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   5213篇
  免费   352篇
  国内免费   20篇
耳鼻咽喉   39篇
儿科学   120篇
妇产科学   66篇
基础医学   810篇
口腔科学   116篇
临床医学   365篇
内科学   1374篇
皮肤病学   268篇
神经病学   344篇
特种医学   112篇
外科学   490篇
综合类   21篇
一般理论   1篇
预防医学   261篇
眼科学   165篇
药学   397篇
中国医学   15篇
肿瘤学   621篇
  2024年   4篇
  2023年   29篇
  2022年   78篇
  2021年   165篇
  2020年   103篇
  2019年   100篇
  2018年   164篇
  2017年   124篇
  2016年   153篇
  2015年   118篇
  2014年   174篇
  2013年   251篇
  2012年   371篇
  2011年   382篇
  2010年   214篇
  2009年   198篇
  2008年   354篇
  2007年   384篇
  2006年   343篇
  2005年   335篇
  2004年   336篇
  2003年   295篇
  2002年   284篇
  2001年   63篇
  2000年   45篇
  1999年   58篇
  1998年   61篇
  1997年   60篇
  1996年   38篇
  1995年   37篇
  1994年   20篇
  1993年   30篇
  1992年   18篇
  1991年   12篇
  1990年   18篇
  1989年   27篇
  1988年   16篇
  1987年   15篇
  1986年   16篇
  1985年   8篇
  1984年   13篇
  1983年   7篇
  1982年   10篇
  1981年   4篇
  1979年   13篇
  1977年   3篇
  1976年   5篇
  1973年   3篇
  1969年   6篇
  1967年   4篇
排序方式: 共有5585条查询结果,搜索用时 31 毫秒
91.
Wee1, the Cdc2 inhibitory kinase, needs to be down-regulated at the onset of mitosis to ensure rapid activation of Cdc2. Previously, we have shown that human somatic Wee1 (Wee1A) is down-regulated both by protein phosphorylation and degradation, but the underlying mechanisms had not been elucidated. In the present study, we have identified the beta-transducin repeat-containing protein 1/2 (beta-TrCP1/2) F-box protein-containing SKP1/Cul1/F-box protein (SCF) complex (SCF(beta-TrCP1/2)) as an E3 ubiquitin ligase for Wee1A ubiquitination. Although Wee1A lacks a consensus DS(p)GXXS(p) phospho-dependent binding motif for beta-TrCP, recognition of Wee1A by beta-TrCP depended on phosphorylation, and two serine residues in Wee1A, S53 and S123, were found to be the most important phosphorylation sites for beta-TrCP recognition. We have found also that the major M-phase kinases polo-like kinase 1 (Plk1) and Cdc2 are responsible for the phosphorylation of S53 and S123, respectively, and that in each case phosphorylation generates an unconventional phospho-degron (signal for degradation) that can be recognized by beta-TrCP. Phosphorylation of Wee1A by these kinases cooperatively stimulated the recognition and ubiquitination of Wee1A by SCF(beta-TrCP1/2) in vitro. Mutation of these residues or depletion of beta-TrCP by small-interfering RNA treatment increased the stability of Wee1A in HeLa cells. Moreover, our analysis indicates that beta-TrCP-dependent degradation of Wee1A is important for the normal onset of M-phase in vivo. These results also establish the existence of a feedback loop between Cdc2 and Wee1A in somatic cells that depends on ubiquitination and protein degradation and ensures the rapid activation of Cdc2 when cells are ready to divide.  相似文献   
92.
Summary A modified version of Brockenbrough's trans-septal catheterization technique was carried out in 11 patients indicated for percutaneous transvenous mitral commissurotomy (PTMC). In 8/11 (72.7%), a coiled guide-wire was successfully inserted through theforamen ovale without atrial septal puncture. The Brockenbrough needle was used merely to maintain stiffness and the orientation of the dilator. PTMC was performed with an Inoue single balloon without incident.Patent foramen ovale was found by transesophageal echocardiography prior to the operation in only 1/11 patients (9.0%); nonetheless, it proved not to be a critical factor for the success of the procedure. This procedure seems to have much potential to enable the treatment of mitral stenosis with a lowered risk to the patient, as long as it is performed with precision and caution.  相似文献   
93.

Background

Several studies have reported that viral infections are related to lung cancer. We previously reported the involvement of Torque teno virus (TTV) in patients with lung cancer and idiopathic pulmonary fibrosis. However, the role of TTV in lung cancer growth, and its influence on changes in TTV DNA titers due to idiopathic pulmonary fibrosis (IPF) in lung cancer patients are poorly understood.

Methods

Serum TTV DNA titers were measured in serum samples obtained from patients with lung cancer. Forty-eight patients with primary lung cancer, including 8 patients with IPF, were enrolled. Serum TTV DNA titers were quantitated before and after chemotherapy. In addition, patients were classified into two groups according to the presence or absence of IPF, and clinical characteristics were compared between these two groups.

Results

Among the 33 patients with partial response to treatment or stable disease in the lung cancer, the mean TTV DNA titer in 28 patients without IPF had significantly decreased after chemotherapy. In contrast, the mean TTV DNA titer in the 5 patients with IPF tended to increase after chemotherapy. In the 15 patients with progressive lung cancer, TTV DNA titers were significantly elevated in those with and without IPF.

Conclusion

In lung cancer patients without IPF, changes in TTV titers may be correlated with tumor growth. However, in lung cancer patients with IPF, TTV titers were not consistently associated with chemotherapy responses. Therefore, IPF may have an influence on changes in TTV DNA titers.  相似文献   
94.

Background

Long-term oxygen therapy (LTOT) is sometimes prescribed for patients with advanced lung cancer who are potential candidates for chemotherapy. The aim of this study was to assess the usefulness of chemotherapy for patients with this disease who require LTOT.

Methods

The medical records of 40 patients with advanced lung cancer who received LTOT while undergoing systemic chemotherapy at our institution between January 2009 and December 2014 were retrospectively reviewed. Chemotherapy consisted of cytotoxic or molecular-targeted agents.

Results

Twenty-four patients had adenocarcinoma, 6 had squamous cell carcinoma, and 10 had small cell lung cancer (SCLC). The median survival time from the date of the first chemotherapy cycle performed in conjunction with LTOT was 194 days. In a multivariate analysis, the only factor significantly associated with better prognosis was the line (first or second) of the first chemotherapy with LTOT (hazard ratio =0.42; 95% confidence interval, 0.18 to 0.94). Among the 40 patients, 10 (25%) received chemotherapy during the last 30 days of their lives, 2 of whom died of chemotherapy-related adverse events.

Conclusions

Chemotherapy for patients with advanced lung cancer who receive LTOT may be acceptable if it is the first- or second-line treatment. However, we should be mindful of the potential overuse of chemotherapy and its negative impact on quality of life.  相似文献   
95.
BackgroundEosinophilic chronic rhinosinusitis (ECRS) is often complicated by asthma and can be difficult to diagnose. This study aimed to clarify the usefulness of the self-administered odor questionnaire (SAOQ) and visual analog scale (VAS) to identify olfactory disorders in patients with asthma.MethodsThis retrospective study was conducted on patients with asthma who were referred to the Otolaryngology clinic between May and September 2018. The treatment step of asthma, asthma control test (ACT), pulmonary function test, peripheral blood eosinophils, and fractional exhaled nitric oxide (FeNO) were analyzed. ECRS was diagnosed based on the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis Study score. Olfactory dysfunction was evaluated using the SAOQ and VAS for olfactory disorders.ResultsThe study included 56 patients (18 males and 38 females), who were divided into two groups; those with ECRS (n = 18) and those without ECRS (n = 38). Age, sex, treatment step, ACT score, and pulmonary function were not significantly different between the groups. The ECRS group had a significantly higher FeNO value (89.1 ppb vs. 39.1 ppb) and a significantly lower SAOQ score (40.1% vs. 96.1%). The area under the receiver operating characteristic curve for the efficacy of ECRS diagnosis was 0.88, 0.889, 0.799, and 0.757 for SAOQ, VAS, blood eosinophil count, and FeNO, respectively.ConclusionThe SAOQ and VAS scores were useful tools that presented similar results to the blood eosinophil count and FeNO, and may help to improve the diagnosis of ECRS in patients with asthma.  相似文献   
96.
Castleman's disease is a rare atypical lymphoproliferative disorder. Renal manifestations, such as proteinuria, hematuria, and renal dysfunction, are common in Castleman's disease; however, a nephrotic syndrome rarely occurs. We have encountered an unusual case of Castleman's disease of the plasma cell type characterized by nephrotic syndrome because of glomerulopathy mimicking membranoproliferative glomerulonephritis. Our patient showed higher levels of circulating cytokines (interleukin-6/vascular endothelial cell-derived growth factor), the glomerular lesions not associated with immunocomplex deposition, and the resolution of nephrotic syndrome after successful corticosteroids therapy resulting in a decline in cytokines levels, thereby implicating a cytokine-induced glomerular cell injury/activation as a possible cause of the glomerular pathological changes in this case.  相似文献   
97.
We describe the case of an 85-year-old woman in whom pericardiocentesis, prolonged bed rest and blood pressure control were performed without surgery to successfully treat an oozing-type myocardial rupture due to myocardial infarction.  相似文献   
98.
The relationship between sphincter of Oddi pressure and the morphological structure of the sphincter was studied in eight dogs prepared with a duodenal cannula. Sphincter of Oddi manometry was performed in awake animals in three directions, ventral, left dorsal, and right dorsal, using a catheter with three radial side holes for recording at one level. The pressure in the ventral direction (26.6 ± 1.06 mmHg) (mean ± SEM) was significantly lower than that in the left and right dorsal directions (30.6 ± 1.42 and 31.2 ± 1.23 mmHg, respectively). This functional manometric difference in the three directions correlated closely with the morphological structure of the sphincter of Oddi; the sum of the thickness of the sphincter of Oddi muscle and duodenal proper muscle was greater on the dorsal than on the ventral side. To our knowledge, this is the first report of axial asymmetry in sphincter of Oddi pressure. (Received May 27, 1997; accepted April 24, 1998)  相似文献   
99.

Background

Topical corticosteroids (TCS) can induce adverse effects, such as skin atrophy. Although TCS can cause increases in intraocular pressure (IOP), the effects of daily TCS use on IOP have not been fully elucidated. We evaluated the clinical doses of TCS and the change in the IOP during the daily treatment of atopic dermatitis (AD).

Methods

We collected clinical data on a total of 65 patients who were diagnosed with AD and underwent 2 or more IOP measurements at our hospital.

Results

Mean monthly facial steroid volumes of ≤11.8 g and ≤15.0 g of TCS were applied to 90% of the patients aged 2–12 years and those aged ≥13 years, respectively. During the treatment, there were no TCS-related increases in IOP in any patient.

Conclusions

Our study suggests that TCS might not cause increases in IOP at the abovementioned doses. However, the IOP of steroid responders is known to be highly responsive to steroids. Therefore, patients who have steroids applied to their eyelids had better undergo regular IOP measurements at ophthalmological clinics.  相似文献   
100.
Roles of Fos in apoptosis of epithelia in the mouse male accessory sex organs and uterus were investigated using Fos-deficient mice. Normal 30- and 50-day-old and Fos-deficient 50-day-old male and female mice were castrated, and testosterone propionate and estradiol-17 beta were daily injected into male and female mice, respectively, for 5 days. An apoptotic index (a percentage of apoptotic cells) in the epithelium was examined from the day following the last injection (day 1) to day 8. The body weights and the weights of the ventral prostate (VP), coagulating gland (C), seminal vesicle (SV) and epididymis (Ep) and uterus of 50-day-castrated Fos-deficient mice on day 1 suggested that the development of these mice corresponded to that of 30-day-castrated normal mice at the most. The extents of apoptosis estimated by an apoptotic index in the VP, C, SV, Ep and uterus in 50-day-castrated Fos-deficient mice were comparable to those in 30-day-castrated normal mice. The extents of apoptosis in the SV, Ep and uterus in 30-day-castrated normal and 50-day-castrated Fos-deficient mice were similar to those in 50-day-castrated normal mice, while the extents of apoptosis in the VP and C in the former two groups of mice were less than those in the latter mice. The present results show that Fos-deficiency does not affect apoptosis in the SV, EP and uterus. However, the extents of apoptosis in the VP and C were less in 50-day-castrated Fos-deficient mice than in 50-day-castrated normal mice. This seems to be due to the retarded development of 50-day-castrated Fos-deficient mice, but not to a role of Fos in apoptosis.  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