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   1688篇
  免费   79篇
  国内免费   4篇
耳鼻咽喉   46篇
儿科学   58篇
妇产科学   130篇
基础医学   133篇
口腔科学   98篇
临床医学   151篇
内科学   380篇
皮肤病学   57篇
神经病学   139篇
特种医学   63篇
外科学   226篇
综合类   2篇
一般理论   1篇
预防医学   53篇
眼科学   22篇
药学   87篇
中国医学   2篇
肿瘤学   123篇
  2022年   12篇
  2021年   36篇
  2020年   10篇
  2019年   31篇
  2018年   24篇
  2017年   22篇
  2016年   39篇
  2015年   40篇
  2014年   36篇
  2013年   76篇
  2012年   101篇
  2011年   107篇
  2010年   59篇
  2009年   55篇
  2008年   104篇
  2007年   125篇
  2006年   130篇
  2005年   110篇
  2004年   98篇
  2003年   108篇
  2002年   83篇
  2001年   12篇
  2000年   17篇
  1999年   19篇
  1998年   9篇
  1997年   16篇
  1996年   16篇
  1995年   15篇
  1994年   13篇
  1993年   12篇
  1992年   18篇
  1991年   11篇
  1990年   12篇
  1989年   17篇
  1988年   10篇
  1987年   9篇
  1986年   8篇
  1985年   8篇
  1984年   14篇
  1983年   9篇
  1982年   8篇
  1981年   8篇
  1978年   9篇
  1977年   8篇
  1975年   6篇
  1974年   6篇
  1973年   6篇
  1971年   6篇
  1970年   6篇
  1968年   6篇
排序方式: 共有1771条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
Thirty-three patients with primary gastrointestinal lymphoma (GIL) followed at Ankara University Medical School have been evaluated. The most frequent locations of the disease are the small intestine (48.4%) and the stomach (39.3%). The intermediate and high grade lymphomas constitute 84.8% of the cases. The mean age of the patients with small intestinal lymphoma is 28.7 years and 47.1 years for those with gastric lymphoma. The patients treated with surgery and chemotherapy (S+CT) have a longer survival than those treated with chemotherapy (CT) alone. In conclusion: 1) Small intestinal lymphoma occurs more frequently than gastric lymphoma in our study. 2) The median age of the Turkish patients with primary GIL is approximately 10 years less than those in the Western countries. 3) The therapeutic results of S+CT are superior to those of CT in the early stages of the disease.  相似文献   
5.
Gene amplification occurs frequently in tumour tissues yet is,in general, non-inheritable. To study the molecular mechanismsconferring this restraint, we created transgenic mice carryinga human butyrylcholinesterase (BCHE) coding sequence, previouslyfound to be amplified in a father and son. Blot hybridizationof tail DNA samples revealed somatic transgene amplificationswith variable restriction patterns and intensities, suggestingthe occurrence of independent amplification events, in 31% (11/35)of mice from the FII generation but in only 3.5% (2/58) of theFII and FIV generations. In contrast, >10-fold amplificationsof the BCHE transgene and the endogenous acetylcholinesteraseand c-raf genes appeared in both testis and epididymis DNA from>80% of FIII mice. Drastic, selective reductions in testisBCHEmRNA but not in actin mRNA were detected by the PCR amplificationof testis cDNA from the transgenic mice, and apparently resultedin the limited transmission of amplified genes. The testicularamplification of the BCHE transgene may potentially representa general phenomenon with clinical implications in human infertility.  相似文献   
6.
48 patients with stage I-II low-grade non-Hodgkin's lymphoma were treated by radiation and/or chemotherapy between 1970 and 1986. The histologic types were diffuse lymphocytic well differentiated, eleven patients; nodular lymphocytic poorly differentiated, 28 patients; nodular mixed, nine patients. Complete remission was obtained in 45 patients (94%). Overall survival was 83% and 68% at five and ten years, respectively. Five and ten-year relapse-free survival of complete responders was 71% and 57%, respectively. Univariate analysis of potential prognosticators showed the following to significantly increase the survival rate: one or two sites of disease (p less than 0.01), stage I (p less than 0.02), age less than 65 years (p less than 0.02), complete excision of tumor mass (p less than 0.03), and the use of radiotherapy (p less than 0.02). The extent of radiotherapy field did not affect survival. Multivariate analysis by the stepwise proportional hazards model of Cox showed that the use of radiotherapy was the factor which significantly produced better survival figures (p less than 0.03). It is concluded that two thirds of stage I-II low-grade lymphoma patients are potentially curable; radiotherapy plays a major role in the management.  相似文献   
7.
A case of subserosal gastric neurilemmoma is hereby presented. This reported case is unique in its clinical presentation including the appearance of acute abdomen and fever subsequent to unremarkable and uneventful upper gastrointestinal endoscopy. The tendency of neurilemmoma to cause mucosal ulceration with fistula formation probably led to this clinical presentation. The role of computed tomography in establishing diagnosis of exogastric tumor is emphasized.  相似文献   
8.
The spondylometaphyseal dysplasias are a very heterogeneous group of disorders. Only one has been clearly defined, namely, the spondylometaphyseal dysplasia — Kozlowski type, known also as the common type. This disorder is inherited as an autosomal dominant trait. In this report we describe an Arabic-Moslem kindred with spondylometaphyseal dysplasia, not of the common type, with an autosomal dominant mode of inheritance, indicating further heterogeneity.  相似文献   
9.
The time for reproduction in mammals largely depends on the availability of water and food in their habitat. Therefore, in regions where rains are limited to definite seasons of the year, mammals presumably will restrict their breeding correspondingly. But while mammals living in predictable ecosystems would benefit by timing their season to an ultimate predictable cue, such as photoperiod, in unpredictable ecosystems (e.g., deserts) they will need to use a more proximate signal. We suggest a mechanism by which water shortage (low water content in plants) could act as a proximate cue for ending the reproductive season. The golden spiny mouse (Acomys russatus), a diurnal rodent living in extreme deserts, may face an increased dietary salt content as the summer progresses and the vegetation becomes dry. Under laboratory conditions, increased diet salinity lead to reproductive hiatus in females, notable in imperforated vagina, and a significant decrease in the ovaries, uteri, and body masses. In females treated with vasopressin (VP), a hormone expressed during water stress, the uteri and body masses have decreased significantly, and the ovaries exhibited an increased number of atretic follicles. VP has also led to a significant decrease in relative medullary thickness (RMT) of the kidney. It is thus suggested that VP could act as a modulator linking the reproductive system with water economy in desert rodents, possibly through its act on the energetic pathways.  相似文献   
10.
Langerhans' cells were studied in the epidermis of two patients with active Behçet's disease and compared with those in two normal controls. Ultrastructural morphology and the percentage of Langerhans' cells found were similar in patients' (1.88%) and the control epidermis (1.79%). The density of Langerhans' cells in adjacent sites of the same epidermis was not homogeneous, being in the range of 0.8-2.8% in Behçet's disease and 0.6-4% in the controls. In the controls, Langerhans' cells were distributed unevenly. Some were located near the basal layer of the epidermis while the rest were in the mid and upper layers. In Behçet's disease most Langerhans' cells were in the mid-epidermis, but some were immediately beneath the stratum granulosum. In the Behçet's disease epidermis the area occupied by Langerhans' cells was increased by about 25% and the number of granules found increased by about 44%. It is suggested that in Behçet's disease the Langerhans' cells are in a more active state.  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