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   871篇
  免费   24篇
  国内免费   67篇
耳鼻咽喉   1篇
儿科学   25篇
妇产科学   10篇
基础医学   154篇
口腔科学   10篇
临床医学   101篇
内科学   274篇
皮肤病学   17篇
神经病学   17篇
特种医学   139篇
外科学   30篇
综合类   25篇
预防医学   39篇
眼科学   2篇
药学   86篇
肿瘤学   32篇
  2021年   4篇
  2016年   7篇
  2015年   7篇
  2014年   11篇
  2013年   16篇
  2012年   13篇
  2011年   8篇
  2010年   26篇
  2009年   26篇
  2008年   20篇
  2007年   64篇
  2006年   31篇
  2005年   17篇
  2004年   23篇
  2003年   16篇
  2002年   16篇
  2001年   23篇
  2000年   41篇
  1999年   28篇
  1998年   31篇
  1997年   37篇
  1996年   30篇
  1995年   27篇
  1994年   25篇
  1993年   24篇
  1992年   19篇
  1991年   17篇
  1990年   20篇
  1989年   26篇
  1988年   34篇
  1987年   22篇
  1986年   15篇
  1985年   22篇
  1984年   14篇
  1983年   15篇
  1982年   19篇
  1981年   16篇
  1980年   27篇
  1979年   12篇
  1978年   11篇
  1977年   12篇
  1976年   15篇
  1975年   11篇
  1974年   8篇
  1973年   9篇
  1972年   8篇
  1971年   5篇
  1970年   5篇
  1968年   10篇
  1967年   5篇
排序方式: 共有962条查询结果,搜索用时 62 毫秒
1.
2.
In the isolated perfused rat pancreas, D,L-difluoromethylornithine, tested at a concentration of 3 mmol/L, failed to affect the release of glucagon and insulin caused, over 15 min stimulation, by either L-arginine or L-ornithine (2.0, 5.0 or 10.0 mmol/L) in the presence of either 3.3 or 5.6 mmol/L D-glucose. The inhibition of ornithine decarboxylase also failed to affect the release of glucagon provoked by either L-leucine (2 or 3 mmol/L) or L-glutamine (2 mmol/L) and the secretion of insulin stimulated by a rise in glucose concentration from 5.6 to 10.6 mmol/L. These data are interpreted to suggest that the rapid generation of polyamines from either L-arginine or L-ornithine does not play any significant role in the immediate glucagonotropic and insulinotropic action of these cationic amino acids.  相似文献   
3.
麦冬类中药组织切片计算机三维重建图鉴   总被引:9,自引:0,他引:9  
利用计算机技术实现麦冬类中药组织连续切片三维重建与动态显示,为计算机辅助生药学鉴定和教学提供了新的三维图像技术和研究资料。  相似文献   
4.
5.
Pre-clerking of all patients undergoing elective general surgical operations was introduced at our hospital in an attempt to reduce an unacceptably high operation cancellation rate. A prospective audit has been performed on the effect of this policy on the cancellation rate. Before the introduction of pre-clerking there was a marked seasonal variation in the number of patients who failed to attend for surgery, which could be explained by absence on holiday. This seasonal variation disappeared after the start of pre-clerking clinics, but there has been no reduction in the number of cancellations for medical reasons.  相似文献   
6.
Impact of clinical history on fracture detection with radiography   总被引:3,自引:0,他引:3  
The effect of knowledge of localizing symptoms and signs in the detection of fractures was studied. Forty radiographs of the extremities were examined twice by seven radiologists; the sessions were separated by 4 months. In 26 cases, a subtle fracture was present; 14 cases were normal. In half of the cases at each session, the precise location of pain, tenderness, or swelling was provided. The observer was asked to determine if the case was normal or abnormal (provide the exact location of the fracture) and to indicate the degree of confidence in the diagnosis. Responses were converted to a numeric scale for analysis. Analysis of receiver operator characteristic parameters indicates that clues regarding location of trauma facilitate detection of fractures. The improvement is based largely on an increased true-positive rate without an increased false-positive rate, regardless of the decision criteria of the radiologist (overall willingness to "overread" or "underread"). This has direct clinical applicability and reinforces the plea of radiologists for precise clinical information.  相似文献   
7.
王文杰  朱秀媛 《药学学报》1989,24(2):151-154
Lei Wan, Poliporus mylittae Cook et Mass(Omphalia lapidescena Scbraet) is a kind of fungus used in traditional Chinese medicine, as an antheiminthie From Lei Wan, an "active component designated as. S-4001 had been isolated.Preliminary results indicate that S-4001 belongs to D, β, 1-3 glucan with some 1-6 linkages.After administration of S-4001, significant antiinflammatory activity was found in various experimental animal models, including croton oil induced ear edema in mice and agar or yeast induced ankle swelling in rats. An inhibitory action on leucocyte migration inducced by intraperitoneal injection of CMC in rats was also observed. The plasma content of corticosterone was significantly increased, but the content of ascorbic acid in the adrenals did not change in rats given S-4001. Apart from these actions, S-4001 showed a number of immunostimulating actions such as increasing the clearance of Congo red from mice blood and potentiating the immunohemolysis reaction in 615 mice.  相似文献   
8.

Background  

There is currently an unprecedented expressed need and demand for estimates of maternal mortality in developing countries. This has been stimulated in part by the creation of a Millennium Development Goal that will be judged partly on the basis of reductions in maternal mortality by 2015.  相似文献   
9.
We report a rare case of early-stage endometrial adenocarcinoma in a 22 year old nullipara with polycystic ovaries undergoing conservative treatment. Pretreatment evaluation including tumour grade, depth of myometrial invasion, tumour size, hormone receptor status and flow cytometric analysis indicated a favourable prognosis. The patient underwent repeat endometrial curettage and a 6 month period of therapy with megestrol acetate and tamoxifen. A combination contraceptive pill was then prescribed to ensure withdrawal of the menstrual cycle thereafter. Now, 1 year after the last curettage, there is no evidence of disease. During the treatment period, hysteroscopy allowed for a more precise approach in panoramically examining the tumour nest in the endometrial cavity, and the subsequent endometrial response to hormone therapy. Laparoscopy using bulldog clamps applied to the isthmic portion of the Fallopian tubes prevented i.p. spread of endometrial tissue from retrograde regurgitation during hysteroscopy. Laparoscopic ovarian electrocautery resulted in the reduction of abnormal hypervascularization on the surface of polycystic ovaries postoperatively but caused a peri-ovarian adhesion complication. It is interesting that this case posed a unique opportunity to demonstrate the tumour regression under the assistance of laparoscopy and hysteroscopy.   相似文献   
10.
The possible priming by D-glucose of metabolic events in islets from control rats and Goto-Kakizaki rats (GK rats) was investigated by first incubating the islets for 120 min either in the absence of any exogenous nutrient or presence of 16.7 mM D-glucose. The islets were then incubated for a second period of 120 min either at 2.8 mM or 16. 7 mM D-glucose, the hexose being now mixed with tracer amounts of D-[U-14C]glucose and D-[5-3H]glucose. In islets from control rats first incubated in the absence of exogenous nutrient the hierarchy in the 16.7 mM/2.8 mM ratio for metabolic variables was as follows: D-[U-14C]glucose oxidation > D-[5-3H]glucose utilization and D-[U-14C]glucose conversion to amino acids > D-[U-14C]glucose conversion to acidic metabolites. When the islets from control rats were first incubated in the presence of 16.7 mM D-glucose, the preferential stimulation of mitochondrial oxidative events at high hexose concentration, as documented by the increase in the paired ratio between D-[U-14C]glucose oxidation and D-[5-3H]glucose utilization, was further enhanced. The 16.7 mM/2.8 mM ratio for the conversion of D-[U-14C]glucose to amino acids, relative to that for D-[U-14C]glucose conversion to acidic metabolites, was much lower, however, after a first incubation in the presence of D-glucose, rather than in its absence, probably as a result of the progressive exhaustion of endogenous amino acids considered as transamination partners. The major differences between these results and those obtained in islets from GK rats consisted, in the latter animals, in i) higher absolute values for all metabolic fluxes, ii) lower 16.7 mM/ 2.8 mM ratios, iii) lower paired ratio between D-[U-14C]glucose oxidation and D-[5-3H]glucose utilization, and iv) absence of a priming effect of D-glucose (16.7 mM) upon such a paired ratio in the islets incubated at 16.7 mM D-glucose during the second incubation. Taken as a whole, these observations confirm that the preferential stimulation of mitochondrial oxidative events, in response to a rise in D-glucose concentration, is impaired in islets from GK rats and extend this knowledge to the priming action of D-glucose, in high concentration, on the catabolism of the hexose during a subsequent incubation.  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