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   15449篇
  免费   780篇
  国内免费   98篇
耳鼻咽喉   112篇
儿科学   297篇
妇产科学   170篇
基础医学   1959篇
口腔科学   317篇
临床医学   1066篇
内科学   3914篇
皮肤病学   204篇
神经病学   992篇
特种医学   649篇
外科学   3168篇
综合类   47篇
预防医学   388篇
眼科学   253篇
药学   1234篇
中国医学   53篇
肿瘤学   1504篇
  2023年   92篇
  2022年   64篇
  2021年   356篇
  2020年   188篇
  2019年   257篇
  2018年   345篇
  2017年   251篇
  2016年   291篇
  2015年   326篇
  2014年   453篇
  2013年   487篇
  2012年   791篇
  2011年   878篇
  2010年   471篇
  2009年   373篇
  2008年   707篇
  2007年   717篇
  2006年   732篇
  2005年   747篇
  2004年   684篇
  2003年   670篇
  2002年   702篇
  2001年   363篇
  2000年   429篇
  1999年   423篇
  1998年   185篇
  1997年   139篇
  1996年   130篇
  1995年   130篇
  1994年   139篇
  1993年   118篇
  1992年   358篇
  1991年   337篇
  1990年   296篇
  1989年   339篇
  1988年   294篇
  1987年   269篇
  1986年   256篇
  1985年   247篇
  1984年   158篇
  1983年   130篇
  1982年   62篇
  1979年   125篇
  1978年   94篇
  1977年   59篇
  1975年   69篇
  1974年   61篇
  1973年   57篇
  1972年   51篇
  1969年   54篇
排序方式: 共有10000条查询结果,搜索用时 265 毫秒
1.
Adolescence is a vulnerable period for developing anxiety-related mental disorders such as post-traumatic stress disorder (PTSD), which requires a long-term course of therapy when a traumatic event has been experienced during childhood. However, the biological mechanism underlying these age-dependent characteristics remains unclear. In the present study, we used early adolescent, late adolescent and adult (4-, 8-, and 15-week old) male mice to examine age differences in fear memory, fear extinction, and spontaneous recovery of fear. We also measured the activation of extracellular signal-regulated kinase (ERK) 2 in the dorsal hippocampus (dHip) and the basolateral amygdala (BLA) following a spontaneous recovery test. Our major findings were as follows: (1) early adolescent and adult mice did not recover the fear response; only late adolescent mice recovered the fear response. (2) The ERK2 in the dHip was more activated after the spontaneous recovery test in late adolescent mice than in adult mice, and the ERK2 in the BLA was more activated after the spontaneous recovery test in adult mice than in late adolescent mice. These results suggest that there exists a unique period in which spontaneous recovery occurs and that these late adolescent behavioral signatures may be related to alteration in the ERK2 phosphorylation in the dHip and BLA.  相似文献   
2.
Hidroacanthoma simplex (HAS) is a rare benign eccrine adnexal tumor. HAS is sometimes clinically or pathologically misdiagnosed as squamous cell carcinoma in situ (Bowen's disease; BD), seborrheic keratosis (SK) or other adnexal tumor. To date, there has never been a report focusing on dermoscopic features to distinguish HAS from BD and SK. We found the following dermoscopic findings to be characteristic of HAS: fine black dots/globules (75% of cases) and fine scales arranged annularly (100% of cases). In contrast, glomerular vessels, which are typically observed in BD, were not seen in any of the four cases. Cerebriform appearance and milia‐like cysts, which are typically observed in SK, were also not seen in any of the four cases. The existence of “scattered fine black dots/globules” and “fine scales arranged annularly”, and the absence of the glomerular vessels, may contribute to precise diagnosis of HAS. Even though HAS resembles BD or SK clinically, it can be distinguished from these by the characteristic dermoscopic features.  相似文献   
3.
Tirabrutinib is a second‐generation Bruton’s tyrosine kinase inhibitor with greater selectivity than ibrutinib. Here, we conducted a multicenter, phase II study of tirabrutinib in patients with treatment‐naïve (Cohort A) or with relapsed/refractory (Cohort B) Waldenström’s macroglobulinemia (WM). Patients were treated with tirabrutinib 480 mg once daily. The primary endpoint was major response rate (MRR; ≥ partial response). Secondary endpoints included overall response rate (ORR; ≥ minor response), time to major response (TTMR), progression‐free survival (PFS), overall survival (OS), and safety. In total, 27 patients (18 in Cohort A; 9 in Cohort B) were enrolled. The median age was 71 y, and the median serum immunoglobulin M level was 3600 mg/dL. Among the patients, 96.2% had the MYD88L265P mutation. MRR and ORR were 88.9% and 96.3%, respectively (Cohort A: MRR, 88.9%; ORR, 94.4%; Cohort B: MRR, 88.9%; ORR, 100%). Median TTMR was 1.87 mo. PFS and OS were not reached with a median follow‐up of 6.5 and 8.3 mo for Cohorts A and B, respectively. The most common adverse events (AEs) were rash (44.4%), neutropenia (25.9%), and leukopenia (22.2%), with most AEs classified as grade 1 or 2. Grade ≥ 3 AEs included neutropenia (11.1%), lymphopenia (11.1%), and leukopenia (7.4%). No grade 5 AEs were noted. All bleeding events were grade 1; none were associated with drug‐related atrial fibrillation or hypertension. Although the follow‐up duration was relatively short, the study met the primary endpoint. Therefore, tirabrutinib monotherapy is considered to be highly effective for both untreated and relapsed/refractory WM with a manageable safety profile. (JapicCTI‐173646).  相似文献   
4.
Cyclin‐dependent kinase 12 (CDK12), one of the key factors associated with DNA damage response pathways, is located on chromosome 17 proximal to Erb‐B2 receptor tyrosine kinase 2 (ERBB2). In this report, CDK12 and ERBB2 coamplification was detected by targeted next‐generation sequencing in two urothelial carcinomas. The staining intensity of the CDK12 and human epidermal growth factor receptor‐2 proteins was associated with the prognosis of each urothelial carcinoma case. Our results suggest that CDK12 coamplification with ERBB2 might be associated with tumor aggressiveness and contribution to cancer pathogenesis. Therapies targeting CDK12 should be developed for these patients.  相似文献   
5.
Angiotensin II receptor blockers (ARBs) are widely used for the treatment of hypertension. It is believed that treatment with an ARB increases the level of plasma angiotensin II (Ang II) because of a lack of negative feedback on renin activity. However, Ichikawa (Hypertens Res 2001; 24: 641-646) reported that long-term treatment of hypertensive patients with olmesartan resulted in a reduction in plasma Ang II level, though the mechanism was not determined. It has been reported that angiotensin 1-7 (Ang-(1-7)) potentiates the effect of bradykinin and acts as an angiotensin-converting enzyme (ACE) inhibitor. It is known that ACE2, which was discovered as a novel ACE-related carboxypeptidase in 2000, hydrolyzes Ang I to Ang-(1-9) and also Ang II to Ang-(1-7). It has recently been reported that olmesartan increases plasma Ang-(1-7) through an increase in ACE2 expression in rats with myocardial infarction. We hypothesized that over-expression of ACE2 may be related to a reduction in Ang II level and the cardioprotective effect of olmesartan. Administration of 0.5 mg/kg/day of olmesartan for 4 weeks to 12-week-old stroke-prone spontaneously hypertensive rats (SHRSP) significantly reduced blood pressure and left ventricular weight compared to those in SHRSP given a vehicle. Co-administration of olmesartan and (D-Ala7)-Ang-(1-7), a selective Ang-(1-7) antagonist, partially inhibited the effect of olmesartan on blood pressure and left ventricular weight. Interestingly, co-administration of (D-Ala7)-Ang-(1-7) with olmesartan significantly increased the plasma Ang II level (453.2+/-113.8 pg/ml) compared to olmesartan alone (144.9+/-27.0 pg/ml, p<0.05). Moreover, olmesartan significantly increased the cardiac ACE2 expression level compared to that in Wistar Kyoto rats and SHRSP treated with a vehicle. Olmesartan significantly improved cardiovascular remodeling and cardiac nitrite/ nitrate content, but co-administration of olmesartan and (D-Ala7)-Ang-(1-7) partially reversed this anti-remodeling effect and the increase in nitrite/nitrate. These findings suggest that olmesartan may exhibit an ACE inhibitory action in addition to an Ang II receptor blocking action, prevent an increase in Ang II level, and protect cardiovascular remodeling through an increase in cardiac nitric oxide production and endogenous Ang-(1-7) via over-expression of ACE2.  相似文献   
6.
A 23-year-old man was admitted for treatment of acute exacerbation of ileitis and perianal abscess caused by Crohn's disease. After incision and drainage of the abscess, coupled with antibiotic therapy, 6-mercaptopurine (6-MP) was commenced. His white blood cell (WBC) count on day 12 after initiation of 6-MP was not decreased. However, on day 24 he was re-admitted because of severe myelosuppression (WBC: 300/microl), which was complicated by the recurrence of the perianal abscess. Myelosuppression was prolonged and required the administration of granulocyte colony stimulating factor (G-CSF). G-CSF was continued for 17 days to achieve recovery of his WBC count to a normal level.  相似文献   
7.
The Trk family of tyrosine protein kinase receptors plays a significant role in the development and maintenance of neural tissues. It has been recently shown that Trk receptors are also expressed by a wide range of normal non-neuronal tissues in humans in a cell type-specific manner. In the present study, the expression patterns of TrkA in 337 non-neuronal invasive carcinomas of 15 different human tissues were investigated immunohistochemically. Overall, 133 (39%), 101 (30%) and 103 (31%) tumors exhibited strong, moderate and no TrkA Immunoreactivity, respectively. Esophageal and thyroid carcinomas expressed high levels of TrkA, whereas the levels in gastric and colon cancers were low. TrkA expression was detected not only in carcinomas originating from TrkA-positive normal counterpart tissues, Including the esophagus, breast, lung and uterus, but also in those from TrkA-negative tissues/cells of the thyroid, liver and ovary. Immunostaining for nerve growth factor-β, the specific ligand for TrkA, in esophageal and breast carcinomas demonstrated its immunoreactivity in stromal fibroblasts and some TrkA-expressing tumor cells. These results suggest that paracrine/autocrine regulation via stromal/tumoral NGF-tumoral TrkA interaction may be involved In the growth of certain non-neuronal carcinomas.  相似文献   
8.
Laparoscopic cholecystectomy and time-course changes in renal function   总被引:13,自引:3,他引:10  
Background: Recently, the retraction method has been used to reduce intraabdominal pressure (IAP) during laparoscopic surgery. The purpose of this study was to determine the serial changes in renal function during laparoscopic cholecystectomy (LC) using the retraction method. Methods: Urine output, effective renal plasma flow (ERPF), and glomerular filtration rate (GFR) were measured serially in seven patients who underwent LC with 12 mmHg pneumoperitoneum (High-IAP group) and five who underwent LC using the retraction method with 4 mmHg pneumoperitoneum (Low-IAP group). Results: Urine output, ERPF, and GFR were decreased during pneumoperitoneum in the High-IAP group, whereas no significant changes in any of these parameters were observed in the Low-IAP group. Conclusions: Our findings demonstrate that reduction of IAP to 4 mmHg using the retraction method prevents the transient renal dysfunction caused by prolonged 12 mmHg pneumoperitoneum during LC, suggesting that the retraction method reduces the risk of perioperative renal dysfunction during laparoscopic surgery. Received: 26 March 1996/Accepted: 27 July 1996  相似文献   
9.
Clinical effect of LM-001, a prostaglandin synthetic inhibitor developed from a drug delivery system, was evaluated in 54 patients with pain from urinary tract stones (stone pain) and 32 with vesical urgency after an operation on bladder or prostate. LM-001, felbinac ethyl incorporated in lipid microsphere, wes intravenously administered at the onset of stone pain or vesical urgency. Of 54 with stones and 32 with urgency, 53 and 29 were eligible for response, respectively. The symptoms improved or disappeared in some cases just after the administration and in the majority of patients within 15 minutes, in 49 of 53 patients with stone pain. Further, the effectiveness lasted over 24 hours in 26 of the 49 responding to this agent. On one hand, improvement or disappearance of vesical urgency was recognized in 25 of 29 patients, and the effectiveness was observed shortly after injection in 16 and lasted over 24 hours in 13 cases. Toxicities of this drug were investigated in 54 patients with stone pain and 32 with urinary urgency. Side effects consisted of pain at the injection site in 4, a slight fall of blood pressure in 1, slight visual disturbance in 1, body heat sensation in 1, leukocytosis in 3 and elevation of alkaline phosphatase in 1. These symptoms were transient and disappeared without use of any agent. LM-001 is concluded to be a useful drug for controlling stone pain and vesical urgency since an immediate effect, long durability and high response rates were obtained without severe side  相似文献   
10.
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