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   2805篇
  免费   209篇
  国内免费   18篇
耳鼻咽喉   27篇
儿科学   48篇
妇产科学   29篇
基础医学   378篇
口腔科学   71篇
临床医学   220篇
内科学   708篇
皮肤病学   68篇
神经病学   261篇
特种医学   117篇
外科学   484篇
综合类   12篇
一般理论   1篇
预防医学   241篇
眼科学   28篇
药学   163篇
中国医学   10篇
肿瘤学   166篇
  2023年   35篇
  2022年   114篇
  2021年   192篇
  2020年   83篇
  2019年   130篇
  2018年   115篇
  2017年   91篇
  2016年   104篇
  2015年   108篇
  2014年   130篇
  2013年   171篇
  2012年   227篇
  2011年   228篇
  2010年   132篇
  2009年   108篇
  2008年   155篇
  2007年   144篇
  2006年   142篇
  2005年   126篇
  2004年   113篇
  2003年   74篇
  2002年   61篇
  2001年   22篇
  2000年   34篇
  1999年   25篇
  1998年   19篇
  1997年   15篇
  1996年   7篇
  1995年   6篇
  1994年   5篇
  1993年   5篇
  1992年   20篇
  1991年   8篇
  1990年   14篇
  1989年   4篇
  1988年   8篇
  1987年   4篇
  1986年   10篇
  1985年   4篇
  1983年   3篇
  1982年   3篇
  1979年   3篇
  1978年   3篇
  1975年   2篇
  1974年   4篇
  1973年   2篇
  1971年   4篇
  1970年   3篇
  1968年   2篇
  1967年   2篇
排序方式: 共有3032条查询结果,搜索用时 15 毫秒
81.
Treatment of portal hypertension has evolved widely during the last decades. Advances in physiopathology have allowed better application of therapeutic options and also have permitted to know the natural history of varices and variceal bleeding, predicting which patients have a higher risk of bleeding. It also permits probability of designing patient treatment. According to liver function and subadjacent liver disease, it is possible to offer different alternatives within the three possible scenarios (primary prophylaxis, acute bleeding episode, and secondary prophylaxis). For primary prophylaxis, pharmacotherapy offers the best choice. Endoscopic banding is also growing in these scenarios and probably will be accepted in the near future. For the acute bleeding episode, endoscopic therapy (sclerosis and/or bands) and/or pharmacologic therapy (octreotide, terlipresin) represent best choice, considering TIPS as a rescue option. Surgery is not used routinely in this scenario in most centers. For secondary prophylaxis, pharmaco- and endoscopic therapy are first-line treatments, while TIPS and surgery as second-line treatments. TIPS is mainly used in patients on a waiting list for liver transplantation. Surgery offers good results for low-risk patients, with good liver function and with portal blood-flow preserving procedures (selective shunts, extensive devascularizations). Liver transplantation is recommended for patients with poor liver function because together with portal hypertension, it treats subadjacent liver disease.  相似文献   
82.

Introduction

Mainly due to the high percentage of infection and the ineffectiveness of treatments, Helicobacter pylori is a global health problem. Knowing the age at acquisition is key to preventing the infection.

Patients

Sixty-seven mothers and their respective children participated. To evaluate the presence of H. pylori, the faeces of the mother and her child were analysed using the HpSA antigen test.

Results

71.6% (48/67) of pregnant mothers were positive for H. pylori at the term of their pregnancy. In newborns, 8.96% (6/67) of them showed H. pylori colonisation/persistent infection. During the first month of life, a prevalence and incidence of infection of 23.9% and 13%, respectively, was observed.

Conclusion

Overall, the results suggest that there is a high risk of H. pylori infection during the first month of life, even of the persistent type.  相似文献   
83.

Introduction

We aimed to assess the effectiveness of ambulatory blood pressure monitoring (ABPM) and subclinical target organ damage parameters for diagnosis of resistant hypertension (RH).

Methods

We assessed demographic and anthropometric variables, the incidence of cardiovascular events and subclinical target organ damage (n = 112). We also studied the relationship between these variables and the ABPM results.

Results

Of the 112 patients referred from primary care with a diagnosis of RH, 69 (61.6%) were confirmed by ABPM. We found statistically significant differences (P < .001) between patients with RH and pseudo-resistant hypertension in the appearance of subclinical target organ damage. A percentage of 84 of the patients had microalbuminuria: 66.25 ± 30.7 mg/dl); 44.9% had stage 3 chronic kidney disease: the average glomerular filtration was 59 ml/min/1.73 m2; and 56.5% had left ventricular hypertrophy on echocardiography. Fundoscopy revealed that 64% of the patients had hypertensive retinopathy. Three variables were associated with an increased HR risk: microalbuminuria, hypertensive retinopathy and left ventricular hypertrophy (OR 5.7, 6.2 and 11.2, respectively).

Conclusions

This study shows that the systematic testing for target organ damage, particularly in terms of albuminuria, is a simple and inexpensive tool, with a high predictive value for RH (85%), which could be useful for prioritising patients who need ABPM.  相似文献   
84.
85.
So far, no suitable 5‐HT7R radioligand exists for clinical positron emission tomography (PET) imaging. [18F]2FP3 was first tested in vivo in cats, and the results were promising for further evaluations. Here, we evaluate the radioligand in pigs and non‐human primates (NHPs). Furthermore, we investigate species differences in 5‐HT7R binding with [3H]SB‐269970 autoradiography in post‐mortem pig, NHP, and human brain tissue. Specific binding of [18F]2FP3 was investigated by intravenous administration of the 5‐HT7R specific antagonist SB‐269970. [3H]SB‐269970 autoradiography was performed as previously described. [18F]2FP3 was synthesized in an overall yield of 35% to 45%. High brain uptake of the tracer was found in both pigs and NHPs; however, pretreatment with SB‐269970 only resulted in decreased binding of 20% in the thalamus, a 5‐HT7R–rich region. Autoradiography on post‐mortem pig, NHP, and human tissues revealed that specific binding of [3H]SB‐269970 was comparable in the thalamus of pig and NHP. Despite the high uptake of [18F]2FP3 in both species, the binding could only be blocked to a limited degree with the 5‐HT7R antagonists. We speculate that the affinity of the radioligand is too low for imaging the 5‐HT7Rs in vivo and that part of the PET signal arises from targets other than the 5‐HT7R.  相似文献   
86.
87.
A causative association was recently demonstrated between homozygous TREM2 mutations and frontotemporal dementia (FTD)-like syndrome and between heterozygous TREM2 exon2 genetic variations and late-onset Alzheimer's disease (AD). The objective of this study was to evaluate whether heterozygous TREM2 genetic variations might be associated to the risk of FTD. TREM2 exon 2 was sequenced in a group of 1030 subjects—namely, 352 patients fulfilling clinical criteria for FTD, 484 healthy control subjects (HCs), and 194 patients with AD. The mutation frequency and the associated clinical characteristics were analyzed. We identified 8 missense and nonsense mutations in TREM2 exon 2 in 24 subjects. These mutations were more frequent in patients with FTD than in HCs (4.0% vs. 1.0%, p = 0.005). In particular, TREM2 Q33X, R47H, T66M, and S116C mutations were found in FTD and were absent in HCs. These mutations were associated with either the semantic variant of primary progressive aphasia or the behavioral variant FTD phenotypes. The FTD and AD groups were not significantly different with regard to TREM2 genetic variation frequency (AD: 2.6%, p = 0.39). Heterozygous TREM2 mutations modulate the risk of FTD in addition to increasing susceptibility to AD. Additional studies are warranted to investigate the possible role of these mutations in the pathogenesis of neurodegenerative disorders.  相似文献   
88.
Leishmaniasis, Chagas disease and African sleeping sickness have been considered some of the most important tropical protozoan afflictions. As the number of drugs currently available to treat these human illnesses is severely limited and the majority has poor safety profiles and complicated administration schedules, actually there is an urgent need to develop new effective, safe and cost-effective drugs. Because quinoline alkaloids with antiprotozoal activity (quinine, chimanine, cryptolepine or huperzine groups) were historically and are still essential models for drug research to combat these parasitic infections, synthetic or semi-synthetic quinoline-based molecules are important for anti-kinetoplastid drug design approaches and synthetic methods of their preparation become a key task that is the central subject of this review. Its goal is to highlight the advances in the conventional and current syntheses of new 2-(3,4)-alkenyl (aryl) quinoline derivatives, which kill the most important kinetoplastid protozoa, – Leishmania and Trypanosoma and could be useful models for antileishmanial and antitrypanosomal research. An attempt has been made to present and discuss the more recent contributions in this field over the period 2015–2019, paying special attention to molecular design, synthetic efforts to new green reaction conditions for classical methods such as Skraup synthesis, Friedländer synthesis, Conrad–Limpach, Doebner–Miller, as well as contemporary methods like Gould–Jacobs, Meth–Cohn and Povarov reactions. This review includes brief general information on these neglected tropical diseases, their current chemotherapies, and primary natural models (quinoline alkaloids), suitable for development of anti-kinetoplastid quinoline-based agents. The main part of the review comprises critical discussion on the synthesis and chemistry of new quinolines diversely substituted by alkyl (alkenyl, aryl) fragments on the pyridine part of the quinoline skeleton, which could be considered interesting analogues of chimanine alkaloids. The methods described in this review were developed with the aim of overcoming the drawbacks of the traditional protocols using revolutionary precursors and strategies.

Leishmaniasis, Chagas disease and African sleeping sickness have been considered some of the most important tropical protozoan afflictions.  相似文献   
89.
90.
Chlorpromazine is known to produce both systemic phototoxic and photoallergic reactions. However, it may also cause photoallergic contact dermatitis and, albeit exceptionally, allergic contact dermatitis (ACD). We present a series of photoallergic contact dermatitis and ACD to chlorpromazine diagnosed at a tertiary centre cutaneous allergy unit between 1980 and 2019.  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