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   1315篇
  免费   67篇
  国内免费   63篇
耳鼻咽喉   6篇
儿科学   81篇
妇产科学   54篇
基础医学   170篇
口腔科学   32篇
临床医学   135篇
内科学   248篇
皮肤病学   29篇
神经病学   46篇
特种医学   115篇
外科学   224篇
综合类   42篇
预防医学   85篇
眼科学   14篇
药学   73篇
中国医学   2篇
肿瘤学   89篇
  2022年   11篇
  2021年   14篇
  2020年   19篇
  2019年   26篇
  2018年   36篇
  2017年   20篇
  2016年   22篇
  2015年   25篇
  2014年   64篇
  2013年   59篇
  2012年   51篇
  2011年   56篇
  2010年   55篇
  2009年   54篇
  2008年   49篇
  2007年   82篇
  2006年   38篇
  2005年   48篇
  2004年   40篇
  2003年   29篇
  2002年   26篇
  2001年   30篇
  2000年   15篇
  1999年   24篇
  1998年   35篇
  1997年   40篇
  1996年   27篇
  1995年   27篇
  1994年   33篇
  1993年   23篇
  1992年   10篇
  1991年   19篇
  1990年   10篇
  1989年   22篇
  1988年   29篇
  1987年   20篇
  1986年   19篇
  1985年   34篇
  1984年   17篇
  1983年   26篇
  1982年   14篇
  1981年   16篇
  1980年   12篇
  1979年   9篇
  1978年   12篇
  1977年   13篇
  1976年   17篇
  1975年   17篇
  1973年   9篇
  1972年   8篇
排序方式: 共有1445条查询结果,搜索用时 0 毫秒
1.
Balloon dacryocystoplasty: indications and contraindications   总被引:3,自引:0,他引:3  
  相似文献   
2.
3.
4.
In this study, we evaluated the effect of low level occupationalexposure of nurses in a medical oncology unit in Cairo, Egypt,to anticancer drugs. Twenty nurses who constantly handled thesedrugs and 20 controls, matched according to age and sex, wereexamined. Metaphase chromosomes were studied. Percentages ofmetaphases with chromosomal aberrations were significantly higher(P < 0.001) in the exposed group (6.1 ± 2.7) versusthe controls (2.6 ± 1.6). The detected chromosomal aberrationswere in the form of chromatid gaps, chromatid breaks and acentricfragments. Micronucleated peripheral blood lymphocytes werealso analyzed in cytochalasin B treated binucleated lymphocytes.There was significant increase in cells with micronuclei (P< 0.001) in nurses (10.05 ± 4.71) in comparison tothe matched control (5.42 ± 2.22) (P < 0.001). Nursesexposed to the cytotoxic drugs for  相似文献   
5.
6.
Human semen contains large amounts of opioid peptides and cytokines.We have measured the concentrations of interleukin (IL)-6 in140 semen samples and of -endorphinin 77 semen samples. Themedian concentration of endorphinin seminal plasma from normozoospermicmen(n = 23) was 154.7 pg/ml (10th—90th percentiles, 42.0—774.6),and there was no significant difference in the -endorphin concentrationamong normozoospermic, oligozoospermic (n= 28), asthenozoospermic(n= 15), azoospermic(n= 4) and post-vasectomy (n= 7) samples.There was no correlation between -endorphin concentration andsperm characteristics, nor with blood hormones. Endorphinconcentration was lower in cases with immunelogical infertility,as revealed by a positive direct mixedantiglobulin reactiontest (n = 12) ( > 0.01), than inmatched controls. The medianconcentration of IL-6 insamples with normal sperm concentration,motility andmorphology with or without white blood cells (n=39) was 26.1 pg/ml (10th–90th percentiles, 7.3–172.3),and there was no significant difference in the IL-6 concentrationamong normozoospermic, oligozoospermic (n= 46),asthenozoospermic(n= 32), azoospermic (n= 13) and post-vasectomy (n= 10) samples.The IL-6 concentration was significantly higher in cases ofvaricocele (n= 22)without white blood cells in semen (P <0.001) than in matched controls without varicocele (n= 23).In addition, the IL-6 concentration was elevated (P < 0.0001)in cases with accessory sex gland inflammation (n= 40). IL-6concentration was positively correlated with white blood cellsin semen (n= 60, r = 0.59, P < 0.0001), but there was nocorrelation with -endorphin concentration. The IL-6 concentrationchosen to differentiate between cases with and without accessorygland inflammation was 45.3 pg/ml, with a specificity of 80.6%and a sensitivity of 92.5%. It is concluded that -endorphinin seminal plasma playsan immune suppressive role, and thatincreased IL-6 concentration may be related to testicular dysfunctionincases with varicocele. Furthermore, IL-6 is an accurate markerof accessory sex gland inflammation.  相似文献   
7.
8.
A 43-year-old woman had unilateral exophthalmos caused by primary orbital Ewing sarcoma. Specialized immunohistochemical stains, primarily MIC-2 (CD99), aided in the diagnosis of Ewing sarcoma. Twenty-two months after radiotherapy and multiagent chemotherapy, the patient remained tumor free. To our knowledge, this is the first reported case of orbital Ewing sarcoma to present in an adult beyond the fourth decade of life.  相似文献   
9.
PURPOSE: Monocyte CD14 and its soluble form (sCD14) mediate the proinflammatory response to endotoxemia. The aim of this study was to measure the changes to these factors after major aortic surgery and the possible inhibitory role of transforming growth factor-beta(1) (TGF-beta(1)) during these procedures. METHODS: Twenty-four patients with supraceliac aortic crossclamping during thoracoabdominal aortic aneurysm (TAAA) repair and 12 patients with infrarenal aortic crossclamping as part of infrarenal aneurysm repair (AAA) were studied. Blood was collected at incision, aortic clamping, and reperfusion and at 1, 8, and 24 hours after reperfusion. Samples were assayed for endotoxin, peripheral blood monocyte CD14 expression, sCD14, tumor necrosis factor-alpha, and TGF-beta(1). RESULTS: Although there was significant endotoxemia on reperfusion in both groups of patients, peak plasma endotoxin levels were significantly higher in patients with TAAA (P =.001). Monocyte CD14 and plasma sCD14 were significantly decreased in patients with TAAA at reperfusion and 1 hour after reperfusion (P <.01, both points). In patients with AAA, a significant upregulation of CD14 was observed at 24 hours after reperfusion (P <.01), but no significant changes in sCD14 were observed. TNF-alpha showed no significant changes during the study period in both groups. In patients with TAAA, TGF-beta(1) showed significant elevation at all time points (P <.01); whereas in patients with AAA, TGF-beta(1) showed no significant changes. CONCLUSION: Splanchnic ischemia reperfusion in patients who undergo supraceliac aortic clamping is associated with peripheral blood monocyte CD14 suppression and significant elevation of TGF-beta(1). TGF-beta(1) may play an important role in modulating the immune response to endotoxemia during major aortic aneurysm surgery.  相似文献   
10.
OBJECTIVES: To determine the spectrum of N and G genotypes of respiratory syncytial virus (RSV) causing respiratory tract infection and whether particular genotypes are associated with severity of infection. PATIENTS AND METHODS: Nasopharyngeal aspirates (NPAs) were obtained from 114 infants with acute respiratory tract infection due to RSV over two seasons. Viral mRNA was extracted from NPAs or cultured virus, reverse transcribed, and the cDNA amplified by the polymerase chain reaction using primers directed to parts of the N and G gene respectively. Amplicons were separately digested with four different restriction endonucleases for each gene. The fragments were separated by agarose gel, electrophoresis, and the electrophoretic patterns used to assign the various genotypes. Disease severity was assessed as very mild (upper respiratory tract signs only), mild (coryza and signs of lower respiratory tract infection), moderate (requiring nasogastric or intravenous fluids), and severe (requiring oxygen or ventilation). RESULTS: Five of the six known N genotypes were detected, but NP4 and NP2 were found most frequently. There was no association between N genotype and disease severity. Six G (SHL) genotypes were detected. Significantly (p = 0.04) more of the infants infected with the SHL2 genotype had severe or moderate disease. CONCLUSIONS: During the seasonal peaks of RSV respiratory tract infection at least 10 different RSV genotypes cocirculated. While there is no association between N genotypes and disease severity, infection with the SHL2 G genotype appears to result in moderate to severe disease.  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