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   1278篇
  免费   75篇
  国内免费   8篇
耳鼻咽喉   3篇
儿科学   32篇
妇产科学   8篇
基础医学   180篇
口腔科学   37篇
临床医学   70篇
内科学   338篇
皮肤病学   1篇
神经病学   25篇
特种医学   117篇
外科学   258篇
综合类   6篇
预防医学   52篇
眼科学   24篇
药学   64篇
中国医学   2篇
肿瘤学   144篇
  2023年   4篇
  2022年   12篇
  2021年   35篇
  2020年   25篇
  2019年   28篇
  2018年   48篇
  2017年   26篇
  2016年   31篇
  2015年   32篇
  2014年   29篇
  2013年   62篇
  2012年   98篇
  2011年   68篇
  2010年   38篇
  2009年   40篇
  2008年   60篇
  2007年   80篇
  2006年   64篇
  2005年   61篇
  2004年   45篇
  2003年   59篇
  2002年   65篇
  2001年   23篇
  2000年   24篇
  1999年   32篇
  1998年   25篇
  1997年   19篇
  1996年   8篇
  1995年   22篇
  1994年   14篇
  1993年   14篇
  1992年   17篇
  1991年   16篇
  1990年   25篇
  1989年   19篇
  1988年   15篇
  1987年   15篇
  1986年   7篇
  1985年   12篇
  1984年   5篇
  1983年   6篇
  1982年   3篇
  1981年   4篇
  1979年   2篇
  1978年   4篇
  1977年   4篇
  1975年   2篇
  1973年   2篇
  1972年   2篇
  1971年   2篇
排序方式: 共有1361条查询结果,搜索用时 15 毫秒
1.
In order to treat fistulated esophageal cancer using a flexible stent, a covered flexible stent was constructed by wrapping a nitinol stent with a thin sheet of Gore-Tex, preserving the stents original advantages of flexibility and a low-profile introducer system. This stent was used to perform standard radiotherapy in a case of fistulated esophageal cancer.  相似文献   
2.
Carbon fibers with fibrin glue were used as electrodes for diaphragm pacing. The electrodes were applied to three mongrel dogs and the effectiveness was tested. The carbon leads were glued to phrenic nerves by means of the fibrinogen and thrombin bilaterally. The tidal volumes and threshold current level for stimulation were measured at various time up to 9 weeks after implantation. Effective contraction of diaphragm were observed for 9 weeks. By using this electrode, the exfoliation of the nerve is not necessary, the nerve can be maintained in an intact state, and the risk of the implanting operation can be minimized.  相似文献   
3.
A case of early gastric carcinoma accompanied by Dieulafoy ulcer is presented. The patient, a 26‐year‐old female, visited our emergency room with chief complaints of massive hematemesis and tarry stool. The initial endoscopic examination revealed a superficial depressed lesion with a faded color accompanied by a tiny ulcer with converging folds at the anterior wall of the middle gastric body. Although no active bleeding vessel was found at that time, the patient was admitted to our hospital for further check‐ups and treatment. On the 6th hospital day, she developed massive hematemesis resulting in shock. Urgent endoscopy, this time, disclosed an exposed bleeding vessel at the small ulcer floor previously mentioned, and endoscopic hemostasis was achieved. Since, however, a biopsy at initial examination from the surrounding depressed area proved carcinoma, a partial distal gastrectomy was subsequently carried out. Histological examination of the resected specimen confirmed the diagnosis of carcinoma limited to the mucosa and submucosa along with findings consistent with Dieulafoy ulcer. This is a rare case of combination of early cancer and Dieulafoy ulcer particularly in such a young patient. A review of the literature is also presented.  相似文献   
4.
We reported three cases of spontaneous rupture which were surgically treated with direct suture method. One patient was operated on within eight hours after rupture with good results. In two patients diagnoses were made more than two days after rupture. One had esophageal fistula, but completely recovered after cervical oesophageal fistula, and another died of multiple organ failure. In this syndrome, early diagnosis and surgical treatment are essential for acceptable results. For early diagnosis, we emphasized on the presence of roentgenologic mediastinal and cervical emphysema. In patients for whom diagnosis was delayed and post-operative leakage at the oesophageal suture line occurred, temporarily fistulation of the cervical oesophagus proved to be effective in exclusion and diversion of the ruptured segment.  相似文献   
5.
6.
The effect of vitamin E on halothane-induced liver damage was studied in guinea pig halothane hepatitis. Twenty animals were divided into 3 groups, consisting of a control group, a halothane group and a vitamin E + halothane (H) group. The animals in the control group (n = 6) were allowed to inhale air only. The animals in the halothane group (n = 6) and the vitamin E + H group (n = 8) were allowed to inhale 1% halothane with air. Animals in the vitamin E + H group were additionally injected with 30 mg kg-1 of vitamin E 30 minutes prior to inhalation of halothane. Blood was aspirated from the heart immediately after sacrificing to measure the serum activity of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT). A microsomal suspension was prepared from the excised liver. Then the amount of thiobarbituric acid (TBA) reactive products in the microsomes were measured. The amount of tissue TBA-reactive products was increased by inhalation of halothane. The increase in the amount of TBA-reactive product was inhibited by the administration of vitamin E. The serum GPT activity was increased by halothane inhalation. Increased serum GOT and GPT activity were inhibited by the administration of vitamin E. These results demonstrated that vitamin E suppressed halothane-induced liver damage in the guinea pig by inhibiting lipid peroxidation.  相似文献   
7.
Genetic contributions to the etiology of substance abuse and dependence are topics of major interest. Acute and chronic cannabis use can produce drug-induced psychosis resembling schizophrenia and worsen positive symptoms of schizophrenia. The endocannabinoid system is one of the most important neural signaling pathways implicated in substance abuse and dependence. The fatty acid amide hydrolase (FAAH) is a primary catabolic enzyme of endocannabinoids. To clarify a possible involvement of FAAH in the etiology of methamphetamine dependence/psychosis or schizophrenia, we examined the genetic association of a nonsynonymous polymorphism of the FAAH gene (Pro129Thr) by a case-control study. We found no significant association in allele and genotype frequencies of the polymorphism with either disorder. Because the Pro129Thr polymorphism reduces enzyme instability, it is unlikely that dysfunction of FAAH and enhanced endocannabinoid system induce susceptibility to either methamphetamine dependence/psychosis or schizophrenia.  相似文献   
8.
A typical case of the D uchenne type of progressive muscular dystrophy with autopsy findings was presented. Changes in the myocardial and smooth muscle of many organs were found, and the skeletal muscles also revealed florid changes.
Histopathological examination of the skeletal muscle was made in detail through light and electron microscopic observation.  相似文献   
9.
Autosomal recessive form of hyper-IgM syndrome type 2 (AR-HIGM2) is secondary to mutations affecting both alleles of AICDA gene encoding activation-induced cytidine deaminase, characterized by defects of immunoglobulin class switch recombination (CSR) and somatic hypermutation (SHM) in most of the patients. We herein report the immunological phenotype of seven patients carrying a single heterozygous R190X mutation in AICDA. Variable defect in in vivo CSR inherited as an autosomal dominant (AD) trait strongly suggests that this heterozygous AICDA mutation causes HIGM (AD-HIGM2). In AD-HIGM2 B cells, CSR was consistently found impaired in vitro. However, in contrast to AR-HIGM2, the CSR-induced double-stranded DNA breaks in the switch region of IgM heavy chain gene were detected. The SHM frequency in V regions of IgM heavy chain gene in B cells was normal in all (but one patient). The characteristics of the AD-HIGM2 phenotype indicate that the AID C-terminal region may be involved in DNA repair machinery required for CSR.  相似文献   
10.
The cause(s) of sarcoidosis is unknown. Mycobacterium spp. are suspected in Europe and Propionibacterium spp. are suspected in Japan. The present international collaboration evaluated the possible etiological links between sarcoidosis and the suspected bacterial species. Formalin-fixed and paraffin-embedded sections of biopsy samples of lymph nodes, one from each of 108 patients with sarcoidosis and 65 patients with tuberculosis, together with 86 control samples, were collected from two institutes in Japan and three institutes in Italy, Germany, and England. Genomes of Propionibacterium acnes, Propionibacterium granulosum, Mycobacterium tuberculosis, Mycobacterium avium subsp. paratuberculosis, and Escherichia coli (as the control) were counted by quantitative real-time PCR. Either P. acnes or P. granulosum was found in all but two of the sarcoid samples. M. avium subsp. paratuberculosis was found in no sarcoid sample. M. tuberculosis was found in 0 to 9% of the sarcoid samples but in 65 to 100% of the tuberculosis samples. In sarcoid lymph nodes, the total numbers of genomes of P. acnes or P. granulosum were far more than those of M. tuberculosis. P. acnes or P. granulosum was found in 0 to 60% of the tuberculosis and control samples, but the total numbers of genomes of P. acnes or P. granulosum in such samples were less than those in sarcoid samples. Propionibacterium spp. are more likely than Mycobacteria spp. to be involved in the etiology of sarcoidosis, not only in Japanese but also in European patients with sarcoidosis.  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