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   1274篇
  免费   290篇
  国内免费   4篇
耳鼻咽喉   25篇
儿科学   28篇
妇产科学   52篇
基础医学   366篇
口腔科学   60篇
临床医学   239篇
内科学   301篇
皮肤病学   8篇
神经病学   98篇
特种医学   32篇
外科学   119篇
综合类   22篇
预防医学   68篇
眼科学   11篇
药学   68篇
肿瘤学   71篇
  2021年   12篇
  2019年   11篇
  2018年   13篇
  2017年   10篇
  2016年   12篇
  2015年   23篇
  2014年   20篇
  2013年   41篇
  2012年   37篇
  2011年   43篇
  2010年   34篇
  2009年   38篇
  2008年   34篇
  2007年   44篇
  2006年   59篇
  2005年   30篇
  2004年   40篇
  2003年   45篇
  2002年   42篇
  2001年   58篇
  2000年   50篇
  1999年   51篇
  1998年   38篇
  1997年   40篇
  1996年   33篇
  1995年   29篇
  1994年   34篇
  1993年   20篇
  1992年   59篇
  1991年   42篇
  1990年   38篇
  1989年   39篇
  1988年   29篇
  1987年   38篇
  1986年   33篇
  1985年   47篇
  1984年   24篇
  1983年   19篇
  1982年   15篇
  1981年   10篇
  1979年   24篇
  1978年   10篇
  1977年   10篇
  1975年   13篇
  1974年   17篇
  1973年   14篇
  1971年   16篇
  1970年   11篇
  1969年   11篇
  1966年   9篇
排序方式: 共有1568条查询结果,搜索用时 15 毫秒
1.
A 27-year-old man was admitted with high fever and shivers eleven days after returning from vacation in Indonesia. Physical examination, laboratory values, abdominal ultrasound, and chest x-ray were not conclusive. All blood cultures yielded growth of Salmonella enterica serovar Typhi, and typhoid fever was diagnosed. Subsequently, the patient developed septic shock and pulmonary edema.In this case report epidemiological, clinical, and therapeutic aspects of typhoid fever are discussed with special emphasis on criteria for severe typhoid fever, which is treated with additional glucocorticoids.  相似文献   
2.
Anxiety disorders and anxiety symptoms are highly prevalent in the general population and more so in the medically ill. They have a number of negative consequences for these patients and may worsen the outcome of the medical illness and increase health care utilization. In the evaluation of these patients, it is of paramount importance to identify the etiology of the anxiety and, in particular, to differentiate primary from secondary anxiety. Management includes medications (especially benzodiazepines and selective serotonin reuptake inhibitors) and psychotherapy (particularly cognitive-behavioral therapy).  相似文献   
3.
The present study explored the role of murine monocyte chemotactic protein (MCP) in the T cell-mediated hypersensitive granulomatous response to Schistosoma mansoni eggs. The study examined the time course of local production, contribution to cellular infiltration, and the role of T cells in endogenous regulation. Synchronized pulmonary granulomas were induced under conditions of primary and secondary states of immunity. Primer-directed polymerase chain reaction analysis showed increased MCP mRNA expression in granulomatous lungs, mainly in the secondary response. Levels of MCP were measured by enzyme-linked immunosorbent assay in cultures of intact granulomas. Spontaneous MCP production was modest in primary granuloma cultures, reaching a maximum of 5.7 +/- 0.9 ng/ml by 16 days. In contrast, the secondary response showed augmented and accelerated production, achieving 13 +/- 2.0 ng/ml by 2 days. Immunohistochemical staining revealed the strongest MCP expression within microvascular adventitial cells or pericytes as well as in scattered mononuclear cells associated with granulomas. Staining was not detected in normal lungs. Passive immunization with anti-MCP-1 antibodies caused a 40% reduction in the secondary granuloma area but did not significantly affect the primary response. With adoptive cell transfer and T cell subset depletion, it was shown that Thy-1+ and CD5+ cells augmented, whereas CD8+ cells appeared to impair, MCP production. This provides direct evidence that MCP is involved in secondary Th2-mediated response to schistosome eggs and is subject to regulation by T cells.  相似文献   
4.
We have investigated the role of basal insulin concentration on leucine kinetics (determined by means of 1-[13C]leucine) and energy metabolism (determined by indirect calorimetry) in eight septic patients by reducing insulin (and glucagon) secretion by somatostatin infusion. Basal glucagon concentration was elevated (744 +/- 381 pg/mL), and insulin concentration was normal (10 +/- 4 microU/mL). Basal resting energy expenditure (REE) was 151 +/- 8% that of predicted basal energy expenditure, and leucine appearance (Ra), oxidation, and nonoxidative disposal rates were all elevated above the normal ranges. Somatostatin infusion reduced insulin concentration by 52% and glucagon concentration by 64%. This resulted in a significant increase in the rate of leucine oxidation from 0.96 +/- 0.08 to 1.18 +/- 0.14 mumol/kg/min (p less than 0.01), and nonoxidative leucine disposal decreased from 2.95 +/- 0.18 to 2.67 +/- 0.17 mumol/kg/min (p less than 0.01). Somatostatin infusion also caused significant increases in REE and fat oxidation from 1310 +/- 100 to 1505 +/- 128 kcal/m2/day (p less than 0.05) and from 1.72 +/- 0.24 to 2.41 +/- 0.41 mg/kg/min, respectively, and a slight decrease of carbohydrate oxidation from 1.51 +/- 0.49 to 1.31 +/- 0.49 mg/kg/min. These metabolic responses can be attributed to the reduction in insulin concentration, because they are in the opposite direction of changes that would occur as a consequence of a reduction in glucagon concentration. We conclude that the basal insulin plays an important role in attenuating net protein loss and energy expenditure.  相似文献   
5.
6.
Acquired circulating anticoagulants.   总被引:2,自引:0,他引:2  
Acquired inhibitors of blood coagulation, which are pathologic circulating substances that directly inhibit clotting factors or their reactions, most commonly occur in patients with hereditary bleeding disorders. This article contains a discussion of acquired circulating anticoagulants that arise de novo in patients with previously normal hemostatic mechanisms. Pathogenesis and management are also discussed. Treatment of these patients poses a challenge for the hematologist because, unlike hereditary hemophiliacs who have learned to adjust their lifestyle, the acquired hemophiliac is unprepared for hemorrhagic episodes.  相似文献   
7.
Summary A 3-year-old boy developed several subcutaneous nodular lesions on his right arm. Based on the histological examination of one of these nodules furunculosis was suspected and cefuroxime was tentatively given. However, acid-fast bacilli were then detected in the tissue specimen and a few colonies of acid fast, gram-positive rods grew on blood agar. Definitive species diagnosis (Mycobacterium marinum) was rapidly achieved by automated sequencing of amplified 16S-rDNA and antimicrobial therapy was adjusted according to the available literature. After 3 weeks of treatment with clarithromycin, rifampicin and protionamid regression of the nodular lesions was evident.
Infektion der oberen Extremität durchMycobacterium marinum — Diagnose mit Hilfe von 16S-rDNA Analyse
Zusammenfassung Wir berichten von einem 3-jährigen Jungen, der verschiedene subkutane Knoten im rechten Arm entwickelte. Nach histologischer Untersuchung wurde zunächst der Verdacht auf Furunkulose geäußert und eine vorläufige Therapie mit Cefuroxim begonnen. Es wurden dann jedoch säurefeste Stäbchen im entnommenen Gewebe nachgewiesen und eine Woche später auf Blutagar grampositive, säurefeste Stäbchen angezüchtet. Die definitive Speziesdiagnose (Mycobacterium marinum) wurde rasch mit automatischer 16S-rDNA Sequenzbestimmung erzielt und die Therapie entsprechend der verfügbaren Literatur korrigiert. Nach drei Wochen einer Behandlung mit Clarithromycin, Rifampicin und Protionamid war ein Rückgang der subkutanen Knoten erkennbar.
  相似文献   
8.
Absorptiometric, histomorphometric, and chemical analyses of bones from growing rats fed diets with low (0.2%, w/w), marginal (0.4%, w/w), or adequate (0.8%, w/w) calcium (Ca) content with or without phytate were compared. Phytate was added to each diet in a molar ratio of 19:1 to calcium. Male weanling Sprague-Dawley rats were fed one of the six diets for 8 weeks. At the end of 8 weeks, rats were killed, and mandibles, femurs, and tibias were removed. Bone density profiles were determined on the mandibles and femurs using single photon absorptiometry. Femurs were also used for calcium and phosphorus analyses. Tibias were used for histomorphometric analyses. Bone density of the femurs and mandibles increased as dietary Ca increased. The only effect of phytate addition measured was in the 0.8% calcium diet, where density was lower in rats fed the phytate-containing 0.8% calcium diet. Femur calcium concentration also increased as dietary Ca increased and was unaffected by addition of phytate. Femur phosphorus concentration was unaffected by dietary Ca levels but was increased by 10% when phytate was added to the diet. Bone density values were highly correlated with bone calcium and phosphorus levels (r = 0.94). Rats fed the 0.2% calcium diets had 20% lower mineralized bone area and 20% larger medullary cavity area than rats fed the other diets. Bone densitometry appears to be useful for determining changes in bone occurring in growing rats fed low, marginal, and adequate levels of dietary Ca. Bone density values also correlated well with chemically determined calcium and phosphorus concentrations and with histomorphometric data.  相似文献   
9.
To evaluate the role of the dialysate in the stimulation of interleukin-1 (IL-1) production during clinical hemodialysis (HD), we studied maintenance HD patients in two experiments. Cellulosic hollow-fiber dialyzers were obtained after 20 minutes of HD using either nonsterile standard dialysate (n = 6) or sterile pyrogen free 0.9% saline as dialysate (n = 6). After rinsing the blood compartment with normal saline, dialyzers were incubated at 37 degrees C for six hours. Aliquots from the blood compartment were analyzed for the presence of IL-1 by (1) rabbit pyrogenic response after intravenous injection or (2) thymocyte co-proliferation assay. The in vivo assay showed a significantly greater febrile response when standard dialysate was used than in the sterile saline group (P less than .001), and this response could be abolished by heat inactivation of aliquots (P less than .001). The in vitro assay confirmed the presence of significantly greater amounts of IL-1 (P less than .05). Studies were repeated using filter sterilized standard dialysate (n = 6) v standard dialysate (n = 6) for 240 minutes of clinical HD. The in vitro assay revealed significantly lower IL-1 levels in the filtered sterilized dialysate group (P less than .05), however, a blank control assay showed yet significantly lower levels (P less than .05). We conclude that IL-1 is produced during clinical HD and that endotoxin or its fragments play a role in the stimulation of IL-1 production, probably through monocytes adhering to the dialysis membrane. In addition to this dialysate factor, IL-1 production appears also to be stimulated by a blood-membrane interaction.  相似文献   
10.
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