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   3090篇
  免费   248篇
  国内免费   20篇
耳鼻咽喉   14篇
儿科学   152篇
妇产科学   71篇
基础医学   356篇
口腔科学   96篇
临床医学   279篇
内科学   662篇
皮肤病学   166篇
神经病学   281篇
特种医学   293篇
外科学   335篇
综合类   44篇
一般理论   1篇
预防医学   169篇
眼科学   77篇
药学   153篇
  1篇
中国医学   1篇
肿瘤学   207篇
  2023年   14篇
  2022年   27篇
  2021年   62篇
  2020年   45篇
  2019年   87篇
  2018年   90篇
  2017年   52篇
  2016年   66篇
  2015年   69篇
  2014年   87篇
  2013年   110篇
  2012年   119篇
  2011年   128篇
  2010年   120篇
  2009年   111篇
  2008年   138篇
  2007年   124篇
  2006年   132篇
  2005年   119篇
  2004年   96篇
  2003年   99篇
  2002年   96篇
  2001年   71篇
  2000年   100篇
  1999年   76篇
  1998年   102篇
  1997年   98篇
  1996年   78篇
  1995年   70篇
  1994年   46篇
  1993年   58篇
  1992年   41篇
  1991年   55篇
  1990年   35篇
  1989年   71篇
  1988年   53篇
  1987年   44篇
  1986年   43篇
  1985年   37篇
  1984年   28篇
  1983年   22篇
  1982年   23篇
  1981年   22篇
  1980年   27篇
  1979年   12篇
  1978年   21篇
  1977年   16篇
  1976年   19篇
  1975年   21篇
  1973年   17篇
排序方式: 共有3358条查询结果,搜索用时 15 毫秒
41.
Although iron, vltamm B12, and folate deficiency have been well documented after gastric bypass operations performed for morbid obesity, there is surprisingly little information on either the natural course or the treatment of these deficiencies in Roux-en-Y gastric bypass (RYGB) patients Durmg a l0-year period, a complete blood count and serum levels of iron, total iron-binding capacity, vltamin B12, and folate were obtained in 348 patients preoperatively and postoperatively at 6-month intervals for the first 2 years, then annually thereafter The principal objectives of this study were to determine how readily patients who developed metabolic deficiencies after Roux-en-Y gastric bypass responded to postoperative supplements of the deficient micronutrient and to learn whether the risk of developmg these deficiencies decreases over time Hemoglobin and hematocrit levels were slgnificantly decreased at all postoperative intervals in comparison to preoperative values Moreover, at each successive interval through 5 years, hemoglobin and hematocrit were decreased signifiantly compared to the preceding interval Folate levels were significantly increased compared to preoperative levels at all time intervals Iron and vltamin B12 levels were lower than preoperative measurements and remained relatively stable postoperatively Half of the low hemoglobin levels were not associated with iron deficiency Taking multivltamin supplements resulted in a lower incidence of folate deficiency but did not prevent iron or vitamin B12 deficiency Oral supplementation of iron and vitamin B12 corrected defiaencies in 43% and 81% of cases, respectively Folate deficiency was almost always corrected with multivitamins alone No patient had symptoms that could be attributed to either vitamin B12 or folate deficiency Conversely, many patients had symptoms of iron deficiency and anenua Lack of symptoms of vitamin B12 and folate deficiency suggests that these deficiencies are not clinically important after RYGB Conversely, iron deficiency and anemia are potentially serious problems after RYGB, particularly in younger women Hence we recommend prophylactic oral iron supplements to premenopausal women who undergo RYGB  相似文献   
42.

Objective

To evaluate the clinical impact of diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) in staging of malignant lymphoma.

Methods

Twenty-three patients with proven malignant lymphomas were prospectively enrolled. DWIBS (b = 0, 1000 s/mm2) examinations and PET-CT were performed respectively on an Intera 1.5 T unit and a Gyroscan PET-CT scan (Philips Medical system, Best, the Netherland). The criteria for positive node involvement were a size over 10 mm or an apparent diffusion coefficient (ADC) value under 0.75 10−3 mm2/s for nodes under 10 mm. For extranodal analysis, a high or heterogeneous signal on DWIBS was considered as positive. In cases of discordance, the reference standard for each region or organ was established at 6 months after the diagnosis according to all available clinical, biological information, as well as histological evidence or follow-up to prove or disprove the presence of disease.

Results

DWIBS and PET-CT results were congruent in 333 node regions on the 345 areas analyzed, with excellent agreement (κ = 0.97, P < 0.0001). From 433 organs analyzed (one patient had splenectomy) extranodal disease was detected in 22 organs on DWIBS. The two imaging techniques agreed on 430 organs (κ = 0.99, P < 0.0001). Finally, Ann Arbor stages based on DWIBS and those of PET/CT were in agreement for 23 patients.

Conclusions

For malignant lymphoma in a pre-therapeutic context, agreement between diffusion-weighted whole-body imaging and PET/CT is high for Ann Arbor staging.  相似文献   
43.
44.
OBJECTIVE: To evaluate the effects of antagonists of different subfamilies of 5-hydroxytryptamine (5-HT) receptors on bladder function in anaesthetized and conscious rats. MATEERIALS AND METHODS: The urinary bladder of female anaesthetized rats was catheterized urethrally and filled with physiological saline until spontaneous bladder contractions occurred. Infravesical pressure was measured by a pressure transducer and displayed continuously on a chart recorder. The time of bladder quiescence (to the disappearance of rhythmic contractions) after injection with different compounds tested was recorded. Conscious rats underwent cystometry with chronically (infravesical) implanted catheters to continuously record bladder capacity (evaluated as amount of saline infused between voiding cycles) and maximal voiding pressure. The affinity for the human recombinant serotoninergic 5-HT1A subtype (inhibition of specific binding of [3H]8-hydroxy-2-(di-n-propylamino) tetralin) and the effects on the [35S]guanosine 5'-(gamma-thio) triphosphate (GTPgammaS) binding in HeLa cells was also evaluated. RESULTS: Among the compounds tested, only 4-(2'-methoxy-phenyl)-1-[2'-(n-2"-pyridinyl)-p-iodobenzamido]-ethyl-piperazine (p-MPPI) and methiothepin showed nanomolar affinity for the 5-HT1A receptors, the former being a neutral antagonist and the latter an inverse agonist in the [35S]GTPgammaS binding model. Intravenous injection of low doses of p-MPPI and methiothepin induced a dose-dependent disappearance of isovolumic bladder contractions in anaesthetized rats (> 10 min). At the highest doses, the dose-response curves were bell-shaped. The amplitude of bladder contractions was not markedly altered. The tested antagonists of 5-HT2, 5-HT3, 5-HT4, and 5-HT6 serotoninergic subtypes were poorly active or inactive in the model. Similarly, these compounds were inactive on cystometry in conscious rats, whereas p-MPPI and methiothepin induced a consistent increase in bladder capacity. Methiothepin also decreased the voiding pressure, whereas p-MPPI did not affect this variable. CONCLUSIONS: These findings confirm that only selective 5-HT1A receptor antagonists have favourable effects on the bladder, inducing an increase in bladder capacity with no derangement of bladder contractility.  相似文献   
45.
46.
47.

Background

The effectiveness of diclofenac versus paracetamol in primary care patients with pain caused by knee osteoarthritis is unclear.

Aim

To assess the effectiveness of diclofenac compared with paracetamol over a period of 2, 4, and 12 weeks in patients with knee osteoarthritis.

Design and setting

Randomised controlled trial in general practice.

Method

There were 104 patients included in the study, they were aged ≥45 years consulting their GP with knee pain caused by knee osteoarthritis. Patients were randomly allocated to diclofenac (n = 52) or paracetamol (n = 52) for at least 2 weeks. Primary outcomes were daily knee pain severity, and knee pain and function measured with the Knee Injury and Osteoarthritis Outcome Score (KOOS).

Results

Over a period of 2- and 4-weeks follow-up, no significant difference in daily knee pain was found between the patient groups: estimated differences of 0.5 (95% CI = −0.2 to 1.3) and −0.2 (95% CI = −1.0 to 0.7), respectively. Over the 12-weeks follow-up, no significant differences were found between both groups for KOOS pain: estimated difference of −2.8 (95% CI = −10.7 to 5.1) and KOOS function of −2.7 (−10.6 to 5.0).

Conclusion

Over a period of 2- and 4-weeks follow-up no significant difference in daily measured knee pain severity was found between primary care patients with knee osteoarthritis taking paracetamol or diclofenac. Also, over a period of 12-weeks follow-up no significant differences were found regarding KOOS pain and KOOS function between both groups. Patients more frequently reported minor adverse events after taking diclofenac (64%) than paracetamol (46%).  相似文献   
48.
AJ  Fay  T  McMahon  C  Im  C  Bair-Marshall  KJ  Niesner  H  Li  A  Nelson  SM  Voglmaier  Y-H  Fu  LJ  Ptáček 《Neurogenetics》2021,22(3):171-185

Paroxysmal kinesigenic dyskinesia is an episodic movement disorder caused by dominant mutations in the proline-rich transmembrane protein PRRT2, with onset in childhood and typically with improvement or resolution by middle age. Mutations in the same gene may also cause benign infantile seizures, which begin in the first year of life and typically remit by the age of 2 years. Many details of PRRT2 function at the synapse, and the effects of mutations on neuronal excitability in the pathophysiology of epilepsy and dyskinesia, have emerged through the work of several groups over the last decade. However, the age dependence of the phenotypes has not been explored in detail in transgenic models. Here, we report our findings in heterozygous and homozygous Prrt2 knockout mice that recapitulate the age dependence of dyskinesia seen in the human disease. We show that Prrt2 deletion reduces the levels of synaptic proteins in a dose-dependent manner that is most pronounced at postnatal day 5 (P5), attenuates at P60, and disappears by P180. In a test for foot slippage while crossing a balance beam, transient loss of coordination was most pronounced at P60 and less prominent at age extremes. Slower traverse time was noted in homozygous knockout mice only, consistent with the ataxia seen in rare individuals with biallelic loss of function mutations in Prrt2. We thus identify three age-dependent phenotypic windows in the mouse model, which recapitulate the pattern seen in humans with PRRT2-related diseases.

  相似文献   
49.
50.
BACKGROUND AND PURPOSE:Safety analyses in the French Observatory have shown that treatment of intracranial aneurysms by using flow disruption with the Woven EndoBridge Device (WEB) is safe, with low morbidity and no mortality. The objective of this study was to analyze treatment feasibility, complications, and safety results in patients treated with the Woven EndoBridge Device Dual-Layer (WEB DL) and Woven EndoBridge Device Single-Layer/Single-Layer Sphere (WEB SL/SLS) in the French Observatory.MATERIALS AND METHODS:Patients with bifurcation aneurysms were included in this prospective, multicenter good clinical practices study. A medical monitor independently analyzed procedural and clinical data. The study started with the WEB DL, and secondarily, the WEB SL/SLS was authorized in the study.RESULTS:Between November 2012 and January 2014, 10 French centers included 62 patients with 63 aneurysms. Thirty patients with 31 aneurysms were treated with the WEB DL, and 32 patients with 32 aneurysms, with the WEB SL/SLS. The percentage of anterior communicating artery aneurysms treated with WEB SL/SLS was significantly higher (37.5%) compared with WEB DL (12.9%) (P = .04). The WEB SL/SLS was more frequently used in aneurysms of <10 mm than the WEB DL (respectively, 96.9% and 67.7%; P = .002). Morbidity was similar in both groups (WEB DL, 3.3%; WEB SL/SLS, 3.1%), and mortality was 0.0% in both groups.CONCLUSIONS:This comparative study shows increased use of WEB treatment in ruptured, small, and anterior communicating artery aneurysms when using WEB SL/SLS. There was a trend toward fewer thromboembolic complications with the WEB SL/SLS. With both the WEB DL and WEB SL/SLS, the treatment was safe, with low morbidity and no mortality.

Endovascular treatment is the preferred therapeutic option for ruptured aneurysms that are anatomically suitable for endovascular coil treatment, supported by randomized studies, especially in locations less suitable for surgery.1,2 It also has an important place in the management of unruptured aneurysms that are judged appropriate for treatment.3 Complex aneurysms (fusiform, wide-neck, large, or giant) are often untreatable or difficult to treat with standard coiling. For these complex cases, endovascular techniques such as balloon-assisted coiling, stent-assisted coiling, or flow diversion have been used with good results.49Flow disruption is a new endovascular approach, which involves placement of a Woven EndoBridge Device (WEB; Sequent Medical, Aliso Viejo, California), which modifies the blood flow at the level of the neck and induces intra-aneurysmal thrombosis. The WEB was designed initially to treat wide-neck and bifurcation aneurysms. The initial clinical results have shown that treatment is feasible with a low level of complications, low morbidity, and no mortality.1014 The device has been progressively developed from a dual-layer version (WEB Dual-Layer [DL] aneurysm embolization system; Sequent Medical) to single-layer versions (WEB Single-Layer [SL] and WEB Single-Layer Sphere [SLS]).The French Observatory is a prospective, multicenter observational study of consecutive cases, with independent monitoring, across 10 French centers.It has 2 major objectives:
  1. To carefully evaluate the safety of this treatment with an independent assessment of all adverse events and morbidity/mortality.
  2. To evaluate the efficacy of this treatment at 12 and 24 months with independent core lab adjudication.
Patients treated with both WEB DL and WEB SL/SLS were included in the French Observatory. The present analysis reports the feasibility of treatment, adverse events, and morbidity/mortality at 1 month in patients treated with WEB DL and WEB SL/SLS.  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