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   3792篇
  免费   138篇
  国内免费   26篇
耳鼻咽喉   27篇
儿科学   84篇
妇产科学   92篇
基础医学   643篇
口腔科学   76篇
临床医学   187篇
内科学   509篇
皮肤病学   74篇
神经病学   297篇
特种医学   122篇
外科学   544篇
综合类   11篇
一般理论   1篇
预防医学   560篇
眼科学   41篇
药学   401篇
中国医学   10篇
肿瘤学   277篇
  2021年   34篇
  2019年   47篇
  2018年   63篇
  2017年   51篇
  2016年   86篇
  2015年   76篇
  2014年   109篇
  2013年   131篇
  2012年   213篇
  2011年   180篇
  2010年   126篇
  2009年   88篇
  2008年   175篇
  2007年   216篇
  2006年   224篇
  2005年   215篇
  2004年   220篇
  2003年   185篇
  2002年   201篇
  2001年   42篇
  2000年   49篇
  1999年   41篇
  1998年   22篇
  1997年   22篇
  1996年   32篇
  1992年   28篇
  1991年   28篇
  1990年   30篇
  1988年   33篇
  1987年   22篇
  1986年   30篇
  1985年   33篇
  1984年   23篇
  1983年   32篇
  1982年   30篇
  1981年   32篇
  1980年   30篇
  1979年   39篇
  1978年   38篇
  1977年   32篇
  1976年   41篇
  1975年   31篇
  1974年   33篇
  1973年   29篇
  1972年   29篇
  1971年   34篇
  1969年   22篇
  1968年   23篇
  1967年   26篇
  1966年   21篇
排序方式: 共有3956条查询结果,搜索用时 15 毫秒
11.
12.
13.
A retrospective study was performed between 1985 and 1994 on paediatric patients operated for asymptomatic intrascrotal or testicular palpable masses. Tumour was suspected in each case and it was surgically explored. Twenty-six children were affected, their age ranging between 9 days and 14 years. In 11 cases testicular torsion, in 4 epididymitis and in another 2 dystrophic calcification were found. Tumours, including rather rare alterations, were observed in only 9 children. The present results draw attention to the tumour-like occurrence of testicular torsions and other benign alterations of the scrotum.  相似文献   
14.
An unbalanced Y;autosome translocation leading to a male with a 45,X karyotype is rare with about 30 published cases. A male with a 45,X karyotype as a result of a unique, submicroscopic, unbalanced Y;16 translocation is presented with alpha-thalassemia/mental retardation syndrome.  相似文献   
15.
The cytogenetic findings by G- and C-banding in a primary breast carcinoma are reported. The tumor is characterized by a high modal number of chromosomes (79) and 14 markers of ten different origins. Chromosome #1 is more frequently involved in structural and numerical aberrations than is any other chromosome; nine copies of 1q were present in each cell examined. This observation supports the hypothesis that duplication of chromosome 1q may play an important role in the progression of malignant tumors.  相似文献   
16.
Functional and immunogenetic characterization of FcR-blocking antibody   总被引:1,自引:0,他引:1  
The characteristics and functional importance of FcR-blocking antibodies and their production were investigated after immunization with whole blood, "buffy coat" and purified platelets. We studied the presence of FcR-blocking antibody in haemodialyzed, transfused patients waiting for kidney transplantation, and we found strong correlation between the blocking effect and better graft survival. We suggest that this blocking antibody does not attack FcR as primary target. Investigation of blocking activity of ten different immune sera on 50 healthy panel cells showed that target antigen has some polymorphic varieties. On basis of family studies it seems that the target antigen is not linked to HLA haplotype. The blocking effect of sera could be removed by absorption of CD8+ cells, B lymphocytes, platelets and granulocytes, but not with erythrocytes, monocytes, CD8- cells and NK cells.  相似文献   
17.
The central role of interleukin-1 (IL-1) in several disease processes, including fever and inflammation, makes the characterization of ligand-receptor interaction of prime importance.The role of arginine (Arg) side chains of hr-IL-1 in receptor recognition was studied by the modification of Arg residues with the specific reagent 1,2-cyclohexanedione. It was found that chemical modification of Arg residues decreased the binding potential of IL-1 to type I receptor dramatically (by 230-fold) while the affinity to type II receptor was reduced only moderately (by 10-fold), with an insignificant reduction of the dissociation rate.These studies suggest that intact Arg side chains of IL-1 may be necessary for high affinity binding to type I IL-1 receptor, but have less importance for the interaction of IL-1 with type II IL-1 receptor.This observation may be useful in the study of type II IL-1 receptor-mediated biological responses and design of receptor-subtype specific ligands as well.  相似文献   
18.
Summary The ability of lymphocytes from patients with multiple sclerosis (MS) to produce Interferon (IFN-) in response to Newcastle Disease Virus (NDV) was studiedin vitro. The correlation between individual IFN- titers and natural killer (NK) cell activity and the presence of HLA system antigens associated with MS (B-7 and DRW-2) was also investigated.Lymphocytes from MS patients showed a significantly impaired capacity to synthesize IFN-in vitro when compared to lymphocytes from healthy donors (mean titers: 85.9 I.U. and 268.2 I.U., respectively). Marked differences in IFN- titers were observed in the group of MS patients.The production of IFN- by the patients' lymphocytes did not correlate with either the activity of NK cells or with their stimulation by exogenous IFN-. There was also no correlation between IFN- production by lymphocytes from MS patients and the presence or absence of B-7 and DRW-2 antigens.With 3 Figures  相似文献   
19.
A recombinant pseudorabies (Aujeszky’s disease) virus (PrV) designated as vE16lac was constructed by deleting a 3-kbp DNA segment spanning the junction of long and short components of the viral genome, and by replacing the deleted segment with a lacZ-expression cassette. The aim of constructing this mutant was (a) to determine whether the terminal repeat (Tr) can serve as a template for the regeneration of the internal repeat (Ir), and (b) whether this deletion causes a reduction in the neuroinvasiveness of the virus. To analyze the mechanism of equalization, revertant viruses were selected and structurally characterized from vE16lac infection of PK-15 cells, mice and pigs. Because all revertants acquired Ir sequences identical to that of the wild-type virus, the equalization process occurred using the Tr as a template to reconstitute the Ir. We also found that the recombinant virus vE16lac was virulent in both pigs and mice. The data are discussed in view of studies performed with similar PrV mutants by other authors (Rall et al., 1992, Dean and Cheung, 1995 and Dean et al., 1996). This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
20.
This study investigated the relationship between theory of mind (ToM) deficits and visual perception in patients with schizophrenia (N=52; 17 remitted and unmedicated) compared with healthy controls (N=30). ToM was assessed with the Eyes Test, which asked participants to choose which of 4 words best described the mental state of a person whose eyes were depicted in a photograph. Visual perception was evaluated with form and motion coherence threshold measurements. Results revealed that patients with schizophrenia (both remitted and nonremitted) showed deficits on the Eyes Test and the motion coherence task. ToM dysfunctions were associated with higher motion coherence thresholds and more severe negative symptoms. This suggests that ToM deficits are related to motion perception dysfunctions, which indicates a possible role of motion-sensitive areas in the pathophysiology of schizophrenia.  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