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   10342篇
  免费   1022篇
  国内免费   35篇
耳鼻咽喉   83篇
儿科学   344篇
妇产科学   161篇
基础医学   1524篇
口腔科学   341篇
临床医学   1139篇
内科学   1900篇
皮肤病学   223篇
神经病学   761篇
特种医学   422篇
外科学   1376篇
综合类   275篇
一般理论   4篇
预防医学   975篇
眼科学   199篇
药学   650篇
中国医学   14篇
肿瘤学   1008篇
  2021年   134篇
  2020年   91篇
  2019年   125篇
  2018年   156篇
  2017年   129篇
  2016年   136篇
  2015年   159篇
  2014年   201篇
  2013年   383篇
  2012年   445篇
  2011年   474篇
  2010年   288篇
  2009年   266篇
  2008年   401篇
  2007年   492篇
  2006年   438篇
  2005年   419篇
  2004年   428篇
  2003年   388篇
  2002年   370篇
  2001年   301篇
  2000年   332篇
  1999年   288篇
  1998年   141篇
  1997年   136篇
  1996年   113篇
  1995年   104篇
  1994年   100篇
  1993年   108篇
  1992年   278篇
  1991年   252篇
  1990年   210篇
  1989年   229篇
  1988年   178篇
  1987年   198篇
  1986年   192篇
  1985年   214篇
  1984年   136篇
  1983年   132篇
  1982年   103篇
  1981年   91篇
  1980年   91篇
  1979年   133篇
  1978年   90篇
  1977年   92篇
  1976年   95篇
  1974年   87篇
  1973年   93篇
  1972年   92篇
  1971年   92篇
排序方式: 共有10000条查询结果,搜索用时 20 毫秒
31.
Unfractionated wheat gliadin was used to produce murine monoclonal antibodies to gliadin. A dot immunobinding assay, using these antibodies, was developed to detect possible gliadin contamination of nominally gluten-free flour, using dilute ethanol extracts spotted onto nitrocellulose membranes. The sensitivity of the assay was less than 10 micrograms/ml of unfractionated gliadin which permitted the detection of trace amounts of gliadin present in certain wheat starch based 'gluten-free' products. The assay detected not only wheat gliadin, but also prolamine extracts of rye, barley and oats; maize, soya and potato extracts as well as the control proteins casein and ovalbumin, gave negative results. The assay is of value as a simple and rapid method of screening foods for their suitability for consumption by patients with coeliac disease.  相似文献   
32.
1. The effects of capsaicin, calcitonin gene-related peptide and substance P were studied via three parameters in the guinea-pig vas deferens: the overflow of ATP and of tritiated noradrenaline, the mechanical responses to field stimulation and the mechanical responses to exogenous noradrenaline and alpha, beta-methylene ATP. 2. At 2 Hz, capsaicin inhibited the stimulus-evoked release of ATP, whereas it was without effect on the release of noradrenaline. At 20 Hz capsaicin did not affect the release of either of the cotransmitters. Capsaicin enhanced responses to alpha, beta-methylene ATP, but not to exogenous noradrenaline. 3. Calcitonin gene-related peptide, like capsaicin, inhibited the release of ATP, but not noradrenaline at 2 Hz and was without effect on release at 20 Hz. However, calcitonin gene related peptide inhibited responses to alpha, beta-methylene ATP and was without effect on responses to exogenous noradrenaline. 4. Substance P had no effect on the release of either noradrenaline or ATP at either frequency. However, like capsaicin it enhanced responses to alpha, beta-methylene ATP and was without effect on exogenous noradrenaline. 5. These results suggest that the actions of capsaicin on the guinea-pig isolated vas deferens are mediated via the release of both calcitonin gene-related peptide and substance P. Furthermore, as capsaicin and calcitonin gene-related peptide prejunctionally modulate purinergic, but not noradrenergic transmission, this suggests that the mechanisms for the storage and release of the sympathetic co-transmitters noradrenaline and ATP may not be the same.  相似文献   
33.
34.
OBJECTIVE: There are limited and conflicting data available concerning the incidence of inadvertent splenectomy and its impact on the outcome in patients who have undergone oesophagectomy. The aim of this study is to identify the factors associated with a likelihood of inadvertent splenectomy and its influence on early and long-term outcome in patients having oesophagectomy for oesophageal carcinoma. METHODS: A consecutive series of 738 oesophagectomies performed between 1991 and 2004 was analysed. In our practice, the spleen was removed only if damaged intraoperatively. Routine chemo- and immunoprophylaxis would subsequently be used. Multivariate analysis with logistic and Cox models determined significant variables. RESULTS: Of the 738 oesophagectomies, 48 (6.5%) had splenectomy. Neoadjuvant chemotherapy was administered to a minority of patients; none subsequently had splenectomy. There were significant differences between types of operation (Ivor-Lewis 18 (9.0%), left thoracolaparotomy 14 (9.9%) and left thoracophrenotomy 15 (3.9%), p=0.01). Splenectomy was more common with advanced N stage disease (OR=0.44 [0.20-0.95]; p=0.04). Splenectomy resulted in more blood transfusions (median, 2 units vs 0 units; p=0.03) more anastomotic leaks (7 [14.6%] vs 42 [6.1%]; p=0.02) but not an increase in pulmonary complications (p=0.64) or in-hospital mortality (1 [4.6%] vs 37 [5.4%]; p=0.30). Splenectomy did not significantly affect median survival (551 [332-770] days vs 627 [554-700] days; p=0.63). CONCLUSION: Although inadvertent splenectomy increased the morbidity of oesophagectomy, it did not impair survival. Type of operation and advanced N stage are important risks for splenectomy. Though best avoided, most of the consequences of splenectomy can be managed. An unexpected relationship between splenectomy and anastomotic leaks needs further investigation.  相似文献   
35.
36.
Two children developed evidence of subcutaneous fat atrophy after corticosteroid injection of periocular hemangiomas. The atrophy appeared at the site of injection and followed the expected course of lymphatic channels to the vicinity of regional lymph nodes.  相似文献   
37.
N W Law  H Ellis 《Surgery》1990,107(4):449-454
The effect of postoperative parenteral nutrition on the healing of abdominal wall wounds and colonic anastomoses in protein-malnourished rats was studied. The healing of laparotomy wounds and colonic anastomoses was assessed by bursting pressure measurement on the fifth postoperative day. Compared with control animals on a normal diet (group A), rats on a low-protein diet given postoperative dextrose-saline solution (group B) had significantly lower abdominal wall and colonic anastomotic bursting strengths. The detrimental effects of protein malnutrition could be completely reversed for abdominal wall wounds and partially reversed for colonic anastomoses in rats on a low-protein diet given postoperative parenteral nutrition (group C). Autoradiographic studies showed a marked decrease in the activity of wound fibroblasts that was restored by the administration of postoperative parenteral nutrition. Serum protein measurements showed a closer correlation of colonic anastomotic healing to serum albumin than to serum transferrin values but showed no correlation with abdominal wall wound healing.  相似文献   
38.
This multiclinic study was performed to evaluate the safety and efficacy of metaproterenol sulfate (Alupent) metered dose inhaler in children with asthma ages 5 to 12 years. A total of 268 children completed this study according to the protocol, having received either metaproterenol or placebo for 30 consecutive days. Full spirometric testing was done pre- and postdose on Days 1 and 30 for a total duration of 6 hours on each day. The results showed that metaproterenol was consistently superior to placebo in all pulmonary function parameters measured on Days 1 and 30. This difference was statistically significant for peak values and areas under the curves for both FEV1 and FEF25-75%. There were no significant side effects noted. We conclude that metaproterenol metered dose inhaler is safe and effective in the treatment of asthma in children ages 5 to 12 years.  相似文献   
39.
40.
Clinical aspects of FK-506 or cyclosporine immunosuppression regimens were evaluated in 48 consecutive pediatric renal transplant recipients. Tapering and discontinuation of prednisone was employed only in children receiving FK-506 who experienced minor or no rejection episodes during the 1st posttransplant month. At 1 year follow-up, 17 of 22 (77%) of all children with functioning allografts were receiving no prednisone (n=13) or a mean dosage of 0.07 mg/kg per day (n=4). During the 1st month, acute cellular rejection was more common in the FK-506 group (0.58 vs. 0.21 rejections per patient,P<0.05) but allograft survival (92%) and renal function at 1 year posttransplant were identical in both groups. Compared with the cyclosporine regimen, FK-506 immunosuppression may be associated with a higher incidence of cytomegalovirus or reversible Epstein-Barr virus-induced lymphoproliferative disease. However, the FK-506 group had less hirsutism and gingival hypertrophy and required fewer antihypertensive medications independent of steroid use. Height standard deviation scores and weight-for-height index improved only in preadolescents receiving FK-506 but no prednisone (P<0.02 andP<0.05, respectively), but did not differ between children on FK-506 plus prednisone and those in the cyclosporine group. We conclude that the major advantages of FK-506 over cyclosporine immunosuppression are a reduced severity of hypertension and an improved cosmetic appearance which may improve long-term medical compliance. When used as monotherapy, FK-506 also shows promise in relieving the growth retardation associated with cyclosporine regimens that include prednisone.  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