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   1934篇
  免费   108篇
  国内免费   39篇
耳鼻咽喉   17篇
儿科学   52篇
妇产科学   88篇
基础医学   249篇
口腔科学   13篇
临床医学   117篇
内科学   422篇
皮肤病学   89篇
神经病学   115篇
特种医学   109篇
外科学   375篇
综合类   22篇
预防医学   89篇
眼科学   47篇
药学   147篇
中国医学   17篇
肿瘤学   113篇
  2023年   8篇
  2022年   42篇
  2021年   68篇
  2020年   29篇
  2019年   48篇
  2018年   51篇
  2017年   35篇
  2016年   55篇
  2015年   81篇
  2014年   99篇
  2013年   112篇
  2012年   180篇
  2011年   150篇
  2010年   95篇
  2009年   88篇
  2008年   115篇
  2007年   98篇
  2006年   88篇
  2005年   115篇
  2004年   86篇
  2003年   98篇
  2002年   87篇
  2001年   18篇
  2000年   15篇
  1999年   8篇
  1998年   14篇
  1997年   10篇
  1996年   7篇
  1995年   5篇
  1994年   5篇
  1993年   7篇
  1991年   5篇
  1990年   9篇
  1989年   6篇
  1988年   9篇
  1987年   9篇
  1985年   9篇
  1984年   9篇
  1983年   9篇
  1982年   7篇
  1981年   5篇
  1980年   5篇
  1979年   10篇
  1978年   5篇
  1974年   9篇
  1973年   6篇
  1971年   4篇
  1969年   6篇
  1968年   4篇
  1966年   4篇
排序方式: 共有2081条查询结果,搜索用时 0 毫秒
1.
Many studies have recently reported on laparoscopic liver resection, although its development has been slow compared to laparoscopy in other fields. The indications for the location of laparoscopic liver resection have previously been limited to easily accessible lesions. Performing laparoscopic liver resection in the posterior and superior parts of the liver has been considered difficult due to inadequate exposure, the poor operative field and the difficulty with parenchymal dissection. Flexible endoscopy, high definition imaging and various kinds of equipment for parenchymal transection have been introduced for clinical use. In addition, much experience with this procedure has been accumulated at many centers. Accordingly, there are an increasing number of reports on laparoscopic liver resection in difficult locations. At our institution, the location of the tumor is no longer a limitation to laparoscopic liver resection. However, for safer laparoscopic liver resection, the patient positioning and trocar placement should be individualized according to the tumor location. The type of resection also may depend on the remaining liver’s functional capacity. We describe here the technical considerations for performing laparoscopic liver resection, including the technical considerations for performing laparoscopic liver resection for lesions located in the postero-superior segments of the liver.  相似文献   
2.
Jaw tremor can be seen as a component of various neurological disorders such as essential tremor, Parkinson's disease, dystonia, branchial myoclonus, hereditary geniospasm, task-specific tremor, and Whipple's disease, as well as in normal situations such as shivering, and subclinical physiological jaw tremor. In most of these conditions, the jaw tremor is usually associated with tremor or other abnormal involuntary movements affecting additional body parts, and its frequency is lower than 12 Hz. Schrag and colleagues reported a patient with a high-frequency idiopathic jaw tremor, and they speculated it could be related to orthostatic tremor affecting the masseter muscles. We encountered a similar patient with intermittent rapid focal jaw tremor that was successfully treated with botulinum toxin injections to the masseters.  相似文献   
3.
Hemoperitoneum secondary to rupture of cystic artery pseudoaneurysm   总被引:1,自引:0,他引:1  
BACKGROUND:Spontaneous hemoperitoneum of hepato- biliary origin is commonly due to hemorrhage from a liver tumor.It is rarely caused by spontaneous rupture of aneurysm in visceral arteries. METHODS:We report an unusual case of hemoperitoneum caused by rupture of cystic artery pseudoaneurysm,and also outline the approach to its management through surgical and radiological methods. RESULTS:In our patient,the pseudoanurysm was initially treated with percutaneous thrombin injection.However this method of treatment failed after initial success.The pseudoanurysm was finally obliterated successfully using microcoil embolization. CONCLUSIONS:The mainstay of treatment of cystic artery pseudoaneurysm is cholecystectomy and ligation of the aneurysm.Recent publications showed success in using microcoil embolisation.In this case we also outline the use of percutaneous thrombin injection as a definitive treatment method and discuss its success or failure as a new method of treatment.  相似文献   
4.
Spirometry can be used as an objective tool for measuring nasal patency. it is sensitive, easy to perform, comfortable to patient The only limitation being that it only can be done in institution.  相似文献   
5.
Tumor necrosis factor-alpha-induced changes in insulin-producing beta-cells   总被引:1,自引:0,他引:1  
The migration of macrophages and lymphocytes that produce cytokines such as tumor necrosis factor-alpha (TNF-alpha) causes beta-cell death, leading to type 1 diabetes. Similarly, in type 2 diabetes, the adipocyte-derived cytokines including TNF-alpha are elevated in the circulation, causing inflammation and insulin resistance. Thus, the studies described in this article using TNF-alpha are relevant to furthering our understanding of the pathogenesis of diabetes mellitus. We used RINr1046-38 (RIN) insulin-producing beta-cells, which constitutively express calbindin-D(28k), to characterize the effect of TNF-alpha on apoptosis, replication, insulin release, and gene and protein expression. Western blots of TNF-alpha-treated RIN cells revealed a decrease in calbindin-D(28k). By ELISA, TNF-alpha-treated beta-cells had 47% less calbindin-D(28k) than controls. In association with the decline in calbindin-D(28k), TNF-alpha treatment of RIN cells led to a 73% greater increase in changes in intracellular calcium concentration (Delta[Ca(2+)](i)) in TNF-alpha-treated cells as compared to that in control RIN cells upon treatment with 50 mM KCl; caused a greater increase in the [Ca(2+)](i) following the addition of 5.5 microM ionomycin; increased by more than threefold the apoptotic rate, expressed as the percentage of TUNEL-positive nuclei to total nuclei; decreased the rate of cell replication by 36%; and increased and decreased selectively the expression of specific genes as determined by microarray analysis. The subcellular localizations of Bcl-2, an antiapoptotic protein, and Bax, a proapoptotic protein, within RIN cells were altered with TNF-alpha treatment such that the two were colocalized with mitochondria in the perinuclear region. We conclude that the proapoptotic action of TNF-alpha on beta-cells is manifested via decreased expression of calbindin-D(28k) and is mediated at least in part by [Ca(2+)](i).  相似文献   
6.
Impedance plethysmographic observations have been correlated with aortographic observations in 57 patients suspected of aortic occlusive diseases. Aortic occlusions have been characterised by marked decrease in blood flow index and significant increase in differential pulse arrival time at thigh level bilaterally. Atherosclerotic affection of the aorta has been featured by a bilateral decrease in the value of blood flow index as well as differential pulse arrival time at thigh level. Leriche's syndrome, however, has been found to decrease the blood flow index moderately at thigh in both the legs without any significant change in differential pulse arrival time. Aortography in all the patients has confirmed the diagnosis made by impedance plethysmography.  相似文献   
7.
8.
This study examined the prevalence and correlated factors of cigarette smoking in a cross-sectional, epidemiological survey of Korean American men living in Maryland (n=333). In this sample, 26.1% were current smokers and 42.3% were former smokers. The older age group (> or = 40 years) was more likely to have quit smoking than the younger age group (< 40 years). In multiple logistic regression analysis, acculturation was associated with smoking status; those who stayed more than 20 years in the U.S. were less likely to be current smokers (OR=0.32, 95% CI 0.13-0.77) than those who stayed less than 10 years. Alcohol use was associated with smoking status; those who consumed alcohol were more likely to be current smokers (OR=5.24, 95% CI 2.33-11.79) or former smokers (OR=5.45, 95% CI=2.69-11.04) than those did not. Those with hypertension were more likely to have quit smoking (OR=3.11, 95% CI=1.33-7.24). The results suggest that the role of acculturation in smoking status among Korean American men deserves further attention by researchers as well as by health professionals who develop smoking prevention and cessation programs.  相似文献   
9.
The PCBs, DDE, and mirex levels were measured in the subcutaneous fat and breast muscle of fifty-five waterfowl collected in New York State during 1981 and 1982. Levels were obtained by electron capture gas chromatography (EC-GC) on wet weight, dry weight, and lipid weight bases; results were confirmed by gas chromatography-mass spectrometry (GC-MS). The mean PCB levels were 6.1 (g/g in fat and 0.25 g/g in breast muscle on a wet weight basis. The mean DDE and mirex levels were 0.10 g/g and 0.28 g/g in fat and 0.01 g/g and 0.002 g/g in breast muscle on a wet weight basis, respectively.The results of the present study confirm those of the previous study (Kimet al. 1984). The detailed comparison, however, shows that the levels of PCBs and DDE in fat continued to decline while the level of mirex increased slightly.  相似文献   
10.
Primary spinal cord primitive neuroectodermal tumor (PNET) is a rare entity. In all, 13 cases have been reported in the literature, including 3 with intracranial seeding. A 3-month-old girl with involvement of the spinal cord below the mid-thoracic level is described. The brain MRI revealed findings indicative of seeding along the intracranial subarachnoid space. Biopsy, duraplasty and removal of laminotomy flap were done. In spite of a good response to the first cycle of postoperative 8-drugs-in-a-day chemotherapy, further treatment was refused. She died 21 days after the onset of leg weakness, which reveals the rapid progression of untreated cases. To our knowledge, this is the first case of spinal cord PNET with parenchymal involvement that has been described in an infant.  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