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   20340篇
  免费   1070篇
  国内免费   130篇
耳鼻咽喉   262篇
儿科学   337篇
妇产科学   235篇
基础医学   2191篇
口腔科学   464篇
临床医学   1280篇
内科学   5228篇
皮肤病学   539篇
神经病学   1502篇
特种医学   732篇
外科学   3559篇
综合类   97篇
一般理论   1篇
预防医学   637篇
眼科学   264篇
药学   1552篇
中国医学   43篇
肿瘤学   2617篇
  2023年   144篇
  2022年   236篇
  2021年   500篇
  2020年   297篇
  2019年   395篇
  2018年   538篇
  2017年   362篇
  2016年   492篇
  2015年   505篇
  2014年   637篇
  2013年   709篇
  2012年   1238篇
  2011年   1325篇
  2010年   718篇
  2009年   576篇
  2008年   1081篇
  2007年   1138篇
  2006年   1094篇
  2005年   1119篇
  2004年   1036篇
  2003年   895篇
  2002年   967篇
  2001年   494篇
  2000年   469篇
  1999年   461篇
  1998年   231篇
  1997年   194篇
  1996年   164篇
  1995年   146篇
  1994年   144篇
  1993年   111篇
  1992年   289篇
  1991年   276篇
  1990年   271篇
  1989年   266篇
  1988年   247篇
  1987年   227篇
  1986年   181篇
  1985年   199篇
  1984年   151篇
  1983年   129篇
  1982年   53篇
  1981年   50篇
  1980年   48篇
  1979年   94篇
  1978年   64篇
  1977年   64篇
  1974年   57篇
  1971年   49篇
  1967年   46篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
31.
32.
As an intraoperative chemotherapy treatment for the regional lymph nodes in resectable cases of pancreatoduodenal cancer, Neocarzinostatin (NCS) was administered in the duodenal subserosa and the NCS concentration was measured in the resected lymph nodes. Experiments: NCS 4,000 units (n = 4), or 10,000 units (n = 4) was administered into the duodenal subserosa of mongrel dogs, and 2 hours after administration, the lymph nodes of the mesentery root were resected. The NCS concentration in the lymph nodes was 0.21 U/g in the 4,000-U group and 1.39 U/g in the 10,000-U group. Clinical findings: NCS 10,000 U was administered into the duodenal subserosa in 6 cases of pancreatoduodenal cancer. The total number of resected lymph nodes was 49 and the mean NCS concentration was 5.65 U/g. According to site, the highest concentration was measured in lymph nodes from the anterior and posterior region of the pancreas head, which were near to the administration site. Also, NCS was well distributed in the lymph nodes in the hepatoduodenal ligament and mesentery root which lay in the direction of lymph flow. NCS concentration was high in lymph nodes resected 1 hour after administration. According to experimental reports of in vitro studies, an NCS concentration of more than 0.5 U/g is required to obtain an anticancer effect. This method is therefore considered to be useful as a form of intraoperative chemotherapy for the regional lymph nodes in pancreatoduodenal cancer.  相似文献   
33.
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   
34.
CD4+ T cells recognize processed exogenous antigen in the form of peptides bound to syngeneic major histocompatibility complex class II molecules on antigen-presenting cells. We have developed a novel and convenient method to synthesize and map CD4+ T cell epitopes of cloned antigens using polymerase chain reaction (PCR)-directed construction of genes expressing recombinant protein fragments. Unique restriction sites incorporated into the PCR primers were employed for the unidirectional cloning of gene fragments into a bacterial expression vector that can be induced to high-level expression. The bacterial lysate could be used directly in T cell proliferation assays. Overlapping recombinant fragments spanning the entire protein were generated and tested. The length of the sequence containing the epitope was further reduced by utilizing PCR to generate 3' truncations. Finally, a small number of overlapping peptides spanning a sequence of 39 amino acids were synthesized to identify a thirteen-amino acid peptide epitope within chicken transferrin that stimulates the T helper cell clone D10.G4.1. PCR-directed construction of fragments of antigen allows for optimal design of strategies for the mapping and analysis of CD4+ T cell epitopes.  相似文献   
35.
We analyzed the CT images (in vivo) of 5 lobes (right middle lobe, 1; left lower lobe, 1; right lower lobe, 3) with panacinar emphysema (PAE) obtained at autopsy or thoracotomy for solitary lung tumor. The lobes were inflation-fixed by the method of Heitzman and sliced axially for a CT-pathologic correlative study. One lobe with mild PAE had normal appearance on CT; however, the other four lobes with PAE demonstrated low-attenuation areas (LAAs) of various shapes and sizes on CT. LAAs were locally distributed on CT slices in one lobe, dominant in the inner zones in two lobes, and diffuse in one lobe. Relatively normal to diminished vasculature was observed within the LAAs of four lobes. These CT findings differed significantly from those of centriacinar emphysema (CAE) as reported in other studies. We conclude that CT is useful in the clinical diagnosis of PAE and its differentiation from CAE.  相似文献   
36.
A 64-year-old man, who had an aneurysm of aortic arch associated with the aberrant right subclavian artery, was treated successfully. He was pointed out to have an aneurysm of aortic arch three years ago. Three years later angiograms and computed tomography revealed that it became larger compared with the initial finding. He underwent a replacement of the aortic arch using a woven Dacron graft under open distal method. Aberrant subclavian artery was not involved in the aneurysm. But because the left subclavian artery was involved in it, a woven Dacron graft was interposed between the ascending aorta and left subclavian artery. Postoperative course was uneventful and there were no complications.  相似文献   
37.
We report herein a case of spontaneous subcapsular hepatic hemorrhage which occurred in a 33-year-old woman 1 day after she had been delivered of her second child by cesarean section following an uneventful pregnancy. She complained of right upper quadrant pain on the 1st postoperative day, and computed tomography (CT) showed subcapsular low-density masses in both liver lobes, while extravasation was demonstrated by CO2 intraarterial digital subtraction angiography (IADSA). The hemorrhage was successfully controlled by transcatheter arterial embolization (TAE). However, on the 3rd day after TAE, an exploratory laparotomy was performed to establish an exact diagnosis to explain the persistent abdominal pain and abnormal liver function tests. Subcapsular hematomas in both lobes were confirmed and no visible laceration was present. The patient recovered gradually by spontaneous absorption of the hematomas and was discharged on the 22nd postoperative day. Spontaneous hepatic hemorrhage associated with pregnancy is a very rare complication, and establishing a correct diagnosis and initiating appropriate therapy are essential for this life-threatening disease.  相似文献   
38.
39.
BACKGROUND: Hidradenoma papilliferum is an uncommon benign tumor that is located almost exclusively in the vulvar and anal areas. It is usually very small and asymptomatic, and to make a correct diagnosis is clinically very difficult. Occasionally the tumor becomes elevated to form a reddish brown papillary mass, and the surface ulcerates, which may erroneously suggest malignancy. OBJECTIVE: We report a case of a large, perianal hidradenoma papilliferum with suspected malignancy in a young Japanese female. RESULTS: A 22-year-old female had been aware of a perianal nodule for approximately 1 year. Examination of the perianal area revealed a wide pedunculated, reddish nodule with several white maculae. It was ulcerated and bleeding, 2.0 x 1.2 x 0.8 cm in size, and located in the 3 o'clock position. The nodule was totally excised with a narrow margin. The histopathologic diagnosis was hidradenoma papilliferum. No recurrence was observed for 23 months. CONCLUSION: When dermatologists encounter tumors of the anogenital area of adult females, it is important to keep hidradenoma papilliferum in mind as the differential diagnosis. Dermatologists should recognize that the tumor is benign, eliminating the need for wide resection.  相似文献   
40.
Intraosseous ganglia of the glenoid are rare, and their etiology is unknown. This report describes a case of an intraosseous ganglion about to cause fracture of the glenoid. The patient was a 61-year-old woman with a painful left shoulder with a limited range of motion. Her symptoms did not improve after non-operative treatment. Arthroscopic examination showed a cartilage defect and erosion in the posteroinferior portion of the glenoid, behind which computed tomography (CT) showed a cystic lesion of the glenoid. There was no communication between the cyst and the joint space. The patient was treated by curettage and an autogenous cancellous bone graft from the iliac crest. Two years after the operation, the patient was almost free from pain, and CT showed good integration of the bone graft.  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