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   529999篇
  免费   27646篇
  国内免费   495篇
耳鼻咽喉   6681篇
儿科学   16922篇
妇产科学   12537篇
基础医学   92610篇
口腔科学   12347篇
临床医学   48495篇
内科学   95434篇
皮肤病学   11868篇
神经病学   34007篇
特种医学   19755篇
外国民族医学   53篇
外科学   78072篇
综合类   7610篇
现状与发展   2篇
一般理论   107篇
预防医学   38532篇
眼科学   11939篇
药学   41406篇
  1篇
中国医学   1126篇
肿瘤学   28636篇
  2021年   3892篇
  2018年   5731篇
  2017年   4126篇
  2016年   4869篇
  2015年   5360篇
  2014年   7114篇
  2013年   10498篇
  2012年   15572篇
  2011年   17389篇
  2010年   9955篇
  2009年   8821篇
  2008年   15710篇
  2007年   17444篇
  2006年   16939篇
  2005年   16260篇
  2004年   15882篇
  2003年   15263篇
  2002年   14783篇
  2001年   22428篇
  2000年   22973篇
  1999年   18920篇
  1998年   5232篇
  1997年   4364篇
  1996年   4397篇
  1995年   4124篇
  1992年   14414篇
  1991年   15817篇
  1990年   15949篇
  1989年   15625篇
  1988年   14308篇
  1987年   14199篇
  1986年   13168篇
  1985年   12686篇
  1984年   9394篇
  1983年   8000篇
  1982年   4178篇
  1979年   8937篇
  1978年   6382篇
  1977年   5149篇
  1976年   5504篇
  1975年   6613篇
  1974年   7419篇
  1973年   7158篇
  1972年   6597篇
  1971年   6309篇
  1970年   5887篇
  1969年   5467篇
  1968年   5161篇
  1967年   4621篇
  1966年   3963篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
In this study, the lamination pattern of the main olfactory bulb (MOB) of P. hispanica has been described using EM and Golgi-impregnation techniques. Six layers could be distinguished from the external surface to the ventricles: olfactory nerve layer (ONL), glomerular layer (GL), external plexiform layer (EPL), mitral layer (ML), internal plexiform layer (IPL), and granular cell layer (GCL). In ONL unmyelinated axonic bundles from the olfactory mucosa are seen. The GL is defined by the presence of terminal ramifications of the mitral primary dendrites and by axonic terminals of the olfactory nerve. The EPL is a dendritic articulation layer between the mitral and granule cells, where a great density of dendrodendritic synaptic contacts has been found. The ML is defined by the large mitral cell somata, and the IPL by myelinated axonic bundles that run rostro-caudally. Finally, the GCL is characterized by the presence of granule cells. Using the Golgi-impregnation method, five different neuronal types have been described. In the glomerular layer, a small cell population is located; these neurons seem the periglomerular cells described in mammals. The second type corresponds to the mitral cell population and the morphological features of these cells resemble to those of mammals. The three remaining types constitute the granule cell population; this population is characterized by a great morphological heterogeneousness. However, these types have been differentiated according to their dendritic tree morphology and location of the cell body. A morphological gradient depending on the distance of cell body for each type to the ependymal layer, has been observed. In EM, four different types of neuronal cell bodies according to their location and ultrastructure have been defined. The laminar organization of the MOB of Podarcis is similar to that in all vertebrates. The results for the fine structure and dendritic tree morphology have revealed a high similarity between these reptiles and mammals.  相似文献   
92.
Roentgen endovascular occlusion with spiral emboli was used in 240 patients with different diseases. The introduction of spiral emboli into the arteries of abdominal and retroperitoneal organs was fulfilled through usual angiographic catheters. Duration of the arterial occlusion was checked up in the following angiographic examinations and showed the devices described to be appropriate for a continuous arterial blockade. No complications resulting from the introduction of the spiral embolus were noted.  相似文献   
93.
RenNew-D (Alcide), a novel demand-release sporocidal agent, was employed instead of formaldehyde in the reprocessing for reuse of cuprophan hollow fiber dialyzers (Gambro) and the performance of these dialyzers was evaluated over 40 consecutive dialyses in six patients on maintenance hemodialysis. When RenNew-D was part of automated reprocessing performed with 4.3% bleach as specified by the manufacturer (Lixivitron), dialyzer survival was prolonged (16.7 +/- 7.2 uses) and hemodialysis neutropenia was unchanged with reuse. When RenNew-D was part of manual reprocessing conducted in the absence of bleach, marked improvement in dialyzer biocompatibility was observed but with a decreased survival (4.8 +/- 3.0). The majority of dialyzer failures were due to a fall in fiber bundle volume below a 85% set limit. Small solute clearances were maintained with both types of reprocessing. Dialyses were well tolerated throughout. Our data suggest that RenNew-D is a safe and efficacious product which can serve as a valuable alternative to formaldehyde for the purpose of dialyzer reuse.  相似文献   
94.
In comparative histological and cytological studies on 270 prostatic carcinoma patients highly and moderately differentiated tumors were found to be more frequent histologically than cytologically. An early and reliable sign of response to hormone therapy proved to be reticularization and vacuolization of the nuclear chromatin. Follow-up studies by means of multiple aspiration biopsies with cytologic examinations seem to be more reliable in prognostic terms than examination of the histological tumor structure.  相似文献   
95.
The authors suggest additional criteria evidencing inflammations in the gallbladder and colloid stability of the bile: bile acid absorption and cholesterol sedimentation coefficients. Derivation of these coefficients is based on biochemical examination of the bile with measurements of bile acid, cholesterol, and bilirubin concentrations in both portions. The results of examinations of 99 subjects evidence the diagnostic value and specificity of the characteristics, and availability of this method for clinical practice.  相似文献   
96.
97.
BACKGROUND: One previous follow-up study suggested that inpatient bulimic women do quite poorly; after an interval of 2 to 5 years, only 13% were recovered. To examine the course and outcome of a sample of patients with bulimia nervosa that was severe enough to require inpatient hospitalization, the authors conducted the following study. METHOD: Women (N = 52) with DSM-III-R bulimia nervosa were sought 2 to 9 years after hospitalization. Prior to contact, a retrospective chart review was conducted to determine global functioning and admission diagnoses. At follow-up, patients participated in a 4 to 6 hour interview that assessed current and lifetime Axis I disorders (SCID-I), current Axis II disorders (PDE), eating behaviors (EAT, BSQ, EDI, PSR), global functioning (GAF), social adjustment (SAS-SR), and treatment and medical problems experienced since discharge. To assess the significance of differences between the recovered and the currently bulimic women, Yates-corrected chi-square tests and two-tailed t tests were used. RESULTS: Of the 52 women, 46 were interviewed, 1 had died, and 5 could not be located. Of the 46 interviewed women, 39% had fully recovered, 20% had partially recovered, and 41% were currently bulimic. The likelihood of recovery increased with length of time since discharge. While medical problems related to the bulimia were few, treatment with phenelzine was associated with three reports of serious hypertensive episodes, one of which led to death. Global functioning before hospitalization, lifetime DSM-III-R Axis I diagnoses, and current Axis II diagnoses were not associated with outcome. CONCLUSIONS: These findings suggest that even severely ill bulimic patients have a significant chance of achieving full recovery.  相似文献   
98.
BACKGROUND AND PURPOSE: The familial occurrence of intracranial aneurysms and cervical artery dissections has been described in different families and supports the hypothesis that a primary arteriopathy may play a role in the pathogenesis of these disorders. Although the basis for this arteriopathy is generally not believed to be similar among cases of intracranial aneurysms and cervical artery dissections, several similarities exist in the epidemiology of these disorders and a common underlying arterial abnormality may be suspected. SUMMARY OF REPORTS: The medical records of all 175 patients with spontaneous dissections of the cervical arteries who were seen at the Mayo Clinic between 1970 and 1989 were reviewed to identify families in which intracranial aneurysms and cervical dissections coexisted. Three families were identified in which intracranial aneurysms and cervical artery dissections were observed among siblings. These families are described in detail. CONCLUSIONS: The familial occurrence of intracranial aneurysms and cervical artery dissections within the same families provides support to the importance of a common underlying arteriopathy in the pathogenesis of both these disorders. The underlying vascular defect may, at least in some cases, be inherited.  相似文献   
99.
100.
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