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   9598篇
  免费   1133篇
  国内免费   45篇
耳鼻咽喉   107篇
儿科学   278篇
妇产科学   256篇
基础医学   1420篇
口腔科学   201篇
临床医学   1054篇
内科学   1824篇
皮肤病学   132篇
神经病学   767篇
特种医学   617篇
外国民族医学   10篇
外科学   1315篇
综合类   291篇
一般理论   5篇
预防医学   850篇
眼科学   210篇
药学   648篇
中国医学   9篇
肿瘤学   782篇
  2022年   80篇
  2021年   156篇
  2020年   91篇
  2019年   164篇
  2018年   198篇
  2017年   152篇
  2016年   141篇
  2015年   179篇
  2014年   220篇
  2013年   293篇
  2012年   394篇
  2011年   464篇
  2010年   238篇
  2009年   235篇
  2008年   403篇
  2007年   392篇
  2006年   387篇
  2005年   356篇
  2004年   331篇
  2003年   323篇
  2002年   325篇
  2001年   304篇
  2000年   299篇
  1999年   260篇
  1998年   158篇
  1997年   131篇
  1996年   137篇
  1995年   122篇
  1994年   100篇
  1993年   96篇
  1992年   238篇
  1991年   204篇
  1990年   177篇
  1989年   182篇
  1988年   188篇
  1987年   206篇
  1986年   199篇
  1985年   190篇
  1984年   111篇
  1983年   123篇
  1982年   88篇
  1981年   81篇
  1980年   84篇
  1979年   130篇
  1978年   106篇
  1977年   82篇
  1976年   116篇
  1974年   100篇
  1973年   118篇
  1972年   88篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Squamous cell carcinoma (SCC) of the temporal bone is a rare, aggressive and highly malignant tumour that requires specialised, multidisciplinary surgery for its treatment. Reconstruction of the defect is as crucial as the tumour ablation in terms of mortality and postoperative morbidity. METHODS: The experience of the East Anglian Skull Base Surgery Service from 1982 to 2004 in managing 42 consecutive patients (22 females; age range 37-80 years) undergoing extended and lateral temporal bone resection for SCC is presented. RESULTS: The overall 5-year survival was 31.0% (median follow up: 97 months) when both curative and palliative procedures were included. On multivariate analysis, the favourable prognostic factors were male sex, well-differentiated tumours and stage N(0) neck. The reconstructions in 38 patients were analysed. The majority (24/38) had free tissue transfer reconstructions and most of these were radial forearm free flaps. Later in the series, other free flap types such as anterolateral thigh flaps and lateral arm flaps were employed. Pedicled myocutaneous flaps and local flaps were also used. CONCLUSIONS: This paper analyses the outcomes of the various reconstructions and discusses the evolution of their care in our unit. The information obtained from the review of our data is extrapolated to offer guidance on the choice of reconstructive option in these patients.  相似文献   
42.
43.
Looking at the history of epididymal research provides a level of confidence in predictions of cause and effect that looking at the future cannot achieve. Thus, when one of us (Hamilton, 2002) wrote a short essay on the history of the testicular excurrent ducts it became fairly obvious that advances in understanding the epididymis followed advances in other fields, particularly those that provided new instrumentation to probe at ever finer levels of detail. Can this same theme lead to predictions about what will happen in epididymis research over the next century?  相似文献   
44.
Cisplatin and its analogs have become important components of chemotherapeutic regimens for the treatment of solid tumors, however, their overall effectiveness is limited by the emergence of drug-resistant tumor cells. Resistance to the platinum drugs is multifactorial consisting of mechanisms that prevent the formation of lethal platinum-DNA adducts and mechanisms that operate downstream of the drug/target interaction to promote cell survival. Continued progress in the study of the drug resistance phenotype as well as the development of new platinum analogs may eventually lead to improved therapies and increased survival rates.  相似文献   
45.
The traditional method of establishing a pneumoperitoneum before laparoscopic surgery is via a Verres needle inserted in the midline below the umbilicus while tenting the abdominal wall with the hand. A new approach is described in which preliminary surgical exposure and tenting of the linea alba immediately above the umbilicus is achieved before needle insertion through the superior margin of the umbilical ring. The advantages of this new technique over the conventional method are discussed. Further technical features important in the safe formation of the pneumoperitoneum are emphasized.  相似文献   
46.
47.
HLA-DR expression in neuroendothelial cells (NEC) was studied during the course of SIV encephalitis in rhesus monkeys. HLA-DR determinants were detected on NEC in monkeys with SIV encephalitis, but not in control animals. In situ hybridization with an SIV probe indicated that HLA-DR expression was not a consequence of SIV replication within NEC. Cultured rhesus NEC stimulated with gamma interferon expressed HLA-DR to a higher degree than cultured brain fibroblasts or astrocytes. These data support the contention that NEC participate in retrovirus-induced inflammation and autoimmunity within the central nervous system.  相似文献   
48.
Older age, prior transplantation, pulmonary hypertension, and mechanical support are commonly seen in current potential cardiac transplant recipients. Transplants in 436 consecutive adult patients from 1994 to 1999 were reviewed. There were 251 using standard donors in 243 patients (age range 18-69 years). To emphasize recipient risk, 185 patients who received a nonstandard donor were excluded from analysis. The indications for transplant were ischemic heart disease (n = 123, 47%), dilated cardiomyopathy (n = 82, 32%), and others (n=56, 21%). One hundred and forty-nine (57%) recipients were listed as status I; 5 and 6% were supported with an intra-aortic balloon and an assist device, respectively. The 30-d survival and survival to discharge were 94.7 and 92.7%, respectively; 1-year survival was 89.1%. Causes of early death were graft failure (n = 6), infection (n = 4), stroke (n = 4), multiorgan failure (n = 3) and rejection (n = 2). Predictors were balloon pump use alone (OR= 11.4, p =0.002), pulmonary vascular resistance > 4 Wood units (OR = 5.7, p = 0.007), pretransplant creatinine > 2.0 mg/dL (OR = 6.9, p = 0.004) and female donor (OR = 8.3, p = 0.002). Recipient age and previous surgery did not affect short-term survival. Heart transplantation in the current era consistently offers excellent early and 1-year survival for well-selected recipients receiving standard donors. Early mortality tends to reflect graft failure while hospital mortality may be more indicative of recipient selection.  相似文献   
49.
Traditionally, penicillin binding to serum proteins was believed to be a passive chemical process; however, it appears to be facilitated by serum factors. The objectives of this in vitro investigation were to examine facilitated penicillin haptenation, to study the kinetics of haptenation, and to determine the nature of haptenation-facilitating factors. The model involved addition of [3H]benzylpenicillin to serum or albumin solutions (at pH 7.3 to 7.4) and incubation at 37 degrees C for up to 72 h. The extent of penicillin binding to proteins in serum was found to be four- to fivefold higher than with solutions having comparable concentrations of purified albumin, total protein, or total immunoglobulin. Ultrafiltration of serum reduced penicillin binding to serum proteins substantially. An ultrafiltrable haptenation-facilitating factor(s) was found to be less than 0.5 kDa but was not calcium or magnesium. Finally, the extent of penicillin binding was related to albumin purity, as binding substantially increased with albumin purity. These findings suggest that there is a factor(s) in serum that facilitates covalent binding of penicillin to serum proteins. The factor(s) can be removed and then restored to increase penicillin binding to albumin. It appears that at least one component of the facilitation factor is less than 0.5 kDa, which suggests that it is not a peptide and that it is some simple serum component other than calcium or magnesium.  相似文献   
50.
A few hours after servicing illuminated lamps inside a whole body ultraviolet radiation B (UVB) phototherapy cabin, a technician developed erythema to the anterior neck with subsequent peeling, despite wearing a UV-opaque face shield. Measurements using polysulphone film badges attached to various sites on the head and neck of a mannikin were carried out to explore the spatial distribution of UVB exposure. It was found that the lower face and neck can receive sufficient exposure to result in erythema, the reason being that the fluorescent lamps will extend to about 1.5 m inferior to the head of an upright person and so result in irradiation from below. It is important, therefore, that if operators or service personnel need to be in an illuminated UVB cabin for several minutes or more, adequate protection should be provided to the chin and neck, in addition to a UV-opaque face shield.  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