫秒
1.
2.
3.
Ehlers-Danlos syndrome – vascular type, the only lethal form, is rarely reported in dermatology literature. It is characterized by translucent, atrophic skin, easy bruising, arterial, intestinal and/or uterine fragility manifesting as varicose veins, aneurysms and vascular/visceral/uterine rupture. As its dermatopathologic features are not well elucidated, diagnosis is often made after a catastrophic complication or at autopsy. This 36 year-old non-consanguineous male had brown-black plaques with atrophy and frequent ulceration over legs and dorsal feet and tortuous varicose veins around ankles for the past 15 years. Perivenous skin was translucent and hypopigmented. He had multiple and ecchymotic keloids and small atrophic, pityriasis versicolor-like lesions over trunk. He did not have hypermobile/hyperextensible skin and joints and showed no systemic or investigative abnormality. Histopathologic features of atrophic lesion included blood extravasation in atrophic epidermis/dermis, focal clustering and dilatation of blood vessels, malformed vessel walls, abundant hemosiderin in the dermis and homogenously stained/whorled patterned collagen especially around blood vessels. Pathology of keloidal lesion showed new collagen and vascular fragility. These histopathologic features appear of diagnostic value especially in patients who have compatible clinical findings but cannot afford confirmation by biochemical testing for abnormal synthesis of type III procollagen or identification of mutations in the COL3A1 gene.  相似文献   
4.
The abdominal compartment syndrome is a life threatening condition resulting from pathologic elevation of the intraabdominal pressure. Prompt diagnosis is required to avoid significant sequelae. Diagnosis of this syndrome is based on clinical findings and intra abdominal pressure monitoring. Treatment consists of decompressive laparotomy, which corrects the pathology. Various surgical techniques are described to manage the open abdomen. Despite considerable attention accorded to this disorder, it is still associated with high morbidity and mortality. This review article deals with the identification of risk factors, pathophysiology, diagnostic criteria and treatment of critically ill patients with the abdominal compartment syndrome.  相似文献   
5.
6.
Carcinoma gallbladder is the commonest malignancy in the Northern part of India. The heavy metals are known carcinogens while trace metals have protective effect. Aim The aim of the study is to estimate the heavy and trace metal (Lead, Zinc, Copper, Cadmium, Chromium, Manganese and Selenium) concentration in serum, bile, tissue and gallstone in patients with gallbladder diseases. Method This is a pilot study conducted in 45 cases (Group – I: 15 cases of carcinoma gallbladder, Group II: 15 patients of cholecystitis with cholelithiasis and Group – III: 15 patients of healthy control), to detect the relationship between the heavy and trace metal concentration and gall bladder carcinoma. Analysis of metal was done using Perkins‐Elmer model 2380 atomic absorption spectrophotometer. Results The serum concentration of copper and nickel was significantly high in carcinoma gallbladder patients as compared to patients with cholecystitis while zinc and selenium is low in carcinoma gallbladder patients. Bile concentration of zinc, selenium and manganese was significantly low in carcinoma gallbladder patients (p < 0.05) as compared to patients of cholelithiasis while cadmium and nickel was high. Tissue concentration of manganese was significantly low in carcinoma gallbladder patients as compared to patients of cholelithiasis while chromium was high. Gallstone concentration of copper, manganese and lead was significantly low in carcinoma gallbladder patients as compared to patients of cholelithiasis. Conclusion The heavy metals are in higher concentration in carcinoma gallbladder while trace metals are in lower concentration indicating possible role of heavy metal in gallbladder carcinogenesis.  相似文献   
7.
8.
Growing rats were exposed to 5 mg/L Pb,ad libitum in drinking water, and administered low or high doses of Mn and Cd intraperitoneal (i.p.) for 30 days. Some groups of animals were also administered combinations of Pb + Mn and Pb + Cd in an identical manner. Analysis of Pb, Mn, and Cd in tissue samples showed the expected dose-dependent accumulation when the metal was administered singly. However, combined treatment produced different types of metal shift in different tissues. Enhanced accumulation of all three metals in the brain, Mn in liver, Pb in kidney and Cd in testis and kidney after combined exposure may make target organs vulnerable to the toxic effects of metals, even when encountered at low concentrations. Further, the decreased levels of blood Pb after combined treatment with Cd or Mn suggests that the significance of blood Pb level as a diagnostic aid for Pb toxicity in coexposed conditions may not be of much value. Changes in the metallic distribution within the tissues after coexposure may be the result of a competition between the administered metals for common binding sites.  相似文献   
9.
A sublethal concentration of technical grade endosulfan (END) inhibited 35 to 55% of the activities of cytoplasmic malate dehydrogenase (cMDH), mitochondrial malate dehydrogenase (mMDH), and lactate dehydrogenase (LDH) in the liver and the skeletal muscle of a freshwater catfish, Clarias batrachus, after 7 days of exposure. The activity remained in the inhibited state up to 28 days. The withdrawal of END from the medium after 1 week of exposure gradually restored the activities to control levels within 21 days in the skeletal muscle and 28 days in the liver. The administration of actinomycin D or cycloheximide between the 14th and the 21st day of the withdrawal of END almost completely inhibited the withdrawal-dependent recovery in the activities of all the three enzymes. This indicates de novo synthesis of the enzymes during the recovery period. A conjoint treatment of END and triiodothyronine (T3) raised the activities of cMDH, mMDH, and LDH in the liver and the skeletal muscle up to the control levels. This shows that the inhibitory effect of END may be relieved in presence of T3. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed few changes in the pattern of cytoplasmic proteins of the liver and the skeletal muscle in response to exposure to END.  相似文献   
10.
Asymptomatic infection with Loa loa, an eye worm, is reported in a 32-year old Zambian woman. The patient revealed up to 28% eosinophilia but microfileraemia was not noticed. One gravid female parasite 56 X 0.56 mm, extracted from lower lid of left eye of the patient, is described. Treatment with diethylcarbamazine (DEC) extended over three weeks was successful against another parasite in tissues.  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